Document:

Exhibit

Exhibit 4.1

	
					
	 
	 
	 
	 
	 

WINDSTREAM HOLDINGS, INC.
and
COMPUTERSHARE TRUST COMPANY, N.A.
as Rights Agent
382 RIGHTS AGREEMENT
Dated as of September 17, 2015

	
					
	 
	 
	 
	 
	 

TABLE OF CONTENTS
	
				
	 
	 
	Page
	

	Section 1.
	Certain Definitions
	1
	

	 
	 
	 

	Section 2.
	Appointment of Rights Agent
	7
	

	 
	 
	 

	Section 3.
	Issuance of Rights Certificates
	7
	

	 
	 
	 

	Section 4.
	Form of Rights Certificates
	9
	

	 
	 
	 

	Section 5.
	Countersignature and Registration
	10
	

	 
	 
	 

	Section 6.
	Transfer, Split-Up, Combination and Exchange of Rights Certificates; Mutilated, Destroyed, Lost or Stolen Rights Certificates
	11
	

	 
	 
	 

	Section 7.
	Exercise of Rights; Purchase Price; Expiration Date of Rights
	12
	

	 
	 
	 

	Section 8.
	Cancellation and Destruction of Rights Certificates
	14
	

	 
	 
	 

	Section 9.
	Reservation and Availability of Capital Stock
	14
	

	 
	 
	 

	Section 10.
	Preferred Stock Record Date
	16
	

	 
	 
	 

	Section 11.
	Adjustment of Purchase Price, Number and Kind of Shares or Number of Rights
	16
	

	 
	 
	 

	Section 12.
	Certificate of Adjusted Purchase Price or Number of Shares
	23
	

	 
	 
	 

	Section 13.
	Consolidation, Merger or Sale or Transfer of Assets, Cash Flow or Earning Power
	24
	

	 
	 
	 

	Section 14.
	Fractional Rights and Fractional Shares
	26
	

	 
	 
	 

	Section 15.
	Rights of Action
	27
	

	 
	 
	 

	Section 16.
	Agreement of Rights Holders
	28
	

	 
	 
	 

	Section 17.
	Rights Certificate Holder Not Deemed a Stockholder
	28
	

	 
	 
	 

	Section 18.
	Concerning the Rights Agent
	29
	

	 
	 
	 

	Section 19.
	Merger, Share Exchange, or Consolidation or Change of Name of Rights Agent
	30
	

	 
	 
	 

	Section 20.
	Duties of Rights Agent
	30
	

	 
	 
	 

	Section 21.
	Change of Rights Agent
	33
	

	
			
	 
	i
	 

	
				
	Section 22.
	Issuance of New Rights Certificates
	34
	

	 
	 
	 

	Section 23.
	Redemption and Termination
	34
	

	 
	 
	 

	Section 24.
	Exchange
	35
	

	 
	 
	 

	Section 25.
	Notice of Certain Events
	36
	

	 
	 
	 

	Section 26.
	Notices
	36
	

	 
	 
	 

	Section 27.
	Supplements and Amendments
	37
	

	 
	 
	 

	Section 28.
	Successors
	38
	

	 
	 
	 

	Section 29.
	Determinations and Actions by the Board, etc
	38
	

	 
	 
	 

	Section 30.
	Benefits of this Agreement
	38
	

	 
	 
	 

	Section 31.
	Severability
	38
	

	 
	 
	 

	Section 32.
	Governing Law
	39
	

	 
	 
	 

	Section 33.
	Counterparts
	39
	

	 
	 
	 

	Section 34.
	Descriptive Headings; Interpretation
	39
	

	 
	 
	 

	Section 35.
	Force Majeure
	39
	

	 
	 
	 

	
			
	 
	ii
	 

EXHIBITS
	
			
	Exhibit A
	--
	Form of Certificate of Designation, Preferences and Rights of Series A Participating Preferred Stock

	Exhibit B
	--
	Form of Rights Certificate

	Exhibit C
	--
	Form of Summary of Rights

	
			
	 
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382 RIGHTS AGREEMENT
382 RIGHTS AGREEMENT, dated as of September 17, 2015 (this “Agreement”), between Windstream Holdings, Inc., a Delaware corporation (the “Company”), and Computershare Trust Company, N.A., a federally chartered trust company (the “Rights Agent”).
W I T N E S S E T H:
WHEREAS, (a) the Company and certain of its Subsidiaries (as hereinafter defined) have generated certain Tax Benefits (as hereinafter defined) for United States federal income tax purposes; (b) the Company desires to reduce the likelihood of an “ownership change” within the meaning of Section 382 of the Code (as hereinafter defined), and thereby preserve the Company’s current ability to utilize such Tax Benefits, and (c) in furtherance of such objective, the Company desires to enter into this Agreement; and
WHEREAS, on September 17, 2015 (the “Rights Dividend Declaration Date”), the Board of Directors of the Company (the “Board”) authorized and declared a dividend distribution of one Right (as hereinafter defined) for each share of Common Stock (as hereinafter defined) of the Company outstanding at the Close of Business (as hereinafter defined) on September 28, 2015 (the “Record Date”), and has authorized the issuance of one Right (as such number may hereinafter be adjusted pursuant to the provisions of Section 11(p) hereof) for each share of Common Stock issued between the Record Date (whether originally issued or delivered from the Company’s treasury) and the Distribution Date (as hereinafter defined), each Right initially representing the right to purchase 1/10,000th of a share of Series A Participating Preferred Stock, par value $0.0001 per share, of the Company (the “Preferred Stock”) having the rights, powers and preferences set forth in the form of Certificate of Designation, Preferences and Rights attached hereto as Exhibit A, upon the terms and subject to the conditions hereinafter set forth (the “Rights”).
NOW, THEREFORE, in consideration of the premises and the mutual agreements herein set forth, the parties hereby agree as follows:
Section 1.Certain Definitions.  For purposes of this Agreement, the following terms have the meanings indicated:
(a)    “Acquiring Person” shall mean any Person who or which, together with all Affiliates and Associates of such Person, is or becomes the Beneficial Owner of 4.90% or more of the shares of Common Stock then outstanding, regardless of whether or not such Person continues to be the Beneficial Owner of 4.90% or more of the shares of Common Stock then outstanding; provided, however, that an “Acquiring Person” shall not include (i) an Exempt Person or (ii) Existing Holder; provided further, notwithstanding anything to the contrary herein, no regulated investment company under Section 851 of the Code shall be deemed an Acquiring Person, unless such regulated investment company is deemed to beneficially own more than 4.90% or more of Common Stock then outstanding under the applicable standards of Treasury Regulation 1.382-3(a).  In determining whether any regulated investment company is an Acquiring Person, the filing of a statement under Section 13 of the Exchange Act with respect to such regulated investment company shall not be deemed to establish that such regulated

	
			
	 
	 
	 

investment company has acquired Beneficial Ownership of 4.90% or more of Common Stock unless the Board has determined that such regulated investment company actually has acquired Beneficial Ownership of more than 4.90% pursuant to the standards of Treasury Regulation 1.382-3.  Notwithstanding the foregoing, no Person shall become an “Acquiring Person” solely as a result of (x) a reduction in the number of shares of Common Stock outstanding due to the repurchase of shares of Common Stock by the Company, (y) a dividend or distribution paid or made by the Company on the outstanding shares of Common Stock or pursuant to a split or subdivision of the outstanding shares of Common Stock, and/or (z) an Exempt Transaction.  Further, notwithstanding the foregoing, if the Board determines in good faith that a Person who would otherwise be an “Acquiring Person” has become such inadvertently, and such Person divests as promptly as practicable a sufficient number of shares of Common Stock so that such Person would no longer be an “Acquiring Person”, then such Person shall not be deemed to be or have become an “Acquiring Person” at any time for any purposes of this Agreement.  
(b)    “Act” shall mean the Securities Act of 1933, as amended.
(c)    “Affiliate” and “Associate” shall have the respective meanings ascribed to such terms in Rule 12b-2 of the General Rules and Regulations under the Exchange Act.
(d)    “Agreement” shall have the meaning set forth in the preamble to this Agreement, as it may from time to time be supplemented, amended, renewed, restated or extended pursuant to the applicable provisions hereof.
(e)    A Person shall be deemed the “Beneficial Owner” of, and shall be deemed to “Beneficially Own,” and have “Beneficial Ownership” of, any securities:
(i)    which such Person or any of such Person’s Affiliates or Associates, directly or indirectly, owns or has the right to acquire (whether such right is exercisable immediately or only after the passage of time or upon the satisfaction of one or more conditions (whether or not within the control of such Person), compliance with regulatory requirements or otherwise), including all of the securities that such Person would have had the right or the obligation to acquire (whether such right is exercisable, or such obligation is required to be performed,  immediately or only after the passage of time or upon the satisfaction of conditions), pursuant to any agreement, arrangement or understanding (whether or not in writing) or upon the exercise of conversion rights, exchange rights, other rights, warrants or options, or otherwise); provided, however, that a Person shall not be deemed the “Beneficial Owner” of, or to “Beneficially Own,” under this subparagraph (A) securities tendered pursuant to a tender or exchange offer made by such Person or any of such Person’s Affiliates or Associates until such tendered securities are accepted for purchase or exchange, (B) securities issuable upon exercise of Rights at any time prior to the occurrence of a Triggering Event, or (C) securities issuable upon exercise of Rights from and after the occurrence of a Triggering Event which Rights were acquired by such Person or any of such Person’s Affiliates or Associates prior to the Distribution Date or pursuant to Section 3(a) or Section 22 hereof (the “Original Rights”)or pursuant to Section 11(i) hereof in connection with an adjustment made with respect to any Original Rights;  

	
			
	 
	2
	 

(ii)    which such Person or any of such Person’s Affiliates or Associates, directly or indirectly, has the right to vote or dispose of or has “beneficial ownership” of (as determined pursuant to Rule 13d-3 of the General Rules and Regulations under the Exchange Act), including pursuant to any agreement, arrangement or understanding, whether or not in writing; provided, however, that a Person shall not be deemed the “Beneficial Owner” of, or to “Beneficially Own,” any security under this subparagraph (ii) as a result of an agreement, arrangement or understanding (whether or not in writing) to vote such security if such agreement, arrangement or understanding (A) arises solely from a revocable proxy given in response to a public proxy or consent solicitation made pursuant to, and in accordance with, the applicable provisions of the General Rules and Regulations under the Exchange Act and (B) is not reportable by such Person on Schedule 13D under the Exchange Act (or any comparable or successor report); 
(iii)    which are Beneficially Owned, directly or indirectly, by any other Person (or any Affiliate or Associate thereof) with respect to which such Person (or any of such Person’s Affiliates or Associates) has any agreement, arrangement or understanding (whether or not in writing), for the purpose of acquiring, holding, voting (except pursuant to a revocable proxy as described in the proviso to subparagraph (ii) of this paragraph (f)) or disposing of any voting securities of the Company; or
(iv)    which such Person actually owns (directly or indirectly) or would be deemed to actually or constructively own pursuant to Section 382 of the Code and the Treasury Regulations promulgated thereunder. 
Notwithstanding the foregoing, nothing in this paragraph (e) shall cause a Person engaged in business as an underwriter of securities to be the “Beneficial Owner” of, or to “Beneficially Own,” any securities acquired through such Person’s participation in good faith in a firm commitment underwriting until the expiration of forty days after (but not including) the date of such acquisition, and then only if such securities continue to be owned by such Person at such expiration of forty days.
(f)    “Business Day” shall mean any day other than a Saturday, a Sunday or a day on which banking institutions in the State of New York are authorized or obligated by law or executive order to close.
(g)    “Close of Business” on any given date shall mean 5:00 P.M., New York City time, on such date; provided, however, that if such date is not a Business Day, it shall mean 5:00 P.M., New York City time, on the next succeeding Business Day.
(h)    “Common Stock” shall mean the Common Stock, par value $0.0001 per share, of the Company or any other shares of capital stock of the Company into which such stock shall be reclassified or changed, except that “Common Stock” when used with reference to any Person other than the Company shall mean the capital stock of such Person with the greatest voting power, or the equity securities or other equity interest having power to control or direct the management, of such Person.

	
			
	 
	3
	 

(i)    “Company” shall have the meaning set forth in the preamble to this Agreement until a successor corporation or entity shall have become such or until a Principal Party shall assume, and thereafter be liable for, all obligations and duties of the Company hereunder pursuant to the applicable provisions of this Agreement, and thereafter, “Company” shall mean such successor or Principal Party, respectively.
(j)    “Company Bylaws” shall mean the Second Amended and Restated Bylaws of the Company, as the same may be amended after the date hereof.
(k)    “Company Charter” shall mean the Amended and Restated Certificate of Incorporation of the Company, as the same may be amended after the date hereof.
(l)    “Code” shall mean the Internal Revenue Code of 1986, as amended.
(m)    “Distribution Date” shall mean the earlier of (i) the Close of Business on the 15th Business Day (or such later date as may be determined by the Board before the occurrence of the Distribution Date) after the Stock Acquisition Date, or (ii) the Close of Business on the 15th Business Day (or such later date as may be determined by the Board before the occurrence of the Distribution Date) after the Tender Offer Commencement Date; provided, however, that if either of the Stock Acquisition Date or the Tender Offer Commencement Date occurs after the date of this Agreement and on or prior to the Record Date, then the Distribution Date shall be the Record Date.
(n)    “Exchange Act” shall mean the Securities Exchange Act of 1934, as amended.
(o)    “Exempt Person” shall mean the Company or any Subsidiary of the Company and any employee benefit plan of the Company, or of any Subsidiary of the Company, or any Person or entity organized, appointed or established by the Company for or pursuant to the terms of any such plan.
(p)    “Exempt Transaction” shall mean any transaction that the Board determines, in its sole discretion, is exempt from this Agreement, which determination shall be made in the sole and absolute discretion of the Board, upon request by any Person prior to the date upon which such Person would otherwise become an Acquiring Person, including, without limitation, if the Board determines that (i) neither the Beneficial Ownership of shares of Common Stock by such Person, directly or indirectly, as a result of such transaction nor any other aspect of such transaction would jeopardize or endanger the availability to the Company of the Tax Benefits or (ii) such transaction is otherwise in the best interests of the Company.  
(q)    “Existing Holder” shall mean any Person that, as of the date hereof, is (A) the Beneficial Owner of between 4.90% and 5.01% of the shares of Common Stock outstanding unless and until such Existing Holder acquires Beneficial Ownership of one or more additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding shares of Common Stock or pursuant to a split or subdivision of the outstanding shares of Common Stock) unless, upon becoming the Beneficial Owner of such additional share(s), such Existing Holder is not then the Beneficial Owner of 4.90% or more of the then outstanding shares of Common Stock, or (B) the Beneficial Owner of 5.01% or more of 

	
			
	 
	4
	 

Common Stock outstanding unless and until such Existing Holder acquires Beneficial Ownership of 1% or more of additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding shares of Common Stock or pursuant to a split or subdivision of the outstanding shares of Common Stock) unless, upon becoming the Beneficial Owner of such additional share(s), such Existing Holder is not then the Beneficial Owner of 5.01% or more of the then outstanding shares of Common Stock.
(r)    “Expiration Date” shall mean shall mean the earliest of (i) the Final Expiration Date, (ii) the time at which the Rights are redeemed as provided in Section 23 hereof, (iii) the time at which the Rights are exchanged as provided in Section 24 hereof, (iv) the date on which the Board determines in its sole discretion that this Agreement is no longer necessary for the preservation of material valuable Tax Benefits, (v) the beginning of a taxable year of the Company to which the Board determines in its sole discretion that no Tax Benefits may be carried forward, (vi) September 17, 2016 if the Stockholder Approval has not been obtained and (vii) the date on which the Board determines in its sole discretion that this Agreement is no longer in the best interest of the Company and its stockholders.  
(s)    “Final Expiration Date” shall mean the date upon which the Rights expire and shall be the earlier of 5:00 P.M., New York City time on September 17, 2018, unless the Rights are previously redeemed, exchanged or terminated.
(t)    “NASDAQ” shall mean the National Association of Securities Dealers, Inc. Automated Quotation System.
(u)    “Person” shall mean any individual, firm, corporation, partnership, limited liability company, trust, association, syndicate or other entity and includes an unincorporated group of persons who, by formal or informal agreement or arrangement (whether or not in writing), have embarked on a common purpose or act.
(v)    “Preferred Stock” shall have the meaning set forth in the recitals to this Agreement, and, to the extent that there are not a sufficient number of shares of Series A Participating Preferred Stock authorized to permit the full exercise of the Rights, any other series of preferred stock of the Company designated for such purpose containing terms substantially similar to the terms of the Series A Participating Preferred Stock.
(w)    “Section 11(a)(ii) Event” shall mean any event described in Section 11(a)(ii) hereof.
(x)    “Stock Acquisition Date” shall mean the first date of public announcement (which, for purposes of this definition, shall include a report filed or amended pursuant to Section 13(d) under the Exchange Act) by the Company or an Acquiring Person that an Acquiring Person has become such or that discloses information which reveals the existence of an Acquiring Person, or such earlier date as a majority of the Board becomes aware of the existence of an Acquiring Person. 
(y)    “Stockholder Approval” shall mean the ratification of this Agreement by the affirmative vote of the majority of the votes cast at the 2016 annual meeting of stockholders of the Company duly held in accordance with the Company Charter and applicable law.

	
			
	 
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(z)    “Subsidiary” shall mean, with reference to any Person, any corporation or other entity of which an amount of securities or other ownership interest having ordinary voting power sufficient to elect at least a majority of the directors or other Persons having similar functions of such corporation or other entity are at the time, directly or indirectly, Beneficially Owned, or otherwise controlled by such Person.
(aa)    “Tax Benefits” shall mean the net operating loss carryovers, capital loss carryovers, general business credit carryovers, alternative minimum tax credit carryovers and foreign tax credit carryovers, as well as any loss or deduction (whether actual or prospective) attributable to a “net unrealized built-in loss” within the meaning of Section 382 of the Code and the Treasury Regulations promulgated thereunder, of the Company or any of its Subsidiaries.
(bb)    “Tender Offer Commencement Date” shall mean the date that a tender or exchange offer or other transaction by any Person (other than an Exempt Person) is first published or sent or given within the meaning of Rule 14d-2(a) of the General Rules and Regulations under the Exchange Act, if, upon consummation thereof, such Person would become an Acquiring Person.
(cc)    “Treasury Regulations” shall mean final, temporary and proposed regulation of the Department of Treasury under the Code and any successor regulation, including any amendments thereto.
(dd)    “Triggering Event” shall mean any Section 11(a)(ii) Event or any Section 13 Event.
(ee)    The following terms shall have the meanings defined for such terms in the Sections set forth below:	
		
	Term
	Section

	Adjustment Shares
	11(a)(ii)

	Board
	Recitals

	Book Entry Shares
	3(a)

	Common Stock Equivalents
	11(a)(iii)

	Current Market Price
	11(d)(i)

	Current Value
	11(a)(iii)

	Equivalent Preferred Stock
	11(b)

	Exchange Ratio
	24(a)

	Original Rights
	1(e)(i)

	Preferred Stock
	Recitals

	Principal Party
	13(b)

	Purchase Price
	4(a)

	Record Date
	Recitals

	Redemption Price
	23(a)

	Rights
	Recitals

	Rights Agent
	Preamble

	Rights Certificate
	3(a)

	Rights Dividend Declaration Date
	Recitals

	
			
	 
	6
	 

	
		
	Term
	Section

	Section 11(a)(ii) Trigger Date
	11(a)(iii)

	Section 13 Event
	13(a)

	Spread
	11(a)(iii)

	Substitution Period
	11(a)(iii)

	Summary of Rights
	3(b)

	Trading Day
	11(d)(i)

Section 2.    Appointment of Rights Agent.  The Company hereby appoints the Rights Agent to act as rights agent for the Company in accordance with the express terms and conditions hereof, and the Rights Agent hereby accepts such appointment.  The Company may from time to time appoint such co-rights agents as it may deem necessary or desirable, upon ten (10) days’ prior written notice to the Rights Agent setting forth the respective duties of the Rights Agent and any co-rights agent.  The Rights Agent shall have no duty to supervise, and shall in no event be liable for, the acts or omissions of any such co-rights agent.
Section 3.    Issuance of Rights Certificates.  
(a)    Until the Distribution Date, (i) the Rights will be evidenced (subject to the provisions of paragraph (b) or (c) of this Section 3) by the balances indicated in the book-entry account system of the transfer agent for the Common Stock registered in the names of the holders of the Common Stock (which shares of Common Stock shall also be deemed to represent certificates for Rights) for uncertificated shares of Common Stock registered in book-entry form (the “Book Entry Shares”) or, in the case of certificated shares, the certificates for the Common Stock registered in the names of the holders of the Common Stock (which certificates for Common Stock shall also be deemed to be certificates for Rights), and not by separate certificates, and (ii) the Rights will be transferable only in connection with the transfer of the underlying shares of Common Stock (including a transfer to the Company).  As soon as practicable after the Distribution Date, the Company will prepare and execute, the Rights Agent will countersign (either by manual or facsimile signature), and the Company will send or cause to be sent (and the Rights Agent will, if requested and provided with all necessary and relevant information and documents, in proper and complete form, as determined by the Rights Agent) by first-class, postage-prepaid mail, to each record holder of the Common Stock as of the Close of Business on the Distribution Date, at the address of such holder shown on the records of the Company or the transfer agent or registrar for the shares of Common Stock, one or more rights certificates, in substantially the form of Exhibit B hereto (the “Rights Certificates”), evidencing one Right for each share of Common Stock so held, subject to adjustment as provided herein.  In the event that an adjustment in the number of Rights per share of Common Stock has been made pursuant to Section 11(i) or Section 11(p) hereof, at the time of distribution of the Rights Certificates, the Company shall make the necessary and appropriate rounding adjustments (in accordance with Section 14(a) hereof) so that Rights Certificates representing only whole numbers of Rights are distributed and cash is paid in lieu of any fractional Rights.  As of and after the Distribution Date, the Rights will be evidenced solely by such Rights Certificates.  The Company shall promptly notify the Rights Agent in writing upon the occurrence of the Distribution Date.  Until such written notice is received by the Rights Agent, the Rights Agent may presume conclusively for all purposes that the Distribution Date has not occurred.

	
			
	 
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(b)    The Company will make available, as promptly as practicable, a copy of a Summary of Rights, in substantially the form attached hereto as Exhibit C (the “Summary of Rights”), to any holder of Rights who may so request from time to time prior to the Expiration Date.  With respect to the Common Stock outstanding as of the Record Date, or issued subsequent to the Record Date, unless and until the Distribution Date shall occur, the Rights associated with such shares of Common Stock will be evidenced by the balances indicated in the book-entry account system of the transfer agent for the Book Entry Shares or, in the case of certificated shares, such certificates for the Common Stock, and the registered holders of the Common Stock shall also be the registered holders of the associated Rights.  Until the earlier of the Distribution Date or the Expiration Date, the transfer of any shares of Common Stock in respect of which Rights have been issued shall also constitute the transfer of the Rights associated with such shares of Common Stock. 
(c)    Rights shall be issued in respect of all shares of Common Stock which are issued (whether originally issued or from the Company’s treasury) after the Record Date but prior to the earlier of the Distribution Date or the Expiration Date and shall bear legends in substantially the following form:
(i)    Confirmation and account statements sent to holders Book Entry Shares (which shares of Common Stock shall also be deemed to represent certificates for Rights) shall bear a legend in substantially the following form:
“The shares of Common Stock, par value $0.0001 per share, of Windstream Holdings, Inc. (the “Company”) entitle the holder hereof to certain Rights as set forth in the 382 Rights Agreement between the Company and Computershare Trust Company, N.A. (or any successor Rights Agent) (the “Rights Agent”) dated as of September 17, 2015, as it may be amended, restated, renewed or extended from time to time (the “Rights Agreement”), the terms of which are hereby incorporated herein by reference and a copy of which is on file at the principal executive offices of the Company.  Under certain circumstances, as set forth in the Rights Agreement, such Rights will be evidenced by separate certificates and will no longer be evidenced by the shares to which this statement relates.  The Company will mail or cause to be mailed to the holder of shares to which this statement relates a copy of the Rights Agreement, as in effect on the date of mailing, without charge, after receipt of a written request therefor.  Under certain circumstances set forth in the Rights Agreement, Rights Beneficially Owned (as such term is defined in the Rights Agreement) by any Person who is, was or becomes an Acquiring Person or any Affiliate or Associate thereof (as such terms are defined in the Rights Agreement), whether currently held by or on behalf of such Person or by any subsequent holder, may become null and void.”
With respect to Book Entry Shares for which there has been sent a confirmation or account statement containing the foregoing legend, until the earlier of (A) the Distribution Date or (B) the Expiration Date, the Rights associated with the Common Stock represented by such shares of Common Stock shall be evidenced by such shares of 

	
			
	 
	8
	 

Common Stock alone and registered holders of Common Stock shall also be the registered holders of the associated Rights, and the transfer of any of such shares of Common Stock shall also constitute the transfer of the Rights associated with such shares of Common Stock.
(ii)    In the case of certificated shares, certificates representing shares of Common Stock (which certificates shall also be deemed to be certificates for Rights) shall bear the following legend if such certificates are issued after the Record Date but prior to the earlier of the Distribution Date or the Expiration Date in substantially the following form: 
“This certificate also evidences and entitles the holder hereof to certain Rights as set forth in the 382 Rights Agreement between Windstream Holdings, Inc. (the “Company”) and Computershare Trust Company, N.A. (or any successor Rights Agent) (the “Rights Agent”) dated as of September 17, 2015, as it may be amended, restated, renewed or extended from time to time (the “Rights Agreement”), the terms of which are hereby incorporated herein by reference and a copy of which is on file at the principal executive offices of the Company.  Under certain circumstances, as set forth in the Rights Agreement, such Rights will be evidenced by separate certificates and will no longer be evidenced by this certificate.  The Company will mail or cause to be mailed to the holder of this certificate a copy of the Rights Agreement, as in effect on the date of mailing, without charge, after receipt of a written request therefor.  Under certain circumstances set forth in the Rights Agreement, Rights Beneficially Owned (as such term is defined in the Rights Agreement) by any Person who is, was or becomes an Acquiring Person or any Affiliate or Associate thereof (as such terms are defined in the Rights Agreement), whether currently held by or on behalf of such Person or by any subsequent holder, may become null and void.”
With respect to such certificates containing the foregoing legend, until the earlier of (A) the Distribution Date or (B) the Expiration Date, the Rights associated with the Common Stock represented by such certificates shall be evidenced by such certificates alone and registered holders of Common Stock shall also be the registered holders of the associated Rights, and the transfer of any of such certificates shall also constitute the transfer of the Rights associated with the Common Stock represented by such certificates.
Section 4.    Form of Rights Certificates.
(a)    The Rights Certificates (and the forms of election to purchase and of assignment to be printed on the reverse thereof) shall each be substantially in the form set forth in Exhibit B hereto and may have such marks of identification or designation and such legends, summaries or endorsements printed thereon as the Company may deem appropriate and as are not inconsistent with the provisions of this Agreement, or as may be required to comply with any applicable law or with any rule or regulation made pursuant thereto or with any rule or regulation of any stock exchange on which the Rights may from time to time be listed, or to conform to 

	
			
	 
	9
	 

usage (but which shall not, in any case, affect the rights, duties or responsibilities of the Rights Agent).  Subject to the provisions of Section 11 and Section 22 hereof, the Rights Certificates, whenever distributed, shall be dated as of the Record Date and on their face shall entitle the holders thereof to purchase such number of 1/10,000th of a share of Preferred Stock as shall be set forth therein at the price set forth therein (such exercise price per 1/10,000th of a share, the “Purchase Price”), but the amount and type of securities purchasable upon the exercise of each Right and the Purchase Price thereof shall be subject to adjustment as provided herein.
(b)    Any Rights Certificate issued pursuant to Section 3(a), Section 11(i) or Section 22 hereof that represents Rights Beneficially Owned by (i) an Acquiring Person or any Associate or Affiliate of an Acquiring Person, (ii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) who becomes a transferee after the Acquiring Person becomes such, or (iii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) who becomes a transferee prior to or concurrently with the Acquiring Person becoming such and receives such Rights pursuant to either (A) a transfer (whether or not for consideration) from the Acquiring Person to holders of equity interests in such Acquiring Person or to any Person with whom such Acquiring Person has any continuing agreement, arrangement or understanding (whether or not in writing) regarding the transferred Rights or (B) a transfer which the Board, in its sole discretion, has determined is part of a plan, arrangement or understanding which has as a primary purpose or effect the avoidance of Section 7(e) hereof, and any Rights Certificate issued pursuant to Section 6, Section 11, or Section 22 hereof upon transfer, exchange, replacement or adjustment of any other Rights Certificate referred to in this sentence, shall contain (to the extent feasible, and only if the Company has provided specific written instructions to the Rights Agent) a legend in substantially the following form:
The Rights represented by this Rights Certificate are or were Beneficially Owned by a Person who was or became an Acquiring Person or an Affiliate or Associate of an Acquiring Person (as such terms are defined in the Rights Agreement).  Accordingly, this Rights Certificate and the Rights represented hereby may become null and void in the circumstances specified in Section 7(e) of the Rights Agreement.
Section 5.    Countersignature and Registration.  
(a)    The Rights Certificates shall be executed on behalf of the Company by its Chief Executive Officer, its President or any Vice President (or more senior officer) of the Company, either manually or by facsimile signature, and shall have affixed thereto the Company’s seal or a facsimile thereof which shall be attested by the Secretary or an Assistant Secretary of the Company, either manually or by facsimile signature.  The Rights Certificates shall be countersigned by an authorized signatory of the Rights Agent, either manually or by facsimile signature, and shall not be valid for any purpose unless so countersigned.  In case any officer of the Company who shall have signed any of the Rights Certificates shall cease to be such officer of the Company before countersignature by an authorized signatory of the Rights Agent and issuance and delivery by the Company, such Rights Certificates, nevertheless, may be countersigned by an authorized signatory of the Rights Agent and issued and delivered by the Company with the same force and effect as though the person who signed such Rights Certificates had not ceased to be such officer of the Company; and any Rights Certificates may 

	
			
	 
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be signed on behalf of the Company by any person who, at the actual date of the execution of such Rights Certificate, shall be a proper officer of the Company to sign such Rights Certificate, although at the date of the execution of this Agreement any such person was not such an officer.  In case any authorized signatory of the Rights Agent who has countersigned any of the Rights Certificates ceases to be an authorized signatory of the Rights Agent before issuance and delivery by the Company, such Rights Certificates, nevertheless, may be issued and delivered by the Company with the same force and effect as though the person who countersigned such Rights Certificates had not ceased to be an authorized signatory of the Rights Agent; and any Rights Certificates may be countersigned on behalf of the Rights Agent by any person who, at the actual date of the countersignature of such Rights Certificate, is properly authorized to countersign such Rights Certificate, although at the date of the execution of this Agreement any such person was not so authorized.
(b)    Following the Distribution Date, upon receipt by the Rights Agent of notice to that effect and all other relevant information and documents referred to in Section 3(a) hereof, the Rights Agent will keep, or cause to be kept, at its office or offices designated as the appropriate place for surrender of Rights Certificates upon exercise or transfer, books for registration and transfer of the Rights Certificates issued hereunder.  Such books shall show the names and addresses of the respective holders of the Rights Certificates, the number of Rights evidenced on its face by each of the Rights Certificates and the date of each of the Rights Certificates.
Section 6.    Transfer, Split-Up, Combination and Exchange of Rights Certificates; Mutilated, Destroyed, Lost or Stolen Rights Certificates.  
(a)    Subject to the provisions of Section 4(b), Section 7(e) and Section 14 hereof, at any time after the Close of Business on the Distribution Date, and at or prior to the Close of Business on the Expiration Date, any Rights Certificate or Certificates (other than Rights Certificates representing Rights that have become null and void pursuant to Section 7(e) hereof or that may have been redeemed or exchanged pursuant to Section 23 or Section 24 hereof) may be transferred, split up, combined or exchanged for another Rights Certificate or Certificates, entitling the registered holder to purchase a like number of 1/10,000th of a share of Preferred Stock (or, following a Triggering Event, Common Stock, other securities, cash or other assets, as the case may be) as the Rights Certificate or Certificates surrendered then entitles such holder (or former holder in the case of a transfer) to purchase.  Any registered holder desiring to transfer, split up, combine or exchange any Rights Certificate or Certificates shall make such request in writing delivered to the Rights Agent, and shall surrender the Rights Certificate or Certificates to be transferred, split up, combined or exchanged, with the form of assignment and certificate contained therein properly completed and duly executed and with all signatures guaranteed, at the office or offices of the Rights Agent designated for such purpose.  The Rights Certificates are transferable only on the registry books of the Rights Agent.  Neither the Rights Agent nor the Company shall be obligated to take any action whatsoever with respect to the transfer of any such surrendered Rights Certificate until the registered holder shall have properly completed and duly signed the certificate contained in the form of assignment on the reverse side of such Rights Certificate and shall have provided such additional evidence of the identity of the Beneficial Owner (or former Beneficial Owner) or Affiliates or Associates thereof as the Company or the Rights Agent shall reasonably request and shall have paid a sum sufficient to 

	
			
	 
	11
	 

cover any tax or charge that may be imposed in connection with any transfer, split up, combination or exchange of Rights Certificates as required by Section 9(e) hereof.  Thereupon the Rights Agent shall, subject to Section 4(b), Section 7(e), Section 14 hereof and Section 24 hereof, countersign (by manual or facsimile signature) and deliver to the Person entitled thereto a Rights Certificate or Rights Certificates, as the case may be, as so requested.  The Rights Agent shall have no duty or obligation to take any action under any section of this Agreement which requires payment by a Rights holder of applicable taxes or charges unless and until the Rights Agent is satisfied that all such taxes and/or charges have been paid.
(b)    Upon receipt by the Company and the Rights Agent of evidence reasonably satisfactory to them of the loss, theft, destruction or mutilation of a Rights Certificate, and, in case of loss, theft or destruction, of indemnity or security satisfactory to them, along with a signature guarantee and such other and further documentation as the Company or the Rights Agent may reasonably request, and reimbursement to the Company and the Rights Agent of all reasonable expenses incidental thereto, and upon surrender to the Rights Agent and cancellation of the Rights Certificate, if mutilated, the Company will execute and deliver a new Rights Certificate of like tenor to the Rights Agent for countersignature and delivery to the registered owner in lieu of the Rights Certificate so lost, stolen, destroyed or mutilated.
Section 7.    Exercise of Rights; Purchase Price; Expiration Date of Rights.  
(a)    Subject to Section 7(e) hereof, at any time on or after the Distribution Date (or, if the Distribution Date is the Record Date, 15 Business Days after, but not including, the Distribution Date), but prior to the Expiration Date, the registered holder of any Rights Certificate may exercise the Rights evidenced thereby (except as otherwise provided herein, including the restrictions on exercisability set forth in Section 9(c), Section 11(a)(iii) and Section 23(a) hereof) in whole or in part upon surrender of the Rights Certificate, with the form of election to purchase and the certificate on the reverse side thereof properly completed and duly executed, to the Rights Agent at the office or offices of the Rights Agent designated for such purpose, together with payment of the aggregate Purchase Price with respect to the total number of 1/10,000th of a share of Preferred Stock (or other securities, cash or other assets, as the case may be) as to which such surrendered Rights are then exercisable.  Except for those provisions herein that expressly survive the termination of this Agreement, this Agreement shall terminate upon the earlier of the Expiration Date and such time as all outstanding Rights have been exercised, redeemed or exchanged hereunder (other than Rights which have become null and void pursuant to the provisions of Section 7(e) hereof).
(b)    The Purchase Price for each 1/10,000th of a share of Preferred Stock pursuant to the exercise of a Right initially shall be $32.00, shall be subject to adjustment from time to time as provided in Sections 11 and 13(a) hereof and shall be payable in accordance with paragraph (c) below.
(c)    Upon receipt of a Rights Certificate representing exercisable Rights, with the form of election to purchase and the certificate properly completed and duly executed, accompanied by payment, with respect to each Right so exercised, of the Purchase Price per 1/10,000th of a share of Preferred Stock (or other shares, securities, cash or other assets, as the case may be) to be purchased as set forth below and an amount equal to any applicable transfer

	
			
	 
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or similar tax or charge, the Rights Agent shall, subject to Sections 7(f) and 20(k) hereof, thereupon promptly (i) (A) requisition from any transfer agent of the shares of Preferred Stock (or make available, if the Rights Agent is the transfer agent for such shares) certificates for the total number of 1/10,000th of a share of Preferred Stock to be purchased and the Company hereby irrevocably authorizes and directs each such transfer agent to comply with all such requests, or (B) if the Company shall have elected to deposit the total number of shares of Preferred Stock issuable upon exercise of the Rights hereunder with a depositary agent, requisition from the depositary agent depositary receipts representing such number of 1/10,000th of a share of Preferred Stock as are to be purchased (in which case certificates for the shares of Preferred Stock represented by such receipts shall be deposited by the transfer agent with the depositary agent) and the Company hereby irrevocably authorizes and directs each such depositary agent to comply with such request, (ii) when necessary to comply with this Agreement, requisition from the Company the amount of cash, if any, to be paid in lieu of the issuance of fractional shares in accordance with Section 14 hereof, (iii) after receipt of such certificates or depositary receipts, cause the same to be delivered to or, upon the order of the registered holder of such Rights Certificate, registered in such name or names as may be designated by such holder, and (iv) when necessary to comply with this Agreement, after receipt thereof, deliver such cash, to or upon the order of the registered holder of such Rights Certificate.  The payment of the Purchase Price (as such amount may be reduced pursuant to Section 11(a)(iii) hereof) shall be made in cash or by certified check or bank draft payable to the order of the Company.  In the event that the Company is obligated to issue other securities (including Common Stock) of the Company, pay cash and/or distribute other property pursuant to Section 11(a) hereof, the Company will make all arrangements necessary so that such other securities, cash and/or other property are available for distribution by the Rights Agent, if and when necessary to comply with this Agreement.  The Company reserves the right to require prior to the occurrence of a Triggering Event that, upon any exercise of Rights, a number of Rights be exercised so that only whole shares of Preferred Stock would be issued.
(d)    In case the registered holder of any Rights Certificate shall properly exercise less than all of the Rights evidenced thereby, a new Rights Certificate evidencing the Rights remaining unexercised shall be issued by the Rights Agent and delivered to, or upon the order of, the registered holder of such Rights Certificate, registered in such name or names as may be designated by such holder, subject to the provisions of Section 6 and Section 14 hereof. 
(e)    Notwithstanding anything in this Agreement to the contrary, from and after the first occurrence of a Section 11(a)(ii) Event, any Rights Beneficially Owned by (i) an Acquiring Person (or an Associate or Affiliate of an Acquiring Person), (ii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) who becomes a transferee after the Acquiring Person becomes such, or (iii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) who becomes a transferee prior to or concurrently with the Acquiring Person becoming such and receives such Rights pursuant to either (A) a transfer (whether or not for consideration) from the Acquiring Person to holders of equity interests in such Acquiring Person or to any Person with whom the Acquiring Person has any continuing agreement, arrangement or understanding (whether or not in writing) regarding the transferred Rights or (B) a transfer which the Board has determined is part of a plan, arrangement or understanding which has as a primary purpose or effect of the avoidance of this Section 7(e), shall become null and void without any further action and no holder of such Rights shall have any rights whatsoever 

	
			
	 
	13
	 

with respect to such Rights, whether under any provision of this Agreement, the Rights Certificate, or otherwise.  The Company shall use all reasonable efforts to insure that the provisions of this Section 7(e) and Section 4(b) hereof are complied with, but shall have no liability to any holder of Rights Certificates or any other Person as a result of its failure to make any determinations with respect to an Acquiring Person or any of its Affiliates, Associates or transferees hereunder.  The Company shall give the Rights Agent written notice of the identity of any such Acquiring Person, Associate or Affiliate, or the nominee of any of the foregoing, and the Rights Agent may rely on such notice in carrying out its duties under this Agreement and shall be deemed not to have any knowledge of the identity of any such Acquiring Person, Associate or Affiliate, or the nominee of any of the foregoing unless and until it shall have received such notice.
(f)    Notwithstanding anything in this Agreement or any Rights Certificate to the contrary, neither the Rights Agent nor the Company shall be obligated to undertake any action with respect to a registered holder of a Rights Certificate upon the occurrence of any purported exercise as set forth in this Section 7 unless and until such registered holder shall have (i) properly completed and duly executed the certificate contained in the form of election to purchase set forth on the reverse side of the Rights Certificate surrendered for such transfer or exercise, and (ii) provided such additional evidence of the identity of the Beneficial Owner (or former or proposed Beneficial Owner) or Affiliates or Associates of such Beneficial Owner (or former or proposed Beneficial Owner) as the Company or the Rights Agent shall reasonably request.
Section 8.    Cancellation and Destruction of Rights Certificates.  All Rights Certificates surrendered for the purpose of exercise, transfer, split-up, combination, redemption, or exchange shall, if surrendered to the Company or any of its agents, be delivered to the Rights Agent for cancellation or in cancelled form, or, if surrendered to the Rights Agent, shall be cancelled by it, and no Rights Certificates shall be issued in lieu thereof except as expressly permitted by any of the provisions of this Agreement.  The Company shall deliver to the Rights Agent for cancellation and retirement, and the Rights Agent shall so cancel and retire, any other Rights Certificate purchased or acquired by the Company otherwise than upon the exercise thereof.  The Rights Agent shall deliver all cancelled Rights Certificates to the Company, or shall, at the written request of the Company, destroy such cancelled Rights Certificates, and in such case shall deliver a certificate of destruction thereof to the Company.
Section 9.    Reservation and Availability of Capital Stock.  
(a)    The Company covenants and agrees that it will cause to be reserved, authorized for issuance and kept available out of its authorized and unissued shares of Preferred Stock (and, following the occurrence of a Triggering Event, out of its authorized and unissued shares of Common Stock and/or other securities or out of its authorized and issued shares held in its treasury), the number of shares of Preferred Stock (and, following the occurrence of a Triggering Event, Common Stock and/or other securities) that, as provided in and subject to the terms and conditions of this Agreement, including Section 11(a)(iii) hereof, will be sufficient to permit the exercise in full of all outstanding Rights in accordance with this Agreement.

	
			
	 
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(b)    So long as the shares of Preferred Stock (and, following the occurrence of a Triggering Event, Common Stock and/or other securities) issuable and deliverable upon the exercise of the Rights may be listed on any national securities exchange, the Company shall use its best efforts to cause, from and after such time as the Rights become exercisable, all shares reserved for such issuance to be listed on such exchange upon official notice of issuance upon such exercise.
(c)    The Company shall use its best efforts to (i) file, as soon as practicable following the earliest date after the first occurrence of a Section 11(a)(ii) Event on which the consideration to be delivered by the Company upon exercise of the Rights has been determined in accordance with Section 11(a)(iii) hereof, a registration statement under the Act, with respect to the securities purchasable upon exercise of the Rights on an appropriate form, (ii) cause such registration statement to become effective as soon as practicable after such filing, and (iii) cause such registration statement to remain effective (with a prospectus at all times meeting the requirements of the Act) until the earlier of (A) the date as of which the Rights are no longer exercisable for such securities, and (B) the date of the expiration of the Rights.  The Company will also take such action as may be appropriate under, or to ensure compliance with, the securities or “blue sky” laws of the various states in connection with the exercisability of the Rights.  The Company may temporarily suspend, for a period of time not to exceed 90 days after (but not including) the date set forth in clause (i) of the first sentence of this Section 9(c), the exercisability of the Rights in order to prepare and file such registration statement and permit it to become effective.  Upon any such suspension, the Company shall issue a public announcement stating that the exercisability of the Rights has been temporarily suspended, as well as a public announcement at such time as the suspension has been rescinded.  The Company shall notify the Rights Agent in writing whenever it makes a public announcement pursuant to this Section 9(c) and give the Rights Agent a copy of such announcement.  In addition, if the Company shall determine that a registration statement is required following the Distribution Date, the Company may temporarily suspend the exercisability of the Rights until such time as a registration statement has been declared effective and give prompt written notice of the same to the Rights Agent.  Notwithstanding any provision of this Agreement to the contrary, the Rights shall not be exercisable in any jurisdiction if the requisite qualification in such jurisdiction shall not have been obtained, the exercise thereof shall not be permitted under applicable law, or a registration statement shall not have been declared effective.
(d)    The Company covenants and agrees that it will take all such action as may be necessary to ensure that all 1/10,000th of a share of Preferred Stock (and, following the occurrence of a Triggering Event, Common Stock and/or other securities) delivered upon exercise of Rights shall, at the time of delivery of the certificates for such shares (subject to payment of the Purchase Price), be duly and validly authorized and issued and fully paid and nonassessable.
(e)    The Company further covenants and agrees that it will pay when due and payable any and all federal and state transfer and similar taxes and charges which may be payable in respect of the issuance or delivery of the Rights Certificates and of any certificates for a number of 1/10,000th of a share of Preferred Stock (or Common Stock and/or other securities, as the case may be) upon the exercise of Rights.  Neither the Rights Agent nor the Company shall, however, be required to pay any transfer or similar tax or charge which may be payable in 

	
			
	 
	15
	 

respect of any transfer or delivery of Rights Certificates to a Person other than, or the issuance or delivery of a number of 1/10,000th of a share of Preferred Stock (or Common Stock and/or other securities, as the case may be) in respect of a name other than that of the registered holder of the Rights Certificates evidencing Rights surrendered for exercise, nor shall the Rights Agent or the Company be required to register for transfer, issue or deliver any certificates (or make any entries in the book-entry account system of the transfer agent) for a number of 1/10,000th of a share of Preferred Stock (or Common Stock and/or other securities, as the case may be) in a name other than that of the registered holder upon the exercise of any Rights until such tax or charge shall have been paid (any such tax or charge being payable by the holder of such Rights Certificates at the time of surrender) or until it has been established to the Rights Agent’s and the Company’s reasonable satisfaction that no such tax or charge is due.
Section 10.    Preferred Stock Record Date.  Each person in whose name any certificate or entry in the book-entry account system of the transfer agent for a number of 1/10,000th of a share of Preferred Stock (or Common Stock and/or other securities, as the case may be) is issued upon the exercise of Rights shall for all purposes be deemed to have become the holder of record of such fractional shares of Preferred Stock (or Common Stock and/or other securities, as the case may be) represented thereby on, and such certificate or entry in the book-entry account system shall be dated, the date upon which the Rights Certificate evidencing such Rights was duly surrendered and payment of the Purchase Price (and all applicable transfer or similar taxes or charges) was duly made; provided, however, that if the date of such surrender and payment is a date upon which the Preferred Stock (or Common Stock and/or other securities, as the case may be) transfer books of the Company are closed, such Person shall be deemed to have become the record holder of such shares (fractional or otherwise) on, and such certificate or entry in the book-entry account system shall be dated as of, the next succeeding Business Day on which the Preferred Stock (or Common Stock and/or other securities, as the case may be) transfer books of the Company are open.  Prior to the exercise of the Rights evidenced thereby, the holder of a Rights Certificate shall not be entitled to any rights of a stockholder of the Company with respect to shares for which the Rights shall be exercisable, including the right to vote, to receive dividends or other distributions or to exercise any preemptive rights, and shall not be entitled to receive any notice of any proceedings of the Company, except as provided herein.
Section 11.    Adjustment of Purchase Price, Number and Kind of Shares or Number of Rights.  The Purchase Price, the number and kind of shares covered by each Right and the number of Rights outstanding are subject to adjustment from time to time as provided in this Section 11.
(a)    (i)    In the event that the Company shall at any time after the date of this Agreement (A) declare a dividend on the shares of Preferred Stock payable in shares of Preferred Stock, (B) subdivide or split the outstanding shares of Preferred Stock, (C) combine or consolidate the outstanding shares of Preferred Stock into a smaller number of shares, through a reverse stock split or otherwise, or (D) issue any shares of its capital stock in a reclassification of the Preferred Stock (including any such reclassification in connection with a consolidation or merger in which the Company is the continuing or surviving corporation), except as otherwise provided in this Section 11(a) and Section 7(e) hereof, the Purchase Price in effect at the time of the record date for such dividend or of the effective date of such subdivision, split, combination, consolidation or reclassification, and the number and kind of shares of Preferred Stock or capital 

	
			
	 
	16
	 

stock, as the case may be, issuable on such date, shall be proportionately adjusted so that the holder of any Right exercised after such time shall be entitled to receive, upon payment of the Purchase Price then in effect, the aggregate number and kind of shares of Preferred Stock or capital stock, as the case may be, which, if such Right had been exercised immediately prior to such date and at a time when the Preferred Stock transfer books of the Company were open, such holder would have owned upon such exercise and been entitled to receive by virtue of such dividend, subdivision, split, combination, consolidation or reclassification; provided, however, that in no event shall the consideration to be paid upon the exercise of one Right be less than the aggregate par value of the shares of capital stock of the Company issuable upon the exercise of one Right.  If an event occurs which would require an adjustment under both this Section 11(a)(i) and Section 11(a)(ii) hereof, the adjustment provided for in this Section 11(a)(i) shall be in addition to, and shall be made prior to, any adjustment required pursuant to Section 11(a)(ii) hereof.
(ii)    Subject to Section 24 hereof, in the event any Person shall, at any time after the Rights Dividend Declaration Date, become an Acquiring Person, unless the event causing such Person to become an Acquiring Person is a transaction set forth in Section 13(a) hereof, then, promptly following the later of the occurrence of such event and the Record Date, proper provision shall be made so that each holder of a Right (except as provided below and in Section 7(e) hereof) shall thereafter have the right to receive, upon exercise thereof at the then current Purchase Price in accordance with the terms of this Agreement, in lieu of a number of 1/10,000th of a share of Preferred Stock, such number of shares of Common Stock of the Company (or at the option of the Company, such number of 1/10,000th of a share of Preferred Stock) as shall equal the result obtained by (x) multiplying the then current Purchase Price by the then number of 1/10,000th of a share of Preferred Stock for which a Right was exercisable immediately prior to the first occurrence of a Section 11(a)(ii) Event, and (y) dividing that product (which, following such first occurrence, shall thereafter be referred to as the “Purchase Price” for each Right and for all purposes of this Agreement) by 50% of the Current Market Price per share of Common Stock on the date of such first occurrence (such number of shares, the “Adjustment Shares”). 
(iii)    In the event that the number of treasury shares and shares of Common Stock which are authorized by the Company Charter, but not outstanding or reserved for issuance for purposes other than upon exercise of the Rights, is not sufficient to permit the exercise in full of the Rights in accordance with the foregoing subparagraph (ii) of this Section 11(a), the Company shall (A) determine the value of the Adjustment Shares issuable upon the exercise of a Right (the “Current Value”), and (B) with respect to each Right (subject to Section 7(e) hereof), make adequate provision to substitute for the Adjustment Shares, upon the exercise of a Right and payment of the applicable Purchase Price, (1) cash, (2) a reduction in the Purchase Price, (3) Common Stock or other equity securities of the Company (including shares, or units of shares, of preferred stock, such as the Preferred Stock, which the Board has deemed to have essentially the same value or economic rights as shares of Common Stock (such shares of preferred stock being referred to as “Common Stock Equivalents”)), (4) debt securities of the Company, (5) other assets, or (6) any combination of the foregoing, having an aggregate value equal to the Current Value (less the amount of any reduction in the Purchase Price), 

	
			
	 
	17
	 

where such aggregate value has been determined by the Board based upon the advice of a nationally recognized investment banking firm selected by the Board; provided, however, that if the Company shall not have made adequate provision to deliver value pursuant to clause (B) above within 30 days following (but not including) the later of (x) the first occurrence of a Section 11(a)(ii) Event and (y) the date on which the Company’s right of redemption pursuant to Section 23(a) expires (the later of (x) and (y) being referred to herein as the “Section 11(a)(ii) Trigger Date”), then the Company shall be obligated to deliver, upon the surrender for exercise of a Right and without requiring payment of the Purchase Price, shares of Common Stock (to the extent available) and then, if necessary, cash, which shares and/or cash have an aggregate value equal to the Spread.  For purposes of the preceding sentence, the term “Spread” shall mean the excess of (i) the Current Value over (ii) the Purchase Price.  If the Board determines in good faith that it is likely that sufficient additional shares of Common Stock could be authorized for issuance upon exercise in full of the Rights, the 30 day period set forth above may be extended to the extent necessary, but not more than 90 days after (but not including) the Section 11(a)(ii) Trigger Date, in order that the Company may seek stockholder approval for the authorization of such additional shares (such 30 day period, as it may be extended, is herein called the “Substitution Period”).  To the extent that the Company determines that action should be taken pursuant to the first and/or third sentences of this Section 11(a)(iii), the Company (1) shall provide, subject to Section 7(e) hereof, that such action shall apply uniformly to all outstanding Rights, and (2) may suspend the exercisability of the Rights until the expiration of the Substitution Period in order to seek such stockholder approval for such authorization of additional shares and/or to decide the appropriate form of distribution to be made pursuant to such first sentence and to determine the value thereof.  In the event of any such suspension, the Company shall issue a public announcement stating that the exercisability of the Rights has been temporarily suspended, as well as a public announcement at such time as the suspension is no longer in effect.  The Company shall notify the Rights Agent in writing whenever it makes a public announcement pursuant to this Section 11(a)(iii) and give the Rights Agent a copy of such announcement.  For purposes of this Section 11(a)(iii), the value of each Adjustment Share shall be the Current Market Price per share of the Common Stock on the Section 11(a)(ii) Trigger Date and the per share or per unit value of any Common Stock Equivalent shall be deemed to equal the Current Market Price per share of the Common Stock on such date.
(b)    In case the Company shall fix a record date for the issuance of rights or options or warrants to all holders of Preferred Stock entitling them to subscribe for or purchase (for a period expiring within 45 days after, but not including, such record date) Preferred Stock (or shares having the same rights, privileges and preferences as the shares of Preferred Stock (“Equivalent Preferred Stock”)) or securities convertible into Preferred Stock or Equivalent Preferred Stock at a price per share of Preferred Stock or per share of Equivalent Preferred Stock (or having a conversion price per share, if a security convertible into Preferred Stock or Equivalent Preferred Stock) less than the Current Market Price per share of Preferred Stock on such record date, the Purchase Price to be in effect after such record date shall be determined by multiplying the Purchase Price in effect immediately prior to such record date by a fraction, the numerator of which shall be the number of shares of Preferred Stock outstanding on such record date, plus the number of shares of Preferred Stock which the aggregate offering price of the total 

	
			
	 
	18
	 

number of shares of Preferred Stock and/or Equivalent Preferred Stock so to be offered (and/or the aggregate initial conversion price of the convertible securities so to be offered) would purchase at such Current Market Price, and the denominator of which shall be the number of shares of Preferred Stock outstanding on such record date, plus the number of additional shares of Preferred Stock and/or Equivalent Preferred Stock to be offered for subscription or purchase (or into which the convertible securities so to be offered are initially convertible); provided, however, that in no event shall the consideration to be paid upon the exercise of one Right be less than the aggregate par value of the shares of capital stock of the Company issuable upon the exercise of one Right.  In case such subscription price may be paid by delivery of consideration, part or all of which may be in a form other than cash, the value of such consideration shall be as determined in good faith by the Board, whose determination shall be described in a statement filed with the Rights Agent and shall be binding and conclusive for all purposes on the Rights Agent and the holders of the Rights.  Shares of Preferred Stock owned by or held for the account of the Company shall not be deemed outstanding for the purpose of any such computation.  Such adjustment shall be made successively whenever such a record date is fixed, and in the event that such rights, options or warrants are not so issued, the Purchase Price shall be adjusted to be the Purchase Price which would then be in effect if such record date had not been fixed.
(c)    In case the Company shall fix a record date for a distribution to all holders of Preferred Stock (including any such distribution made in connection with a consolidation or merger in which the Company is the continuing or surviving corporation), cash (other than a regular quarterly cash dividend out of the earnings or retained earnings of the Company), assets (other than a dividend payable in Preferred Stock, but including any dividend payable in stock other than Preferred Stock) or evidences of indebtedness, or of subscription rights or warrants (excluding those referred to in Section 11(b) hereof), the Purchase Price to be in effect after such record date shall be determined by multiplying the Purchase Price in effect immediately prior to such record date by a fraction, the numerator of which shall be the Current Market Price per share of Preferred Stock on such record date, less the fair market value (as determined in good faith by the Board, whose determination shall be described in a statement filed with the Rights Agent) of the portion of the cash, assets or evidences of indebtedness so to be distributed or of such subscription rights or warrants applicable to a share of Preferred Stock, and the denominator of which shall be such Current Market Price per share of Preferred Stock; provided that in no event shall the consideration to be paid upon the exercise of one Right be less than the aggregate par value of the shares of capital stock of the Company issuable upon the exercise of one Right.  Such adjustments shall be made successively whenever such a record date is fixed, and in the event that such distribution is not so made, the Purchase Price shall be adjusted to be the Purchase Price which would have been in effect if such record date had not been fixed.
(d)    (i)    For the purpose of any computation hereunder, other than computations made pursuant to Section 11(a)(iii) hereof, the “Current Market Price” per share of Common Stock on any date shall be deemed to be the average of the daily closing prices per share of such Common Stock for the 30 consecutive Trading Days immediately prior to (but not including)  such date, and for purposes of computations made pursuant to Section 11(a)(iii) hereof, the Current Market Price per share of Common Stock on any date shall be deemed to be the average of the daily closing prices per share of such Common Stock for the 10 consecutive Trading Days immediately following (but not including) such date; provided, however, that in the event that the Current Market Price per share of the Common Stock is determined during a 

	
			
	 
	19
	 

period following the announcement by the issuer of such Common Stock of (A) a dividend or distribution on such Common Stock payable in shares of such Common Stock or securities convertible into shares of such Common Stock (other than the Rights), or (B) any subdivision, combination, consolidation, reverse stock split or reclassification of such Common Stock, and the ex-dividend date for such dividend or distribution, or the record date for such subdivision, combination, consolidation, reverse stock split or reclassification shall not have occurred prior to the commencement of the requisite 30 Trading Day or 10 Trading Day period, as set forth above, then, and in each such case, the Current Market Price shall be properly adjusted to take into account ex-dividend trading.  The closing price for each day shall be (i) the last quoted price reported at or prior to 4:00 P.M. Eastern time or, if not so quoted, the average of the high bid and low asked prices in the over-the-counter market, as reported as of 4:00 P.M. Eastern time by NASDAQ or such other quotation system then in use, or, if on any such date the Common Stock is not quoted by any such organization, the average of the closing bid and asked prices as furnished by a professional market maker making a market in the Common Stock selected by the Board of Directors of the Company, or (ii) if the Common Stock (or securities representing the Common Stock) are listed or admitted for trading on any national securities exchange, the last sale price, regular way, or, in case no such sale takes place on such day, the average of the closing bid and asked prices, regular way, in either case as reported in the principal consolidated transaction reporting system with respect to securities listed or admitted for trading on such on such national securities exchange. If on any such date no market maker is making a market in the Common Stock, the fair value of such shares on such date as determined in good faith by the Board of Directors of the Company shall be used. The term “Trading Day” shall mean a day on which NASDAQ is open for the transaction of business or, if the Common Stock is listed or admitted to trading on any national securities exchange, a day on which such national securities exchange is open for transaction of business.  If the Common Stock is not publicly held or not so listed or traded, Current Market Price per share shall mean the fair value per share as determined in good faith by the Board, whose determination shall be described in a statement filed with the Rights Agent and shall be conclusive for all purposes.
(ii)    For the purpose of any computation hereunder, the Current Market Price per share of Preferred Stock shall be determined in the same manner as set forth above for the Common Stock in clause (i) of this Section 11(d) (other than the last sentence thereof).  If the Current Market Price per share of Preferred Stock cannot be determined in the manner provided above or if the Preferred Stock is not publicly held or listed or traded in a manner described in clause (i) of this Section 11(d), the Current Market Price per share of Preferred Stock shall be conclusively deemed to be an amount equal to 10,000 (as such number may be appropriately adjusted for such events as stock splits, stock dividends and recapitalizations with respect to the Common Stock occurring after the date of this Agreement) multiplied by the Current Market Price per share of the Common Stock.  If neither the Common Stock nor the Preferred Stock is publicly held or so listed or traded, Current Market Price per share of the Preferred Stock shall mean the fair value per share as determined in good faith by the Board, whose determination shall be described in a statement filed with the Rights Agent and shall be conclusive for all purposes.
(e)    Anything herein to the contrary notwithstanding, no adjustment in the Purchase Price shall be required unless such adjustment would require an increase or decrease of 

	
			
	 
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at least 1% in the Purchase Price; provided, however, that any adjustments which by reason of this Section 11(e) are not required to be made shall be carried forward and taken into account in any subsequent adjustment.  All calculations under this Section 11 shall be made to the nearest cent or to the nearest ten-thousandth of a share of Common Stock or other share or one-millionth of a share of Preferred Stock, as the case may be.  Notwithstanding the first sentence of this Section 11(e), any adjustment required by this Section 11 shall be made no later than the earlier of (i) 3 years from the date of the transaction which mandates such adjustment, or (ii) the Expiration Date.
(f)    If as a result of an adjustment made pursuant to Section 11(a)(ii) or Section 13(a) hereof, the holder of any Right thereafter exercised shall become entitled to receive any shares of capital stock other than Preferred Stock, thereafter the number of such other shares so receivable upon exercise of any Right and the Purchase Price thereof shall be subject to adjustment from time to time in a manner and on terms as nearly equivalent as practicable to the provisions with respect to the Preferred Stock contained in Sections 11(a), (b), (c), (e), (g), (h), (i), (j), (k) and (m), and the provisions of Sections 7, 9, 10, 13 and 14 hereof with respect to the Preferred Stock shall apply on like terms to any such other shares.
(g)    All Rights originally issued by the Company subsequent to any adjustment made to the Purchase Price hereunder shall evidence the right to purchase, at the adjusted Purchase Price, the number of 1/10,000th of a share of Preferred Stock purchasable from time to time hereunder upon exercise of the Rights, all subject to further adjustment as provided herein.
(h)    Unless the Company shall have exercised its election as provided in Section 11(i), upon each adjustment of the Purchase Price as a result of the calculations made in Sections 11(b) and (c), each Right outstanding immediately prior to the making of such adjustment shall thereafter evidence the right to purchase, at the adjusted Purchase Price, that number of 1/10,000th of a share of Preferred Stock (calculated to the nearest one-millionth) obtained by (i) multiplying (x) the number of 1/10,000th of a share covered by a Right immediately prior to this adjustment, by (y) the Purchase Price in effect immediately prior to such adjustment of the Purchase Price, and (ii) dividing the product so obtained by the Purchase Price in effect immediately after such adjustment of the Purchase Price.
(i)    The Company may elect on or after the date of any adjustment of the Purchase Price to adjust the number of Rights, in lieu of any adjustment in the number of 1/10,000th of a share of Preferred Stock purchasable upon the exercise of a Right.  Each of the Rights outstanding after the adjustment in the number of Rights shall be exercisable for the number of 1/10,000th of a share of Preferred Stock for which a Right was exercisable immediately prior to such adjustment.  Each Right held of record prior to such adjustment of the number of Rights shall become that number of Rights (calculated to the nearest 1/10,000th) obtained by dividing the Purchase Price in effect immediately prior to adjustment of the Purchase Price by the Purchase Price in effect immediately after adjustment of the Purchase Price.  The Company shall make a public announcement (with prompt written notice thereof to the Rights Agent) of its election to adjust the number of Rights, indicating the record date for the adjustment, and, if known at the time, the amount of the adjustment to be made.  This record date may be the date on which the Purchase Price is adjusted or any day thereafter, but, if the Rights Certificates have been issued, shall be at least 10 days later than the date of the public 

	
			
	 
	21
	 

announcement.  If Rights Certificates have been issued, upon each adjustment of the number of Rights pursuant to this Section 11(i), the Company shall, as promptly as practicable, cause to be distributed to holders of record of Rights Certificates on such record date Rights Certificates evidencing, subject to Section 14 hereof, the additional Rights to which such holders shall be entitled as a result of such adjustment, or, at the option of the Company, shall cause to be distributed to such holders of record in substitution and replacement for the Rights Certificates held by such holders prior to the date of adjustment, and upon surrender thereof, if required by the Company, new Rights Certificates evidencing all the Rights to which such holders shall be entitled after such adjustment.  Rights Certificates so to be distributed shall be issued, executed and countersigned in the manner provided for herein (and may bear, at the option of the Company, the adjusted Purchase Price) and shall be registered in the names of the holders of record of Rights Certificates on the record date specified in the public announcement.
(j)    Irrespective of any adjustment or change in the Purchase Price or the number of 1/10,000th of a share of Preferred Stock issuable upon the exercise of the Rights, the Rights Certificates theretofore and thereafter issued may continue to express the Purchase Price per 1/10,000th of a share and the number of 1/10,000th of a share which were expressed in the initial Rights Certificates issued hereunder.
(k)    Before taking any action that would cause an adjustment reducing the Purchase Price below the then stated value, if any, of the number of 1/10,000th of a share of Preferred Stock issuable upon exercise of the Rights, the Company shall take any corporate action which may, in the opinion of its counsel, be necessary in order that the Company may validly and legally issue fully paid and nonassessable such number of 1/10,000th of a share of Preferred Stock at such adjusted Purchase Price.
(l)    In any case in which this Section 11 shall require that an adjustment in the Purchase Price be made effective as of a record date for a specified event, the Company may elect to defer (with prompt written notice thereof to the Rights Agent) until the occurrence of such event the issuance to the holder of any Right exercised after such record date the number of 1/10,000th of a share of Preferred Stock and other capital stock or securities of the Company, if any, issuable upon such exercise over and above the number of 1/10,000th of a share of Preferred Stock and other capital stock or securities of the Company, if any, issuable upon such exercise on the basis of the Purchase Price in effect prior to such adjustment; provided, however, that the Company shall deliver to such holder a due bill or other appropriate instrument evidencing such holder’s right to receive such additional shares (fractional or otherwise) or securities upon the occurrence of the event requiring such adjustment.
(m)    Anything in this Section 11 to the contrary notwithstanding, the Company shall be entitled to make such reductions in the Purchase Price, in addition to those adjustments expressly required by this Section 11, as and to the extent that the Board in its sole discretion shall determine to be advisable in order that any (i) consolidation or subdivision of the Preferred Stock, (ii) issuance wholly for cash of any shares of Preferred Stock at less than the Current Market Price, (iii) issuance wholly for cash of shares of Preferred Stock or securities which by their terms are convertible into or exchangeable for shares of Preferred Stock, (iv) stock dividends or (v) issuance of rights, options or warrants referred to in this Section 11, hereafter made by the Company to holders of its Preferred Stock shall not be taxable to such stockholders.

	
			
	 
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(n)    The Company covenants and agrees that it shall not, at any time after the Distribution Date, (i) consolidate with any other Person (other than a Subsidiary of the Company in a transaction which complies with Section 11(o) hereof), (ii) merge with or into any other Person (other than a Subsidiary of the Company in a transaction which complies with Section 11(o) hereof), or (iii) other than pursuant to a pro rata dividend and/or distribution to all of the then current holders of Common Stock, sell or transfer (or permit any Subsidiary to sell or transfer), in one transaction, or a series of related transactions, assets, cash flow or earning power aggregating more than 50% of the assets, cash flow, or earning power of the Company and its Subsidiaries (taken as a whole) to any other Person or Persons (other than the Company and/or any of its Subsidiaries in one or more transactions each of which complies with Section 11(o) hereof), if (x) at the time of or immediately after such consolidation, merger or sale there are any rights, warrants or other instruments or securities outstanding or agreements in effect which would substantially diminish or otherwise eliminate the benefits intended to be afforded by the Rights or (y) prior to, simultaneously with or immediately after such consolidation, merger or sale, the stockholders of the Person who constitutes, or would constitute, the “Principal Party” for purposes of Section 13(a) hereof shall have received a distribution of Rights previously owned by such Person or any of its Affiliates and Associates.
(o)    The Company covenants and agrees that, after the Distribution Date, it will not, except as permitted by Section 23 or Section 27 hereof, take (or permit any Subsidiary to take) any action if at the time such action is taken it is reasonably foreseeable that such action will diminish substantially or otherwise eliminate the benefits intended to be afforded by the Rights.
(p)    Anything in this Agreement to the contrary notwithstanding, except as provided in the following sentence, in the event that the Company shall at any time after the Rights Dividend Declaration Date and prior to the Distribution Date (i) declare a dividend on the outstanding shares of Common Stock payable in shares of Common Stock, (ii) subdivide the outstanding shares of Common Stock, or (iii) combine the outstanding shares of Common Stock into a smaller number of shares, through a reverse stock split or otherwise, the number of Rights associated with each share of Common Stock then outstanding, or issued or delivered thereafter but prior to the Distribution Date, shall be proportionately adjusted so that the number of Rights thereafter associated with each share of Common Stock following any such event shall equal the result obtained by multiplying the number of Rights associated with each share of Common Stock immediately prior to such event by a fraction the numerator which shall be the total number of shares of Common Stock outstanding immediately prior to the occurrence of the event and the denominator of which shall be the total number of shares of Common Stock outstanding immediately following the occurrence of such event.  The adjustments provided for in this Section 11(p) shall be made successively whenever such a dividend is declared or such a subdivision or combination is effected.
Section 12.    Certificate of Adjusted Purchase Price or Number of Shares.  Whenever an adjustment or any event affecting the exercisability of the Rights (including without limitation an event which causes the Rights to become null and void) is made or any event affecting the exercisability of the Rights (including an event that causes Rights to become null and void) occurs as provided in Section 11 or Section 13 hereof, the Company shall (a) promptly prepare a certificate setting forth such adjustment or describing such event and a brief, reasonably detailed, 

	
			
	 
	23
	 

statement of the facts, computations, and methodology accounting for such adjustment, (b) promptly file with the Rights Agent, and with each transfer agent for the Preferred Stock and the Common Stock, a copy of such certificate and (c) if a Distribution Date has occurred, mail a brief summary thereof to each holder of a Rights Certificate (or, if prior to the Distribution Date, to each holder of shares of Common Stock) in accordance with Section 25 and Section 26 hereof.  The Rights Agent shall be fully protected in relying on any such certificate and on any adjustment or statement therein contained and, except as provided for in this Agreement, shall have no duty or liability with respect to, and shall not be deemed to have knowledge of, any adjustment or any such event unless and until it shall have received such a certificate.
Section 13.    Consolidation, Merger or Sale or Transfer of Assets, Cash Flow or Earning Power.
(a)    In the event that, following the Stock Acquisition Date, directly or indirectly, (x) the Company shall consolidate with, or merge with and into, any other Person (other than a Subsidiary of the Company in a transaction which complies with Section 11(o) hereof), and the Company shall not be the continuing or surviving corporation of such consolidation or merger, (y) any Person (other than a Subsidiary of the Company in a transaction which complies with Section 11(o) hereof) shall consolidate with, or merge with or into, the Company, and the Company shall be the continuing or surviving corporation of such consolidation or merger and, in connection with such consolidation or merger, all or part of the outstanding shares of Common Stock shall be changed into or exchanged for stock or other securities of any other Person or cash or any other property, or (z) the Company shall, other than pursuant to pro rata dividend and/or distribution to all of the then current holders of Common Stock, sell or otherwise transfer (or one or more of its Subsidiaries shall sell or otherwise transfer), in one transaction or a series of related transactions, assets, cash flow or earning power aggregating more than 50% of the assets, cash flow or earning power of the Company and its Subsidiaries (taken as a whole) to any Person or Persons (other than the Company or any Subsidiary of the Company in one or more transactions each of which complies with Section 11(o) hereof) (each event referred to in clauses (x)-(z), a “Section 13 Event”), then, and in each such case, proper provision shall be made so that: (i) each holder of a Right, except as provided in Section 7(e) hereof, shall thereafter have the right to receive, upon the exercise thereof at the then current Purchase Price in accordance with the terms of this Agreement, such number of validly authorized and issued, fully paid, non-assessable and freely tradeable shares of Common Stock of the Principal Party (as such term is hereinafter defined), not subject to any liens, encumbrances, rights of first refusal or other adverse claims, as shall be equal to the result obtained by (1) multiplying the then current Purchase Price by the number of 1/10,000th of a share of Preferred Stock for which a Right is exercisable immediately prior to the first occurrence of a Section 13 Event (or, if a Section 11(a)(ii) Event has occurred prior to the first occurrence of a Section 13 Event, multiplying the number of such 1/10,000th of a share for which a Right was exercisable immediately prior to the first occurrence of a Section 11(a)(ii) Event by the Purchase Price in effect immediately prior to such first occurrence of a Section 11(a)(ii) Event), and (2) dividing that product (which, following the first occurrence of a Section 13 Event, shall be referred to as the “Purchase Price” for each Right and for all purposes of this Agreement) by 50% of the Current Market Price (determined pursuant to Section 11(d)(i) hereof) per share of the Common Stock of such Principal Party on the date of consummation of such Section 13 Event; (ii) such Principal Party shall thereafter be liable for, and shall assume, by 

	
			
	 
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virtue of such Section 13 Event, all the obligations and duties of the Company pursuant to this Agreement; (iii) the term “Company” shall thereafter be deemed to refer to such Principal Party, it being specifically intended that the provisions of Section 11 hereof shall apply only to such Principal Party following the first occurrence of a Section 13 Event; (iv) such Principal Party shall take such steps (including, the reservation of a sufficient number of shares of its Common Stock) in connection with the consummation of any such transaction as may be necessary to assure that the provisions hereof shall thereafter be applicable, as nearly as reasonably may be, in relation to its shares of Common Stock thereafter deliverable upon the exercise of the Rights; and (v) the provisions of Section 11(a)(ii) hereof shall be of no effect following the first occurrence of any Section 13 Event.
(b)    “Principal Party” shall mean:
(i)    in the case of any transaction described in clause (x) or (y) of the first sentence of Section 13(a) hereof, the Person that is the issuer of any securities into which shares of Common Stock of the Company are converted in such merger or consolidation, and if no securities are so issued, the Person that is the other party to such merger or consolidation; and 
(ii)    in the case of any transaction described in clause (z) of the first sentence of Section 13(a) hereof, the Person that is the party receiving the greatest portion of the assets, cash flow or earning power transferred pursuant to such transaction or transactions; provided, however, that in any such case, (1) if the Common Stock of such Person is not at such time or has not been continuously over the preceding 12 month period registered under Section 12 of the Exchange Act, and such Person is a direct or indirect Subsidiary of another Person the Common Stock of which is and has been so registered, “Principal Party” shall refer to such other Person; and (2) in case such Person is a Subsidiary, directly or indirectly, of more than one Person, the Common Stock of two or more of which are and have been so registered, “Principal Party” shall refer to whichever of such Persons is the issuer of the Common Stock having the greatest aggregate market value.
(c)    The Company shall not consummate any such consolidation, merger, sale or transfer unless the Principal Party shall have a sufficient number of authorized shares of its Common Stock which have not been issued or reserved for issuance to permit the exercise in full of the Rights in accordance with this Section 13 and unless prior thereto the Company and such Principal Party shall have executed and delivered to the Rights Agent confirming that the requirements of Section 13(a) and Section 13(b) hereof shall promptly be performed in accordance with their terms and further providing that, as soon as practicable after the date of any consolidation, merger or sale of assets mentioned in paragraph (a) of this Section 13, the Principal Party will:
(i)    prepare and file a registration statement under the Act, with respect to the Rights and the securities purchasable upon exercise of the Rights on an appropriate form, and will use its best efforts to cause such registration statement to (A) become effective as soon as practicable after such filing and (B) remain effective (with a prospectus at all times meeting the requirements of the Act) until the Expiration Date;

	
			
	 
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(ii)    take all such other action as may be necessary to enable the Principal Party to issue the securities purchasable upon exercise of the Rights, including the registration or qualification of such securities under all requisite securities laws or “blue sky” laws of jurisdictions of the various states and the listing of such securities on such exchanges and trading markets as may be necessary or appropriate; and
(iii)    deliver to holders of the Rights historical financial statements for the Principal Party and each of its Affiliates which comply in all respects with the requirements for registration on Form 10 (or any successor form) under the Exchange Act.
(d)    The provisions of this Section 13 shall similarly apply to successive mergers or consolidations or sales or other transfers.  In the event that a Section 13 Event shall occur at any time after the occurrence of a Section 11(a)(ii) Event, the Rights which have not theretofore been exercised shall thereafter become exercisable in the manner described in Section 13(a).
Section 14.    Fractional Rights and Fractional Shares.
(a)    The Company shall not be required to issue fractions of Rights, except prior to the Distribution Date as provided in Section 11(p) hereof, or to distribute Rights Certificates which evidence fractional Rights.  In lieu of such fractional Rights, the Company shall pay to the registered holders of the Rights Certificates with regard to which such fractional Rights would otherwise be issuable, an amount in cash equal to the same fraction of the current market value of a whole Right.  For purposes of this Section 14(a), the current market value of a whole Right shall be the closing price of the Rights for the Trading Day immediately prior to the date on which such fractional Rights would have been otherwise issuable. The closing price of a Right for any Trading Day shall be (i) the last quoted price or, if not so quoted, the average of the high bid and low asked prices in the over-the-counter market, as reported by NASDAQ or such other quotation system then in use, or, if on any such date the Rights are not quoted by any such organization, the average of the closing bid and asked prices as furnished by a professional market maker making a market in the Rights selected by the Board of Directors of the Company, or (ii) if the Rights are listed or admitted for trading on any national securities exchange, the last sale price, regular way, or, in case no such sale takes place on such day, the average of the closing bid and asked prices, regular way, in either case as reported in the principal consolidated transaction reporting system with respect to the Rights listed or admitted for trading on such on such national securities exchange.  If on any such date no such market maker is making a market in the Rights, the fair value of the Rights on such date as determined in good faith by the Board shall be used, which determination shall be described in a statement filed with the Rights Agent and shall be conclusive for all purposes.
(b)    The Company shall not be required to issue fractions of shares of Preferred Stock (other than fractions which are integral multiples of one ten-thousandth of a share of Preferred Stock) upon exercise of the Rights or to distribute certificates which evidence fractional shares of Preferred Stock (other than fractions which are integral multiples of one ten-thousandth of a share of Preferred Stock).  In lieu of fractional shares of Preferred Stock that are not integral multiples of one ten-thousandth of a share of Preferred Stock, the Company may pay 

	
			
	 
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to the registered holders of Rights Certificates at the time such Rights are exercised as herein provided an amount in cash equal to the same fraction of the current market value of one ten-thousandth of a share of Preferred Stock.  For purposes of this Section 14(b), the current market value of one ten-thousandth of a share of Preferred Stock shall be one ten-thousandth of the closing price of a share of Preferred Stock (as determined pursuant to Section 11(d)(ii) hereof) for the Trading Day immediately prior to the date of such exercise.
(c)    Following the occurrence of a Triggering Event, the Company shall not be required to issue fractions of shares of Common Stock upon exercise of the Rights or to distribute certificates which evidence fractional shares of Common Stock.  In lieu of fractional shares of Common Stock, the Company may pay to the registered holders of Rights Certificates at the time such Rights are exercised as herein provided an amount in cash equal to the same fraction of the current market value of 1 share of Common Stock.  For purposes of this Section 14(c), the current market value of one share of Common Stock shall be the closing price per share of Common Stock (as determined pursuant to Section 11(d)(i) hereof) on the Trading Day immediately prior to the date of such exercise.
(d)    The holder of a Right by the acceptance of the Rights expressly waives such holder’s right to receive any fractional Rights or any fractional shares upon exercise of a Right, except as permitted by this Section 14. 
(e)    Whenever a payment for fractional Rights or fractional shares is to be made by the Rights Agent, the Company shall (i) promptly prepare and deliver to the Rights Agent a certificate setting forth in reasonable detail the facts related to such payments and the prices and/or formulas utilized in calculating such payments, and (ii) provide sufficient monies to the Rights Agent in the form of fully collected funds to make such payments. The Rights Agent shall be fully protected in relying upon such a certificate and shall have no duty with respect to, and shall not be deemed to have knowledge of, any payment of cash for fractional Rights or fractional shares under any Section of this Agreement relating to the payment of cash for fractional Rights or fractional shares unless and until the Rights Agent shall have received such a certificate and sufficient monies.
Section 15.    Rights of Action.  All rights of action in respect of this Agreement, excepting the rights of action given to the Rights Agent hereunder, including under Section 18 and Section 20 hereof, are vested in the respective registered holders of the Rights Certificates (and, prior to the Distribution Date, the registered holders of the Common Stock); and any registered holder of any Rights Certificate (or, prior to the Distribution Date, of the Common Stock), without the consent of the Rights Agent or of the holder of any other Rights Certificate (or, prior to the Distribution Date, of the Common Stock), may, in the holder’s own behalf and for the holder’s own benefit, enforce, and may institute and maintain any suit, action or proceeding against the Company to enforce, or otherwise act in respect of, the holder’s right to exercise the Rights evidenced by such Rights Certificate in the manner provided in such Rights Certificate and in this Agreement.  Without limiting the foregoing or any remedies available to the holders of Rights, it is specifically acknowledged that the holders of Rights would not have an adequate remedy at law for any breach of this Agreement and shall be entitled to specific performance of the obligations hereunder and injunctive relief against actual or threatened violations of the obligations hereunder of any Person subject to this Agreement.

	
			
	 
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Section 16.    Agreement of Rights Holders.  Every holder of a Right by accepting the same consents and agrees with the Company and the Rights Agent and with every other holder of a Right that: 
(a)    prior to the Distribution Date, the Rights will be transferable only in connection with the transfer of shares of Common Stock;
(b)    after the Distribution Date, the Rights Certificates are transferable only on the registry books of the Rights Agent if surrendered at the office of the Rights Agent designated for such purposes, duly endorsed or accompanied by a proper instrument of transfer and with the appropriate forms and certificates properly completed and duly executed, as determined in the sole discretion of the Rights Agent; 
(c)    subject to Section 6(a) and Section 7(f) hereof, the Company and the Rights Agent may deem and treat the person in whose name a Rights Certificate (or, prior to the Distribution Date, the associated balance indicated in the book-entry account system of the transfer agent for the Common Stock or, in the case of certificated shares, the associated Common Stock certificate) is registered as the absolute owner thereof and of the Rights evidenced thereby (notwithstanding any notations of ownership or writing on the Rights Certificates or the associated balance indicated in the book-entry account system of the transfer agent for the Common Stock or, in the case of certificated shares, the associated Common Stock certificate, made by anyone other than the Company or the Rights Agent) for all purposes whatsoever, and neither the Company nor the Rights Agent, subject to the last sentence of Section 7(e) hereof, shall be required to be affected by any notice to the contrary; and 
(d)    notwithstanding anything in this Agreement to the contrary, neither the Company nor the Rights Agent nor any of their directors, officers, employees, or agents shall have any liability to any holder of a Right or other Person as a result of its inability to perform any of its obligations under this Agreement by reason of any preliminary or permanent injunction or other order, judgment, decree or ruling issued by a court of competent jurisdiction or by a governmental, regulatory, self-regulatory, or administrative agency or commission, or any statute, rule, regulation or executive order promulgated or enacted by any governmental authority, prohibiting or otherwise restraining performance of such obligation; provided, however, the Company must use its reasonable best efforts to have any such injunction, judgment, order, decree or ruling lifted or otherwise overturned as soon as possible.
Section 17.    Rights Certificate Holder Not Deemed a Stockholder.  No holder, as such, of any Rights Certificate shall be entitled to vote, or to receive dividends or distributions or be deemed for any purpose the holder of the number of 1/10,000th of a share of Preferred Stock or any other securities, cash, or other property which may at any time be issuable on the exercise of the Rights represented thereby, nor shall anything contained herein or in any Rights Certificate be construed to confer upon the holder of any Rights Certificate, as such, any of the rights of a stockholder of the Company or any right to vote for the election of directors or upon any matter submitted to stockholders at any meeting thereof, or to give or withhold consent to any corporate action, or to receive notice of meetings or other actions affecting stockholders (except as provided in Section 25 hereof), or to receive dividends or subscription rights, or otherwise, until 

	
			
	 
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the Right or Rights evidenced by such Rights Certificate shall have been exercised in accordance with the provisions hereof.
Section 18.    Concerning the Rights Agent.  
(a)    The Company agrees to promptly pay to the Rights Agent reasonable compensation for all services rendered by it hereunder and, from time to time, on demand of the Rights Agent, its actual expenses, reasonable counsel fees and disbursements, and other disbursements incurred in the preparation, administration, amendment and execution of this Agreement and the exercise and performance of its duties hereunder.  The Company also covenants and agrees to indemnify the Rights Agent for, and to hold it harmless against, any loss, liability, damages, judgment, fine, penalty, claim, demand, settlement (subject to the provisions of this Section 18(a)), cost or expense (including reasonable documented fees and expenses of its outside legal counsel), incurred on the part of the Rights Agent, for any action taken, suffered or omitted by the Rights Agent in connection with the acceptance and administration of its duties under this Agreement, including the costs and expenses of defending against any claim of liability arising therefrom, directly or indirectly; provided, however, that such covenant and agreement of the Company does not extend to, and the Rights Agent shall not be indemnified with respect to, such costs, expenses, losses, damages or other amounts incurred or suffered by the Rights Agent as a result of, or arising out of, its own gross negligence, bad faith, or willful misconduct (each as determined by a final, non-appealable, judgment of a court of competent jurisdiction).  The costs and expenses incurred in successfully enforcing this right of indemnification shall also be paid by the Company.  The Rights Agent will notify the Company within thirty (30) days of Rights Agent having actual knowledge of any claims for which it seeks indemnification (“Indemnifiable Claim”); provided, however, that the Rights Agent’s failure to timely notify the Company of an Indemnifiable Claim shall not limit its rights to indemnification under this Agreement unless the Company has been significantly prejudiced by such failure, but only to the extent of such prejudice. The Company may assume full control of the defense of the Indemnifiable Claim at its own expense with counsel reasonably satisfactory to Rights Agent.  Notwithstanding the foregoing, the Company shall not be entitled to assume the defense of an Indemnifiable Claim (a) brought by the Rights Agent, or (b) as to which Rights Agent has reasonably determined that there may be a conflict of interest between the Company and Rights Agent in the defense of such Indemnifiable Claim and Rights Agent does in fact assume and conduct the defense. If the Company does not assume control of the defense of the Indemnifiable Claim within a reasonable time of receiving notice of it from the Rights Agent, then the Rights Agent may assume control of the defense of it, with full recourse against the Company for all reasonable costs and expenses incurred in connection with the defense and/or settlement of the Indemnifiable Claim. The Company and the Rights Agent will reasonably cooperate with each other in defense of the Indemnifiable Claim, regardless of which party has assumed control of the defense of it. The Rights Agent will not settle any Indemnifiable Claim without the Company’s prior written consent, which will not be unreasonably withheld.  If the Company assumes the defense of the Indemnifiable Claim, the Company shall take steps in good faith to defend, settle or otherwise dispose of the Indemnifiable Claim.  The provisions of this Section 18 and Section 20 below shall survive the termination of this Agreement, the exercise or expiration of the Rights and the resignation, replacement or removal of the Rights Agent.

	
			
	 
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(b)    The Rights Agent shall be protected and shall incur no liability for or in respect of any action taken, suffered or omitted to be taken by it in connection with its administration of this Agreement, in reliance upon any certificate for securities (or registration on the stock transfer books of the Company) purchasable upon exercise of Rights, Rights Certificate, certificate for other securities of the Company, instrument of assignment or transfer, power of attorney, endorsement, affidavit, letter, notice, direction, consent, certificate, statement, or other paper or document believed by it to be genuine and to have been executed and, where necessary, verified, guaranteed, or acknowledged, by the proper Person or Persons, or otherwise upon the advice of counsel as set forth in Section 20. The Rights Agent shall not be deemed to have any knowledge of any event of which it was supposed to receive written notice thereof hereunder, but for which it has not received such written notice, and the Rights Agent shall be fully protected and shall incur no liability for failing to take any action in connection therewith, unless and until it has received such notice in writing.
Section 19.    Merger, Share Exchange, or Consolidation or Change of Name of Rights Agent.  
(a)    Any Person into which the Rights Agent or any successor Rights Agent may be merged or with which it may effect a share exchange or be consolidated, or any Person resulting from any merger, share exchange, conversion, or consolidation to which the Rights Agent or any successor Rights Agent shall be a party, or any Person succeeding to the corporate trust, stock transfer or other stockholder services business of the Rights Agent or any successor Rights Agent, shall be the successor to the Rights Agent under this Agreement without the execution or filing of any paper or any further act on the part of any of the parties hereto; but only if such Person would be eligible for appointment as a successor Rights Agent under the provisions of Section 21 hereof.  In case at the time such successor Rights Agent shall succeed to the agency created by this Agreement, any of the Rights Certificates shall have been countersigned but not delivered, any such successor Rights Agent may adopt the countersignature of an authorized signatory of a predecessor Rights Agent and deliver such Rights Certificates so countersigned; and in case at that time any of the Rights Certificates shall not have been countersigned, an authorized signatory of any successor Rights Agent may countersign such Rights Certificates either in the name of the predecessor or in the name of the successor Rights Agent; and in all such cases such Rights Certificates shall have the full force provided in the Rights Certificates and in this Agreement.
(b)    In case at any time the name of the Rights Agent shall be changed and at such time any of the Rights Certificates shall have been countersigned but not delivered, the Rights Agent may adopt the countersignature of an authorized signatory under its prior name and deliver Rights Certificates so countersigned; and in case at that time any of the Rights Certificates shall not have been countersigned, an authorized signatory of the Rights Agent may countersign such Rights Certificates either in its prior name or in its changed name; and in all such cases such Rights Certificates shall have the full force provided in the Rights Certificates and in this Agreement.
Section 20.    Duties of Rights Agent.  The Rights Agent undertakes to perform only the duties and obligations expressly set forth in this Agreement (and no implied duties), upon the 

	
			
	 
	30
	 

following terms and conditions, by all of which the Company and the holders of Rights Certificates, by their acceptance thereof, shall be bound:
(a)    The Rights Agent may consult with legal counsel (who may be legal counsel for the Company or an employee of the Rights Agent), and the advice or opinion of such counsel shall be full and complete authorization and protection to the Rights Agent as to any action taken, suffered, or omitted to be taken by it and in accordance with such advice or opinion.
(b)    Whenever in the performance of its duties under this Agreement the Rights Agent shall deem it necessary or desirable that any fact or matter (including the identity of any Acquiring Person or any Affiliate or Associate of an Acquiring Person or the determination of Current Market Price) be proved or established by the Company prior to taking, suffering, or omitting to take any action hereunder, such fact or matter (unless other evidence in respect thereof be herein specifically prescribed) may be deemed to be conclusively proved and established by a certificate signed by the Chairman of the Board, the Chief Executive Officer, the President, any Vice President, the Treasurer, any Assistant Treasurer, the Secretary or any Assistant Secretary of the Company and delivered to the Rights Agent; and such certificate shall be full authorization and protection to the Rights Agent and the Rights Agent shall incur no liability for or in respect of any action taken or suffered or omitted to be taken by it under the provisions of this Agreement in reliance upon such certificate.  The Rights Agent shall have no duty to act without such a certificate from an officer of the Company as set forth in the preceding sentence.
(c)    The Rights Agent shall be liable hereunder only for its own gross negligence, bad faith or willful misconduct (each as determined by a final, non-appealable, judgment of a court of competent jurisdiction); provided, however, that the Rights Agent shall under no circumstances be liable for indirect, consequential, special, punitive or incidental damages (including but not limited to lost profits) under any provisions of this Agreement, even if the Rights Agent has been advised of or has foreseen the possibility or likelihood of such damages.  Notwithstanding anything in this Agreement to the contrary, the liability of the Rights Agent under this Agreement will be limited to the amount of the annual fees paid by the Company to the Rights Agent during the twelve (12) months immediately preceding the event for which recovery from the Rights Agent is being sought.
(d)    The Rights Agent shall not be liable for or by reason of any of the statements of fact or recitals contained in this Agreement or in the Rights Certificates or be required to verify the same (except as to its countersignature on such Rights Certificates).  All such statements and recitals are and shall be deemed to have been made by the Company only.
(e)    The Rights Agent shall not have any liability for or be under any responsibility in respect of the legality or validity of this Agreement or the execution and delivery hereof (except the due execution hereof by the Rights Agent) or in respect of the validity or execution of any Rights Certificate (except its countersignature thereof), or any modification or order of any court, tribunal, or governmental authority in connection with the foregoing; nor shall it be liable or responsible for any breach by the Company of any covenant or condition contained in this Agreement or in any Rights Certificate; nor shall it be liable or

	
			
	 
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responsible for any change or adjustment required under the provisions of Section 11, Section 13 or Section 24 hereof or responsible for the manner, method or amount of any such change or adjustment or the ascertaining of the existence of facts that would require any such change or adjustment (except with respect to the exercise of Rights evidenced by Rights Certificates after receipt of notice of any such adjustment, upon which the Rights Agent may rely); nor shall it by any act hereunder be deemed to make any representation or warranty as to the authorization or reservation of any shares of Common Stock or Preferred Stock or other securities to be issued pursuant to this Agreement or any Rights Certificate or as to whether any shares of Common Stock or Preferred Stock or other securities will, when so issued, be validly authorized and issued, fully paid and nonassessable.
(f)    The Company agrees that it will perform, execute, acknowledge and deliver or cause to be performed, executed, acknowledged and delivered all such further and other acts, instruments and assurances as may reasonably be required or requested by the Rights Agent for the carrying out or performance by the Rights Agent of the provisions of this Agreement, in the reasonable discretion of the Rights Agent.
(g)    The Rights Agent is hereby authorized and directed to accept instructions with respect to the performance of its duties hereunder and certificates delivered pursuant to any provision hereof from the Chairman of the Board, the Chief Executive Officer, the President, any Vice President, the Secretary, any Assistant Secretary, the Treasurer or any Assistant Treasurer of the Company, or legal counsel to the Company, and to apply to such officers or representatives for advice or instructions in connection with its duties, and such instructions shall be full authorization and protection to the Rights Agent and the Rights Agent shall not be liable for any action taken, suffered or omitted to be taken by it in accordance with instructions of any such officer (or for any delay in acting while waiting for those instructions).  The Rights Agent shall be fully authorized and protected in relying upon the most recent instructions received from any such officer.  
(h)    The Rights Agent and any member, affiliate, stockholder, director, officer, employee, agent, or representative, of the Rights Agent may buy, sell or deal in any of the Rights or other securities of the Company or become pecuniarily interested in any transaction in which the Company may be interested, or contract with or lend money to the Company or otherwise act as fully and freely as though it were not Rights Agent under this Agreement.  Nothing herein shall preclude the Rights Agent or any such stockholder, member, affiliate, director, officer or employee of the Rights Agent from acting in any other capacity for the Company or for any other Person.
(i)    The Rights Agent may execute and exercise any of the rights or powers hereby vested in it or perform any duty hereunder either itself (or through its directors, officers or employees) or by or through its attorneys or agents, and the Rights Agent shall not be answerable or accountable for any act, omission, default, neglect or misconduct of any such attorneys or agents or for any loss to the Company or any other Person resulting from any such act, omission, default, neglect or misconduct.
(j)    No provision of this Agreement shall require the Rights Agent to expend or risk its own funds or otherwise incur any financial liability in the performance of any of its 

	
			
	 
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duties hereunder or in the exercise of any of its rights or powers if it believes that repayment of such funds or adequate indemnification against such risk or liability is not reasonably assured to it.  The Rights Agent shall not be required to take any action or to follow any instruction of the Company that the Rights Agent believes, upon the advice of counsel, would cause the Rights Agent to take action that is illegal.
Section 21.    Change of Rights Agent.  The Rights Agent or any successor Rights Agent may resign and be discharged from its duties under this Agreement upon at least 30 days’ notice in writing to the Company in the manner set forth in Section 26 herein, and to the transfer agent in the event that the Rights Agent or one of its Affiliates is not also the transfer agent for the Company.  If at any time the Rights Agent or one of its Affiliates is also the transfer agent for the Company, in the event such transfer agency relationship terminates, the Rights Agent will be deemed to have resigned automatically and be discharged from its duties under this Agreement as of the effective date of such termination, and the Company shall be responsible for sending any required notice.  The Company may remove the Rights Agent or any successor Rights Agent upon at least 30 days’ notice in writing to the Rights Agent or successor Rights Agent, as the case may be, and to each transfer agent of the Common Stock and Preferred Stock, in the manner set forth in Section 26 herein, and, if such removal occurs after the Distribution Date, to the holders of the Rights Certificates by first-class mail.  If the Rights Agent shall resign or be removed or shall otherwise become incapable of acting, the Company shall appoint a successor to the Rights Agent.  If the Company shall fail to make such appointment within a period of 30 days after, but not including, giving notice of such removal or after it has been notified in writing of such resignation or incapacity by the resigning or incapacitated Rights Agent or by the holder of a Rights Certificate (who shall, with such notice, submit his Rights Certificate for inspection by the Company), then any registered holder of any Rights Certificate may apply to any court of competent jurisdiction for the appointment of a new Rights Agent.  Any successor Rights Agent, whether appointed by the Company or by such a court, shall be (a) a legal business entity organized and doing business under the laws of the United States or any State thereof, in good standing, which is authorized under such laws to exercise corporate trust, stock transfer or stockholder services powers and which has, along with its Affiliates, at the time of its appointment as Rights Agent a combined capital and surplus of at least $50,000,000 or (b) an affiliate of a legal business entity described in clause (a) of this sentence.  After appointment, the successor Rights Agent shall be vested with the same powers, rights, duties and responsibilities as if it had been originally named as Rights Agent under this Agreement without further act or deed; but the predecessor Rights Agent shall deliver and transfer to the successor Rights Agent any property at the time held by it hereunder, and execute and deliver any further assurance, conveyance, act or deed necessary for the foregoing purpose, but the Rights Agent shall not be required to make any additional expenditure or assume any additional liability in connection with the foregoing.  Not later than the effective date of any such appointment, the Company shall file notice thereof in writing with the predecessor Rights Agent and each transfer agent of the Common Stock and the Preferred Stock, and, if such appointment occurs after the Distribution Date, mail a notice thereof in writing to the registered holders of the Rights Certificates.  Failure to give any notice provided for in this Section 21, however, or any defect therein, shall not affect the legality or validity of the resignation or removal of the Rights Agent or the appointment of the successor Rights Agent, as the case may be.

	
			
	 
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Section 22.    Issuance of New Rights Certificates.  Notwithstanding any of the provisions of this Agreement or of the Rights to the contrary, the Company may, at its option, issue new Rights Certificates evidencing Rights in such form as may be approved by the Board to reflect any adjustment or change in the Purchase Price and the number or kind or class of shares or other securities or property purchasable under the Rights Certificates made in accordance with the provisions of this Agreement.  In addition, in connection with the issuance or sale of shares of Common Stock following the Distribution Date and prior to the redemption, exchange, or expiration of the Rights, the Company (a) shall, with respect to shares of Common Stock so issued or sold pursuant to the exercise of stock options or under any employee benefit plan or arrangement, granted or awarded as of the Distribution Date, or upon the exercise, conversion or exchange of securities hereinafter issued by the Company (except as may otherwise be provided in the instrument(s) governing such securities), and (b) may, in any other case, if deemed necessary or appropriate by the Board, issue Rights Certificates representing the appropriate number of Rights in connection with such issuance or sale; provided, however, that (i) no such Rights Certificate shall be issued if, and to the extent that, the Company shall be advised by counsel that such issuance would create a significant risk of material adverse tax consequences to the Company or the Person to whom such Rights Certificate would be issued, and (ii) no such Rights Certificate shall be issued if, and to the extent that, appropriate adjustment shall otherwise have been made in lieu of the issuance thereof.
Section 23.    Redemption and Termination.  
(a)    The Board may, at its option, at any time prior to the earlier of (i) Distribution Date, or (ii) the Final Expiration Date, redeem all but not less than all of the then outstanding Rights at a redemption price of $0.0001 per Right, as such amount may be appropriately adjusted to reflect any stock split, stock dividend or similar transaction occurring after the date hereof (such redemption price being hereinafter referred to as the “Redemption Price”).  Notwithstanding anything contained in this Agreement to the contrary, the Rights shall not be exercisable after the first occurrence of a Section 11(a)(ii) Event until such time as the Company’s right of redemption hereunder has expired.  The Company may, at its option, pay the Redemption Price in cash, shares of Common Stock (based on the Current Market Price, as defined in Section 11(d)(i) hereof, of the Common Stock at the time of redemption) or any other form of consideration deemed appropriate by the Board.
(b)    Immediately upon the action of the Board electing to redeem the Rights pursuant to Section 23(a) above, written evidence of which shall have been filed with the Rights Agent and without any further action and without any notice, the right to exercise the Rights will terminate and the only right thereafter of the holders of Rights shall be to receive the Redemption Price for each Right so held.  Promptly after the action of the Board electing to redeem the Rights, the Company shall give notice of such redemption to the Rights Agent and the holders of the then outstanding Rights by mailing such notice to all such holders at each holder’s last address as it appears upon the registry books of the Rights Agent or, prior to the Distribution Date, on the registry books of the transfer agent for the Common Stock.  Any notice which is mailed in the manner herein provided shall be deemed given, whether or not the holder receives the notice.  Each such notice of redemption will state the method by which the payment of the Redemption Price will be made.

	
			
	 
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Section 24.    Exchange. 
(a)    The Board may, at its option, at any time after the Stock Acquisition Date, exchange all or part of the then outstanding and exercisable Rights (which shall not include Rights that have become null and void pursuant to Section 7(e) hereof or Rights that have been exercised pursuant to Section 7 hereof) for Common Stock at an exchange ratio of 1 share of Common Stock per Right, appropriately adjusted to reflect any stock split, stock dividend or similar transaction occurring after the date hereof (such exchange ratio being hereinafter referred to as the “Exchange Ratio”). 
(b)    Immediately upon the action of the Board electing to exchange Rights pursuant to subsection (a) of this Section 24 and without any further action and without any notice, the right to exercise such Rights shall terminate and the only right thereafter of a holder of such Rights shall be to receive that number of shares of Common Stock equal to the number of such Rights held by such holder multiplied by the Exchange Ratio.  The Company shall promptly give public notice of any such exchange (with prompt written notice thereof to the Rights Agent); provided, however, that the failure to give, or any defect in, such notice shall not affect the validity of such exchange.  The Company promptly shall mail a notice of any such exchange to all of the holders of such Rights at their last addresses as they appear upon the registry books of the Rights Agent.  Any notice which is mailed in the manner herein provided shall be deemed given, whether or not the holder receives the notice.  Each such notice of exchange will state the method by which the exchange of the Common Stock for Rights will be effected and, in the event of any partial exchange, the number of Rights which will be exchanged.  Any partial exchange shall be effected pro rata based on the number of Rights (other than Rights which have become null and void pursuant to the provisions of Section 7(e) hereof) held by each holder of Rights.
(c)    In any exchange pursuant to this Section 24, the Company, at its option, may substitute Preferred Stock (or Equivalent Preferred Stock, as such term is defined in paragraph (b) of Section 11 hereof) for Common Stock exchangeable for Rights, at the initial rate of one ten-thousandth of a share of Preferred Stock (or Equivalent Preferred Stock) for each share of Common Stock, as appropriately adjusted to reflect stock splits, stock dividends and other similar transactions after the date hereof.
(d)    In the event that there shall not be sufficient shares of Common Stock issued but not outstanding or authorized but unissued to permit any exchange of Rights as contemplated in accordance with this Section 24, the Company may at its option substitute for each Common Stock that would otherwise be issuable upon exercise of a Right, a number of Preferred Shares or faction thereof such that the Current Market Price of one Preferred Stock multiplied by such number or fraction is equal to the Current Market Price of one Common Share as of the date of such exchange.
(e)    The Company shall not be required to issue fractions of shares of Common Stock or, in the case of certificated shares, to distribute certificates which evidence fractional shares of Common Stock.  In lieu of such fractional shares of Common Stock, there shall be paid to the registered holders of the Rights Certificates with regard to which such fractional shares of Common Stock would otherwise be issuable, an amount in cash equal to the 

	
			
	 
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same fraction of the current market value of a whole share of Common Stock.  For the purposes of this subsection (e), the current market value of a whole share of Common Stock shall be the closing price of a share of Common Stock (as determined pursuant to the second sentence of Section 11(d)(i) hereof) for the Trading Day immediately prior to the date of exchange pursuant to this Section 24.
Section 25.    Notice of Certain Events.
(a)    In case the Company shall propose, at any time after the Distribution Date, (i) to pay any dividend payable in stock of any class to the holders of Preferred Stock or to make any other distribution to the holders of Preferred Stock (other than a regular quarterly cash dividend out of earnings or retained earnings of the Company), or (ii) to offer to the holders of Preferred Stock rights or warrants to subscribe for or to purchase any additional shares of Preferred Stock or shares of stock of any class or any other securities, rights or options, or (iii) to effect any reclassification of its Preferred Stock (other than a reclassification involving only the subdivision of outstanding shares of Preferred Stock), or (iv) to effect any consolidation or merger into or with any other Person (other than a Subsidiary of the Company in a transaction which complies with Section 11(o) hereof), or, other than pursuant to a pro rata dividend and/or distribution to all of the then current holders of Common Stock, to effect any sale or other transfer (or to permit one or more of its Subsidiaries to effect any sale or other transfer), in one transaction or a series of related transactions, of more than 50% of the assets, cash flow or earning power of the Company and its Subsidiaries (taken as a whole) to any other Person or Persons (other than the Company and/or any of its Subsidiaries in one or more transactions each of which complies with Section 11(o) hereof), or (v) to effect the liquidation, dissolution or winding up of the Company, then, in each such case, the Company shall give to the Rights Agent and to each holder of a Rights Certificate, to the extent feasible and in accordance with Section 26 hereof, a notice of such proposed action, which shall specify the record date for the purposes of such stock dividend, distribution of rights or warrants or the date on which such reclassification, consolidation, merger, sale, transfer, liquidation, dissolution, or winding up is to take place and the date of participation therein by the holders of the shares of Preferred Stock, if any such date is to be fixed, and such notice shall be so given in the case of any action covered by clause (i) or (ii) above at least 10 days prior to (but not including) the record date for determining holders of the shares of Preferred Stock for purposes of such action, and in the case of any such other action, at least 10 days prior to (but not including) the date of the taking of such proposed action or the date of participation therein by the holders of the shares of Preferred Stock, whichever shall be the earlier.
(b)    In case any of the events set forth in Section 11(a)(ii) hereof shall occur, then, in any such case, (i) the Company shall as soon as practicable thereafter give to each holder of a Rights Certificate, to the extent feasible and in accordance with Section 26 hereof, and to the Rights Agent in accordance with Section 26 hereof, a notice of the occurrence of such event, which shall specify the event and the consequences of the event to holders of Rights under Section 11(a)(ii) hereof, and (ii) all references in the preceding paragraph to Preferred Stock shall be deemed thereafter to refer to Common Stock and/or, if appropriate, other securities.
Section 26.    Notices.  Notices or demands authorized by this Agreement to be in writing and shall given or made by the Rights Agent or by the holder of any Rights Certificate to 

	
			
	 
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or on the Company shall be sufficiently given or made if sent by overnight delivery service or first-class mail, postage prepaid, addressed (until another address is delivered in writing to the Rights Agent by the Company) as follows:
Windstream Holdings, Inc. 
4001 Rodney Parham Road 
Little Rock, AR 72212 
Attention:  Chief Executive Officer

With a copy to: 

Windstream Holdings, Inc. 
4001 Rodney Parham Road 
Little Rock, AR 72212 
Attention:  General Counsel

Subject to the provisions of Section 21, any notice or demand authorized by this Agreement to be given or made by the Company or by the holder of any Rights Certificate to or on the Rights Agent shall be in writing and be sufficiently given or made if sent by overnight delivery service or first-class mail, postage prepaid, addressed (until another address is delivered in writing by the Rights Agent to the Company) as follows:
Computershare Trust Company, N.A.
250 Royall Street
Canton, MA 02021
Attention: Client Services

Notices or demands authorized by this Agreement to be given or made by the Company or the Rights Agent to the holder of any Rights Certificate (or, if prior to the Distribution Date, to the holder of certificates representing shares of Common Stock) shall be in writing and sufficiently given or made if sent by overnight delivery service or by first-class mail, postage prepaid, addressed to such holder at the address of such holder as shown on the registry books of the Company. 
Section 27.    Supplements and Amendments.  Prior to the Distribution Date, the Company and the Rights Agent shall, if the Company so directs, supplement or amend any provision of this Agreement without the approval of any holders of certificates representing shares of Common Stock, including, without limitation, to change the Final Expiration Date to another date, including an earlier date.  From and after the Distribution Date, the Company and the Rights Agent may supplement or amend this Agreement without the approval of any holders of Rights Certificates in order (i) to cure any ambiguity, (ii) to correct or supplement any provision contained herein which may be defective or inconsistent with any other provisions herein, (iii) to shorten or lengthen any time period hereunder or (iv) to change or supplement the provisions hereunder in any manner which the Company and the Rights Agent may deem necessary or desirable and which shall not adversely affect the interests of the holders of Rights Certificates (other than an Acquiring Person or an Affiliate or Associate of an Acquiring Person).  Any such supplement or amendment shall be evidenced by a writing signed by the Company and 

	
			
	 
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the Rights Agent.  As a condition precedent to the Rights Agent’s execution of any amendment, the Company shall deliver a certificate executed by an appropriate officer of the Company, which states that the proposed supplement or amendment is in compliance with the terms of this Section 27.  Prior to the Distribution Date, the interests of the holders of Rights shall be deemed coincident with the interests of the holders of Common Stock.  Notwithstanding anything herein to the contrary, this Agreement may not be amended (other than pursuant to clauses (i) or (ii) of the preceding sentence) at a time when the Rights are not redeemable.  Notwithstanding anything herein to the contrary, the Rights Agent may, but shall not be obligated to, enter into any supplement or amendment that affects the Rights Agent’s own rights, duties, obligations or immunities under this Agreement, in the sole discretion of the Rights Agent.
Section 28.    Successors.  All the covenants and provisions of this Agreement by or for the benefit of the Company or the Rights Agent shall bind and inure to the benefit of their respective successors and assigns hereunder.
Section 29.    Determinations and Actions by the Board, etc.  For all purposes of this Agreement, any calculation of the number of shares of Common Stock or any other class of capital stock outstanding at any particular time, including for purposes of determining the particular percentage of such outstanding shares of Common Stock of which any Person is the Beneficial Owner, shall be made in accordance with the last sentence of Rule 13d-3(d)(1)(i) of the General Rules and Regulations under the Exchange Act.  Without limiting the rights of the Rights Agent hereunder, the Board shall have the exclusive power and authority to administer this Agreement and to exercise all rights and powers specifically granted to the Board, or as may be necessary or advisable in the administration of this Agreement, including the right and power to (i) interpret the provisions of this Agreement, and (ii) make all determinations deemed necessary or advisable for the administration of this Agreement (including a determination to redeem or not redeem the Rights or to amend the Agreement).  All such actions, calculations, interpretations and determinations (including, for purposes of clause (y) below, all omissions with respect to the foregoing) which are done or made by the Board in good faith, shall (x) be final, conclusive and binding on the Company, the Rights Agent (except with respect to the Rights Agent’s rights, duties, obligations or immunities under this Agreement), the holders of the Rights and all other parties, and (y) not subject the Board, or any of the directors on the Board to any liability to the holders of the Rights.  In connection with the preceding sentence, the Rights Agent is entitled to assume that the Board acted in good faith with respect to all such actions, calculations, interpretations and determinations and shall be fully protected and incur no liability in reliance thereon.
Section 30.    Benefits of this Agreement.  Nothing in this Agreement shall be construed to give to any Person other than the Company, the Rights Agent and the registered holders of the Rights Certificates (and, prior to the Distribution Date, registered holders of the Common Stock) any legal or equitable right, remedy or claim under this Agreement; but this Agreement shall be for the sole and exclusive benefit of the Company, the Rights Agent and the registered holders of the Rights Certificates (and, prior to the Distribution Date, registered holders of the Common Stock).
Section 31.    Severability.  If any term, provision, covenant or restriction of this Agreement is held by a court of competent jurisdiction or other authority to be invalid, void or 

	
			
	 
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unenforceable, the remainder of the terms, provisions, covenants and restrictions of this Agreement shall remain in full force and effect and shall in no way be affected, impaired or invalidated; provided, however, that notwithstanding anything in this Agreement to the contrary, if any such term, provision, covenant or restriction is held by such court or authority to be invalid, void or unenforceable and the Board determines in its good faith judgment that severing the invalid language from this Agreement would adversely affect the purpose or effect of this Agreement, the right of redemption set forth in Section 23 hereof shall be reinstated and shall not expire until the Close of Business on the 10th Business Day following the date of such determination by the Board; and provided further, that if any such excluded term, provision, covenant or restriction shall materially and adversely affect the rights, immunities, duties or obligations of the Rights Agent, the Rights Agent shall be entitled to resign immediately. 
Section 32.    Governing Law.  This Agreement, each Right and each Rights Certificate issued hereunder shall be deemed to be a contract made under the laws of the State of Delaware and for all purposes shall be governed by and construed in accordance with the laws of such State applicable to contracts made and to be performed entirely within such State; provided, however, that all provisions, regarding the rights, duties, obligations and liabilities of the Rights Agent shall be governed by and construed in accordance with the laws of the State of New York applicable to contracts made and to be performed entirely within such State.
Section 33.    Counterparts.  This Agreement may be executed in any number of counterparts and each of such counterparts shall for all purposes be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument.  A signature to this Agreement transmitted electronically shall have the same authority, effect, and enforceability as an original signature.
Section 34.    Descriptive Headings; Interpretation.  
(a)    Descriptive headings of the several sections of this Agreement are inserted for convenience only and shall not control or affect the meaning or construction of any of the provisions hereof.  
(b)    Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”  The words “hereof,” “herein” and “herewith” and words of similar import shall, unless otherwise stated, be construed to refer to this Agreement as a whole and not to any particular provision of this Agreement, and article, section, subsection, paragraph and exhibit references are to the articles, sections, paragraphs and exhibits of this Agreement unless otherwise specified. The meaning assigned to each term defined herein shall be equally applicable to both the singular and the plural forms of such term, and words denoting any gender shall include all genders. Where a word or phrase is defined herein, each of its other grammatical forms shall have a corresponding meaning.
Section 35.    Force Majeure.  Notwithstanding anything to the contrary contained herein, the Rights Agent shall not be liable for any delays or failures in performance resulting from acts beyond its reasonable control including, without limitation, acts of God, terrorist acts, shortage of supply, breakdowns or malfunctions, interruptions or malfunction of computer 

	
			
	 
	39
	 

facilities, or loss of data due to power failures or mechanical difficulties with information storage or retrieval systems, labor difficulties, war, or civil unrest. 
[Signature page follows]

	
			
	 
	40
	 

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed, all as of the day and year first above written.
	
		
	 
	 

	WINDSTREAM HOLDINGS, INC.

	 
	 

	By:
	/s/ Anthony W. Thomas

	Name:
	Anthony W. Thomas

	Title:
	President and Chief Executive Officer

	
		
	 
	 

	COMPUTERSHARE TRUST COMPANY,
N.A., as Rights Agent

	 
	 

	By:
	/s/ Joseph S. Campbell

	Name:
	Joseph S. Campbell

	Title:
	Vice President

Exhibit A

CERTIFICATE OF DESIGNATIONS
OF
SERIES A PARTICIPATING PREFERRED STOCK
OF
WINDSTREAM HOLDINGS, INC.
Pursuant to Section 151 of the General Corporation Law 
of the State of Delaware
Windstream Holdings, Inc., a Delaware corporation (the “Corporation”), pursuant to the provisions of Sections 103 and 151 of the General Corporation Law of the State of Delaware, does hereby state and certify that pursuant to the authority vested in the Board of Directors of the Corporation (the “Board”) by the Amended and Restated Certificate of Incorporation of the Corporation, as amended, the Board on September 17, 2015 duly adopted the following resolutions creating a series of Preferred Stock designated as Series A Participating Preferred Stock: 
RESOLVED, that pursuant to the authority vested in the Board in accordance with the provisions of its Amended and Restated Certificate of Incorporation, a series of Preferred Stock, par value $0.0001 per share, of the Corporation be and hereby is created, and that the designation and amount thereof and the voting powers, preferences and relative, participating, optional and other special rights of the shares of such series, and the qualifications, limitations or restrictions thereof are as follows:
Section 1.    Designation and Amount.  The shares of such series shall be designated as “Series A Participating Preferred Stock” and the number of shares constituting such series shall be 500,000.  Such number of shares may be increased or decreased by resolution of the Board; provided, that no decrease shall reduce the number of shares of Series A Participating Preferred Stock to a number less than the number of shares then outstanding plus the number of shares reserved for issuance upon the exercise of outstanding options, rights or warrants or upon the conversion of any outstanding securities issued by the Corporation convertible into Series A Participating Preferred Stock.
Section 2.    Dividends and Distributions. 
(a)    Subject to the prior and superior rights of the holders of any shares of any series of Preferred Stock ranking prior and superior to the shares of Series A Participating Preferred Stock with respect to dividends, the holders of shares of Series A Participating Preferred Stock shall be entitled to receive, when, as and if  (such date, the “Rights Dividend Declaration Date”) declared by the Board out of funds legally available for the purpose, quarterly 

A-1

dividends payable in cash on the 15th day of April, July, November and January in each year (each such date being referred to herein as a “Quarterly Dividend Payment Date”), commencing on the first Quarterly Dividend Payment Date after the first issuance of a share or fraction of a share of Series A Participating Preferred Stock, in an amount per share (rounded to the nearest cent) subject to the provision for adjustment hereinafter set forth, equal to 10,000 times the aggregate per share amount of all cash dividends, and 10,000 times the aggregate per share amount (payable in kind) of all non-cash dividends or other distributions, declared on the common stock, par value $0.0001 per share, of the Corporation (the “Common Stock”) since the immediately preceding Quarterly Dividend Payment Date, or, with respect to the first Quarterly Dividend Payment Date, since the first issuance of any share or fraction of a share of Series A Participating Preferred Stock, other than, in each case, a dividend payable in shares of Common Stock or a subdivision of the outstanding shares of Common Stock (by reclassification or otherwise).  In the event the Corporation shall at any time after any Rights Dividend Declaration Date (i) declare any dividend on Common Stock payable in shares of Common Stock, (ii) subdivide the outstanding Common Stock, or (iii) combine the outstanding Common Stock, through a reverse stock split or otherwise, into a smaller number of shares, then in each such case the amount to which holders of shares of Series A Participating Preferred Stock were entitled immediately prior to such event under the preceding sentence shall be adjusted by multiplying such amount by a fraction the numerator of which is the number of shares of Common Stock outstanding immediately after such event and the denominator of which is the number of shares of Common Stock that were outstanding immediately prior to such event.
(b)    The Corporation shall declare a dividend or distribution on the Series A Participating Preferred Stock as provided in Paragraph (A) above immediately after it declares a dividend or distribution on the Common Stock (other than a dividend payable in shares of Common Stock).
(c)    Dividends shall begin to accrue and be cumulative on outstanding shares of Series A Participating Preferred Stock from the Quarterly Dividend Payment Date next preceding the date of issue of such shares of Series A Participating Preferred Stock, unless the date of issue of such shares is prior to the record date for the first Quarterly Dividend Payment Date, in which case dividends on such shares shall begin to accrue from the date of issue of such shares, or unless the date of issue is a Quarterly Dividend Payment Date or is a date after the record date for the determination of holders of shares of Series A Participating Preferred Stock entitled to receive a quarterly dividend and before such Quarterly Dividend Payment Date, in either of which events such dividends shall begin to accrue and be cumulative from such Quarterly Dividend Payment Date.  Accrued but unpaid dividends shall not bear interest.  Dividends paid on the shares of Series A Participating Preferred Stock in an amount less than the total amount of such dividends at the time accrued and payable on such shares shall be allocated pro rata on a share-by-share basis among all such shares at the time outstanding.  The Board may fix a record date for the determination of holders of shares of Series A Participating Preferred Stock entitled to receive payment of a dividend or distribution declared thereon, which record date shall be no more than 30 days prior to the date fixed for the payment thereof. 
Section 3.    Voting Rights.  The holders of shares of Series A Participating Preferred Stock shall have the following voting rights: 

A-2

(a)    Subject to the provision for adjustment hereinafter set forth, each share of Series A Participating Preferred Stock shall entitle the holder thereof to 10,000 votes on all matters submitted to a vote of the stockholders of the Corporation.  In the event the Corporation shall at any time after the Rights Dividend Declaration Date (i) declare any dividend on Common Stock payable in shares of Common Stock, (ii) subdivide the outstanding Common Stock, or (iii) combine the outstanding Common Stock into a smaller number of shares, through a reverse stock split or otherwise, then in each such case the number of votes per share to which holders of shares of Series A Participating Preferred Stock were entitled immediately prior to such event shall be adjusted by multiplying such number by a fraction the numerator of which is the number of shares of Common Stock outstanding immediately after such event and the denominator of which is the number of shares of Common Stock that were outstanding immediately prior to such event.
(b)    Except as otherwise provided herein or by law, the holders of shares of Series A Participating Preferred Stock and the holders of shares of Common Stock shall vote together as one class on all matters submitted to a vote of stockholders of the Corporation. 
(c)    (i)     If at any time dividends on any Series A Participating Preferred Stock shall be in arrears in an amount equal to 6 quarterly dividends thereon, the occurrence of such contingency shall mark the beginning of a period (herein called a “default period”) which shall extend until such time when all accrued and unpaid dividends for all previous quarterly dividend periods and for the current quarterly dividend period on all shares of Series A Participating Preferred Stock then outstanding shall have been declared and paid or set apart for payment.  During each default period, all holders of Preferred Stock (including holders of the Series A Participating Preferred Stock) with dividends in arrears in an amount equal to 6 quarterly dividends thereon, voting as a class, irrespective of series, shall have the right to elect 2 directors.
(ii)     During any default period, such voting right of the holders of Series A Participating Preferred Stock may be exercised initially at a special meeting called pursuant to subparagraph (iii) of this Section 3(c) or at any annual meeting of stockholders, and thereafter at annual meetings of stockholders; provided that such voting right shall not be exercised unless the holders of 10% in number of shares of Preferred Stock outstanding shall be present in person or by proxy.  The absence of a quorum of the holders of Common Stock shall not affect the exercise by the holders of Preferred Stock of such voting right.  At any meeting at which the holders of Preferred Stock shall exercise such voting right initially during an existing default period, they shall have the right, voting as a class, to elect directors to fill such vacancies, if any, in the Board as may then exist up to 2 directors or, if such right is exercised at an annual meeting, to elect 2 directors.  If the number which may be so elected at any special meeting does not amount to the required number, the holders of the Preferred Stock shall have the right to make such increase in the number of directors as shall be necessary to permit the election by them of the required number.  After the holders of the Preferred Stock shall have exercised their right to elect directors in any default period and during the continuance of such period, the number of directors shall not be increased or decreased except by vote of 

A-3

the holders of Preferred Stock as herein provided or pursuant to the rights of any equity securities ranking senior to or pari passu with the Series A Participating Preferred Stock. 
(iii)     Unless the holders of Preferred Stock shall, during an existing default period, have previously exercised their right to elect directors, the Board may order, or any stockholder or stockholders owning in the aggregate not less than 10% of the total number of shares of Preferred Stock outstanding, irrespective of series, may request, the calling of a special meeting of the holders of Preferred Stock, which meeting shall thereupon be called by the President, a Vice-President or the Secretary of the Corporation.  Notice of such meeting and of any annual meeting at which holders of Preferred Stock are entitled to vote pursuant to this Paragraph (c)(iii) shall be given to each holder of record of Preferred Stock by mailing a copy of such notice to him at his last address as the same appears on the books of the Corporation.  Such meeting shall be called for a time not earlier than 20 days and not later than 60 days after such order or request or in default of the calling of such meeting within 60 days after such order or request, such meeting may be called on similar notice by any stockholder or stockholders owning in the aggregate not less than 10% of the total number of shares of Preferred Stock outstanding.  Notwithstanding the provisions of this Paragraph (c)(iii), no such special meeting shall be called during the period within 60 days immediately preceding the date fixed for the next annual meeting of the stockholders. 
(iv)     In any default period, the holders of Common Stock, and other classes of stock of the Corporation if applicable, shall continue to be entitled to elect the whole number of directors until the holders of Preferred Stock shall have exercised their right to elect 2 directors voting as a class, after the exercise of which right (x) the directors so elected by the holders of Preferred Stock shall continue in office until their successors shall have been elected by such holders or until the expiration of the default period, and (y) any vacancy in the Board may (except as provided in Paragraph (c)(ii) of this Section 3) be filled by vote of a majority of the remaining directors theretofore elected by the holders of the class of stock which elected the director whose office shall have become vacant.  References in this Paragraph (c) to directors elected by the holders of a particular class of stock shall include directors elected by such directors to fill vacancies as provided in clause (y) of the foregoing sentence. 
(v)     Immediately upon the expiration of a default period, (x) the right of the holders of Preferred Stock as a class to elect directors shall cease, (y) the term of any directors elected by the holders of Preferred Stock as a class shall terminate, and (z) the number of directors shall be such number as may be provided for in the certificate of incorporation or by-laws irrespective of any increase made pursuant to the provisions of Paragraph (c)(ii) of this Section 3 (such number being subject, however, to change thereafter in any manner provided by law or in the certificate of incorporation or by-laws).  Any vacancies in the Board effected by the provisions of clauses (y) and (z) in the preceding sentence may be filled by a majority of the remaining directors.
(d)    Except as set forth herein, holders of Series A Participating Preferred Stock shall have no special voting rights and their consent shall not be required (except to the 

A-4

extent they are entitled to vote with holders of Common Stock as set forth herein) for taking any corporate action. 
Section 4.    Certain Restrictions.  
(a)    Whenever quarterly dividends or other dividends or distributions payable on the Series A Participating Preferred Stock as provided in Section 2 are in arrears, thereafter and until all accrued and unpaid dividends and distributions, whether or not declared, on shares of Series A Participating Preferred Stock outstanding shall have been paid in full, the Corporation shall not: 
(i)    declare or pay dividends on, make any other distributions on, or redeem or purchase or otherwise acquire for consideration any shares of stock ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Series A Participating Preferred Stock; 
(ii)    declare or pay dividends on or make any other distributions on any shares of stock ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Series A Participating Preferred Stock, except dividends paid ratably on the Series A Participating Preferred Stock and all such parity stock on which dividends are payable or in arrears in proportion to the total amounts to which the holders of all such shares are then entitled; 
(iii)    redeem or purchase or otherwise acquire for consideration shares of any stock ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Series A Participating Preferred Stock; provided that the Corporation may at any time redeem, purchase or otherwise acquire shares of any such parity stock in exchange for shares of any stock of the Corporation ranking junior (either as to dividends or upon dissolution, liquidation or winding up) to the Series A Participating Preferred Stock; or
(iv)    purchase or otherwise acquire for consideration any shares of Series A Participating Preferred Stock, or any shares of stock ranking on a parity with the Series A Participating Preferred Stock, except in accordance with a purchase offer made in writing or by publication (as determined by the Board) to all holders of such shares upon such terms as the Board, after consideration of the respective annual dividend rates and other relative rights and preferences of the respective series and classes, shall determine in good faith will result in fair and equitable treatment among the respective series or classes. 
(b)    The Corporation shall not permit any subsidiary of the Corporation to purchase or otherwise acquire for consideration any shares of stock of the Corporation unless the Corporation could, under Paragraph (a) of this Section 4, purchase or otherwise acquire such shares at such time and in such manner. 
Section 5.    Required Shares.  Any shares of Series A Participating Preferred Stock purchased or otherwise acquired by the Corporation in any manner whatsoever shall be retired 

A-5

and cancelled promptly after the acquisition thereof.  All such shares shall upon their cancellation become authorized but unissued shares of Preferred Stock and may be reissued as part of a new series of Preferred Stock to be created by resolution or resolutions of the Board, subject to the conditions and restrictions on issuance set forth herein, in the Amended and Restated Certificate of Incorporation, or in any other Certificate of Designations creating a series of preferred stock or similar stock of the Company or as otherwise required by law. 
Section 6.    Liquidation, Dissolution or Winding Up.
(a)    Upon any liquidation (voluntary or otherwise), dissolution or winding up of the Corporation, no distribution shall be made to the holders of shares of stock ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Series A Participating Preferred Stock unless, prior thereto, the holders of shares of Series A Participating Preferred Stock shall have received an amount equal to $10,000 per share of Series A Participating Preferred Stock, plus an amount equal to accrued and unpaid dividends and distributions thereon, whether or not declared, to the date of such payment (the “Series A Liquidation Preference”).  Following the payment of the full amount of the Series A Liquidation Preference, no additional distributions shall be made to the holders of shares of Series A Participating Preferred Stock unless, prior thereto, the holders of shares of Common Stock shall have received an amount per share (the “Common Adjustment”) equal to the quotient obtained by dividing (i) the Series A Liquidation Preference by (ii) 10,000 (as appropriately adjusted as set forth in subparagraph (C) below to reflect such events as stock splits, stock dividends and recapitalizations with respect to the Common Stock) (such number in clause (ii), the “Adjustment Number”).  Following the payment of the full amount of the Series A Liquidation Preference and the Common Adjustment in respect of all outstanding shares of Series A Participating Preferred Stock and Common Stock, respectively, holders of Series A Participating Preferred Stock and holders of shares of Common Stock shall receive their ratable and proportionate share of the remaining assets to be distributed in the ratio of the Adjustment Number to 1 with respect to such Preferred Stock and Common Stock, on a per share basis, respectively. 
(b)    In the event, however, that there are not sufficient assets available to permit payment in full of the Series A Liquidation Preference and the liquidation preferences of all other series of preferred stock, if any, which rank on a parity with the Series A Participating Preferred Stock, then such remaining assets shall be distributed ratably to the holders of such parity shares in proportion to their respective liquidation preferences.  In the event, however, that there are not sufficient assets available to permit payment in full of the Common Adjustment, then such remaining assets shall be distributed ratably to the holders of Common Stock. 
(c)    In the event the Corporation shall at any time after the Rights Dividend Declaration Date (i) declare any dividend on Common Stock payable in shares of Common Stock, (ii) subdivide the outstanding Common Stock, or (iii) combine the outstanding Common Stock into a smaller number of shares, through a reverse stock split or otherwise, then in each such case the Adjustment Number in effect immediately prior to such event shall be adjusted by multiplying such Adjustment Number by a fraction the numerator of which is the number of shares of Common Stock outstanding immediately after such event and the denominator of 

A-6

which is the number of shares of Common Stock that were outstanding immediately prior to such event.
Section 7.    Consolidation, Merger, etc.  In case the Corporation shall enter into any consolidation, merger, combination or other transaction in which the shares of Common Stock are exchanged for or changed into other stock or securities, cash and/or any other property, then in any such case the shares of Series A Participating Preferred Stock shall at the same time be similarly exchanged or changed in an amount per share (subject to the provision for adjustment hereinafter set forth) equal to 10,000 times the aggregate amount of stock, securities, cash and/or any other property (payable in kind), as the case may be, into which or for which each share of Common Stock is changed or exchanged.  In the event the Corporation shall at any time after the Rights Dividend Declaration Date (i) declare any dividend on Common Stock payable in shares of Common Stock, (ii) subdivide the outstanding Common Stock, or (iii) combine the outstanding Common Stock into a smaller number of shares, through a reverse stock split or otherwise, then in each such case the amount set forth in the preceding sentence with respect to the exchange or change of shares of Series A Participating Preferred Stock shall be adjusted by multiplying such amount by a fraction the numerator of which is the number of shares of Common Stock outstanding immediately after such event and the denominator of which is the number of shares of Common Stock that were outstanding immediately prior to such event.
Section 8.    No Redemption.  The shares of Series A Participating Preferred Stock shall not be redeemable.
Section 9.    Ranking.  The Series A Participating Preferred Stock shall rank junior to all other series of the Corporation’s Preferred Stock as to the payment of dividends and the distribution of assets, unless the terms of any such series shall provide otherwise. 
Section 10.    Amendment.  At any time when any shares of Series A Participating Preferred Stock are outstanding, the Amended and Restated Certificate of Incorporation of the Corporation nor this Certificate of Designation shall be amended in any manner which would materially alter or change the powers, preferences or special rights of the Series A Participating Preferred Stock so as to affect them adversely without the affirmative vote of the holders of a majority or more of the outstanding shares of Series A Participating Preferred Stock, voting separately as a class. 
Section 11.    Fractional Shares.  Series A Participating Preferred Stock may be issued in fractions of a share which shall entitle the holder, in proportion to such holder’s fractional shares, to exercise voting rights, receive dividends, participate in distributions and to have the benefit of all other rights of holders of Series A Participating Preferred Stock.

A-7

IN WITNESS WHEREOF, this Certificate of Designations is executed on behalf of the Corporation by its duly authorized officer on this 17th day of September 2015. 
	
		
	 
	 

	WINDSTREAM HOLDINGS, INC.

	 
	 

	By:
	 

	Name:
	 

	Title:
	 

A-8

Exhibit B
[Form of Rights Certificate]
Certificate No. R-________ Rights
NOT EXERCISABLE AFTER 5:00 P.M., NEW YORK CITY TIME ON _______ __, ______, UNLESS THE RIGHTS ARE PREVIOUSLY REDEEMED, EXCHANGED OR TERMINATED.  THE RIGHTS ARE SUBJECT TO REDEMPTION, AT THE OPTION OF THE COMPANY, AT $[●] PER RIGHT ON THE TERMS SET FORTH IN THE RIGHTS AGREEMENT.  UNDER CERTAIN CIRCUMSTANCES, RIGHTS BENEFICIALLY OWNED BY AN ACQUIRING PERSON (AS SUCH TERM IS DEFINED IN THE RIGHTS AGREEMENT) AND ANY SUBSEQUENT HOLDER OF SUCH RIGHTS MAY BECOME NULL AND VOID.  [THE RIGHTS REPRESENTED BY THIS RIGHTS CERTIFICATE ARE OR WERE BENEFICIALLY OWNED BY A PERSON WHO WAS OR BECAME AN ACQUIRING PERSON OR AN AFFILIATE OR ASSOCIATE OF AN ACQUIRING PERSON (AS SUCH TERMS ARE DEFINED IN THE RIGHTS AGREEMENT).  ACCORDINGLY, THIS RIGHTS CERTIFICATE AND THE RIGHTS REPRESENTED HEREBY MAY BECOME NULL AND VOID IN THE CIRCUMSTANCES SPECIFIED IN SECTION 7(e) OF SUCH AGREEMENT.] 
Rights Certificate
Windstream Holdings, Inc.
This certifies that ______________________, or registered assigns, is the registered owner of the number of Rights set forth above, each of which entitles the owner thereof, subject to the terms, provisions and conditions of the 382 Rights Agreement, dated as of September 17, 2015 (the “Rights Agreement”), as it may be amended, restated, renewed or extended from time to time, between Windstream Holdings, Inc., a Delaware corporation (the “Company”), and Computershare Trust Company, N.A., a federally chartered trust company (the “Rights Agent”), to purchase from the Company at any time prior to 5:00 P.M., New York City time on  September 17, 2018 unless the Rights are previously redeemed, exchanged or terminated, at the office or offices of the Rights Agent designated for such purpose, or its successors as Rights Agent, one ten-thousandth of a fully paid, non-assessable share of Series A Participating Preferred Stock (the “Preferred Stock”) of the Company, at a purchase price of $32.00 per one ten-thousandth of a share (the “Purchase Price”), upon presentation and surrender of this Rights Certificate with the Form of Election to Purchase and related Certificate duly executed.  The number of Rights evidenced by this Rights Certificate (and the number of shares which may be purchased upon exercise thereof) set forth above, and the Purchase Price per share set forth above, are the number and Purchase Price as of September 17, 2015, based on the Preferred Stock as constituted at such date.  The Company reserves the right to require prior to the occurrence of a Triggering Event (as such term is defined in the Rights Agreement) that a number of Rights be exercised so that only whole shares of Preferred Stock will be issued.

B-1

Upon the occurrence of a Section 11(a)(ii) Event (as such term is defined in the Rights Agreement), if the Rights evidenced by this Rights Certificate are Beneficially Owned by (i) an Acquiring Person or an Affiliate or Associate of any such Acquiring Person (as such terms are defined in the Rights Agreement), (ii) a transferee of any such Acquiring Person, Associate or Affiliate, or (iii) under certain circumstances specified in the Rights Agreement, a transferee of a person who, after such transfer, became an Acquiring Person, or an Affiliate or Associate of an Acquiring Person, such Rights shall become null and void and no holder hereof shall have any right with respect to such Rights from and after the occurrence of such Section 11(a)(ii) Event.
As provided in the Rights Agreement, the Purchase Price and the number and kind of shares of Preferred Stock or other securities, which may be purchased upon the exercise of the Rights evidenced by this Rights Certificate are subject to modification and adjustment upon the happening of certain events, including Triggering Events.
This Rights Certificate is subject to all of the terms, provisions and conditions of the Rights Agreement, which terms, provisions and conditions are hereby incorporated herein by reference and made a part hereof and to which Rights Agreement reference is hereby made for a full description of the rights, limitations of rights, obligations, duties and immunities hereunder of the Rights Agent, the Company and the holders of the Rights Certificates, which limitations of rights include the temporary suspension of the exercisability of such Rights under the specific circumstances set forth in the Rights Agreement.  Copies of the Rights Agreement are on file at the principal executive offices of the Company and the above-mentioned office of the Rights Agent.
This Rights Certificate, with or without other Rights Certificates, upon surrender at the office of the Rights Agent designated for such purpose, may be exchanged for another Rights Certificate or Rights Certificates of like tenor and date representing Rights entitling the holder to purchase a like aggregate number of 1/10,000th of a share of Preferred Stock as the Rights represented by the Rights Certificate or Rights Certificates surrendered shall have entitled such holder to purchase.  If this Rights Certificate shall be exercised in part, the holder shall be entitled to receive upon surrender hereof, along with a signature guarantee and such other and further documentation as the Company or Rights Agent may reasonably request, another Rights Certificate or Rights Certificates representing the number of whole Rights not exercised.
Subject to the provisions of the Rights Agreement, the Rights represented by this Certificate may be redeemed by the Company at its option at any time prior to the earlier of (A) the Distribution Date (as such term is defined in the Rights Agreement), and (B) the Final Expiration Date (as such term is defined in the Rights Agreement), at a redemption price of $0.0001 per Right. 
No fractional shares of Preferred Stock will be issued upon the exercise of any Right or Rights evidenced hereby (other than fractions which are integral multiples of one ten-thousandth of a share of Preferred Stock, which may, at the election of the Company, be evidenced by depositary receipts), but in lieu thereof a cash payment will be made, as provided in the Rights Agreement.  The Company, at its election, may require that a number of Rights be exercised so that only whole shares of Preferred Stock would be issued.

B-2

No holder of this Rights Certificate shall be entitled to vote or receive dividends or be deemed for any purpose the holder of shares of Preferred Stock or of any other securities of the Company which may at any time be issuable on the exercise hereof, nor shall anything contained in the Rights Agreement or herein be construed to confer upon the holder hereof, as such, any of the rights of a stockholder of the Company or any right to vote for the election of directors or upon any matter submitted to stockholders at any meeting thereof, or to give consent to or withhold consent from any corporate action, or, to receive notice of meetings or other actions affecting stockholders (except as provided in the Rights Agreement), or to receive dividends or subscription rights, or otherwise, until the Right or Rights evidenced by this Rights Certificate shall have been exercised as provided in the Rights Agreement.
This Rights Certificate shall not be valid or obligatory for any purpose until it shall have been countersigned by the Rights Agent.

B-3

WITNESS the facsimile signature of the proper officers of the Company and its corporate seal.
Dated as of _________ __, ____.
	
					
	ATTEST:
	 
	Windstream Holdings, Inc.

	 
	 
	 
	 
	 

	 
	 
	 
	By:
	 

	Secretary
	 
	 
	Title:

	 
	 
	 
	 
	 

	Countersigned:
	 
	 
	 

	[•]
	 
	 
	 

	 
	 
	 
	 
	 

	By:
	 
	 
	 
	 

	 
	 Authorized Signature
	 
	 
	 

[Form of Reverse Side of Rights Certificate]
FORM OF ASSIGNMENT
(To be executed by the registered holder if such holder desires to transfer the Rights Certificate.)
	
		
	FOR VALUE RECEIVED
	 

	hereby sells, assigns and transfers unto
	 

	 
	 

	 (Please print name and address of transferee)

	 
	 

	 
	 

this Rights Certificate, together with all right, title and interest therein, and does hereby irrevocably constitute and appoint __________________ Attorney, to transfer the within Rights Certificate on the books of the within named Company, with full power of substitution.
Dated: __________________,__
___________________________________ 
Signature
Signature Guaranteed:
Signatures must be guaranteed by a participant in the Securities Transfer Agent Medallion Program, the Stock Exchanges Medallion Program or the New York Stock Exchange, Inc. Medallion Signature Program. A notary public is not sufficient.

B-4

Certificate
The undersigned hereby certifies by checking the appropriate boxes that:
(1) this Rights Certificate [ ] is [ ] is not being sold, assigned and transferred by or on behalf of a Person who is or was an Acquiring Person or an Affiliate or Associate of any such Acquiring Person (as such terms are defined pursuant to the Rights Agreement);
(2) after due inquiry and to the best knowledge of the undersigned, it [ ] did [ ] did not acquire the Rights evidenced by this Rights Certificate from any Person who is, was or subsequently became an Acquiring Person or an Affiliate or Associate of an Acquiring Person.
	
			
	Dated: _______________, __
	 
	_______________________________ 
Signature:

Signature Guaranteed:
Signatures must be guaranteed by a participant in the Securities Transfer Agent Medallion Program, the Stock Exchanges Medallion Program or the New York Stock Exchange, Inc. Medallion Signature Program. A notary public is not sufficient.

B-5

NOTICE
The signature to the foregoing Assignment and Certificate must correspond to the name as written upon the face of this Rights Certificate in every particular, without alteration or enlargement or any change whatsoever.

B-6

FORM OF ELECTION TO PURCHASE
(To be executed if holder desires to exercise Rights  
represented by the Rights Certificate.)
To: WINDSTREAM HOLDINGS, INC.
The undersigned hereby irrevocably elects to exercise __________ Rights represented by this Rights Certificate to purchase the shares of Preferred Stock issuable upon the exercise of the Rights (or such other securities of the Company or of any other person which may be issuable upon the exercise of the Rights) and requests that certificates for such shares be issued in the name of and delivered to:
Please insert social security  
or other identifying number
	
					
	 
	 
	 
	 
	 

	(Please print name and address)

	 
	 
	 
	 
	 

	 
	 
	 
	 
	 

If such number of Rights shall not be all the Rights evidenced by this Rights Certificate, a new Rights Certificate for the balance of such Rights shall be registered in the name of and delivered to:
Please insert social security 
or other identifying number
	
					
	 
	 
	 
	 
	 

	(Please print name and address)

	 
	 
	 
	 
	 

	 
	 
	 
	 
	 

	 
	 
	 
	 
	 

Dated: _______________,__
_______________________________
Signature: 
Signature Guaranteed:
Signatures must be guaranteed by a participant in the Securities Transfer Agent Medallion Program, the Stock Exchanges Medallion Program or the New York Stock Exchange, Inc. Medallion Signature Program. A notary public is not sufficient.

B-7

Certificate
The undersigned hereby certifies by checking the appropriate boxes that:
(1) the Rights evidenced by this Rights Certificate [ ] are [ ] are not being exercised by or on behalf of a Person who is or was an Acquiring Person or an Affiliate or Associate of any such Acquiring Person (as such terms are defined pursuant to the Rights Agreement);
(2) after due inquiry and to the best knowledge of the undersigned, it [ ] did [ ] did not acquire the Rights evidenced by this Rights Certificate from any Person who is, was or became an Acquiring Person or an Affiliate or Associate of an Acquiring Person.
Dated: _______________,__
_______________________________
Signature: 
Signature Guaranteed:
Signatures must be guaranteed by a participant in the Securities Transfer Agent Medallion Program, the Stock Exchanges Medallion Program or the New York Stock Exchange, Inc. Medallion Signature Program. A notary public is not sufficient.

B-8

NOTICE
The signature to the foregoing Election to Purchase and Certificate must correspond to the name as written upon the face of this Rights Certificate in every particular, without alteration or enlargement or any change whatsoever. 

B-9

Exhibit C
FORM OF 
SUMMARY OF RIGHTS TO PURCHASE 
STOCK UNDER 382 RIGHTS AGREEMENT
On September 17, 2015, the Board of Directors (the “Board”) of Windstream Holdings, Inc. (the “Company”) authorized and declared a dividend distribution of one right (a “Right”) for each outstanding share of Common Stock, par value $0.0001 per share, of the Company (the “Common Stock”), to stockholders of record at the close of business on September 28, 2015 (the “Record Date”).  Each Right entitles the registered holder to purchase from the Company a unit consisting of one ten-thousandth of a share (a “Unit”) of Series A Participating Preferred Stock, par value $0.0001 per share (the “Preferred Stock”) at a purchase price of $32.00 per Unit, subject to adjustment (the “Purchase Price”).  The description and terms of the Rights are set forth in a 382 Rights Agreement, dated as of September 17, 2015 (the “Rights Agreement”), by and between the Company and Computershare Trust Company, N.A., a federally chartered trust company, as Rights Agent.  The Rights are intended to reduce the likelihood of an “ownership change” within the meaning of Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”), and thereby preserve the current ability of the Company to utilize certain net operating loss carryovers and other tax benefits of the Company and its subsidiaries (the “Tax Benefits”).
Initially, the Rights will be attached to the shares of Common Stock underlying the balances indicated in the book-entry account system of the transfer agent for the Common Stock or, in the case of certificated shares, all Common Stock certificates representing shares then outstanding, and no separate rights certificates (“Rights Certificates”) will be distributed.  Subject to certain exceptions specified in the Rights Agreement, the Rights will separate from the Common Stock and a distribution date (a “Distribution Date”) will occur upon the earlier of (i) 15 business days (or such later date as the Board shall determine) following a public announcement that a person or group of affiliated or associated persons has become an Acquiring Person (as described below) or (ii) 15 business days (or such later date as the Board shall determine) following the commencement of a tender offer, exchange offer or other transaction that, upon consummation thereof, would result in a person or group of affiliated or associated persons becoming an Acquiring Person.  Until the Distribution Date, (A) the Rights will be evidenced by the balances indicated in the book-entry account system of the transfer agent for the Common Stock registered in the names of the holders of the Common Stock or, in the case of certificated shares, the Common Stock certificates, and will be transferred with and only with such shares or, in the case of certificated shares, Common Stock certificates, (B) confirmation and account statements sent to the holders of shares of Common Stock in book-entry form or, in the case of certificated shares, new Common Stock certificates issued after the Record Date, will contain a notation incorporating the Rights Agreement by reference and (C) the transfer of any shares of Common Stock or, in the case of certificated shares, certificates for Common Stock, outstanding will also constitute the transfer of the Rights associated with such shares of Common Stock or, in the case of certificated shares, the Common Stock represented by such certificates.  Pursuant to the Rights Agreement, the Company reserves the right to require prior to the occurrence of a Triggering Event (as defined below) that, upon any exercise of Rights, a number of Rights be exercised so that only whole shares of Preferred Stock will be issued. 

C-1

An Acquiring Person is any person or group of affiliated or associated persons who is or becomes the beneficially owner of 4.90% or more of the shares of Common Stock outstanding other than as a result of repurchases of stock by the Company, dividends or distributions by the Company or certain inadvertent actions by stockholders.  Beneficial ownership is determined as provided in the Rights Agreement and generally includes, without limitation, any ownership of securities a Person would be deemed to actually or constructively own for purposes of Section 382 of the Code or the Treasury Regulations promulgated thereunder, including all of the shares of Common Stock that a Person would have had the right or the obligation to acquire (whether such right is exercisable, or such obligation is required to be performed,  immediately or only after the passage of time or upon the satisfaction of conditions).  The Rights Agreement provides that the following shall not be deemed an Acquiring Person for purposes of the Rights Agreement: (i) the Company or any Subsidiary of the Company and any employee benefit plan of the Company, or of any Subsidiary of the Company, or any Person or entity organized, appointed or established by the Company for or pursuant to the terms of any such plan; or (ii) any person (each such person, an “Existing Holder”) that, as of September 17, 2015, is (A) the beneficial owner of between 4.90% and 5.01% of the shares of Common Stock outstanding unless and until such Existing Holder acquires beneficial ownership of one or more additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding shares of Common Stock or pursuant to a split or subdivision of the outstanding shares of Common Stock) or (B) the beneficial owner of 5.01% or more of Common Stock outstanding unless and until such Existing Holder acquires beneficial ownership of 1% or more of additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding shares of Common Stock or pursuant to a split or subdivision of the outstanding shares of Common Stock).
The Rights Agreement provides that a Person shall not become an Acquiring Person for purpose of the Rights Agreement in a transaction that the Board determines, in its sole discretion, is exempt from the Rights Agreement, which determination shall be made in the sole and absolute discretion of the Board, upon request by any Person prior to the date upon which such Person would otherwise become an Acquiring Person, including, without limitation, if the Board determines that (i) neither the beneficial ownership of shares of Common Stock by such Person, directly or indirectly, as a result of such transaction nor any other aspect of such transaction would jeopardize or endanger the availability to the Company of the Tax Benefits or (ii) such transaction is otherwise in the best interests of the Company.  
The Rights are not exercisable until the Distribution Date and will expire on the earliest of (i) 5:00 P.M., New York City time on September 17, 2018 (the “Final Expiration Date”), (ii) the time at which the Rights are redeemed or exchanged as provided in the Rights Agreement, (iii) the date on which the Board determines in its sole discretion that this Agreement is no longer necessary for the preservation of material valuable Tax Benefits, (iv) the beginning of a taxable year of the Company to which the Board determines in its sole discretion that no Tax Benefits may be carried forward, (v) September 17, 2016 if the affirmative vote of the majority of the votes cast at the 2016 annual meeting of the Company’s shareholders has not been obtained with respect to the ratification of the Rights Agreement or (vi) the date on which the Board determines in its sole discretion that the Rights Agreement is no longer in the best interest of the Company and its stockholders.  

C-2

As soon as practicable after the Distribution Date, Rights Certificates will be mailed to holders of record of the Common Stock as of the close of business on the Distribution Date and, thereafter, the separate Rights Certificates alone will represent the Rights. 
In the event that a person or group of affiliated or associated persons becomes an Acquiring Person, each holder of a Right will thereafter have the right to receive, upon exercise on or after the Distribution Date, Common Stock (or, in certain circumstances, cash, property or other securities of the Company) having a value equal to two times the exercise price of the Right.  Notwithstanding any of the foregoing, following the occurrence of the event set forth in this paragraph, all Rights that are, or (under certain circumstances specified in the Rights Agreement) were, Beneficially Owned by any Acquiring Person will be null and void.  
For example, at an exercise price of $32.00 per Right, each Right not owned by an Acquiring Person (or by certain related parties) following the event set forth in the preceding paragraph would entitle its holder to purchase $64.00 worth of Common Stock (or other consideration, as noted above) for $32.00.  Assuming that the Common Stock had a per share value of $8.00 at such time, the holder of each valid Right would be entitled to purchase eight shares of Common Stock for $32.00. 
In the event that, at any time following the first date of public announcement that a person has become an Acquiring Person or that discloses information which reveals the existence of an Acquiring Person or such earlier date as a majority of the Board becomes aware of the existence of an Acquiring Person (any such date, the “Stock Acquisition Date”), (i) the Company engages in a merger or other business combination transaction in which the Company is not the surviving corporation, (ii) the Company engages in a merger or other business combination transaction in which the Company is the surviving corporation and the Common Stock of the Company is changed or exchanged, or (iii) other than pursuant to a pro rata dividend and/or distribution to all of the then current holders of Common Stock, 50% or more of the Company’s assets, cash flow or earning power is sold or transferred, each holder of a Right (except Rights which have previously been voided as set forth above) shall thereafter have the right to receive, upon exercise, common stock of the acquiring company having a value equal to two times the Purchase Price.  The events set forth in this paragraph and in the second preceding paragraph are referred to as the “Triggering Events.” 
At any time after the Stock Acquisition Date, the Board may, exchange the Rights (other than Rights owned by such person or group which have become null and void), in whole or in part, for Common Stock or Preferred Stock at an exchange ratio of one share of Common Stock, or one ten-thousandth of a share of Preferred Stock (or of a share of a class or series of the Company’s preferred stock having equivalent rights, preferences and privileges), per Right (subject to adjustment).
The Purchase Price payable, and the number of Units of Preferred Stock or other securities or property issuable, upon exercise of the Rights are subject to adjustment from time to time to prevent dilution (i) in the event of a stock dividend on, or a subdivision, combination or reclassification of, the Preferred Stock, (ii) if holders of the Preferred Stock are granted certain rights to subscribe for Preferred Stock or convertible securities at less than the current market price of the Preferred Stock, or (iii) upon the distribution to holders of the Preferred Stock of 

C-3

evidences of indebtedness or assets (excluding regular quarterly cash dividends) or of subscription rights (other than those referred to above).
With certain exceptions, no adjustment in the Purchase Price will be required until cumulative adjustments amount to at least 1% of the Purchase Price.  No fractional Units will be issued and, in lieu thereof, an adjustment in cash will be made based on the market price of the Preferred Stock on the last trading date prior to the date of exercise.
At any time until the earlier of (A) the Distribution Date or (B) the Final Expiration Date, the Company may redeem the Rights in whole, but not in part, at a price of $0.0001 per Right.  Immediately upon the action of the Board ordering redemption of the Rights, the Rights will terminate and the only right of the holders of Rights will be to receive the $0.0001 redemption price.
Until a Right is exercised, the holder thereof, as such, will have no separate rights as a stockholder of the Company, including the right to vote or to receive dividends in respect of Rights.  While the distribution of the Rights generally should not be taxable to stockholders or to the Company, stockholders may, depending upon the circumstances, recognize taxable income in the event that the Rights become exercisable for Common Stock (or other consideration) of the Company or for common stock of the acquiring company or in the event of the redemption of the Rights as set forth above. 
Any of the provisions of the Rights Agreement may be amended by the Board and the Rights Agent prior to the Distribution Date, including, without limitation, to change the Final Expiration Date to another date, including an earlier date.  After the Distribution Date, the provisions of the Rights Agreement may be amended by the Board and the Rights Agent in order to cure any ambiguity, to make changes which do not adversely affect the interests of holders of Rights, or to shorten or lengthen any time period under the Rights Agreement.  
A copy of the Rights Agreement has been or will be filed with the Securities and Exchange Commission as an Exhibit to a Registration Statement on Form 8-A or Current Report on Form 8-K.  A copy of the Rights Agreement is available free of charge from the Rights Agent.  This summary description of the Rights does not purport to be complete and is qualified in its entirety by reference to the Rights Agreement, which is incorporated herein by reference.

C-4EX-10.17

 Exhibit 10.17 

FOIA CONFIDENTIAL TREATMENT REQUESTED 

RESEARCH COLLABORATION AGREEMENT 

BETWEEN 
 CYTOMX
THERAPEUTICS, INC. 
 AND 

IMMUNOGEN, INC. 

JANUARY 8, 2014 
 ***Certain
information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 TABLE OF CONTENTS 

 

									
	 	  	 	  	 	  	Page	 
			
	 1.
	  	 DEFINITIONS
	  	 	1	 
			
	 2.
	  	 RESEARCH PROGRAM
	  	 	14	 
				
		  	 2.1.
	  	 Selection of Research Program Targets
	  	 	14	 
				
		  	 2.2.
	  	 Scope and Conduct of the Research Program
	  	 	16	 
				
		  	 2.3.
	  	 Work Plans
	  	 	16	 
				
		  	 2.4.
	  	 Governance of the Research Program
	  	 	18	 
				
		  	 2.5.
	  	 Alliance Managers
	  	 	19	 
				
		  	 2.6.
	  	 Conformance with Law
	  	 	19	 
				
		  	 2.7.
	  	 Personnel Matters
	  	 	20	 
				
		  	 2.8.
	  	 Debarment Certification
	  	 	20	 
				
		  	 2.9.
	  	 Records
	  	 	20	 
				
		  	 2.10.
	  	 Transfer and Use of Proprietary Materials
	  	 	20	 
			
	 3.
	  	 OPTION FOR LICENSE AND COMMERCIAL LICENSE GRANTS.
	  	 	21	 
				
		  	 3.1.
	  	 Grants to ImmunoGen
	  	 	21	 
				
		  	 3.2.
	  	 Grants to CytomX
	  	 	24	 
				
		  	 3.3.
	  	 Section 365(n) of Bankruptcy Code
	  	 	26	 
				
		  	 3.4.
	  	 No Implied Rights
	  	 	26	 
			
	 4.
	  	 EXPENSES
	  	 	27	 
				
		  	 4.1.
	  	 Expenses
	  	 	27	 
			
	 5.
	  	 INTELLECTUAL PROPERTY.
	  	 	27	 
				
		  	 5.1.
	  	 Inventions
	  	 	27	 

  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 i 

									
				
		  	 5.2.
	  	 Filing, Prosecution and Maintenance of Patent Rights
	  	 	28	 
				
		  	 5.3.
	  	 Joint Research Agreement
	  	 	32	 
			
	 6.
	  	 CONFIDENTIALITY
	  	 	32	 
				
		  	 6.1.
	  	 Confidentiality
	  	 	32	 
				
		  	 6.2.
	  	 Authorized Disclosure
	  	 	33	 
				
		  	 6.3.
	  	 Public Announcements; Publications
	  	 	34	 
			
	 7.
	  	 REPRESENTATIONS AND WARRANTIES
	  	 	36	 
				
		  	 7.1.
	  	 Mutual Representations and Warranties
	  	 	36	 
				
		  	 7.2.
	  	 Representations and Warranties of CytomX
	  	 	36	 
				
		  	 7.3.
	  	 Representations and Warranties of ImmunoGen
	  	 	37	 
				
		  	 7.4.
	  	 Government Approvals
	  	 	37	 
				
		  	 7.5.
	  	 Further Covenants
	  	 	38	 
				
		  	 7.6.
	  	 Representation by Legal Counsel
	  	 	38	 
				
		  	 7.7.
	  	 Warranty Disclaimers
	  	 	38	 
			
	 8.
	  	 TERM AND TERMINATION.
	  	 	38	 
				
		  	 8.1.
	  	 Term
	  	 	38	 
				
		  	 8.2.
	  	 Termination by Either Party for Cause
	  	 	39	 
				
		  	 8.3.
	  	 Termination on Insolvency
	  	 	39	 
				
		  	 8.4.
	  	 Effects of Expiration or Termination
	  	 	39	 
				
		  	 8.5.
	  	 Effect of Expiration of this Agreement
	  	 	41	 
				
		  	 8.6.
	  	 Remedies
	  	 	42	 
				
		  	 8.7.
	  	 Survival of Certain Obligations
	  	 	42	 

  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 ii 

									
			
	 9.
	  	 LIMITATION ON LIABILITY, INDEMNIFICATION AND INSURANCE.
	  	 	42	 
				
		  	 9.1.
	  	 No Consequential Damages
	  	 	42	 
				
		  	 9.2.
	  	 Indemnification by ImmunoGen
	  	 	42	 
				
		  	 9.3.
	  	 Indemnification by CytomX
	  	 	43	 
				
		  	 9.4.
	  	 Procedure
	  	 	43	 
				
		  	 9.5.
	  	 Insurance
	  	 	44	 
			
	 10.
	  	 MISCELLANEOUS.
	  	 	45	 
				
		  	 10.1.
	  	 Assignment
	  	 	45	 
				
		  	 10.2.
	  	 Further Actions
	  	 	45	 
				
		  	 10.3.
	  	 Force Majeure
	  	 	45	 
				
		  	 10.4.
	  	 Notices
	  	 	45	 
				
		  	 10.5.
	  	 Amendment
	  	 	46	 
				
		  	 10.6.
	  	 Waiver
	  	 	46	 
				
		  	 10.7.
	  	 Severability
	  	 	47	 
				
		  	 10.8.
	  	 Descriptive Headings
	  	 	47	 
				
		  	 10.9.
	  	 Dispute Resolution
	  	 	47	 
				
		  	 10.10.
	  	 Patent Disputes and Disputes Relating to Article 6
	  	 	49	 
				
		  	 10.11.
	  	 Governing Law
	  	 	50	 
				
		  	 10.12.
	  	 Entire Agreement
	  	 	50	 
				
		  	 10.13.
	  	 Purpose and Scope
	  	 	50	 
				
		  	 10.14.
	  	 Counterparts
	  	 	50	 
				
		  	 10.15.
	  	 No Third Party Rights or Obligations
	  	 	50	 
				
		  	 10.16.
	  	 Interpretation
	  	 	50	 

  
 ***Certain information contained herein has been
omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 iii 

 EXHIBITS 

Exhibit A – CytomX Research Program Target 

Exhibit B – Form of Joint Press Release 

Exhibit C – Form of License Agreement where CytomX is licensing the ImmunoGen Technology upon exercise of the CytomX Option 

Exhibit D – Form of License where ImmunoGen is licensing the CytomX Technology upon exercise of an ImmunoGen Option 

Exhibit E – Form of Work Plan 
 Exhibit F –
Representatives to the Joint Research Committee 
 Schedule 1.104 – List of Cytotoxic Compound Patent Rights 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 RESEARCH COLLABORATION AGREEMENT 

This Research Collaboration Agreement (the “Agreement”) is entered into as of January 8, 2014 (the “Effective
Date”), by and between CytomX Therapeutics, Inc., a corporation organized and existing under the laws of Delaware and having a place of business at 343 Oyster Point Blvd., Suite 100, South San Francisco, California, 94080 United
States (“CytomX”) and ImmunoGen, Inc., a corporation organized and existing under the laws of Massachusetts and having a p lace of business at 830 Winter Street, Waltham, Massachusetts, 02451 (“ImmunoGen”).
CytomX and ImmunoGen may each be referred to herein individually as a “Party” and collectively as the “Parties.” 

WHEREAS, ImmunoGen is engaged in the development of novel, targeted anti-cancer therapeutic products using tumor-targeting monoclonal
antibodies to deliver cancer-cell killing agents and has developed and owns proprietary rights to certain Cytotoxic Compound and Linker (both as defined below) technology; 

WHEREAS, CytomX has developed and owns proprietary rights to certain technology relating to a proprietary platform to enable the development
of fully recombinant, protease-activated monoclonal antibodies, including Probodies (as defined below); and 
 WHEREAS, ImmunoGen and CytomX
desire to collaborate to discover and research novel Probodies and Probody drug conjugates active against certain designated targets and to provide for each Party to further research, develop, manufacture and commercialize Probody drug conjugates,
as provided for herein. 
 NOW THEREFORE, in consideration of the mutual promises and covenants set forth below and other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, the Parties hereby agree as follows: 
  

	1.	DEFINITIONS. 

 When used in this Agreement, the following capitalized terms shall have
the meanings set forth in this Article 1. 
 1.1. “ADC” means a compound that incorporates, is comprised of or
is otherwise derived from an Antibody (or other cell-binding moiety) conjugated to a Payload using a Linker, other than a PDC. 
 1.2.
“Affiliate” means, with respect to any Person, any other Person that controls, is controlled by or is under common control with such Person. A Person shall be regarded as in control of another entity if it owns or controls at least
fifty percent (50%) of the equity securities of the subject entity entitled to vote in the election of directors (or, in the case of an entity that is not a corporation, for the election of the corresponding managing authority), provided,
however, that the term “Affiliate” shall not include subsidiaries or other entities in which a Party or its Affiliates owns a majority of the ordinary voting 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 1 

 
power necessary to elect a majority of the board of directors or other managing authority, but is restricted from electing such majority by contract or otherwise, until such time as such
restrictions are no longer in effect. A Person shall be deemed an Affiliate only so long as it satisfies the foregoing definition. 
 1.3.
“Agreement PDC” means any PDC created or developed in the course of the Research Program. 
 1.4. “Agreement
Probody” means any Probody that is created or developed in the course of the Research Program to Target a Research Program Target. 

1.5. “Alliance Manager” is defined in Section 2.5 hereof. 

1.6. “Antibody” means a molecule which comprises or contains: (a) one or more immunoglobulin variable domains; or
(b) fragments, variants, modifications or derivatives of such immunoglobulin variable domains irrespective of origin or source, including but not limited to antigen binding portions including Fab, Fab’, F(ab’)2, Fv, dAb and CDR
fragments, single chain antibodies (scFv), chimeric antibodies, monospecific antibodies, diabodies and polypeptides (including humanized versions thereof) that contain at least a portion of an immunoglobulin that is sufficient to confer specific
antigen binding to the polypeptide. For clarity, as used in this Agreement, the term “Antibody” shall not include Probodies or PDCs. 

1.7. “Applicable Law” means the laws, statutes, rules, regulations, guidelines, or other requirements that may be in effect
from time to time and apply to a particular activity contemplated hereby, including any such laws, statutes, rules, regulations, guidelines or other requirements of the FDA or the EMA or any applicable securities regulatory authorities or national
securities exchanges or securities listing organizations. 
 1.8. “Bankruptcy Code” is defined in Section 3.3
hereof. 
 1.9. “Binding Obligation” means, with respect to a Party (a) any oral or written agreement or arrangement
that binds or legally affects such Party’s operations or property, including any assignment, license agreement, loan agreement, guaranty, or financing agreement; (b) the provisions of such Party’s charter, bylaws or other
organizational documents or (c) any order, writ, injunction, decree or judgment of any court or Governmental Authority entered against such Party or by which any of such Party’s operations or property are bound. 

1.10. Business Day” means a day other than a Saturday, a Sunday or other day on which banking institutions in Boston, Massachusetts
or San Francisco, California are required to be closed or are actually closed with legal authorization. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 2 

 1.11. “Calendar Quarter” means the respective periods of three
(3) consecutive calendar months ending on March 31, June 30, September 30 or December 31, for so long as this Agreement is in effect. 

1.12. “Calendar Year” means each successive period of twelve (12) calendar months commencing on January 1 and ending
on December 31. 
 1.13. “Commercially Reasonable Efforts” means, with respect to the efforts to be expended by a Party
with respect to any objective, those reasonable, good faith efforts to accomplish such objective as such Party would normally use to accomplish a similar objective under similar circumstances. 

1.14. “Confidential Information” of a Party means (a) with respect to ImmunoGen, (i) the identity of the ImmunoGen
Research Program Targets and (ii) the identification by ImmunoGen of any Target proposed by CytomX to be a Replacement Target as an ImmunoGen Excluded Target, (b) with respect to CytomX, (i) the identity of the CytomX Research Program
Target and (ii) the identification by CytomX of any Target proposed by ImmunoGen to be a Replacement Target as a CytomX Excluded Target, and (c) with respect to both Parties, all Know-How or other information, including proprietary
information and materials (whether or not patentable) regarding such Party’s technology, products, business or objectives, that is communicated in any way or form by or on behalf of such Party (in such capacity, the “Disclosing
Party”) to the other Party (in such capacity, the “Receiving Party”) or to any of the Receiving Party’s or its Affiliates’ employees, consultants or subcontractors (collectively,
“Representatives”), either prior to or after the Effective Date of this Agreement (including any information disclosed pursuant to the Confidentiality Agreement), and whether or not such Know-How or other information is identified
as confidential at the time of disclosure. The terms and conditions of this Agreement shall be deemed to be the Confidential Information of each Party. Confidential Information within the CytomX Program Technology shall be deemed to be the
Confidential Information of CytomX. Confidential Information within the ImmunoGen Program Technology shall be deemed to be the Confidential Information of ImmunoGen. Confidential Information within the Joint Improvements shall be deemed to be the
Confidential Information of each Party. Certain other information is designated as Confidential Information throughout this Agreement and is included in this definition. 

1.15. “Confidentiality Agreement” means that certain Mutual Confidential Disclosure Agreement between the Parties effective as
of March 21, 2013. 
 1.16. “Conjugation Probody Platform Improvements” is defined in Section 1.104 hereof.

  
 ***Certain information contained herein has been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 3 

 1.17. “Control” or “Controlled” means, with respect to any
(a) item of information, including Know-How, (b) intellectual property right, or (c) Proprietary Material, the possession (whether by ownership interest or license, other than pursuant to this Agreement) by a Party of the ability to
grant to the other Party access to or a license under such item, right or material, as provided herein, without violating the terms of any agreement or other arrangements with any Third Party. 

1.18. “Covered Results” is defined in Section 6.3.2 hereof. 

1.19. “CytomX Activities” means the Work Plan Activities that are to be undertaken by CytomX or its Affiliates. 

1.20. “CytomX Agreement PDCs” means Agreement PDCs that Target the CytomX Research Program Target. 

1.21. “CytomX Background Technology” means any Proprietary Material, Patent Right, Know-How or other intellectual property
right that is (a) owned or Controlled by CytomX or any Affiliate of CytomX and (b) exists as of and/or was conceived prior to the Effective Date or is developed or obtained by CytomX or any of its Affiliates independently of this
Agreement without the use of ImmunoGen’s Confidential Information. For purposes of clarity, CytomX Background Technology includes CytomX Proprietary Materials, but does not include Agreement PDCs or ImmunoGen Probodies, although the Parties
acknowledge that CytomX Background Technology may be incorporated into Agreement PDCs and ImmunoGen Probodies. 
 1.22. “CytomX
Excluded Target” means any Target as to which (a) CytomX or an Affiliate of CytomX is pursuing a CytomX Internal Program with respect to such Target, (b) CytomX has granted, or is obligated to grant, an option or license to a
Third Party under any [***] or [***] by CytomX that are necessary or useful for the development, manufacture, use or sale of any compound or product that [***] (as used in this definition, a “Third Party Right”), (c) CytomX has
entered into a [***] agreement or [***] with a Third Party that is in effect as of the date of CytomX’s receipt of a Proposed Target Notice from ImmunoGen, that [***] CytomX from [***] the [***] in the [***] or [***] to [***] a [***] for the
[***] on the terms and conditions of this Agreement or (d) CytomX is in [***] discussions with a Third Party with respect to [***] in which confidential information has been shared under the terms of a written confidential
disclosure agreement entered into by CytomX and such Third Party within the [***]-day period immediately preceding the date of CytomX’s receipt of the applicable Proposed Target Notice from ImmunoGen. A Target shall be deemed a CytomX Excluded
Target only so long as it satisfies the foregoing definition. 
  
 ***Certain
information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 4 

 1.23. “CytomX Indemnified Party” is defined in Section 9.2 hereof.

 1.24. “CytomX Internal Product Candidate” means any cell-binding agent (which may or may not be a Probody), which may be
unconjugated or conjugated to a cell-killing or cell-modulating agent (other than a Cytotoxic Compound). 
 1.25. “CytomX Internal
Program” means a bona fide internal research, development or commercialization undertaken by CytomX with respect to a Target, with respect to which [***]. 

1.26. “CytomX License Agreement” means the written license agreement in the form of Exhibit C attached hereto that
will be entered into by the Parties upon CytomX’s exercise of the CytomX Option. 
 1.27. “CytomX Licensed Intellectual
Property” means any and all intellectual property (including Patent Rights and Know-How) owned or Controlled by CytomX, including the CytomX Technology, that is necessary or useful for ImmunoGen to conduct the ImmunoGen Activities.
Notwithstanding the foregoing, CytomX Licensed Intellectual Property shall not include Tools. 
 1.28. “CytomX Licensed
Product” means a PDC having a Payload that is a Cytotoxic Compound and Targeting a CytomX Licensed Target. 
 1.29. “CytomX
Licensed Target” is defined in Section 3.2.3 hereof. 
 1.30. “CytomX Option” is defined in
Section 3.2.1 hereof. 
 1.31. “CytomX Option Exercise Cut-Off Date” is defined in Section 3.2.2
hereof. 
 1.32. “CytomX Option Exercise Date” is defined in Section 3.2.2 hereof. 

1.33. “CytomX Patent Right” means any Patent Right comprised in the CytomX Technology. 

1.34. “CytomX Program Technology” means any Program Technology (other than Joint Program Technology) the inventors of which
are employees, agents or independent contractors of CytomX or any of its Affiliates. 
 1.35. “CytomX Proprietary Materials”
means biological materials (including any Probodies, Masks or Substrates) and other tangible research materials owned or Controlled by CytomX and provided by CytomX to ImmunoGen under this Agreement. Agreement PDCs and ImmunoGen Probodies, in and of
themselves, will not be considered to be CytomX Proprietary Materials, although the Parties acknowledge that CytomX Proprietary Materials may be incorporated into Agreement PDCs and ImmunoGen Probodies. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 5 

 1.36. “CytomX Research Program Target” means the Target selected by CytomX
(other than an ImmunoGen Excluded Target) for inclusion in the Research Program in accordance with Section 2.1 hereof. A Target ceases to be a CytomX Research Program Target once (a) it has become the subject of a Development and
Commercialization License in accordance with Section 3.2.2 hereof or (b) it has been dropped from the Research Program in accordance with Section 2.1.3 hereof. 

1.37. “CytomX TAP Platform Improvements” means any TAP Platform Improvements (other than TAP Platform Improvements comprised
in the Joint Program Technology) the inventors of which (alone or with others) area employees of, or others obligated to assign inventions to, CytomX or any of its Affiliates or Permitted Third Party Service Providers pursuant to the conduct of the
Research Program. 
 1.38. “CytomX Technology” means, collectively, the CytomX Background Technology and the CytomX Program
Technology. 
 1.39. “Cytotoxic Compound” means [***] Compounds and [***] Compounds. 

1.40. “Development and Commercialization License” means a license under the intellectual property rights (including Patent
Rights and Know-How) owned or Controlled by the licensor Party with respect to the Research Program Target specified in the applicable Option Exercise Notice as set forth in the applicable License Agreement. 

1.41. “Disclosing Party” is defined in Section 1.14 hereof. 

1.42. “Disclosure Letter” has the meaning ascribed to such term, with respect to each Development and Commercialization
License, as set forth in the applicable License Agreement. 
 1.43. “Dispute” is defined in Section 10.9 hereof.

 1.44. “Effective Date” is defined in the introduction to this Agreement. 

1.45. “EMA” means the European Medicines Agency, or any successor agency thereto. 

1.46. “Field” means all human therapeutic, prophylactic and diagnostic uses. 

1.47. “FD&C Act” means the United States Federal Food, Drug, and Cosmetic Act (21 U.S.C. § 301 et seq.), as
amended, and the rules and regulations promulgated thereunder. 
  
 ***Certain
information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 6 

 1.48. “FDA” means the United States Food and Drug Administration or any
successor agency thereto. 
 1.49. “GLP” means all good laboratory practices under Title 21 of the United States Code
of Federal Regulations, as amended from time to time. 
 1.50. “Governmental Authority” means any court, agency, department,
authority or other instrumentality of any national, state, county, city or other political subdivision. 
 1.51. “[***]
Compounds” means [***]. 
 1.52. “ImmunoGen Activities” means the Work Plan Activities that are to be undertaken
by ImmunoGen or its Affiliates. 
 1.53. “ImmunoGen Agreement PDCs” means Agreement PDCs that Target the ImmunoGen Research
Program Target(s). 
 1.54. “ImmunoGen Background Technology” means any Proprietary Material, Patent Right, Know-How or
other intellectual property right that is (a) owned or Controlled by ImmunoGen or any Affiliate of ImmunoGen and (b) exists as of and/or was conceived prior to the Effective Date or is developed or obtained by ImmunoGen or any of
its Affiliates independently of this Agreement and without the use of CytomX’s Confidential Information. For purposes of clarity, ImmunoGen Background Technology includes ImmunoGen Proprietary Materials, but does not include Agreement PDCs,
although the Parties acknowledge that ImmunoGen Background Technology may be incorporated into Agreement PDCs. 
 1.55. “ImmunoGen
Excluded Target” means any Target as to which (a) ImmunoGen or an Affiliate of ImmunoGen is pursuing an ImmunoGen Internal Program with respect to such Target, (b) ImmunoGen has granted, or is obligated to grant, an option or
license to a Third Party under any [***] or [***] by ImmunoGen that are necessary or useful for the development, manufacture, use or sale of any compound or product that [***] (as used in this definition, a “Third Party Right”),
(c) ImmunoGen has entered into a [***] agreement or [***] with a Third Party that is in effect as of the date of ImmunoGen’s receipt of a Proposed Target Notice from CytomX, that [***] ImmunoGen from [***] the [***] in the [***] or [***]
to [***] a [***] for the [***] on the terms and conditions of this Agreement, (d) ImmunoGen is in [***] discussions with a Third Party with respect to a [***] in which [***] has been shared under the terms of a written
confidential disclosure agreement entered into by ImmunoGen and such Third Party within the [***]-day period immediately preceding the date of ImmunoGen’s receipt of the applicable Proposed Target Notice from CytomX or (e) [***]. A Target
shall be deemed an ImmunoGen Excluded Target only so long as it satisfies the foregoing definition. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 7 

 1.56. “ImmunoGen Indemnified Party” is defined in Section 9.3
hereof. 
 1.57. “ImmunoGen Internal Product Candidate” means any cell-binding agent (other than a Probody), which may be
unconjugated or conjugated to a cell-killing or cytostatic agent (which may or may not be a Cytotoxic Compound). 
 1.58. “ImmunoGen
Internal Program” means a bona fide internal research, development or commercialization undertaken by ImmunoGen with respect to a Target, with respect to which[***] 

1.59. “ImmunoGen License Agreement” means the written license agreement in the form of Exhibit D attached hereto
that will be entered into by the Parties upon ImmunoGen’s exercise of each ImmunoGen Option. 
 1.60. “ImmunoGen Licensed
Intellectual Property” means any and all intellectual property (including Patent Rights and Know-How) owned or Controlled by ImmunoGen, including the ImmunoGen Technology, that is necessary or useful for CytomX to conduct the CytomX
Activities. 
 1.61. “ImmunoGen Licensed Product” means a PDC having a Payload that is a Cytotoxic Compound and Targeting an
ImmunoGen Licensed Target. 
 1.62. “ImmunoGen Licensed Target” is defined in Section 3.1.3 hereof. 

1.63. “ImmunoGen Option” is defined in Section 3.1.1 hereof. 

1.64. “ImmunoGen Option Exercise Cut-Off Date” is defined in Section 3.1.2 hereof. 

1.65. “ImmunoGen Option Exercise Date” is defined in Section 3.1.2 hereof. 

1.66. “ImmunoGen Patent Right” means any Patent Right comprised in the ImmunoGen Technology. 

1.67. “ImmunoGen Probody(ies)” means the Agreement Probody(ies) Targeting the ImmunoGen Research Program Targets. 

1.68. “ImmunoGen Probody Platform Improvements” means any Probody Platform Improvements (other than Probody Platform
Improvements comprised in the Joint Program Technology) the inventors of which (alone or with others) area employees of, or others obligated to assign inventions to, ImmunoGen or any of its Affiliates or Permitted Third Party Service Providers
pursuant to the conduct of the Research Program. 
  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 8 

 1.69. “ImmunoGen Program Technology” means any Program Technology (other than
Joint Program Technology) the inventors of which are employees, agents or independent contractors of ImmunoGen or any of its Affiliates. 

1.70. “ImmunoGen Proprietary Materials” means any chemical (including any Cytotoxic Compounds), biological (including any
Antibodies) and other tangible research materials owned or Controlled by ImmunoGen and provided by ImmunoGen to CytomX under this Agreement. Agreement PDCs, in and of themselves, will not be considered to be ImmunoGen Proprietary Materials, although
the Parties acknowledge that ImmunoGen Proprietary Materials may be incorporated into Agreement PDCs. 
 1.71. “ImmunoGen Research
Program Target” means a Target selected by ImmunoGen (other than a CytomX Excluded Target) for inclusion in the Research Program in accordance with Section 2.1 hereof. A Target ceases to be an ImmunoGen Research Program Target
once (a) it has become the subject of a Development and Commercialization License in accordance with Section 3.1.2 hereof or (b) it has been dropped from the Research Program in accordance with Section 2.1.3 hereof.

 1.72. “ImmunoGen Technology” means, collectively, the ImmunoGen Background Technology and the ImmunoGen Program
Technology. 
 1.73. “Improvement” is defined in Section 1.104 hereof. 

1.74. “IND” means an Investigational New Drug Application, as defined in the FD&C Act, that is required to be filed with
the FDA before beginning clinical testing of a Licensed Product in human subjects, or an equivalent foreign filing. 
 1.75.
“Indemnified Party” is defined in Section 9.4.1 hereof. 
 1.76. “Indemnifying Party” is
defined in Section 9.4.1 hereof. 
 1.77. “Independent Patent Counsel” means an outside patent counsel
reasonably acceptable to both Parties who (and whose firm) is not at the time of the dispute, and was not at any time during the five (5)-year period preceding the dispute, performing legal services of any nature for either of the Parties or their
respective Affiliates and which did not, at any time, employ either of the Parties’ chief patent counsels (or persons with similar responsibilities). 

1.78. “Insolvency Event” means the occurrence of any of the following: (a) a case is commenced by or against a Party
under applicable bankruptcy, insolvency or similar laws, and is not dismissed within ninety (90) days, (b) a Party files for or is subject to the institution of bankruptcy, reorganization, liquidation, receivership or similar proceedings,
(c) a Party assigns all or a substantial portion of its assets for the benefit of creditors, (d) a receiver or custodian is appointed for a Party’s business, (e) a substantial portion of a 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 9 

 
Party’s business is subject to attachment or similar process, or (f) anything analogous to any of the events described in the foregoing clauses (a) through (e) occurs under the laws of any
applicable jurisdiction. 
 1.79. “Joint Patent Right” means any Patent Right comprised in the Joint Program Technology.

 1.80. “Joint Program Technology” means any Program Technology the inventors of which are jointly (a) employees, agents or
independent contractors of CytomX or any of its Affiliates and (b) employees, agents or independent contractors of ImmunoGen or any of its Affiliates. 

1.81. “Joint Research Committee” or “JRC” is defined in Section 2.4.1 hereof. 

1.82. “Know-How” means any proprietary invention, discovery, data, information, process, method, technique, material,
technology, result or other know-how, whether or not patentable. 
 1.83. “Liability” is defined in Section 9.2
hereof. 
 1.84. “License Agreement” means the CytomX License Agreement and/or the ImmunoGen License Agreement, as
applicable. 
 1.85. “Licensed Product” has the meaning ascribed to such term in the License Agreement applicable to a
particular Licensed Target. 
 1.86. “Licensed Target” means a CytomX Licensed Target or an ImmunoGen Licensed Target, as
applicable. 
 1.87. “Linker” means any compound or composition that is useful for linking a cytotoxic or cytostatic moiety,
including, without limitation, a Cytotoxic Compound, and a cell-binding moiety, including, without limitation, an Antibody or a Probody, together to form a conjugate of the cytotoxic or cytostatic moiety with the cell-binding moiety. 

1.88. “Mask” means a peptide or polypeptide linked to an Antibody that is capable of inhibiting the specific binding of the
Antibody to its Target. 
 1.89. “Material Breach” is defined in Section 8.2 hereof. 

1.90. “[***] Compound” means [***]. 

1.91. “Non-Disclosing Party” is defined in Section 6.3.2 hereof. 

1.92. “Notice of Dispute” is defined in Section 10.9.1 hereof. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 10 

 1.93. “Option” means the CytomX Option and/or the ImmunoGen Options, as
applicable. 
 1.94. “Option Exercise Date” means the CytomX Option Exercise Date or the ImmunoGen Option Exercise Date, as
applicable. 
 1.95. “Option Exercise Notice” means the written notice of exercise of an Option delivered by ImmunoGen to
CytomX pursuant to Section 3.1.2 hereof or by CytomX to ImmunoGen pursuant to Section 3.2.2 hereof. 
 1.96.
“Party” and “Parties” is defined in the introduction to this Agreement. 
 1.97. “Patent
Committee” is defined in Section 5.2.4 hereof. 
 1.98. “Patent Rights” means any and all
(a) patents, (b) pending patent applications, including all provisional applications, substitutions, continuations, continuations-in-part, divisions and renewals, and all patents granted thereon, (c) all patents-of-addition, reissues,
reexaminations and extensions or restorations by existing or future extension or restoration mechanisms, including patent term extensions, supplementary protection certificates or the equivalent thereof, (d) inventor’s certificates,
(e) any other form of government-issued right substantially similar to any of the foregoing and (f) all United States and foreign counterparts of any of the foregoing. 

1.99. “Payload” means a therapeutic cytotoxic or cytostatic compound, including, without limitation, a Cytotoxic Compound.

 1.100. “PDC” means a compound that incorporates, is comprised of or is otherwise derived from, a Probody conjugated to a
Payload using a Linker. 
 1.101. “Permitted Third Party Service Providers” is defined in Section 3.1.1 hereof.

 1.102. “Person” means an individual, sole proprietorship, partnership, limited partnership, limited liability
partnership, corporation, limited liability company, business trust, joint stock company, trust, incorporated association, joint venture or similar entity or organization, including a government or political subdivision or department or agency of a
government. 
 1.103. “Probody” means an Antibody linked to a Substrate and a Mask that is claimed or covered by CytomX
Technology. 
 1.104. “Probody Platform Improvements” means any Patent Right, Know-How or other intellectual property right
that is an enhancement, improvement or modification (each, an “Improvement”) to the CytomX Technology invented by either Party or any of its Affiliates (or by a Third Party on behalf of either Party or its Affiliates) that is an

  
 ***Certain information contained herein has been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 11 

 
Improvement to the composition of, or any method of using or method of making or any Tools for developing, any unconjugated Probody, Mask or Substrate (collectively, “Unconjugated Probody
Platform Improvements”). Probody Platform Improvements also include Improvements (a) to any of the analytical methods used for making, releasing and characterizing any Agreement PDCs that are necessary because of the presence of a Mask
and/or Substrate, or (b) consisting of conjugation chemistry or conjugation methods that are necessary because of the presence of a Mask and/or Substrate (collectively, “Conjugation Probody Platform Improvements”). Agreement
PDCs and ImmunoGen Probodies, in and of themselves, will not be considered to be Probody Platform Improvements, although the Parties acknowledge that Probody Platform Improvements may be incorporated into Agreement PDCs and ImmunoGen Probodies.
[***]1[***] 
 1.105. “Program Technology” means any and all
intellectual property (including Patent Rights and Know-How) that either Party or any of its Affiliates or Permitted Third Party Service Providers (or any of their respective employees, agents or independent contractors), alone or with others,
makes, creates, develops, discovers, conceives or first actually reduces to practice pursuant to the Research Program, including any Patent Rights related thereto. For purposes of clarity, all Agreement PDCs and ImmunoGen Probodies shall be deemed
to be Program Technology. 
 1.106. “Proposed Target” means the Target identified in a Proposed Target Notice. 

1.107. “Proposed Target Notice” means the written notice provided by one Party to the other Party pursuant to
Section 2.1.1 or 2.1.3 hereof requesting that a Target be included in the Research Program as a Research Program Target or a Replacement Target. 

1.108. “Proprietary Material” means any CytomX Proprietary Material or ImmunoGen Proprietary Material. 

1.109. “Publishing Party” is defined in Section 6.3.2 hereof. 

1.110. “Receiving Party” is defined in Section 1.14 hereof. 

1.111. “Regulatory Approval” means any technical, medical, scientific or other license, registration, authorization or
approval of any Regulatory Authority (including any approval of a New Drug Application or Biologic License Application) necessary for the development, manufacture or commercialization of a pharmaceutical product in any regulatory jurisdiction. 

 

	1 	[***] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 12 

 1.112. “Regulatory Authority” means the FDA or any counterpart of the FDA
outside the United States, or other national, supra-national, regional, state or local regulatory jurisdiction, any agency, department, bureau, commission, council or other governmental entity with authority over the conduct of the Research Program
and the Work Plan Activities. 
 1.113. “Replacement Target” is defined in Section 2.1.2 hereof. 

1.114. “Replacement Target Cut-Off Date” is defined in Section 2.1.2 hereof. 

1.115. “Representatives” is defined in Section 1.14 hereof. 

1.116. “Research Program” is defined in Section 2.2 hereof. 

1.117. “Research Program Target” means a CytomX Research Program Target and/or an ImmunoGen Research Program Target, as
applicable. 
 1.118. “Review Period” is defined in Section 6.3.2 hereof. 

1.119. “[***]” means [***]. 

1.120. “Substrate” means a moiety that is linked to the Antibody and to the Mask of a Probody and is capable of being cleaved,
reduced or photolysed. 
 1.121. “TAP Platform Improvements” means any Improvement to the ImmunoGen Technology invented by
[***] or any of its Affiliates (or by a Third Party on behalf of [***] or its Affiliates) that is (a) an Improvement to the [***] of or [***] of [***], (b) an Improvement to the [***] for [***] or [***] (including, for example, [***] or [***]
that create improvements in the [***] of such [***]), (c) an Improvement to the [***] of or [***] for [***], (d) an Improvement to any of the [***] used for [***] and [***] any [***] or [***], or (e) an Improvement to the [***] of
[***] or [***]. [***], in and of themselves, will not be deemed to be TAP Platform Improvements, although the Parties acknowledge that TAP Platform Improvements may be incorporated into [***]. 

1.122. “Target” means a protein described by a unique UniProtKB/Swiss Prot accession number (and all fragments, mutations and
splice variants thereof) that is bound by a cell-binding agent. 
 1.123. “Target,” “Targeting” or
“Targeted” means, when used as a verb to describe the relationship between a molecule and a Target, where the molecule’s primary intended mechanism of action requires that it bind to the Target (or a portion thereof). 

1.124. “Term” is defined in Section 8.1 hereof. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 13 

 1.125. “Territory” means the entire world. 

1.126. “Third Party” means any Person other than CytomX, ImmunoGen or their respective Affiliates. 

1.127. “Third Party Claims” is defined in Section 9.2 hereof. 

1.128. “Tools” means [***]. 

1.129. “Unauthorized Use” is defined in Section 2.10.3 hereof. 

1.130. “Unconjugated Probody Platform Improvements” is defined in Section 1.104 hereof. 

1.131. “Work Plan” is defined in Section 2.3.1 hereof. 

1.132. “Work Plan Activities” is defined in Section 2.3.2 hereof. 

1.133. “Work Plan Change” is defined in Section 2.3.3 hereof. 

 

	2.	RESEARCH PROGRAM. 

 2.1. Selection of Research Program Targets. 

2.1.1. Research Project Targets. The Parties’ respective initial Research Program Targets are set forth on Exhibit A. Subject to
Sections 2.1.2 and 2.1.3 hereof, CytomX is permitted to include one (1) Research Program Target in the Research Program at any given time, and ImmunoGen is permitted to include up to two (2) Research Program Targets in
the Research Program at any given time. In no event will CytomX be required to engage in material activities under a Work Plan for more than one (1) ImmunoGen Research Program Target at a time. 

2.1.2. Target Replacement Right. Each Party shall have the right to replace each of its initial Research Program Targets with another
single Target (a “Replacement Target”), exercisable upon written notice to the other Party, at any time on or prior to the three (3)-year anniversary of the Effective Date (the “Replacement Target Cut-Off Date”),
provided that neither Party may replace an initial Research Program Target with a Replacement Target once the Party has exercised its Option with respect to such initial Research Program Target. [***] A Replacement Target may not be a Target that is
or was previously a Research Program Target of the other Party. 
 2.1.3. Availability of Replacement Target. If a Party desires to
replace a Research Program Target with a Replacement Target, it shall provide the other 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 14 

 
Party with a Proposed Target Notice no later than the Replacement Target Cut-Off Date identifying both the Proposed Target and the existing Research Program Target to be replaced. Within [***]
following the other Party’s receipt of a Proposed Target Notice, such other Party shall notify the Party requesting the Replacement Target in writing whether or not, as of the date of the other’s Party’s receipt of such Proposed
Target Notice, the Proposed Target is a CytomX Excluded Target or an ImmunoGen Excluded Target, as applicable. If the other Party timely notifies the Party requesting the Replacement Target that the Proposed Target is not a CytomX Excluded Target or
an ImmunoGen Excluded Target, as applicable, or if the other Party fails to timely provide any response to the Proposed Target Notice, then such Proposed Target shall thereafter automatically be considered a Research Program Target, the original
Target (listed in Exhibit A) shall thereupon cease to be a Research Program Target for all purposes under this Agreement, and the Parties shall adopt a Work Plan for such new Research Program Target in accordance with
Section 2.3.1 hereof. 
 2.1.4. Excluded Target Verification. Subject to the other terms of this Section, at the request
of the Party submitting a Proposed Target Notice (which request may not be given more than [***] after the Proposed Target has been identified by the other Party as a CytomX Excluded Target or an ImmunoGen Excluded Target, as applicable), at any
time during normal business hours within [***] of such other Party’s delivery to the requesting Party of written acknowledgement of such other Party’s receipt of such request, such other Party shall permit an independent law firm [***] to
inspect (during regular business hours) the relevant records upon which the other Party based its determination that the Proposed Target was a CytomX Excluded Target or an ImmunoGen Excluded Target, as applicable, at the time of the other
Party’s receipt of the Proposed Target Notice; provided that such other Party shall have sole discretion in determining which records will be made available to such law firm. Before permitting such law firm to have access to such records, the
other Party may require such law firm to enter into a confidentiality agreement (in form and substance reasonably acceptable to both Parties) as to any confidential information that is to be provided to such law firm while conducting the
verification contemplated hereby. The law firm shall be instructed to provide both Parties with a written report stating its conclusion as to whether the other Party’s determination that a Proposed Target was a CytomX Excluded Target or an
ImmunoGen Excluded Target, as applicable, was correct within [***] after the completion of its inspection. Such law firm may not reveal to the requesting Party any other information learned in the course of such examination, including, without
limitation, the basis for the other Party’s determination. The requesting Party agrees to treat all information disclosed to it in accordance with this Section as the other Party’s Confidential Information, except to the extent necessary
for the requesting Party to enforce its rights under this Agreement. If the law firm’s report concludes that the other Party’s 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 15 

 
determination was correct, the requesting Party shall be responsible for paying all fees and expenses invoiced by the law firm. If the law firm’s report concludes that the other Party’s
determination was incorrect, (a) the requesting Party shall automatically be deemed to have delivered to the other Party another Proposed Target Notice for such Target as of the date of such determination, (b) the other Party shall be
responsible for paying all reasonable fees and expenses invoiced by the law firm, and (c) if the date of such determination occurs after the Replacement Target Cut-Off Date set forth in Section 2.1.2 hereof, the Replacement Target
Cut-Off Date shall be extended, with respect to such Proposed Target only, to the date of such determination. If the law firm’s report concludes that, based on the records provided to it by the other Party, it is unable to determine whether the
other Party’s determination was correct or incorrect, such determination shall be deemed to be a Dispute, which shall be resolved in accordance with Section 10.9 hereof. 

2.1.5. Exclusivity of Research Program Targets. During the Research Term, for each ImmunoGen Research Program Target, CytomX will not,
and will cause its Affiliates not to [***]. During the Research Term, ImmunoGen will not, and will cause its Affiliates not to[***]. The foregoing shall not restrict either Party’s or their respective Affiliates’ right to [***]. 

2.2. Scope and Conduct of the Research Program. Under the terms and conditions set forth herein, CytomX and ImmunoGen shall collaborate
to conduct discovery and certain pre-clinical development activities to generate and validate Agreement Probodies and generate Agreement PDCs to the Research Program Targets (the “Research Program”). The Research Program shall be
conducted in accordance with the Work Plan for each Research Program Target (as more fully provided in Section 2.3 hereof), and each Party shall use its Commercially Reasonable Efforts to perform all activities assigned to it and fulfill
all of its obligations under each Work Plan. In addition, each Party shall conduct its activities under the Work Plan(s) in accordance with Applicable Law. 

2.3. Work Plans. 
 2.3.1.
Adoption of Work Plans. The Parties shall adopt a work plan (each a “Work Plan”) for each Research Program Target. Each Work Plan shall be approved by the JRC within [***] days of the Effective Date for the initial
CytomX Research Program Target and the first initial ImmunoGen Research Program Target listed on Exhibit A hereof or as determined by the JRC with respect to the second initial ImmunoGen Research Program Target. Each Work Plan will be in
the form of the sample Work Plan attached hereto as Exhibit E. For a Replacement Target that becomes a Research Program Target, a Work Plan shall be approved by the JRC within [***] days of the date on which such 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 16 

 
Replacement Target becomes a Research Program Target. Each Work Plan shall reference this Agreement and shall be subject to all of the provisions of this Agreement, in addition to the specific
details set forth in such Work Plan. To the extent any provisions of a Work Plan conflict or are inconsistent with the provisions of this Agreement, the provisions of this Agreement shall control. If the Parties are unable to agree on a Work Plan
within the specified time period, the JRC may specify the Work Plan, and all Disputes regarding the preparation or modification of any Work Plan (including the approval of any Work Plan Change) shall be resolved in accordance with
Section 10.9 hereof. 
 2.3.2. Responsibilities. Each Work Plan shall set forth the services and the obligations and
responsibilities assigned to each Party (collectively the “Work Plan Activities”), and shall include the following minimum terms: 

(a) Each Party shall provide Antibodies Targeting the applicable Research Program Target at its own expense, which CytomX will use to generate
a panel of Probodies that Target such Research Program Target. The amount of material to be provided by each Party will be specified in the applicable Work Plan. CytomX will provide the construction, expression and purification of all Agreement
Probodies at its expense. [***]. 
 (b) CytomX will investigate and validate each Agreement Probody in accordance with the applicable Work
Plan. 
 (c) ImmunoGen will conjugate the Agreement Probodies to Linkers and Cytotoxic Compounds using the ImmunoGen Technology to generate
a panel of Agreement PDCs in accordance with the applicable Work Plan. [***]. 
 (d) Each Party will perform in vivo modeling and
IND-enabling studies with respect to its own Agreement PDCs in accordance with the applicable Work Plan. 
 (e) Each Party that enters into
a License Agreement covering that Party’s Agreement PDC(s) will develop and commercialize its Agreement PDC(s) as set forth in the applicable License Agreement. 

(f) If, after completion of the ImmunoGen Activities under the Work Plan relating to the CytomX Agreement PDCs, CytomX requests that ImmunoGen
provide additional services with respect to (i) process development, (ii) analytical method development, or (iii) manufacturing and/or supply of the CytomX Agreement PDCs for any GLP toxicology studies, then the Parties shall
negotiate in good faith the terms of separate written agreements with respect to such activities. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 17 

 2.3.3. Changes in Work Plans. Proposed changes to a Work Plan (“Work Plan
Changes”) shall be subject to review and approval by the JRC. Each Work Plan Change shall then be written up in documentation setting forth the agreed changes to the applicable task, protocol, specifications, responsibility, timeline or
other matter. As used in this Agreement, a Work Plan will be deemed to include any Work Plan Changes with respect thereto. 
 2.4.
Governance of the Research Program. 
 2.4.1. Formation of the Joint Research Committee. CytomX and ImmunoGen hereby establish
a “Joint Research Committee” (or “JRC”) to oversee and coordinate the activities of the Parties under this Agreement in regard to the Research Program. The JRC shall also serve as a forum to facilitate
communications between the Parties regarding the Research Program. The JRC shall be comprised of three (3) representatives from each Party as appointed by such Party, with such representatives possessing appropriate expertise and seniority to carry
out the Research Program. The initial members of the JRC for each Party are set forth in Exhibit F attached hereto. The JRC may change its size from time to time by mutual consent of its members. A Party may replace one or more of its
representatives from time to time upon written notice to the other Party. The JRC shall exist until expiration or earlier termination of the Term, unless the Parties otherwise agree in writing. 

2.4.2. Co-Chairpersons and Secretary of the Joint Research Committee. Each Party shall designate a co-chairperson of the JRC, and a
secretary of the JRC shall be designated by agreement of the members of the JRC. A Party may change the designation of its co-chairperson from time to time upon written notice to the other Party. The co-chairpersons or their designees shall be
responsible for scheduling meetings of the JRC, preparing agendas for meetings and sending to all JRC members notices of all regular meetings and agendas for such meetings at least [***] Business Days before such meetings. The co-chairpersons shall
solicit input from both Parties regarding matters to be included on the agenda, and any matter either Party desires to have included on the agenda shall be included for discussion. Nothing herein shall be construed to prohibit the JRC from
discussing or acting on matters not included on the applicable agenda. The secretary shall (a) record the minutes of the meeting, (b) circulate copies of meeting minutes to the Parties and each JRC member promptly following the meeting for review,
comment and approval by the JRC members and (c) finalize approved meeting minutes. The co-chairpersons shall be members of the JRC but the secretary need not be a member of the JRC. The initial co-chairpersons are listed in Exhibit F hereof.

  
 ***Certain information contained herein has been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 18 

 2.4.3. Meetings. The JRC shall meet at least three (3) times each Calendar Year
(unless the Parties mutually agree in advance of any scheduled meeting that there is no need for such meeting, in which case the next JRC meeting shall also be scheduled as agreed upon by the Parties) until it has been terminated in accordance with
Section 2.4.1 hereof at dates and times mutually agreed by the JRC. The initial meeting of the JRC shall be held within [***] days after the Effective Date. Either Party may call a special meeting of the JRC on [***] days written
notice to the other Party’s members of the JRC (or upon such shorter notice as exigent circumstances may require). Such written notice shall include an agenda for the special meeting. In-person meetings, including special meetings, of the JRC
shall alternate between the offices of the Parties, unless otherwise agreed upon by the members of the JRC. Meetings of the JRC may be held telephonically or by video conference; provided, however, that at least [***] meetings per year shall be
held in-person. Meetings of the JRC shall be effective only if at least one (1) representative of each Party is in attendance or participating in the meeting. Members of the JRC shall have the right to participate in and vote at meetings held
by telephone or video conference. In addition, the JRC may act on any matter or issue without a meeting if it is documented in a written consent signed by each member of the JRC. 

2.4.4. Responsibilities of the Joint Research Committee. The JRC shall be responsible for (a) planning and overseeing research
under this Agreement, including establishing, reviewing and recommending modifications and updates to the Work Plans; (b) receiving and reviewing relevant data and other information obtained by either Party in connection with the Research
Program and monitoring and reporting to the Parties on activities conducted pursuant to the Work Plans; (c) resolving Disputes between the Parties; and (d) such other functions as expressly specified hereunder or as agreed by the Parties.

 2.4.5. Decisions by [***]. All decisions of the JRC shall be made by [***]. If the JRC cannot or does not reach [***] on a matter
within the purview of the JRC, then such Dispute shall be resolved in accordance with Section 10.9 hereof. 
 2.5. Alliance
Managers. In addition to the foregoing governance provisions, each of the Parties shall appoint a single individual to serve as that Party’s alliance manager (“Alliance Manager”). The role of each Alliance Manager will be
to participate and otherwise facilitate the relationship between the Parties as established by this Agreement. A Party may replace its Alliance Manager from time to time upon written notice to the other Party. 

2.6. Conformance with Law. Each Party shall perform and discharge its obligations under this Agreement and the Research Program in
conformance with (a) professional standards and practices, (b) this Agreement and the Work Plan(s) and (c) all Applicable 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 19 

 
Laws. Without limiting the generality of the foregoing, each Party shall retain all records relating to its performance of this Agreement and the Work Plan(s) for the time periods required by
Applicable Laws. 
 2.7. Personnel Matters. Each Party acknowledges and agrees that it is solely responsible for the compensation of
its personnel assigned to the Work Plan activities, and shall be responsible for withholding all national, state, local or other applicable taxes and similar items for such personnel. 

2.8. Debarment Certification. Neither Party nor any Person employed or retained to perform services by either Party has been debarred
under Section 306(a) or (b) of the FD&C Act or any comparable provision of foreign law and no debarred Person shall in the future be employed or retained to perform services by either Party in connection with any work to be performed
for or on behalf of the other Party. If, at any time after execution of this Agreement, either Party becomes aware that such Party or any Person employed or retained to perform services by such Party in connection with any work performed for or on
behalf of such Party is, or is in the process of being, debarred, such Party shall so notify the other Party immediately. 
 2.9.
Records. Each Party shall prepare, complete and accurate written records, accounts, notes, reports and data of the Work Plan activities and its performance under this Agreement and the Work Plan(s), in a form and of quality reasonably
acceptable to both Parties. 
 2.10. Transfer and Use of Proprietary Materials. 

2.10.1. Transfer. From time to time, pursuant to a Work Plan, or otherwise, ImmunoGen may provide CytomX with ImmunoGen Proprietary
Materials and Agreement PDCs and CytomX may provide ImmunoGen with CytomX Proprietary Materials and Agreement Probodies. Each Party’s Proprietary Materials, Agreement PDCs and Agreement Probodies are provided by such Party on an
“as-is” basis without representation or warranty of any type, express or implied, including any representation or warranty of merchantability, non-infringement, title or fitness for a particular purpose, each of which is hereby disclaimed
by such providing Party. 
 2.10.2. Use of Proprietary Materials. Each Party shall use the other Party’s Proprietary Materials
(including, without limitation, the other Party’s Proprietary Materials incorporated into Agreement PDCs and Agreement Probodies) solely in connection with conducting the specific activities under this Agreement for which such other
Party’s Proprietary Materials are provided to the receiving Party, including, if applicable, the provisions of any specific Work Plan under which such Proprietary Materials are provided, and for no other purpose. Without 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 20 

 
limiting the generality of the foregoing, except as expressly set forth in this Agreement or in any applicable Work Plan, neither Party shall make or attempt to make analogues, progeny or
derivatives of, or modifications to, the other Party’s Proprietary Materials, using the other Party’s Confidential Information or the tangible materials provided by the other Party, and each Party shall not use the other Party’s
Proprietary Materials for the benefit of any Third Party or of its own internal research programs outside of the Research Program or as otherwise licensed to the other Party under a Development and Commercialization License. Each Party shall comply
with all Applicable Laws regarding the handling and use of the other Party’s Proprietary Materials. Each Party agrees to retain possession over the other Party’s Proprietary Materials and not to provide the other Party’s Proprietary
Materials to any Third Party without the providing Party’s prior written consent, except as required to perform the Research Program. 

2.10.3. Unauthorized Use of Confidential Information and Proprietary Materials. In the event that either Party uses the other
Party’s Confidential Information or Proprietary Materials (including, without limitation, the other Party’s Proprietary Materials incorporated into Agreement PDCs and Agreement Probodies) for any purpose other than the purposes authorized
herein (an “Unauthorized Use”), the results of such Unauthorized Use, and any discoveries or inventions that arise from such Unauthorized Use, whether patentable or not, shall belong solely and exclusively to the Party providing its
Confidential Information or Proprietary Materials. If required in order to perfect or enforce a Party’s ownership of such results, discoveries or inventions, each hereby assigns and agrees to assign to the other Party all of its right, title
and interest in and to all such results, discoveries or inventions made through the Unauthorized Use with the other Party’s Confidential Information or Proprietary Materials. Each Party agrees to cooperate with the other Party, and to execute
and deliver any and all documents that the providing Party reasonably deems necessary, to perfect and enforce its rights hereunder. 
  

	3.	OPTION FOR LICENSE AND COMMERCIAL LICENSE GRANTS. 

 3.1. Grants to ImmunoGen. 

3.1.1. Research License and Option Grants. Subject to the terms and conditions of this Agreement, CytomX hereby grants to ImmunoGen
during the Term (a) a non-exclusive, non-sublicensable (except to Affiliates and Permitted Third Party Service Providers), non-transferable (except as expressly permitted by this Agreement), royalty-free license under the CytomX Licensed
Intellectual Property for the sole purpose of conducting the ImmunoGen Work Plan Activities in the Territory, and (b) an exclusive option (each, an “ImmunoGen Option”) to obtain a Development and Commercialization License with
respect to up to two 
  
 ***Certain information contained herein has been omitted
and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 21 

 
(2) Research Program Targets as set forth in Section 3.1.2. ImmunoGen shall have the right to engage one or more Affiliates or Third Parties (the latter being referred to as
“Permitted Third Party Service Providers”) as subcontractors to perform some or all of the ImmunoGen Activities; provided that (i) ImmunoGen shall [***] and (ii) ImmunoGen shall [***]. 

3.1.2. Exercise of each ImmunoGen Option. On an ImmunoGen Research Program Target-by-ImmunoGen Research Program Target basis, each of
the ImmunoGen Options may be separately exercised by ImmunoGen at any time during the Term, but in each case no later than one hundred eighty-two (182) days after the first dosing of any animal in the first IND-enabling GLP toxicology study of
the applicable ImmunoGen Agreement PDC (each, the “ImmunoGen Option Exercise Cut-Off Date”), by providing CytomX with an Option Exercise Notice (the date of CytomX’s receipt of any such Option Exercise Notice, the
“ImmunoGen Option Exercise Date”). If ImmunoGen does not provide CytomX with an Option Exercise Notice with respect to any Research Program Target during the Term and prior the ImmunoGen Option Exercise Cut-Off Date, then the
applicable Target shall no longer be considered an ImmunoGen Research Program Target. Notwithstanding the foregoing, the ImmunoGen Option Exercise Cut-Off Date with respect to each of the first two (2) ImmunoGen Research Program Targets shall
be the [***] day after the Replacement Target Cut-Off Date if ImmunoGen has not notified CytomX on or prior to the Replacement Target Cut-Off Date of its intention to replace such ImmunoGen Research Program Target with a Replacement Target in
accordance with Sections 2.1.2 and 2.1.3 hereof. 
 3.1.3. Development and Commercialization License. Subject to
the terms and conditions of this Agreement, on a Research Program Target-by-Research Program Target basis and effective on the ImmunoGen Option Exercise Date for such Research Program Target, (a) the Licensed Intellectual Property (as defined
in the ImmunoGen License Agreement) shall be licensed by CytomX to ImmunoGen with respect to the Research Program Target specified in the Option Exercise Notice (each, an “ImmunoGen Licensed Target”) on the terms and subject to the
conditions set forth in the ImmunoGen License Agreement, and (b) the foregoing Development and Commercialization License shall be effective as of the ImmunoGen Option Exercise Date. CytomX shall deliver to ImmunoGen, within ten
(10) Business Days following the ImmunoGen Option Exercise Date, an ImmunoGen License Agreement executed on behalf of CytomX in which CytomX has (i) inserted the name and unique UniProtKB/Swiss Prot accession number of the applicable
ImmunoGen Licensed Target in Schedule A of the ImmunoGen License Agreement, and (ii) inserted the ImmunoGen Option Exercise Date as the effective date of the ImmunoGen License Agreement. If either Party fails to deliver an executed copy of
the ImmunoGen License 
  
 ***Certain information contained herein has been
omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 22 

 
Agreement as described above, CytomX shall nevertheless be deemed to have granted ImmunoGen the rights with respect to the ImmunoGen Licensed Target consistent with the ImmunoGen License
Agreement. 
 3.1.4. Rescission of Exercise of ImmunoGen Option. Anything contained in this Agreement to the contrary notwithstanding,
if, in connection with ImmunoGen’s exercise of an ImmunoGen Option, CytomX delivers to ImmunoGen a Disclosure Letter within [***] of CytomX’s receipt of the applicable Option Exercise Notice, then ImmunoGen shall be entitled to rescind the
exercise of such ImmunoGen Option by delivering to CytomX written notice of such rescission within [***] of ImmunoGen’s receipt of the Disclosure Letter. Any failure by CytomX to deliver a Disclosure Letter to ImmunoGen within the applicable
[***] period described above shall be deemed a waiver of CytomX’s right to qualify its representations and warranties in the applicable ImmunoGen License Agreement by any information CytomX may have intended to include in the Disclosure Letter.
If CytomX delivers the Disclosure Letter on a timely basis, then any failure by ImmunoGen to deliver a rescission notice to CytomX within the applicable [***] period described above shall be deemed a waiver of ImmunoGen’s right to rescind the
exercise of such ImmunoGen Option pursuant to this Section 3.1.4, and CytomX’s representations and warranties in the applicable ImmunoGen License Agreement shall be qualified by any information contained in such Disclosure Letter.
If an ImmunoGen Option is rescinded pursuant to this Section 3.1.4, then such ImmunoGen Option shall remain outstanding in accordance with its original terms; provided, however, that: 

(a) if the Replacement Target Cut-Off Date occurs within the period beginning on the applicable ImmunoGen Option Exercise Date and ending on
the [***] after ImmunoGen’s delivery of the rescission notice to CytomX, then anything set forth in this Agreement to the contrary notwithstanding, ImmunoGen shall have the right to replace the applicable ImmunoGen Research Program Target with
a Replacement Target, subject to the terms and conditions set forth in Sections 2.1.2 and 2.1.3 hereof; and 
 (b) if the
applicable ImmunoGen Option Exercise Cut-Off Date occurs within the period beginning on the applicable ImmunoGen Option Exercise Date and ending on the [***] after ImmunoGen’s delivery of the rescission notice to CytomX, then anything set forth
in this Agreement to the contrary notwithstanding, ImmunoGen shall have the right to exercise the applicable ImmunoGen Option for the same ImmunoGen Research Program Target or, as contemplated by clause (a) above, a different ImmunoGen Research
Program Target, within [***] (or such longer period as may be mutually agreed to in writing by the Parties) after ImmunoGen’s delivery of the rescission notice to CytomX. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 23 

 3.1.5. License to CytomX TAP Platform Improvements. CytomX, on behalf of itself and its
Affiliates, hereby grants to ImmunoGen a non-exclusive, sublicensable, perpetual, irrevocable, royalty-free worldwide license under CytomX’s interest in any CytomX TAP Platform Improvements, including, without limitation, any Patent Rights
claiming such CytomX TAP Platform Improvements, to exploit such CytomX TAP Platform Improvements (a) for any purpose other than developing, manufacturing, using or commercializing PDCs and (b) for any purpose outside of the Field. Except
in connection with the performance of the CytomX Activities under the Work Plans related to the ImmunoGen Research Program Targets, nothing in this Agreement shall be construed as obligating CytomX to [***] or any of its Affiliates or any Third
Party [***]. 
 3.2. Grants to CytomX. 

3.2.1. Research License and Option Grant. Subject to the terms and conditions of this Agreement, ImmunoGen hereby grants to CytomX
during the Term (a) a non-exclusive, non-sublicensable (except to Affiliates and Permitted Third Party Service Providers), non-transferable (except as expressly permitted by this Agreement) royalty-free license under the ImmunoGen Licensed
Intellectual Property for the sole purpose of conducting the CytomX Work Plan Activities in the Territory, and (b) an exclusive option (the “CytomX Option”) to obtain a Development and Commercialization License with respect to
one (1) CytomX Research Program Target as set forth in Section 3.3.2. CytomX shall have the right to engage one or more Affiliates or Permitted Third Party Service Providers as subcontractors to perform some or all of the CytomX
Activities; provided that (i) CytomX shall [***] and (ii) CytomX shall [***]. 
 3.2.2. Exercise of the CytomX Option. The
CytomX Option may be exercised by CytomX at any time during the Term, but in no event later than one hundred eighty-two (182) days after the first dosing of any animal in the first IND-enabling GLP toxicology studies of the applicable CytomX
Agreement PDC (the “CytomX Option Exercise Cut-Off Date”), by providing ImmunoGen with an Option Exercise Notice (the date of ImmunoGen’s receipt of the Option Exercise Notice, the “CytomX Option Exercise
Date”). If CytomX does not provide ImmunoGen with an Option Exercise Notice with respect to its Research Program Target during the Term and prior to the CytomX Option Exercise Cut-Off Date, then the applicable Target shall no longer be
considered a CytomX Research Program Target. Notwithstanding the foregoing, the CytomX Option Exercise Cut-Off Date with respect to the CytomX Research Program Target shall be the [***] day after the Replacement Target Cut-Off Date if CytomX
has not notified ImmunoGen on or prior to the Replacement Target Cut-Off Date of its intention to replace such CytomX Research Program Target with a Replacement Target in accordance with Sections 2.1.2 and 2.1.3 hereof. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 24 

 3.2.3. Development and Commercialization License. Subject to the terms and conditions of
this Agreement, effective on the CytomX Option Exercise Date for its Research Program Target, (a) the Licensed Intellectual Property (as defined in the CytomX License Agreement) shall be licensed by ImmunoGen to CytomX with respect to the
Research Program Target specified in the Option Exercise Notice (the “CytomX Licensed Target”) on the terms and subject to the conditions set forth in the CytomX License Agreement, and (b) the foregoing license shall be
effective as of the CytomX Option Exercise Date. ImmunoGen shall deliver to CytomX, within [***] following the CytomX Option Exercise Date, a CytomX License Agreement executed on behalf of ImmunoGen in which ImmunoGen has (i) inserted the name
and unique UniProtKB/Swiss Prot accession number of the applicable Licensed Target in Schedule A of the CytomX License Agreement, and (ii) inserted the CytomX Option Exercise Date as the effective date of the CytomX License Agreement. If
either Party fails to deliver an executed copy of the CytomX License Agreement as described above, ImmunoGen shall nevertheless be deemed to have granted CytomX the rights with respect to the CytomX Licensed Target consistent with the CytomX License
Agreement. 
 3.2.4. Rescission of Exercise of CytomX Option. Anything contained in this Agreement to the contrary notwithstanding,
if, in connection with CytomX’s exercise of the CytomX Option, ImmunoGen delivers to CytomX a Disclosure Letter within [***] of ImmunoGen’s receipt of the applicable Option Exercise Notice, then CytomX shall be entitled to rescind the
exercise of the CytomX Option by delivering to ImmunoGen written notice of such rescission within [***] of CytomX’s receipt of the Disclosure Letter. Any failure by ImmunoGen to deliver a Disclosure Letter to CytomX within the applicable [***]
period described above shall be deemed a waiver of ImmunoGen’s right to qualify its representations and warranties in the CytomX License Agreement by any information ImmunoGen may have intended to include in the Disclosure Letter. If ImmunoGen
delivers the Disclosure Letter on a timely basis, then any failure by CytomX to deliver a rescission notice to ImmunoGen within the applicable [***] period described above shall be deemed a waiver of CytomX’s right to rescind the exercise of
the CytomX Option pursuant to this Section 3.2.4, and ImmunoGen’s representations and warranties in the CytomX License Agreement shall be qualified by any information contained in such Disclosure Letter. If the CytomX Option is
rescinded pursuant to this Section 3.2.4, then the CytomX Option shall remain outstanding in accordance with its original terms; provided, however, that: 

(a) if the Replacement Target Cut-Off Date occurs within the period beginning on the CytomX Option Exercise Date and ending on the [***] after
CytomX’s delivery of the rescission notice to ImmunoGen, then anything set forth in this Agreement to the contrary notwithstanding, CytomX shall have the right to replace the CytomX Research Program Target with a Replacement Target, subject to
the terms and conditions set forth in Sections 2.1.2 and 2.1.3 hereof; and 
 (b) if the CytomX Option Exercise Cut-Off
Date occurs within the period beginning on the CytomX Option Exercise Date and ending on the [***] after CytomX’s delivery of the rescission notice to ImmunoGen, then anything set forth in this Agreement to the contrary notwithstanding, CytomX
shall have the right to exercise the CytomX Option for the same CytomX Research Program Target or, as contemplated by clause (a) above, a different ImmunoGen Research Program Target, within [***] (or such longer period as may be mutually agreed
to in writing by the Parties) after CytomX’s delivery of the rescission notice to ImmunoGen. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 25 

 3.2.5. License to ImmunoGen Probody Platform Improvements. ImmunoGen, on behalf of itself
and its Affiliates, hereby grants to CytomX a non-exclusive, sublicensable, perpetual, irrevocable, royalty-free worldwide license under ImmunoGen’s interest in any ImmunoGen Probody Platform Improvements, including, without limitation, any
Patent Rights claiming such ImmunoGen Probody Platform Improvements, to exploit such ImmunoGen Probody Platform Improvements (a) for any purpose other than developing, manufacturing, using or commercializing PDCs having a Payload that is a
Cytotoxic Compound2 and (b) for any purpose outside of the Field. For the avoidance of doubt, the license granted pursuant to this subsection excludes any rights in and to ImmunoGen
Background Technology or any ImmunoGen Program Technology other than the ImmunoGen Probody Platform Improvements. Except in connection with the performance of the ImmunoGen Activities under the Work Plan(s) related to the CytomX Research Program
Target(s), nothing in this Agreement shall be construed as obligating ImmunoGen to [***] or any of its Affiliates or any Third Party [***]. 

3.3. Section 365(n) of Bankruptcy Code. All rights and licenses now or hereinafter granted by either Party to the other Party under
or pursuant to any section of this Agreement, including the licensed granted in this Article 3, are rights to “intellectual property” (as defined in Section 101(35A) of Title 11 of the United States Code, as amended
(such Title 11, the “Bankruptcy Code”)). 
 3.4. No Implied Rights. Except as expressly provided in this
Agreement, neither Party shall be deemed, by estoppel, implication or otherwise, to have granted the other Party any license or other right with respect to any intellectual property owned or Controlled by such Party. 

 

	2 	[***] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 26 

	4.	EXPENSES. 

 4.1. Expenses. Except as expressly stated herein or in a Work Plan,
each Party hereto shall be responsible for its own costs for all activities conducted pursuant to this Agreement. 
  

	5.	INTELLECTUAL PROPERTY. 

 5.1. Inventions. 

5.1.1. Ownership. All determinations of inventorship under this Agreement shall be made in accordance with the laws of the United
States. Determinations of ownership of intellectual property hereunder will be made in accordance with inventorship. 
 (a) ImmunoGen
Solely Owned Technology. As between the Parties, ImmunoGen shall be the sole owner of all ImmunoGen Licensed Intellectual Property (other than Joint Program Technology included therein and any Joint Patent Rights). 

(b) CytomX Solely Owned Technology. As between the Parties, CytomX shall be the sole owner of all CytomX Licensed Intellectual Property
(other than Joint Program Technology included therein and any Joint Patent Rights). 
 (c) Jointly Owned Technology. All Joint
Program Technology (including, without limitation, all Joint Patent Rights) shall be jointly owned by the Parties, with each Party holding an undivided one-half interest therein. Subject to the Parties’ other rights and obligations under this
Agreement and any then-outstanding License Agreement(s), each Party shall be [***]. ImmunoGen’s one-half interest in Joint Program Technology and Joint Patent Rights shall be included in the Licensed Intellectual Property (as defined in the
CytomX License Agreement) under the CytomX License Agreement to the extent it otherwise comes within such definition. CytomX’s one-half interest in Joint Program Technology and Joint Patent Rights shall be included in the Licensed Intellectual
Property (as defined in each ImmunoGen License Agreement) under each ImmunoGen License Agreement to the extent it otherwise comes within such definition. Nothing in this Section 5.1.1(c) shall be construed to grant 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 27 

 
(i) CytomX any rights in and to ImmunoGen Background Technology or any ImmunoGen Program Technology in connection with its exploitation of Joint Program Technology and Joint Patent Rights
outside the scope of the Research Program hereunder or the development, manufacture and commercialization of Licensed Products under a Development and Commercialization License, or (ii) ImmunoGen any rights in and to CytomX Background
Technology and CytomX Program Technology in connection with its exploitation of Joint Program Technology and Joint Patent Rights outside the scope of the Research Program hereunder or the development, manufacture and commercialization of Licensed
Products under a Development and Commercialization License. 
 5.1.2. Disclosure. CytomX shall, no less than [***] before filing any
initial Patent Right disclosing CytomX TAP Platform Improvements or any Joint Program Technology or any other Patent Right that contains ImmunoGen’s Confidential Information, provide a copy of such disclosure to ImmunoGen. ImmunoGen shall, no
less than [***] before filing any initial Patent Right disclosing ImmunoGen Probody Platform Improvements or Joint Program Technology or any other Patent Right that contains CytomX’s Confidential Information, provide a copy of such disclosure
to CytomX. In each case, such disclosures to the other Party shall include all invention disclosures or other similar documents submitted to such Party by its, or its Affiliates’, employees, agents or independent contractors describing such
invention and the proposed inventorship of any new Patent Rights intended to be filed. The other Party shall promptly raise any issue regarding inventorship of any such Patent Rights, and the Parties agree to use their best efforts to determine in
good faith the correct inventorship of any Patent Rights in accordance with Section 10.10.1 hereof. 
 5.2. Filing,
Prosecution and Maintenance of Patent Rights. 
 5.2.1. Cooperation. Without limiting any other rights and obligations of the
Parties under this Agreement, the Parties shall cooperate with respect to the timing, scope and filing of patent applications and patent claims relating to any Joint Program Technology to preserve and enhance the patent protection for Agreement
PDCs, including the manufacture and use thereof and to allow the Party owning the technology underlying an Improvement to have reasonable input to preserve and enhance its patent portfolio and patenting strategy. 

5.2.2. ImmunoGen Patent Rights. ImmunoGen, at its own expense, shall have the sole right, but not the obligation, to prepare, file,
prosecute and maintain, throughout the world, all ImmunoGen Patent Rights. With respect to any ImmunoGen Patent Rights disclosing or claiming Program Technology (other than TAP Platform Improvements included in the Program Technology), ImmunoGen
shall keep CytomX reasonably informed of the status of the filing, 
  
 ***Certain
information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 28 

 
prosecution and maintenance of such Patent Rights and shall consider in good faith any recommendations made by CytomX in regard to the filing, prosecution or maintenance of any such Patent Right.
ImmunoGen shall consult with CytomX in the filing, prosecution and maintenance of any ImmunoGen Patent Right related to ImmunoGen Probody Platform Improvements and shall not unreasonably refuse to incorporate any recommendations made by CytomX in
regard to such filing, prosecution or maintenance. Communications regarding the filing, prosecution and maintenance of any ImmunoGen Patent Rights related to ImmunoGen Probody Platform Improvements will be made through the Patent Committee
established as set forth in Section 5.2.4 hereof. To the extent ImmunoGen decides not to file, prosecute or maintain any ImmunoGen Patent Right that ImmunoGen reasonably believes covers or may cover the development, manufacture,
commercialization or use of any CytomX Licensed Product (other than any such Patent Right owned or co-owned by a Third Party licensor or the filing of a new initial patent application or any ImmunoGen Patent Rights related to Conjugation Probody
Platform Improvements) and except in the case in which the decision not to file, prosecute or maintain such Patent Right is made by ImmunoGen in the ordinary course of filing continuation applications or as part of an overall strategy to optimize
the scope or other aspects of the ImmunoGen Technology, ImmunoGen shall provide CytomX with [***] prior written notice to such effect (i.e., at least [***] prior to the date on which any such filing is intended or due or on which any other
such action is due), in which event CytomX may elect to file or continue prosecution or maintenance of such Patent Right, at CytomX’s expense, and ImmunoGen, upon CytomX’s written request received within such [***] period, shall execute
such documents and perform such acts, at CytomX’s expense, as may be reasonably necessary to permit CytomX to file, prosecute and maintain such Patent Right; provided that CytomX (a) shall keep ImmunoGen reasonably informed of the status
of the filing, prosecution and maintenance of such Patent Rights, (b) shall consider in good faith any recommendations made by ImmunoGen in regard to such filing, prosecution and maintenance of such Patent Right, and (c) shall not
unreasonably refuse to incorporate any recommendations made by ImmunoGen in regard to such filing, prosecution or maintenance. Any such Patent Right that is prosecuted or maintained by CytomX pursuant to this Section 5.2.2 (i) will
continue to be owned by ImmunoGen, and (ii) subject to the Parties’ other rights and obligations under this Agreement or any then-outstanding License Agreement, may be licensed by ImmunoGen to one or more Third Parties. For avoidance of
doubt, “prosecution” as used in this Section 5.2 includes oppositions, nullity or revocation actions, post-grant reviews and other patent office proceedings involving the referenced Patent Rights. Nothing contained in this
Agreement shall be construed as obligating ImmunoGen to file any patent application in any country or other jurisdiction relating to ImmunoGen Probody Platform Improvements. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 29 

 5.2.3. CytomX Patent Rights. CytomX, at its own expense, shall have the sole right, but
not the obligation, to prepare, file, prosecute and maintain, throughout the world, all CytomX Patent Rights. With respect to any CytomX Patent Rights disclosing or claiming Program Technology (other than Unconjugated Probody Platform Improvements
included in the Program Technology), CytomX shall keep ImmunoGen reasonably informed of the status of the filing, prosecution and maintenance of such Patent Rights and shall consider in good faith any recommendations made by ImmunoGen in regard to
the filing, prosecution or maintenance of any such Patent Right. CytomX shall consult with ImmunoGen in the filing, prosecution and maintenance of any CytomX Patent Right related to CytomX TAP Platform Improvements and shall not unreasonably refuse
to incorporate any recommendations made by ImmunoGen in regard to such filing, prosecution or maintenance. Communications regarding the filing, prosecution and maintenance of any CytomX Patent Rights that are Improvements to ImmunoGen Technology
will be made through the Patent Committee established as set forth in Section 5.2.4 hereof. To the extent CytomX decides not to file, prosecute or maintain any CytomX Patent Right that CytomX reasonably believes covers or may cover the
development, manufacture, commercialization or use of any ImmunoGen Licensed Product (other than any such Patent Right owned or co-owned by a Third Party licensor or the filing of a new initial patent application or any CytomX Patent Right related
to CytomX TAP Platform Improvements) and except in the case in which the decision not to file, prosecute or maintain such Patent Right is made by CytomX in the ordinary course of filing continuation applications or as part of an overall strategy to
optimize the scope or other aspects of the CytomX Technology, CytomX shall provide ImmunoGen with [***] prior written notice to such effect (i.e., at least [***] prior to the date on which any such filing is intended or due or on which any
other such action is due), in which event ImmunoGen may elect to continue prosecution or maintenance of such Patent Right, at ImmunoGen’s sole expense, and CytomX, upon ImmunoGen’s written request, shall execute such documents and perform
such acts, at ImmunoGen’s expense, as may be reasonably necessary to permit ImmunoGen to file, prosecute and maintain, at its own discretion, such Patent Right; provided that ImmunoGen (a) shall keep CytomX reasonably informed of the
status of the filing, prosecution and maintenance of such Patent Rights, (b) shall consider in good faith any recommendations made by CytomX in regard to such filing, prosecution and maintenance of such Patent Right, and (c) shall not
unreasonably refuse to incorporate any recommendations made by CytomX in regard to such filing, prosecution or maintenance. Any such Patent Right that is prosecuted or maintained by ImmunoGen pursuant to this Section 5.2.3 (a) will
continue to be owned by CytomX, and (b) subject to the Parties’ other rights and obligations under this Agreement or any then-outstanding License Agreement, may be licensed by CytomX to one or more Third Parties. Nothing contained in this
Agreement shall be construed as obligating CytomX to file any patent application in any country or other jurisdiction relating to CytomX TAP Platform Improvements. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 30 

 5.2.4. Joint Patent Rights. Prior to either Party filing any Patent Right disclosing Joint
Program Technology, disclosing an Improvement made by ImmunoGen to CytomX Technology or disclosing an Improvement made by CytomX to the ImmunoGen Technology, the Parties shall establish a patent committee (the “Patent Committee”)
comprised of at least one (1) representative of each Party for the purpose of facilitating communication as described in Sections 5.2.2 and 5.2.3 hereof and the preparation, filing, prosecution, maintenance and defense of
Joint Patent Rights. As agreed upon by the Parties, meetings of the Patent Committee may be face-to-face or may be conducted by teleconferences or videoconferences, from time to time as needed. The Patent Committee will be the forum through which
the Parties coordinate their respective obligations to each other described in Sections 5.2.2 and 5.2.3 hereof and in this Section. In the event the Parties conceive or generate any Joint Program Technology, the Parties shall
promptly meet to discuss and determine, based on mutual consent, whether to seek patent protection thereon, which Party will control filing, prosecution and maintenance of such patents and how to pay for the filing, prosecution and maintenance of
such patents. [***] The Party controlling filing and prosecution of any such Joint Patent Right (a) shall keep the other Party informed regarding each Patent Right, (b) shall consider in good faith any recommendations made by the other
Party in regard to the filing, prosecution or maintenance of any such Patent Right and (c) shall not unreasonably refuse to incorporate any recommendations made by the other Party in regard to such filing, prosecution or maintenance. 

5.2.5. Restrictions on Disclosures in Patent Applications. Anything contained in this Agreement to the contrary notwithstanding, unless
and until the Parties enter into a License Agreement with respect to a Research Program Target, neither Party may, without the prior written consent of the other Party, which consent may be withheld by such other Party in its sole discretion,
(a) identify or describe Agreement Probodies or Agreement PDCs in any patent application, or (b) disclose any data generated under a Work Plan in support of any Patent Rights that disclose or claim Probodies or PDCs Targeting such Research
Program Target; provided, that the foregoing shall not apply to any CytomX Patent Rights covering Agreement Probodies Targeting the CytomX Research Program Target. 

5.2.6. Improper Patent Filings. Each Party agrees that, without the prior written consent of the other Party, neither it nor any of its
Affiliates will [***]. 
 5.2.7. Liability. Except for breaches of Section 5.2.5 or 5.2.6 hereof, to the extent
that a Party is obtaining, prosecuting or maintaining a Patent Right 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 31 

 
included in the CytomX Licensed Intellectual Property, the ImmunoGen Licensed Intellectual Property or Joint Patent Rights or otherwise exercising its rights under this Section 5.2,
such Party, and its Affiliates, employees, agents or representatives, shall not be liable to the other Party in respect of any act or omission on the part of any such Party, or its Affiliates, employees, agents or representatives, in connection with
such activities undertaken in good faith. 
 5.2.8. Extensions. The decision to file for a patent term extension and particulars
thereof (including which patent(s) to extend) will be made with the goal of obtaining the optimal patent term and scope of protection for Licensed Products. If a Party wishes to file for a patent term extension based on Patent Rights owned by the
other Party, it will so notify the other Party, and the Parties will meet to discuss and determine whether and how to proceed with such patent term extension. 

5.3. Joint Research Agreement. This Agreement shall be understood to be a joint research agreement under 35 U.S.C.
§ 103(c)(3) entered into for the purpose of researching and identifying Agreement PDCs. 
  

	6.	CONFIDENTIALITY 

 6.1. Confidentiality. Except to the extent expressly authorized
by this Agreement, the Parties agree that, during the Term and for [***] thereafter, each Party, in its capacity as the Receiving Party shall: (a) keep the Disclosing Party’s Confidential Information confidential; (b) not disclose, or
permit the disclosure of, the Disclosing Party’s Confidential Information; and (c) not use, or permit to be used, the Disclosing Party’s Confidential Information for any purpose, in each case, except for the performance of its
obligations or exercise of its rights under this Agreement, provided, however, that the foregoing obligations shall not apply, or shall cease to apply, to the extent that such Confidential Information (i) was already known by the Receiving
Party or its Affiliates (other than under an obligation of confidentiality to the Disclosing Party) at the time of disclosure by the Disclosing Party; (ii) was generally available to the public or otherwise part of the public domain at the time
of its disclosure to the Receiving Party; (iii) became generally available to the public or otherwise part of the public domain after its disclosure to the Receiving Party, other than through any act or omission of the Receiving Party or its
Affiliates or any of their respective Representatives in breach of its obligations under this Agreement; (iv) was disclosed to the Receiving Party or its Affiliates, other than under an obligation of confidentiality, by a Third Party who had no
obligation to the Disclosing Party not to disclose such information to the Receiving Party; or (v) was independently discovered or developed by or on behalf of the Receiving Party without the use of any Confidential Information of the
Disclosing Party. 
  
 ***Certain information contained herein has been omitted
and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 32 

 6.2. Authorized Disclosure. 

6.2.1. Disclosure to Party Representatives. Notwithstanding the foregoing provisions of Section 6.1 hereof, the Receiving
Party may disclose Confidential Information belonging to the Disclosing Party to the Receiving Party’s Representatives who (a) have a need to know such Confidential Information in connection with the performance of the Receiving
Party’s obligations or the exercise of the Receiving Party’s rights under this Agreement and (b) have agreed in writing to non-disclosure and non-use provisions with respect to such Confidential Information that are at least as
restrictive as those set forth in this Article 6. 
 6.2.2. Disclosure to Third Parties. 

(a) Notwithstanding the foregoing provisions of Section 6.1 hereof, the Parties may disclose Confidential Information belonging to
the other Party: 
 (i) subject to Section 5.2 hereof, to the extent reasonably necessary, in connection with filing or
prosecuting Patent Rights as permitted by this Agreement; 
 (ii) to the extent reasonably necessary, in connection with prosecuting or
defending litigation as permitted by this Agreement; 
 (iii) (A) regarding the existence of this Agreement, this Agreement itself or the
material and financial terms of this Agreement, to its accountants, lawyers, and other advisers, and to actual or potential investors, lenders, licensors, licensees, acquirers, investment bankers, or agents of the foregoing in connection with a
financing, licensing transaction, merger, or acquisition, and (B) to any other third parties in connection with the events in (A) with the consent of the disclosing Party, such consent not to be unreasonably withheld, in each case
(A)-(B) under confidentiality obligations no less restrictive than those set forth in this Agreement; 
 (iv) subject to
Section 6.3.2 hereof, in connection with or included in scientific presentations and publications relating to Licensed Products, including abstracts, posters, journal articles and the like, and posting results of and other information
about clinical trials to clinicaltrials.gov or PhRMA websites; and 
 (v) to the extent necessary in order to enforce its rights under this
Agreement. 
 (b) Subject to the restrictions in Section 5.2.5 hereof, data generated by a Party using that Party’s own
Agreement PDC(s) shall not be considered Confidential Information of the other Party, and, therefore, not subject to this Article 6. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 33 

 6.2.3. SEC Filings and Other Disclosures. Notwithstanding any provision of this Agreement
to the contrary, either Party may disclose the existence or terms of this Agreement to the extent required, in the reasonable opinion of such Party’s legal counsel, to comply with Applicable Law. Notwithstanding the foregoing, before disclosing
this Agreement or any of the terms hereof pursuant to this Section 6.2.3, the Parties will consult with one another on the terms of this Agreement to be redacted in making any such disclosure. Further, if a Party discloses this Agreement
or any of the terms hereof in accordance with this Section 6.2.3, such Party shall, at its own expense, use Commercially Reasonable Efforts to seek such confidential treatment of confidential portions of this Agreement and such other
terms, as may be reasonably requested by the other Party. 
 6.3. Public Announcements; Publications. 

6.3.1. Announcements. Except as may be expressly permitted under Section 6.2.3, neither Party will make any public
announcement regarding the existence or terms of this Agreement without the prior written approval of the other Party. For the sake of clarity, nothing in this Agreement shall prevent either Party from making any public disclosure relating to this
Agreement if the contents of such public disclosure have previously been made public other than through a breach of this Agreement by the issuing Party or its Affiliates. The Parties agree that they will issue a joint press release, substantially in
the form attached as Exhibit B attached hereto, regarding the signing of this Agreement following the Effective Date. The Parties agree that each Party may issue future announcements concerning the other Party’s achievement of any
significant milestones, including the selection of a clinical candidate, under this Agreement, provided that the content of any such announcement has been mutually agreed upon by the Parties but a Party will not unreasonably withhold its agreement
to such an announcement. 
 6.3.2. Publications. The Parties acknowledge that scientific publications and presentations must be
strictly monitored to prevent any adverse effect from premature publication or dissemination of results of the activities hereunder. Each Party (in such capacity the “Publishing Party”) agrees that, except as required by Applicable
Laws, it shall not publish or present, or permit to be published or presented, any results of the Research Program to the extent such results refer to, derive from or otherwise relate to (a) in cases where CytomX is the Publishing Party, the
ImmunoGen Technology, (b) in cases where ImmunoGen is the Publishing Party, the CytomX Technology, and (c) in cases 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 34 

 
where either Party is the Publishing Party, the Joint Program Technology, the Agreement PDCs or the ImmunoGen Probodies (the “Covered Results”), without the prior review by and
approval of the other Party (in such capacity, the “Non-Disclosing Party”), which approval shall not be unreasonably withheld; provided that (i) it shall not be deemed unreasonable for CytomX to withhold its consent to any
request by ImmunoGen to publish or disseminate Covered Results relating to CytomX Agreement PDCs prior to the publication or dissemination of such Covered Results by CytomX, and (ii) it shall not be deemed unreasonable for ImmunoGen to withhold
its consent to any request by CytomX to publish or disseminate Covered Results relating to ImmunoGen Probodies and ImmunoGen Agreement PDCs prior to the publication or dissemination of such Covered Results by ImmunoGen. The Publishing Party shall
submit to the Non-Disclosing Party for review and approval any proposed academic, scientific and medical publication or public presentation which contains Covered Results or otherwise contains the Non-Disclosing Party’s Confidential
Information. In both instances, such review and approval will be conducted for the purposes of preserving the value of the CytomX Technology and ImmunoGen Technology and determining whether any portion of the proposed publication or presentation
containing the Non-Disclosing Party’s Confidential Information should be modified or deleted. Written copies of such proposed publication or presentation required to be submitted hereunder shall be submitted to the Non-Disclosing Party no later
than [***] before submission for publication or presentation (the “Review Period”). The Non-Disclosing Party shall provide its comments with respect to such publications and presentations within [***] after its receipt of such
written copy, and the Publishing Party shall delete any Confidential Information of the Non-Disclosing Party upon request. The Review Period may be extended for an additional [***] in the event the Non-Disclosing Party can, within [***] of receipt
of the written copy, demonstrate reasonable need for such extension, including for the preparation and filing of patent applications. The Parties will each comply with standard academic practice regarding authorship of scientific publications and
recognition of contribution of other parties in any publication governed by this Section 6.3.2. 
 6.3.3. Integration. As
to the subject matter of this Agreement, this Article 6 supersedes any confidential disclosure agreements between the Parties, including, without limitation, the Confidentiality Agreement. Any confidential information of a Party
disclosed under the Confidentiality Agreement relating to the subject matter of this Agreement shall be treated as Confidential Information of such Party hereunder, subject to the terms of this Article 6. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 35 

	7.	REPRESENTATIONS AND WARRANTIES. 

 7.1. Mutual Representations and Warranties. Each
of CytomX and ImmunoGen hereby represents and warrants to the other that: 
 7.1.1. it is duly organized, validly existing and in good
standing under the laws of the jurisdiction of its organization; 
 7.1.2. the execution, delivery and performance of this Agreement by such
Party has been duly authorized by all requisite action under the provisions of its charter, bylaws and other organizational documents, and does not require any action or approval by any of its shareholders or other holders of its voting securities
or voting interests; 
 7.1.3. it has the power and authority to execute and deliver this Agreement and to perform its obligations hereunder;

 7.1.4. this Agreement has been duly executed and is a legal, valid and Binding Obligation on it, enforceable against it in accordance with
its terms; and 
 7.1.5. the execution, delivery and performance by such Party of this Agreement and its compliance with the terms and
provisions hereof does not and will not conflict with or result in a breach of or default under any Binding Obligation existing as of the Effective Date. 

7.2. Representations and Warranties of CytomX. CytomX hereby represents and warrants to ImmunoGen that as of the Effective Date: 

7.2.1. to its Knowledge: (a) the issued and unexpired patents within the CytomX Licensed Intellectual Property are valid and enforceable
patents and (b) CytomX has received no written notice from a Third Party challenging or threatening to challenge the extent, validity or enforceability of any CytomX Patent Rights within the CytomX Licensed Intellectual Property; 

7.2.2. to its Knowledge, CytomX has received no written notice from a Third Party claiming that the use, practice or application by CytomX or
ImmunoGen of any CytomX Licensed Intellectual Property pursuant to the license granted hereunder will infringe any valid claim of an issued and unexpired patent of any such Third Party (excluding, for clarity, any potential infringement that might
arise solely as a result of the combination of any CytomX Licensed Intellectual Property with any other technology or intellectual property); and 

7.2.3. there is no (a) claim, demand, suit, proceeding, arbitration, inquiry, investigation or other legal action of any nature, civil,
criminal, regulatory or otherwise, pending or, to the Knowledge of CytomX, threatened against CytomX 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 36 

 
or any of its Affiliates or (b) judgment or settlement against or owed by CytomX or any of its Affiliates, in each case in connection with the CytomX Licensed Intellectual Property or
relating to the transactions contemplated by this Agreement. 
 For purposes of this Section 7.2, “Knowledge”
means the actual knowledge (without having conducted, or having any duty to conduct, any specific inquiry) of its Chief Executive Officer, President, any Vice President or other officer who is in charge of a principal business unit or function or
who performs a policy-making function, and its Senior Director, Head of Intellectual Property (or person with similar responsibilities). 

7.3. Representations and Warranties of ImmunoGen. ImmunoGen hereby represents and warrants to CytomX that as of the Effective Date: 

7.3.1. to its Knowledge: (a) the issued and unexpired patents within the ImmunoGen Licensed Intellectual Property are valid and
enforceable patents and (b) ImmunoGen has received no written notice from a Third Party challenging or threatening to challenge the extent, validity or enforceability of any ImmunoGen Patent Rights within the ImmunoGen Licensed Intellectual
Property; 
 7.3.2. to its Knowledge, ImmunoGen has received no written notice from a Third Party claiming that the use, practice or
application by CytomX or ImmunoGen of any ImmunoGen Licensed Intellectual Property pursuant to the license granted hereunder will infringe any valid claim of an issued and unexpired patent of any Third Party (excluding, for clarity, any potential
infringement that might arise solely as a result of the combination of any ImmunoGen Licensed Intellectual Property with any other technology or intellectual property); and 

7.3.3. there is no (a) claim, demand, suit, proceeding, arbitration, inquiry, investigation or other legal action of any nature, civil,
criminal, regulatory or otherwise, pending or, to its Knowledge, threatened against ImmunoGen or any of its Affiliates or (b) judgment or settlement against or owed by ImmunoGen or any of its Affiliates, in each case in connection with the
ImmunoGen Licensed Intellectual Property or relating to the transactions contemplated by this Agreement. 
 For purposes of this
Section 7.3, “Knowledge” means the actual knowledge (without having conducted, or having any duty to conduct, any specific inquiry) of the following ImmunoGen employees: (i) any “executive officer” (as
defined in Rule 3b-7 promulgated under the Securities Exchange Act of 1934, as amended) [***]. 
 7.4. Government Approvals. Each
of CytomX and ImmunoGen shall cooperate with the other Party and use Commercially Reasonable Efforts to make all registrations, filings and applications, to give all notices and to obtain as soon as practicable all governmental 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 37 

 
or other consents, transfers, approvals, orders, qualifications authorizations, permits and waivers, if any, and to do all other things necessary or desirable for the consummation of the
transactions as contemplated hereby. 
 7.5. Further Covenants. In addition to the covenants made elsewhere in this Agreement, each
Party hereby covenants to the other Party that, from the Effective Date until expiration or termination of this Agreement, it will not (a) knowingly take any action that conflicts with the rights under the Licensed Intellectual Property granted
to the other Party under this Agreement or (b) knowingly fail to take any action that is reasonably necessary to avoid a conflict with the rights under the Licensed Intellectual Property granted to the other Party under this Agreement. 

7.6. Representation by Legal Counsel. Each Party hereto represents that it has been represented by legal counsel in connection with this
Agreement and acknowledges that it has participated in the drafting hereof. In interpreting and applying the terms and provisions of this Agreement, the Parties agree that no presumption shall exist or be implied against the Party which drafted such
terms and provisions. 
 7.7. Warranty Disclaimers. 

7.7.1. Except as expressly set forth in Section 7.2 or 7.3 hereof, nothing in this Agreement is or shall be construed as a
warranty or representation by either Party (a) as to the validity or scope of any patent application or patent within such Party’s Patent Rights or (b) that anything made, used, sold or otherwise disposed of under any license granted
under this Agreement is or will be free from infringement of patents, copyrights and other rights of Third Parties. 
 7.7.2. EXCEPT AS
OTHERWISE EXPRESSLY PROVIDED IN THIS AGREEMENT, NEITHER PARTY MAKES ANY REPRESENTATION OR EXTENDS ANY WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REPECT TO ANY TECHNOLOGY, GOODS, SERVICES, RIGHTS OR OTHER SUBJECT MATTER OF THIS AGREEMENT,
INCLUDING, WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. 
  

	8.	TERM AND TERMINATION. 

 8.1. Term. The term of this Agreement (the
“Term”) shall commence on the Effective Date and shall extend until the fourth (4th) anniversary of the Effective Date, unless this Agreement is terminated earlier in
accordance with this Article 8. Notwithstanding the foregoing, this Agreement shall terminate as to each Research Program Target upon the exercise of the Option with respect to such Research Program Target. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 38 

 8.2. Termination by Either Party for Cause. Either Party may terminate this Agreement in
its entirety at any time during the Term by giving written notice to the other Party if the other Party commits a material breach of its obligations under this Agreement (a “Material Breach”), such notice to describe such Material
Breach in reasonable detail, and such Material Breach remains uncured for [***] days, measured from the date written notice of such breach is given to the breaching Party; provided, however, that if the nature of the asserted breach is such
that more than [***] days are reasonably required to cure, then the cure period shall be extended for a period not to exceed an additional [***] days so long as the Party seeking to cure the asserted breach is diligently pursuing such cure
to completion. Notwithstanding the foregoing, a Party shall have the right to terminate this Agreement pursuant to this Section 8.2 only if such Material Breach fundamentally frustrates the objectives of or transactions contemplated by
this Agreement taken as a whole or a Work Plan relating to the non-breaching Party’s Research Program Target(s). 
 8.3. Termination
on Insolvency. This Agreement may be terminated upon written notice by either Party at any time in the event of an Insolvency Event of the other Party. 

8.4. Effects of Expiration or Termination. 

8.4.1. Effect of Termination by ImmunoGen. If ImmunoGen terminates this Agreement pursuant to Section 8.2 or
Section 8.3 hereof, then: 
 (a) the license granted by ImmunoGen to CytomX under Section 3.2.1 hereof and the
CytomX Option shall immediately terminate; 
 (b) without limiting ImmunoGen’s rights set forth in clause (c) below, CytomX
and ImmunoGen and their respective Affiliates shall immediately cease any and all work under any then-outstanding Work Plan; 
 (c) the
license and Options granted to ImmunoGen by CytomX under Section 3.1.1 hereof with respect to the ImmunoGen Research Program Targets shall continue on the terms set forth herein, and such license shall be expanded to permit ImmunoGen and
its Affiliates to perform any and all activities in connection with the Research Program with respect to the ImmunoGen Program Targets that would otherwise have been performed by CytomX; 

(d) each Party shall promptly destroy all CytomX Agreement PDCs; and 

(e) CytomX shall promptly return or destroy all of ImmunoGen’s Confidential Information and Proprietary Material, provided that CytomX
may retain, subject to Article 6 hereof, (i) one (1) copy of ImmunoGen’s Confidential Information in its archives solely for the purpose of 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 39 

 
establishing the contents thereof and ensuring compliance with its obligations hereunder, (ii) any Confidential Information of ImmunoGen contained in its laboratory notebooks or databases
and (iii) any Confidential Information and Proprietary Material of ImmunoGen to the extent reasonably required to exercise its rights and perform its obligations under any outstanding License Agreement. 

The foregoing notwithstanding, and subject to Article 6 hereof, ImmunoGen may retain and use CytomX’s Confidential Information
and Proprietary Material in connection with the exercise of its rights set forth in clause (c) above and to the extent reasonably required to exercise its rights and perform its obligations under any outstanding License Agreement. 

8.4.2. Effect of Termination by CytomX. If CytomX terminates this Agreement pursuant to Section 8.2 or
Section 8.3 hereof, then 
 (a) the license granted by CytomX to ImmunoGen under Section 3.1.1 hereof and the
ImmunoGen Options shall immediately terminate; 
 (b) without limiting CytomX’s rights under clause (c) below, CytomX and
ImmunoGen and their respective Affiliates shall immediately cease any and all work under any then-outstanding Work Plan(s); 
 (c) the
license and Option granted to CytomX by ImmunoGen under Section 3.2.1 hereof with respect to the CytomX Research Program Target shall continue on the terms set forth herein, and such license shall be expanded to permit CytomX and its
Affiliates to perform any and all activities in connection with the Research Program with respect to the CytomX Research Target that would otherwise have been performed by ImmunoGen; 

(d) each Party shall promptly destroy all ImmunoGen Agreement PDCs; and 

(e) ImmunoGen shall promptly return or destroy all of CytomX’s Confidential Information and Proprietary Material, provided that ImmunoGen
may retain, subject to Article 6 hereof, (i) one (1) copy of CytomX’s Confidential Information in its archives solely for the purpose of establishing the contents thereof and ensuring compliance with its obligations
hereunder, (ii) any Confidential Information of CytomX contained in its laboratory notebooks or databases and (iii) any Confidential Information and Proprietary Material of CytomX to the extent reasonably required to exercise its rights
and perform its obligations under any outstanding License Agreement. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 40 

 The foregoing notwithstanding, and subject to Article 6 hereof, CytomX may retain and
use ImmunoGen’s Confidential Information and Proprietary Material in connection with the exercise of its rights set forth in clause (c) above and to the extent reasonably required to exercise of its rights and perform its
obligations under any outstanding License Agreement. 
 8.4.3. Satisfaction of Obligations During Notice Period. During the period
from providing a notice of termination through the termination of the Agreement, the Parties shall continue to perform their obligations under this Agreement. 

8.4.4. Pending Dispute Resolution. If a Party gives notice of termination and the other Party disputes whether such notice was proper,
then the issue of whether this Agreement has been terminated shall be resolved in accordance with Section 10.9 and this Agreement shall remain in effect pending the resolution of such dispute. If as a result of such dispute resolution
process it is determined that the notice of termination was proper, then such termination shall be effective immediately. If as a result of such dispute resolution process it is determined that the notice of termination was improper, then no
termination shall have occurred and this Agreement shall remain in effect. Anything contained in this Agreement to the contrary notwithstanding, if the asserted breach is cured or shown to be non-existent within the applicable cure period, the first
notice of breach hereunder shall be deemed automatically withdrawn and of no effect. 
 8.5. Effect of Expiration of this Agreement.
If this Agreement expires in accordance with its terms (other than by reason of termination under Section 8.2 or 8.3 hereof), then: 

8.5.1. the licenses granted by each Party to the other Party under Section 3.1.1 and Section 3.2.1 hereof and all
Options shall immediately terminate; 
 8.5.2. CytomX and ImmunoGen and their respective Affiliates shall immediately cease any and all work
under any then-outstanding Work Plans; 
 8.5.3. each Party shall promptly destroy all ImmunoGen Probodies and Agreement PDCs except those,
if any, Targeting a Licensed Target: 
 8.5.4. each Party shall promptly return or destroy all of the Confidential Information and
Proprietary Material of the other Party, provided that each Party may retain, subject to Article 6 hereof, (a) one (1) copy of the other Party’s Confidential Information in its archives solely for the purpose of
establishing the contents thereof and ensuring compliance with its obligations hereunder, (b) any Confidential Information of the other Party contained in its laboratory notebooks or databases and (c) any Confidential Information and
Proprietary Material of the other Party to the extent reasonably required to exercise its rights and perform its obligations under any outstanding License Agreement. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 41 

 8.6. Remedies. [***], the rights of the non-breaching Party set forth in
Section 8.4 hereof shall be the exclusive legal remedy to a Party arising from a Material Breach; provided, however, that (a) in addition to the foregoing legal remedy, the Parties may seek any and all equitable remedies, including,
without limitation, declarative and injunctive relief and specific performance in accordance with applicable law, and (b) nothing in this Section shall limit the Parties’ respective rights and obligations with respect to
(i) Unauthorized Use of the other Party’s Confidential Information or Proprietary Materials, (ii) unauthorized disclosure of the other Party’s Confidential Information or (iii) indemnification as set forth in
Article 9 hereof. 
 8.7. Survival of Certain Obligations. Expiration or termination of this Agreement shall not relieve
the Parties of any obligation that accrued before such expiration or termination. The following provisions shall survive expiration or termination of this Agreement: Sections 2.6, 2.10, 3.1.5 and 3.2.5,
Articles 4, 5 and 6, Sections 7.7, 8.1, 8.4, 8.5, 8.6 and 8.7, and Articles 9 and 10. For avoidance of doubt, any other Section that explicitly states it
survives expiration or termination of this Agreement shall so survive. 
  

	9.	LIMITATION ON LIABILITY, INDEMNIFICATION AND INSURANCE. 

 9.1. No Consequential
Damages. Except with respect to liability arising from a breach of Article 6 hereof, in no event will either Party, its Affiliates or any of its or its Affiliates’ respective Representatives be liable under this Agreement for any
special, indirect, incidental, consequential or punitive or exemplary damages, whether in contract, warranty, tort, negligence, strict liability or otherwise, (a) including loss of profits or revenue suffered by either Party or any of its
respective Affiliates or Representatives or (b) cost of procurement of substitute goods, technology or services, even if either Party is informed in advance of the possibility of such damages and even if the remedies provided for in this
Agreement fail of their essential purpose. For purposes of clarity, a Party’s monetary liability under a Third Party Claim for such Third Party’s special, indirect, incidental or consequential damages or for any punitive or exemplary
damages payable in connection with such Third Party Claim, shall be deemed to be the direct damages of such Party for purposes of this Article 9. 

9.2. Indemnification by ImmunoGen. ImmunoGen will indemnify, defend and hold harmless CytomX, its Affiliates and each of its and their
respective employees, officers, directors and agents (each, a “CytomX Indemnified Party”) from and against any and all liability, loss, damage, expense (including reasonable attorneys’ fees and expenses) and cost (collectively,
a “Liability”) as a direct result of any Third Party claims, suits, actions, demands or judgments, including, without limitation, personal injury and product liability matters (collectively, “Third Party Claims”)
arising out of: 
 (a) the conduct of any Work Plan by ImmunoGen or any of its Affiliates; or 

(b) a Material Breach of this Agreement by ImmunoGen; 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 42 

 except, in each case, to the extent any such Third Party Claim or Liability results from a
Material Breach of this Agreement by CytomX or the negligence, recklessness or intentional acts of CytomX or any CytomX Indemnified Party; provided that with respect to any Third Party Claim for which CytomX also has an obligation to indemnify any
ImmunoGen Indemnified Party pursuant to Section 9.3 hereof, ImmunoGen shall indemnify each CytomX Indemnified Party for its Liability to the extent of ImmunoGen’s responsibility, relative to CytomX (or to Persons for whom CytomX is legally
responsible), for the facts underlying the Third Party Claim. 
 9.3. Indemnification by CytomX. CytomX will indemnify, defend and
hold harmless ImmunoGen, its Affiliates, contractors, distributors and each of its and their respective employees, officers, directors and agents (each, a “ImmunoGen Indemnified Party”) from and against any and all Liabilities as a
direct result of any Third Party Claims arising out of: 
 (a) the conduct of any Work Plan by CytomX or any of its Affiliates; or 

(b) a Material Breach of this Agreement by CytomX; 

except to the extent any such Third Party Claim or Liability results from a Material Breach of this Agreement by ImmunoGen or the negligence,
recklessness or intentional acts of ImmunoGen or any ImmunoGen Indemnified Party; provided that with respect to any Third Party Claim for which ImmunoGen also has an obligation to indemnify any CytomX Indemnified Party pursuant to Section 9.2
hereof, CytomX shall indemnify each ImmunoGen Indemnified Party for its Liability to the extent of CytomX’s responsibility, relative to ImmunoGen (or to Persons for whom ImmunoGen is legally responsible), for the facts underlying the Third
Party Claim. 
 9.4. Procedure. 

9.4.1. Notice. Each Party will notify the other Party in writing in the event it becomes aware of a claim for which indemnification may
be sought hereunder. In the event that any Third Party asserts a claim or other proceeding (including any governmental investigation) with respect to any matter for which a Party (the “Indemnified Party”) is entitled to
indemnification hereunder, then the Indemnified Party shall promptly notify the Party obligated to indemnify the Indemnified Party (the “Indemnifying Party”) thereof; provided, however, that no delay on the part of the Indemnified
Party in notifying the Indemnifying Party shall relieve the Indemnifying Party from any obligation hereunder unless (and then only to the extent that) the Indemnifying Party is prejudiced thereby. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 43 

 9.4.2. Control. The Indemnifying Party shall have the right, at its sole cost and expense,
exercisable by notice to the Indemnified Party within ten (10) Business Days after receipt of notice from the Indemnified Party of the commencement of or assertion of any Third Party Claim, to assume direction and control of the defense,
litigation, settlement, appeal or other disposition of the Third Party Claim (including the right to settle the claim solely for monetary consideration) with counsel selected by the Indemnifying Party and reasonably acceptable to the Indemnified
Party. The Indemnified Party shall cooperate, and shall cause its Affiliates and agents to cooperate upon request of the Indemnifying Party, in the defense or prosecution of the Third Party Claim, including by furnishing such records, information
and testimony and attending such conferences, discovery proceedings, hearings, trials or appeals as may reasonably be requested by the Indemnifying Party. The Indemnified Party shall have the right to join in (including the right to conduct
discovery, interview and examine witnesses and participate in all settlement conferences), but not control, at its own expense, the defense of any Third Party Claim that the other Party is defending as provided in this Agreement. 

9.4.3. Settlement. Neither the Indemnifying Party nor the Indemnified Party shall enter into any compromise or settlement of a Third
Party Claim for which the right to indemnification hereunder has been asserted without the Indemnified Party’s prior written consent, which consent shall not be unreasonably withheld, conditioned or delayed; provided that the Indemnifying Party
may, without the Indemnified Party’s prior written consent, agree or consent to any settlement or other resolution of such Third Party Claim which requires solely money damages paid by the Indemnifying Party, and which includes as an
unconditional term thereof the giving by such claimant or plaintiff to the Indemnified Party of a release from all liability in respect of such Third Party Claim. Each of the Indemnifying Party and the Indemnified Party shall not make any admission
of liability in respect of any Third Party Claim without the prior written consent of the other Party, and the Indemnified Party shall use reasonable efforts to mitigate Liabilities arising from such Third Party Claim. 

9.5. Insurance. Each Party shall obtain and maintain, during the Term, commercial general liability insurance, including products
liability insurance, with reputable and financially secure insurance carriers (or pursuant to a program of self-insurance reasonably satisfactory to the other Party) to cover its indemnification obligations under Section 9.2 or
Section 9.3 hereof with respect to bodily injury (including death) and damage to property, as applicable, in each case with limits of not less than $3,000,000 per occurrence and in the aggregate. Insurance (other than permitted
self-insurance) shall be procured with carriers having an A.M. Best Rating of A-VII or better. Any indemnification payment hereunder shall be made net of any insurance proceeds which the Indemnified Party is entitled to recover; provided,
however, that if, following the 
  
 ***Certain information contained herein has
been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 44 

 
payment to the Indemnified Party of any amount under this Article 9, such Indemnified Party becomes entitled to recover any insurance proceeds in respect of the claim for which such
indemnification payment was made, the Indemnified Party shall promptly pay an amount equal to the amount of such proceeds (but not exceeding the amount of such indemnification payment) to the Indemnifying Party. 

 

	10.	MISCELLANEOUS. 

 10.1. Assignment. Neither Party may assign this Agreement without
the prior written consent of the other Party, which consent will not be unreasonably withheld, conditioned or delayed; provided, however, that such consent shall not be required in connection with any assignment of this Agreement to an Affiliate of
the assigned Party, or to a Third Party in connection with the transfer or sale of the business to which this Agreement relates, or to any successor Person resulting from any merger or consolidation of such Party with or into such Person, provided
that the assignee shall have agreed in writing to assume all of the assignor’s obligations hereunder, and provided, further, that the other Party shall be notified promptly after such assignment has been effected. This Agreement shall be
binding upon the successors and permitted assigns of the Parties and the name of a Party appearing herein shall be deemed to include the names of such Party’s successors and permitted assigns to the extent necessary to carry out the intent of
this Agreement. Any purported assignment not in accordance with this Section 10.1 shall be null and void. 
 10.2. Further
Actions. Each Party agrees to execute, acknowledge and deliver such further instruments, and to do all such other acts, as may be necessary or appropriate in order to carry out the purposes and intent of the Agreement. 

10.3. Force Majeure. Each Party shall be excused from the performance of its obligations under this Agreement to the extent that such
performance is prevented by force majeure (defined below) and the nonperforming Party promptly provides notice of the prevention to the other Party. Such excuse shall be continued so long as the condition constituting force majeure
continues and the nonperforming Party takes Commercially Reasonable Efforts to resume performance. For purposes of this Agreement, “force majeure” shall include conditions beyond the control of the Parties, including an act of God,
voluntary or involuntary compliance with any Applicable Law or order of any government, war, act of terror, civil commotion, labor strike or lock-out, epidemic, failure or default of public utilities or common carriers, or destruction of production
facilities or materials by fire, earthquake, storm or like catastrophe. 
 10.4. Notices. Any notice or notification required or
permitted to be provided pursuant to the terms and conditions of this Agreement (including any notice of force majeure, breach, termination, change of address, etc.) shall be in writing and shall be deemed given upon receipt if delivered
personally or by facsimile transmission (receipt verified), five (5) Business Days after deposited in the mail if mailed by certified mail (return 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 45 

 
receipt requested) postage prepaid, or on the next Business Day if sent by overnight delivery using a nationally recognized express courier service and specifying next Business Day delivery
(receipt verified), to the Parties at the following addresses or facsimile numbers (or at such other address or facsimile number for a Party as shall be specified by like notice, provided, however, that notices of a change of address shall be
effective only upon receipt thereof): 
 All correspondence to ImmunoGen shall be addressed as follows: 

ImmunoGen, Inc. 
 830 Winter
Street 
 Waltham, MA 02451 

Attn: Vice President, Business Development 

Fax: [***] 
 All correspondence
to CytomX shall be addressed as follows: 
 CytomX Therapeutics, Inc. 

343 Oyster Point Blvd., Suite 100 

South San Francisco, CA 94080-7014 

Attn: CEO 
 Fax:
(650) 351-0353 
 To help expedite the other Party’s awareness and response, copies of notices may be provided to the other Party
by email but must be supplemented by one of the following methods: (a) personal delivery, (b) first class certified mail with return receipt requested, or (c) next-day delivery by major international courier, with confirmation of
delivery. Electronic copies may be sent via email to [***] at CytomX and to [***] at ImmunoGen so long as such individuals remain employed by CytomX or ImmunoGen, respectively. 

10.5. Amendment. No amendment, modification or supplement of any provision of this Agreement shall be valid or effective unless made in
writing and signed by a duly authorized officer of the Party to be bound. 
 10.6. Waiver. No provision of this Agreement shall be
waived by any act, omission or knowledge of a Party or its agents or employees except by an instrument in writing expressly waiving such provision and signed by a duly authorized officer of the waiving Party. The waiver by either of the Parties of
any breach of any provision hereof by the other Party shall not be construed to be a waiver of any succeeding breach of such provision or a waiver of the provision itself. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 46 

 10.7. Severability. If any clause or portion thereof in this Agreement is for any reason
held to be invalid, illegal or unenforceable, the same shall not affect any other portion of this Agreement, as it is the intent of the Parties that this Agreement shall be construed in such fashion as to maintain its existence, validity and
enforceability to the greatest extent possible. In any such event, this Agreement shall be construed as if such clause or portion thereof had never been contained in this Agreement, and there shall be deemed substituted therefor such provision as
will most nearly carry out the intent of the Parties as expressed in this Agreement to the fullest extent permitted by Applicable Law. 

10.8. Descriptive Headings. The descriptive headings of this Agreement are for convenience only and shall be of no force or effect in
construing or interpreting any of the provisions of this Agreement. 
 10.9. Dispute Resolution. The Parties recognize that a
bona fide dispute as to certain matters may arise from time to time during the Term relating to the conduct of the Research Program, Work Plan Activities, either Party’s rights or obligations hereunder or otherwise relating to the
validity, enforceability or performance of this Agreement, including disputes relating to alleged breach or termination of this Agreement but excluding any disputes relating to Article 6 hereof or disputes relating to the determination
of the validity, scope, infringement, enforceability, inventorship or ownership of the Parties’ respective Patent Rights (hereinafter, a “Dispute”). In the event of the occurrence of any Dispute, the Parties shall follow the
following procedures in an attempt to resolve the dispute or disagreement: 
 10.9.1. The Party claiming that such a Dispute exists shall
give notice in writing (a “Notice of Dispute”) to the other Party of the nature of the Dispute. 
 10.9.2. Within
[***] days of receipt of a Notice of Dispute, the ImmunoGen Alliance Manager and the CytomX Alliance Manager shall meet in person or by teleconference and exchange written summaries reflecting, in reasonable detail, the nature and extent of the
Dispute, and at this meeting they shall use their reasonable endeavors to resolve the Dispute. 
 10.9.3. If the Alliance Managers are unable
to resolve the Dispute during the meeting described in Section 10.9.2 hereof or if for any reason such meeting does not take place within the period specified in Section 10.9.2 hereof, then the Dispute will be referred to the
JRC which shall meet no later than [***] days following the initial receipt of the Notice of Dispute and use reasonable endeavors to resolve the Dispute. 

10.9.4. If the JRC is unable to resolve the Dispute during the meeting described in Section 10.9.3 hereof or if for any reason such
meeting does not take place within the period specified in Section 10.9.3 hereof, then the Chief Executive Officer of ImmunoGen and the Chief Executive Officer of CytomX shall meet at a mutually agreed-upon time and location for the
purpose of resolving such Dispute. 
  
 ***Certain information contained herein
has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 47 

 10.9.5. If, within [***] days of initial receipt of the Notice of Dispute, the Dispute has
not been resolved, or if, for any reason, the meeting described in Section 10.9.4 hereof has not been held within [***] days of initial receipt of the Notice of Dispute, then the Parties agree that such Dispute shall be finally
resolved through binding arbitration to be administered by JAMS pursuant to its Comprehensive Arbitration Rules and Procedures and in accordance with the Expedited Procedures in those Rules, as specifically modified by the provisions of this
Section 10.9.5. 
 (a) Arbitration Panel. The arbitration shall be conducted by a panel of three (3) arbitrators.
Within [***] days after the initiation of the arbitration, each Party will nominate one person to act as arbitrator, and the two arbitrators so named will then jointly appoint the third arbitrator within [***] days of their appointment,
who will serve as chairman of the panel. All three (3) arbitrators must be independent Third Parties having at least [***] years of dispute resolution experience (which may include judicial experience) and/or legal or business experience
in the biotech or pharmaceutical industry. If either Party fails to nominate its arbitrator, or if the arbitrators selected by the Parties cannot agree on a person to be named as chairman within such [***] day period, JAMS will make the
necessary appointments for such arbitrator(s) or the chairman. Once appointed by a Party, such Party shall have no ex parte communication with its appointed arbitrator. 

(b) Location and Proceedings. The place of arbitration will be in the Borough of Manhattan, City of New York, NY or such other venue as
the Parties may mutually agree. The arbitration proceedings and all communications with respect thereto shall be in English. Any written evidence originally in another language will be submitted in English translation accompanied by the original or
a true copy thereof. The arbitrators have the power to decide all matters in Dispute, including any questions of whether or not such matters are subject to arbitration hereunder. The arbitration shall be governed by the Federal Arbitration Act,
9 U.S.C. §§1 et seq., and judgment upon the award rendered by the arbitrators may be entered in any court having competent jurisdiction thereof. 

(c) Limitation on Awards. The arbitrators shall have no authority to award any special, indirect, incidental, consequential, punitive,
exemplary or other similar damages. Each Party shall bear its own costs and expenses (including attorneys’ fees and expert or consulting fees) incurred 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 48 

 
in connection with the arbitration. The Parties shall equally (50/50) share the arbitrators’ fees and other administrative costs and expenses associated with the arbitration. 

(d) Confidentiality. The existence, content and results of any arbitration proceedings pursuant to this Section 10.9.5
shall be deemed the Confidential Information of both Parties. 
 10.9.6. Notwithstanding any provision of this Agreement to the contrary,
either Party may immediately initiate litigation in any court of competent jurisdiction seeking any remedy at law or in equity, including the issuance of a preliminary, temporary or permanent injunction, to preserve or enforce its rights under this
Agreement. 
 10.10. Patent Disputes and Disputes Relating to Article 6. 

10.10.1. Inventorship. Any dispute, controversy or claim between the Parties involving the inventorship of any Program Technology that
is not resolved by mutual agreement of the Party’s respective chief patent counsels (or persons with similar responsibilities) within [***] days after the date the dispute is raised by one or both of the Parties shall be submitted to an
Independent Patent Counsel for resolution. Such Independent Patent Counsel’s determination of inventorship, absent manifest error, shall be final and binding on the Parties; provided, however, that any such determination with respect to a
patent application shall not preclude either Party from disputing inventorship with respect to any patents issuing from such patent application, which disputes shall be resolved in accordance with this Section. The Parties shall equally
(50/50) share the Independent Patent Counsel fees and expenses related to his determination of inventorship. 
 10.10.2. Other Patent
Disputes. Any dispute, controversy or claim between the Parties that involves the validity, scope, infringement, enforceability or ownership of the Parties’ respective Patent Rights (a) that are pending or issued in the United States
shall be subject to actions before the United States Patent and Trademark Office and/or submitted exclusively to the federal court located in the jurisdiction where the Party whose Patent Rights are the subject to such dispute, controversy or claim
resides (provided that if such Party does not reside in the United States, venue shall be the jurisdiction where such Party’s principal U.S. Affiliate resides) and (b) that are pending or issued in any other country (or region) shall be
brought before an appropriate regulatory or administrative body or court in that country (or region), and the Parties hereby consent to jurisdiction and venue in such courts and bodies. 

10.10.3. Disputes Relating to Article 6. Any dispute, controversy or claim between the Parties that relates to the
enforcement of Article 6 hereof shall be subject to action in any court of competent jurisdiction. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 49 

 10.11. Governing Law. This Agreement, and all claims arising under or in connection
therewith, shall be governed by and interpreted in accordance with the substantive laws of the State of New York, without regard to conflict of law principles thereof. 

10.12. Entire Agreement. This Agreement, including its Exhibits and Schedules, constitutes and contains the complete, final and
exclusive understanding and agreement of the Parties and cancels and supersedes any and all prior negotiations, correspondence, understandings and agreements, whether oral or written, between the Parties respecting the subject matter hereof and
thereof, including the Confidentiality Agreement. 
 10.13. Purpose and Scope. The Parties understand and agree that this
Agreement is limited to the activities, rights and obligations as expressly set forth herein. Nothing herein contained shall be deemed to create an employment, agency, joint venture or partnership relationship between the Parties hereto or any of
their agents or employees, or any other legal arrangement that would impose liability upon one Party for the act or failure to act of the other Party. Neither Party shall have any express or implied power to enter into any contracts or commitments
or to incur any liabilities in the name of, or on behalf of, the other Party, or to bind the other Party in any respect whatsoever. 
 10.14.
Counterparts. This Agreement may be executed in two or more counterparts, each of which shall be an original and both of which shall constitute together the same document. Counterparts may be signed and delivered by facsimile or PDF
file, each of which shall be binding when received by the applicable Party. 
 10.15. No Third Party Rights or Obligations.
Except as set forth in Article 9 hereof, no provision of this Agreement shall be deemed or construed in any way to result in the creation of any rights or obligation in any Person not a Party to this Agreement. However, either Party may
decide, in its sole discretion, to use one or more of its Affiliates to perform its obligations and duties hereunder, provided that such Party shall remain liable hereunder for the performance by any such Affiliates of any such obligations. 

10.16. Interpretation. The Parties hereto acknowledge and agree that: (a) each Party and its counsel reviewed and negotiated
the terms and provisions of this Agreement and have contributed to its revision; (b) the rule of construction to the effect that any ambiguities are resolved against the drafting Party shall not be employed in the interpretation of this
Agreement; and (c) the terms and provisions of this Agreement shall be construed fairly as to each Party hereto and not in a favor of or against any Party, regardless of which Party was generally responsible for the preparation of this
Agreement. In addition, unless the context otherwise requires, wherever used in this Agreement: 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 50 

 
(i) the singular shall include the plural, the plural the singular; (ii) the use of any gender shall be applicable to all genders; (iii) the word “or” is used in the
inclusive sense (and/or); (iv) the words “include” or “including” shall be construed as incorporating, also, “but not limited to” or “without limitation” (irrespective of whether the words are used in the
applicable instance); (v) the words “hereof,” “herein,” “hereby” and derivative or similar words refer to this Agreement as a whole and not to any particular provision of this Agreement; and (vi) all
references to “will” are interchangeable with the word “shall” and shall be understood to be imperative or mandatory in nature. 

[The remainder of this page has been intentionally left blank. The signature page follows.] 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 51 

 IN WITNESS WHEREOF, duly authorized representatives of the Parties have duly executed this
Agreement to be effective as of the Effective Date. 
  

									
	IMMUNOGEN, INC.	 		 	CYTOMX THERAPEUTICS, INC.
					
	By:	 	 /s/ Peter Williams
	 		 	By:	 	 /s/ Sean McCarthy

	Name:	 	Peter Williams	 		 	Name:	 	Sean McCarthy
	Title:	 	Vice President, Business Development	 		 	Title:	 	CEO
	Date:	 	January 8, 2014	 		 	Date:	 	

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 EXHIBIT A 

CytomX Research Program Target 

[***] 
 ImmunoGen Research
Program Targets 
 [***] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 EXHIBIT B 

Form of Joint Press Release 

[See Attached 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 

 

					
			
		 	 Contacts for CytomX:
  

For Investors:
 Monique Allaire

Pure Communications, Inc.
 781-631-0759

Monique@purecommunicationsinc.com
  

For Media:
 Kathryn Cook

Pure Communications, Inc.
 910-509-3976

Kathryn@purecommunicationsinc.com
	  	 Contacts for ImmunoGen, Inc.:
  

For Investors:
 Carol Hausner

Executive Director, Investor Relations
 and Corporate
Communications
 ImmunoGen, Inc.
 781-895-0600

info@immunogen.com
  

For Media:
 Barbara Yates

The Yates Network
 781-258-6153

 CytomX Therapeutics and ImmunoGen, Inc. Announce Strategic Collaboration 

to Develop Probody-Drug Conjugates Against Cancer Targets 

– Collaboration enables creation of PDCs using 

CytomX’s Probody Platform and ImmunoGen’s ADC technology – 

SOUTH SAN FRANCISCO, CA, and WALTHAM, MA, January 9, 2014 – CytomX Therapeutics, the ProbodyTM therapeutics company, and
ImmunoGen, Inc. (NASDAQ: IMGN), a biotechnology company that develops targeted anticancer therapies using its validated, industry-leading antibody-drug conjugate (ADC) technology, today announced a multi-year, strategic collaboration to
develop Probody-drug conjugate (PDC) therapies for the treatment of cancer. Probodies are a potentially disruptive class of antibody therapeutics that may further broaden the opportunities for ADCs by localizing therapeutic activity to the
tumor microenvironment. 
 Under the terms of the agreement, the companies will collaborate to develop PDCs against a defined number of targets. This
collaboration brings together CytomX’s proprietary antibody masking technology and tumor-selective protease substrates with ImmunoGen’s highly potent ADC cell-killing agents and engineered linkers. 

Each company retains full development control of PDC compounds resulting from its target selection and is responsible for preclinical and clinical testing,
manufacturing, and commercialization. Each company is entitled to potentially receive clinical and post-approval milestone payments from the other company, as well as royalties on the sales of any marketed products resulting from this collaboration.

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 “This strategic collaboration with ImmunoGen is designed to allow each company to build pipeline value by
capitalizing on the best of both technology platforms,” said Sean McCarthy, D.Phil., chief executive officer of CytomX. “By combining our Probody technology with ImmunoGen’s world class linker-payload capabilities we will accelerate
towards our vision of bringing safer, more effective therapies to patients.” 
 “ImmunoGen is committed to developing better therapies for the
treatment of patients with cancer,” commented John Lambert, PhD, EVP and Chief Scientific Officer. “We believe using our state-of-the-art ADC technology with CytomX’s highly promising Probody Platform will enable us to develop
therapies particularly well-suited for certain challenging cancers.” 
 CytomX’s Probodies are masked monoclonal antibodies that are
designed to remain inert in healthy tissue but be activated specifically in the disease microenvironment. Through precise targeting of the disease microenvironment, Probodies have the potential to address diseases in ways that have not been possible
to-date, enabling a new level of tissue targeting, selectivity and activation. 
 ImmunoGen’s ADC technology is used in Roche’s Kadcyla® and in multiple other ADC compounds now in clinical and preclinical testing. It includes highly potent cancer-cell killing agents developed specifically for targeted delivery to cancer cells
using monoclonal antibodies, and linkers engineered to keep the agent attached to the antibody in the blood steam and control its release and activation inside a cancer cell. 

About CytomX 
 CytomX Therapeutics, the ProbodyTM
therapeutics company, is dedicated to transforming lives with safer, more effective therapies. CytomX’s Probody Platform represents a disruptive approach to discovering and developing the next generation of antibody therapeutics and is enabling
the development of a diversified pipeline in major unmet medical needs including cancer and inflammation. CytomX is led by a seasoned and proven management team and is financed by leading life science investors including Third Rock Ventures, Canaan
Partners and the Roche Venture Fund. For more information, please visit www.cytomx.com. 
 About ImmunoGen, Inc. 

ImmunoGen, Inc. develops targeted anticancer therapeutics. The Company’s ADC technology uses a tumor-targeting engineered antibody to deliver one of
ImmunoGen’s highly potent cancer-cell killing agents specifically to tumor cells; the Company has also developed antibodies with anticancer activity of their own. The most advanced compound with ImmunoGen’s ADC technology is Roche’s
Kadcyla®, which is marketed in the US by Genentech and is also gaining approvals internationally. Additional compounds are in clinical testing by ImmunoGen and through the Company’s
partnerships with Amgen, Bayer HealthCare, Biotest and Sanofi. More information about ImmunoGen can be found at www.immunogen.com. 
 Kadcyla® is a registered trademark of Genentech, Inc., a member of the Roche Group. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 This press release includes forward-looking statements. For these statements, ImmunoGen claims the protection
of the safe harbor for forward-looking statements provided by the Private Securities Litigation Reform Act of 1995. It should be noted that there are risks and uncertainties related to the development of novel anticancer products, including PDCs. A
review of these risks can be found in ImmunoGen’s Annual Report on Form 10-K for the fiscal year ended June 30, 2013 and other reports filed with the Securities and Exchange Commission. ### 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 EXHIBIT C 

Form of CytomX License Agreement 

[See Attached 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 Exhibit C 

LICENSE AGREEMENT 

BETWEEN 
 CYTOMX
THERAPEUTICS, INC. 
 AND 

IMMUNOGEN, INC. 

            , 201     

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 TABLE OF CONTENTS 

 

									
	 	 	 	 	 	  	Page	 
			
	 1.
	 	 DEFINITIONS.
	  	 	1	  
			
	 2.
	 	 PRODUCT DEVELOPMENT, MANUFACTURING AND COMMERCIALIZATION.
	  	 	19	  
				
		 	 2.1.
	 	 General
	  	 	19	  
				
		 	 2.2.
	 	 Development Diligence
	  	 	20	  
				
		 	 2.3.
	 	 Joint Development Committee
	  	 	21	  
				
		 	 2.4.
	 	 Alliance Managers
	  	 	23	  
				
		 	 2.5.
	 	 Updates and Reports; Product Recalls
	  	 	23	  
				
		 	 2.6.
	 	 Transfer and Use of Proprietary Materials
	  	 	24	  
				
		 	 2.7.
	 	 Services
	  	 	26	  
			
	 3.
	 	 LICENSE GRANTS.
	  	 	26	  
				
		 	 3.1.
	 	 License Grants
	  	 	26	  
				
		 	 3.2.
	 	 Retained Rights and Covenants
	  	 	27	  
				
		 	 3.3.
	 	 License to CytomX TAP Platform Improvements
	  	 	27	  
				
		 	 3.4.
	 	 Section 365(n) of Bankruptcy Code
	  	 	27	  
				
		 	 3.5.
	 	 No Implied Rights
	  	 	27	  
			
	 4.
	 	 PAYMENTS.
	  	 	28	  
				
		 	 4.1.
	 	 Milestone Payments
	  	 	28	  
				
		 	 4.2.
	 	 Royalties
	  	 	29	  
				
		 	 4.3.
	 	 Reports and Payments
	  	 	33	  
				
		 	 4.4.
	 	 Maintenance of Records; Audits
	  	 	35	  

  
 ***Certain information contained herein has been
omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 i 

									
	5.	 	 INTELLECTUAL PROPERTY.
	  	 	36	  
				
		 	5.1.	 	 Inventions
	  	 	36	  
				
		 	5.2.	 	 Filing, Prosecution and Maintenance of Patent Rights
	  	 	37	  
				
		 	5.3.	 	 Joint Research Agreement
	  	 	40	  
				
		 	5.4.	 	 Enforcement of Patent Rights
	  	 	40	  
				
		 	5.5.	 	 Response to Biosimilar Applicants
	  	 	43	  
				
		 	5.6.	 	 Interference, Opposition, Revocation and Declaratory Judgment Actions
	  	 	48	  
				
		 	5.7.	 	 Infringement of Third Party Patent Rights
	  	 	48	  
			
	6.	 	 CONFIDENTIALITY.
	  	 	48	  
				
		 	6.1.	 	 Confidentiality
	  	 	48	  
				
		 	6.2.	 	 Authorized Disclosure
	  	 	49	  
				
		 	6.3.	 	 Public Announcements; Publications
	  	 	51	  
			
	7.	 	 REPRESENTATIONS AND WARRANTIES.
	  	 	52	  
				
		 	7.1.	 	 Mutual Representations and Warranties
	  	 	52	  
				
		 	7.2.	 	 Representations and Warranties of ImmunoGen
	  	 	53	  
				
		 	7.3.	 	 Government Approvals
	  	 	53	  
				
		 	7.4.	 	 Further Covenants
	  	 	54	  
				
		 	7.5.	 	 Representation by Legal Counsel
	  	 	54	  
				
		 	7.6.	 	 Warranty Disclaimers
	  	 	54	  
			
	8.	 	 TERM AND TERMINATION.
	  	 	54	  
				
		 	8.1.	 	 Term
	  	 	54	  
				
		 	8.2.	 	 Voluntary Termination by CytomX
	  	 	55	  
				
		 	8.3.	 	 Termination by Either Party for Cause
	  	 	55	  

  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 ii 

									
		 	8.4.	 	 Termination on Insolvency
	  	 	55	  
				
		 	8.5.	 	 Termination for Material Breach of the Research Collaboration Agreement by CytomX
	  	 	55	  
				
		 	8.6.	 	 Effects of Expiration or Termination
	  	 	55	  
				
		 	8.7.	 	 Disposition of Inventories of Products
	  	 	57	  
				
		 	8.8.	 	 Remedies
	  	 	57	  
				
		 	8.9.	 	 Survival of Certain Obligations
	  	 	58	  
			
	9.	 	 LIMITATION ON LIABILITY, INDEMNIFICATION AND INSURANCE.
	  	 	58	  
				
		 	9.1.	 	 No Consequential Damages
	  	 	58	  
				
		 	9.2.	 	 Indemnification by ImmunoGen
	  	 	58	  
				
		 	9.3.	 	 Indemnification by CytomX
	  	 	59	  
				
		 	9.4.	 	 Procedure
	  	 	59	  
				
		 	9.5.	 	 Insurance
	  	 	60	  
			
	10.	 	 MISCELLANEOUS.
	  	 	61	  
				
		 	10.1.	 	 Assignment
	  	 	61	  
				
		 	10.2.	 	 Further Actions
	  	 	61	  
				
		 	10.3.	 	 Force Majeure
	  	 	61	  
				
		 	10.4.	 	 Notices
	  	 	61	  
				
		 	10.5.	 	 Amendment
	  	 	62	  
				
		 	10.6.	 	 Waiver
	  	 	62	  
				
		 	10.7.	 	 Severability
	  	 	63	  
				
		 	10.8.	 	 Descriptive Headings
	  	 	63	  
				
		 	10.9.	 	 Dispute Resolution
	  	 	63	  

  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 iii 

									
		 	10.10.	 	 Patent Disputes and Disputes Relating to Article 6
	  	 	65	  
				
		 	10.11.	 	 Governing Law
	  	 	66	  
				
		 	10.12.	 	 Entire Agreement
	  	 	66	  
				
		 	10.13.	 	 Purpose and Scope
	  	 	66	  
				
		 	10.14.	 	 Counterparts
	  	 	66	  
				
		 	10.15.	 	 No Third Party Rights or Obligations
	  	 	66	  
				
		 	10.16.	 	 Interpretation
	  	 	66	  

  
 ***Certain information contained herein has been
omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 iv 

 EXHIBITS 
  

	
	Exhibit A – Licensed Target
	
	Exhibit B – Royalty Rate Reduction Methodology

  
 ***Certain information contained herein has been
omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 v 

 LICENSE AGREEMENT 

This Research Collaboration and License Agreement (the “Agreement”) is entered into as of
                    1 (the “Effective Date”), by and between CytomX
Therapeutics, Inc., a corporation organized and existing under the laws of Delaware and having a place of business at 343 Oyster Point Blvd., Suite 100, South San Francisco, California, 94080 United States (“CytomX”) and
ImmunoGen, Inc., a corporation organized and existing under the laws of Massachusetts and having a place of business at 830 Winter Street, Waltham, Massachusetts, 02451 (“ImmunoGen”). CytomX and ImmunoGen may each be referred
to herein individually as a “Party” and collectively as the “Parties.” 
 WHEREAS, the
Parties have entered into a Research Collaboration Agreement, pursuant to which, among other things, ImmunoGen granted to CytomX the right to obtain a license to certain Know-How and related Patent Rights owned or Controlled by ImmunoGen with
respect to certain Targets; and 
 WHEREAS, pursuant to the Research Collaboration Agreement, CytomX has exercised the CytomX
Option (as defined in the Research Collaboration Agreement), pursuant to which the Parties have agreed to enter into this Agreement setting forth the terms and conditions of an exclusive license from ImmunoGen to CytomX with respect to the Licensed
Target. 
 NOW THEREFORE, in consideration of the mutual promises and covenants set forth below and other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, the Parties hereby agree as follows: 
  

	1.	DEFINITIONS. 

 When used in this Agreement, the following capitalized
terms shall have the meanings set forth in this Article 1. 
 1.1. “ADC” means a compound that incorporates, is
comprised of or is otherwise derived from an Antibody conjugated to a Payload using a Linker, other than a PDC. 
 1.2.
“Affiliate” means, with respect to any Person, any other Person that controls, is controlled by or is under common control with such Person. A Person shall be regarded as in control of another entity if it owns or controls at least
fifty percent (50%) of the equity securities of the subject entity entitled to vote in the election of directors (or, in the 
  

	1 	Insert date of receipt by ImmunoGen of Option Exercise Notice with respect to the Licensed Target. 

  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 1 

 
case of an entity that is not a corporation, for the election of the corresponding managing authority), provided, however, that the term “Affiliate” shall not include subsidiaries or
other entities in which a Party or its Affiliates owns a majority of the ordinary voting power necessary to elect a majority of the board of directors or other managing authority, but is restricted from electing such majority by contract or
otherwise, until such time as such restrictions are no longer in effect. A Person shall be deemed an Affiliate only so long as it satisfies the foregoing definition. 

1.3. “Alliance Manager” is defined in Section 2.4 hereof. 

1.4. “Annual Maintenance Fees” is defined in Section 2.2.1 hereof. 

1.5. “Annual Net Sales” means, with respect to any Licensed Product in a Calendar Year during the applicable Royalty Term for
such Licensed Product, the aggregate Net Sales by a Party, its Affiliates and its Sublicensees from the sale of such Licensed Product in the Territory during such Calendar Year. 

1.6. “Antibody” means a molecule which comprises or contains: (a) one or more immunoglobulin variable domains; or
(b) fragments, variants, modifications or derivatives of such immunoglobulin variable domains irrespective of origin or source, including but not limited to antigen binding portions including Fab, Fab’, F(ab’)2, Fv, dAb and CDR
fragments, single chain antibodies (scFv), chimeric antibodies, monospecific antibodies, diabodies and polypeptides (including humanized versions thereof) that contain at least a portion of an immunoglobulin that is sufficient to confer specific
antigen binding to the polypeptide. For clarity, as used in this Agreement, the term “Antibody” shall not include Probodies or PDCs. 

1.7. “Applicable Law” means the laws, statutes, rules, regulations, guidelines, or other requirements that may be in effect
from time to time and apply to a particular activity contemplated hereby, including any such laws, statutes, rules, regulations, guidelines or other requirements of the FDA or the EMA or any applicable securities regulatory authorities or national
securities exchanges or securities listing organizations. 
 1.8. “Applicant” is defined in Section 5.5.2
hereof. 
 1.9. “Applicant Response” is defined in Section 5.5.3(b) hereof. 

1.10. “Bankruptcy Code” is defined in Section 3.4 hereof. 

1.11. “Baseline Net Sales” is defined in Section 1.94 hereof. 

1.12. “Binding Obligation” means, with respect to a Party (a) any oral or written agreement or arrangement that binds or
legally affects such Party’s operations or property, 
  
 ***Certain
information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 2 

 
including any assignment, license agreement, loan agreement, guaranty, or financing agreement; (b) the provisions of such Party’s charter, bylaws or other organizational documents or
(c) any order, writ, injunction, decree or judgment of any court or Governmental Authority entered against such Party or by which any of such Party’s operations or property are bound. 

1.13. “Biosimilar Application” means an application submitted to the FDA under subsection (k) of the PHSA or a similar
application submitted under a similar regulatory scheme to another Regulatory Authority. 
 1.14. “BLA” means a
Biologics License Application (as that term is used in Title 21 of the United States Code of Federal Regulations) filed with the FDA seeking Regulatory Approval to market and sell any Licensed Product in the United States for a particular
indication. 
 1.15. “BPCIA” means the Biologics Price Competition and Innovation Act of 2009. 

1.16. “Business Day” means a day other than a Saturday, a Sunday or other day on which banking institutions in Boston,
Massachusetts or San Francisco, California are required to be closed or are actually closed with legal authorization. 
 1.17.
“Calendar Quarter” means the respective periods of three (3) consecutive calendar months ending on March 31, June 30, September 30 or December 31, for so long as this Agreement is in effect. 

1.18. “Calendar Year” means each successive period of twelve (12) calendar months commencing on January 1 and ending
on December 31. 
 1.19. “Challenge” means any challenge to the [***], or [***] of any of the Licensed Patent Rights,
including without limitation: (a) filing a declaratory judgment action in which any of the Licensed Patent Rights is alleged to be invalid or unenforceable; (b) citing prior art pursuant to 35 U.S.C. §122 or §301, filing a
request for re-examination of any of the Licensed Patent Rights pursuant to 35 U.S.C. §302 or §311, filing [***] of the Licensed Patent Rights pursuant to [***], or filing [***] of the Licensed Patent Rights pursuant to [***]; or
(c) filing or commencing any re-examination, opposition, cancellation, nullity or similar proceeding against any of the Licensed Patent Rights in any country. 

1.20. “Challenge Jurisdiction” is defined in Section 4.2.3(d) hereof. 

1.21. “Challenged Patent Rights” is defined in Section 4.2.3(d) hereof. 

1.22. “Challenge-Related Royalty Increase” is defined in Section 4.2.3 (d) hereof. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 3 

 1.23. “Clawback Amount” is defined in Section 4.2.3(d) hereof. 

1.24. “Combination” is defined in Section 1.104 hereof. 

1.25. “Commercialization” or “Commercialize” means activities with respect to a Licensed Product relating to
commercialization in the Field in the Territory, including pre-launch and launch activities, pricing and reimbursement activities, marketing, promoting, detailing, distributing, offering for sale and selling such Licensed Product, importing and
exporting such Licensed Product for sale, conducting post-marketing human clinical trials, reporting of adverse events in patients and interacting with Regulatory Authorities regarding any of the foregoing. Commercialization shall not include any
activities related to Manufacturing or Development. When used as a verb, “Commercialize” means to engage in Commercialization and “Commercialized” has a corresponding meaning. 

1.26. “Commercially Reasonable Efforts” means, with respect to the efforts to be expended by a Party with respect to any
objective, those reasonable, good faith efforts to accomplish such objective as such Party would normally use to accomplish a similar objective under similar circumstances. With respect to any efforts relating to the Development of a Licensed
Product by CytomX, [***] or with respect to [***] in the [***], CytomX will be deemed to have exercised Commercially Reasonable Efforts if it has exercised those efforts normally used by CytomX, in the [***], with respect to a [***] or [***], as
applicable, [***] or [***] CytomX, or to which CytomX [***], which [***] is of [***], and is [***] in its [***] or [***] as [***], taking into account [***] in effect [***]. It is expressly understood that, so long as this Agreement may be
terminated by CytomX [***] pursuant to Section 8.2 hereof, [***] the [***] of a [***] shall be deemed to be [***]. Further, to the extent that the performance of CytomX’s obligations hereunder is [***] by [***] to [***], the impact of such
[***] will be taken into account in determining whether CytomX has used its Commercially Reasonable Efforts to perform [***]. 
 1.27.
“Confidential Information” of a Party means (a) with respect to CytomX, the identity of the Licensed Target, and (b) with respect to each Party, all Know-How or other information, including proprietary information and
materials (whether or not patentable) regarding such Party’s technology, products, business or objectives, that is communicated in any way or form by or on behalf of such Party (in such capacity, the “Disclosing Party”) to the
other Party (in such capacity, the “Receiving Party”) or to any of the Receiving Party’s or its Affiliates’ employees, consultants or subcontractors 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 4 

 
(collectively, “Representatives”), either prior to or after the Effective Date of this Agreement (including any information disclosed pursuant to the Confidentiality Agreement),
and whether or not such Know-How or other information is identified as confidential at the time of disclosure. The terms and conditions of this Agreement shall be deemed to be the Confidential Information of each Party. Confidential Information
within the CytomX Program Technology shall be deemed to be the Confidential Information of CytomX. Confidential Information within the ImmunoGen Program Technology shall be deemed to be the Confidential Information of ImmunoGen. Confidential
Information within the Joint Program Technology shall be deemed to be the Confidential Information of each Party. Certain other information is designated as Confidential Information throughout this Agreement and is included in this definition. 

1.28. “Confidentiality Agreement” means that certain Mutual Confidential Disclosure Agreement between the Parties effective as
of March 21, 2013. 
 1.29. “Conjugation Probody Platform Improvements” has the meaning ascribed to such term in the
Research Collaboration Agreement. 
 1.30. “Control” or “Controlled” means, with respect to any
(a) item of information, including Know-How, (b) intellectual property right, or (c) Proprietary Material, the possession (whether by ownership interest or license, other than pursuant to this Agreement) by a Party of the ability to
grant to the other Party access to or a license under such item, right or material, as provided herein, without violating the terms of any agreement or other arrangements with any Third Party. 

1.31. “Covered Results” is defined in Section 6.3.2 hereof. 

1.32. “Cover(s)” is defined in Section 4.2.3(b)(iii) hereof. 

1.33. “CytomX Accounting Standards” means GAAP, as generally and consistently applied throughout CytomX’s organization.
Beginning upon the First Commercial Sale of a Licensed Product and thereafter during the Term as long as CytomX has an obligation to pay royalties under Section 4.2 hereof, CytomX shall promptly notify ImmunoGen in the event it changes
the accounting principles pursuant to which its records are maintained, it being understood and agreed that only internationally recognized accounting principles may be used (e.g., GAAP, IFRS (International Financial Reporting Standards),
etc.). 
 1.34. “CytomX Indemnified Party” is defined in Section 9.2 hereof. 

1.35. “CytomX Program Technology” means any Program Technology (other than Joint Program Technology) the inventors of which
(alone or with others) are employees of, or others obligated to assign inventions to, CytomX or any of its Affiliates, Sublicensees or Permitted Third Party Service Providers. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 5 

 1.36. “CytomX Proprietary Materials” means biological materials (including any
Probodies, Masks or Substrates) and other tangible research materials Controlled by CytomX and provided by CytomX to ImmunoGen under this Agreement. 

1.37. “CytomX Response” is defined in Section 5.5.3(c) hereof. 

1.38. “CytomX Standard Exchange Rate Methodology” means, with respect to amounts invoiced in U.S. Dollars, all such
amounts shall be expressed in U.S. Dollars. With respect to amounts invoiced in a currency other than U.S. Dollars, all such amounts shall be expressed both in the currency in which the amount was invoiced and in the U.S. Dollar
equivalent. The U.S. Dollar equivalent shall be calculated using CytomX’s then-current standard exchange rate methodology, which is in accordance with the CytomX Accounting Standards applied in its external reporting for the conversion of
foreign currency sales into U.S. Dollars or, in the case of Sublicensees, such similar methodology, consistently applied. 
 1.39.
“CytomX TAP Platform Improvements” means any TAP Platform Improvement (other than a Joint TAP Platform Improvements) the inventors of which (alone or with others) are employees of, or others obligated to assign inventions to, CytomX
or any of its Affiliates, Sublicensees or Permitted Third Party Service Providers pursuant to the Development, Manufacture, use and Commercialization of any Licensed Product. 

1.40. “CytomX Technology” means any Patent Right, Know-How or other intellectual property right that is Controlled by CytomX
or any Affiliate of CytomX or that comes into the Control of CytomX at any time during the Term of this Agreement and is actually used by CytomX in Developing Licensed Products under this Agreement or is otherwise necessary for Developing,
Manufacturing, using or Commercializing Licensed Products and that claims, covers or is specifically directed to the composition of, or any method of using or method of making or any Tools for Developing, any Probody, Mask or Substrate. 

1.41. “Cytotoxic Compound” means [***] Compounds and [***] Compounds. 

1.42. “Deemed Royalty Portion” is defined in Section 5.4.2(g)(iii) hereof. 

1.43. “Develop” or “Development” means, with respect to a Licensed Product, all pre-clinical, non-clinical
and clinical research and drug development activities with respect to such Licensed Product relating to research and development in connection with seeking, obtaining or maintaining any Regulatory Approval for such Licensed Product, including 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 6 

 
research, toxicology, pharmacology and other similar efforts, test method development and stability testing, manufacturing process development, formulation development, delivery system
development, quality assurance and quality control development, statistical analysis, clinical studies (including pre- and post-approval studies), development of diagnostic assays in connection with clinical studies, and all activities directed to
obtaining any Regulatory Approval, including any marketing, pricing or reimbursement approval. When used as a verb, “Develop” means to engage in Development and “Developed” has a corresponding meaning. 

1.44. “Development Milestone” is defined in Section 4.1.1 hereof. 

1.45. “Development Milestone Payment” is defined in Section 4.1.1 hereof. 

1.46. “Diligence Obligation” is defined in Section 2.2.2 hereof. 

1.47. “Disclosing Party” is defined in Section 1.27 hereof. 

1.48. “Disclosure Letter” is defined in Section 7.2 hereof. 

1.49. “Dispute” is defined in Section 10.9 hereof. 

1.50. “Effective Date” is defined in the introduction to this Agreement. 

1.51. “EMA” means the European Medicines Agency, or any successor agency thereto. 

1.52. “Field” means all human therapeutic, prophylactic and diagnostic uses. 

1.53. “FD&C Act” means the United States Federal Food, Drug, and Cosmetic Act (21 U.S.C. § 301 et seq.), as
amended, and the rules and regulations promulgated thereunder. 
 1.54. “FDA” means the United States Food and Drug
Administration or any successor agency thereto. 
 1.55. “First Commercial Sale” means, with respect to any Licensed Product
and any country of the world, the first sale of such Licensed Product under this Agreement by CytomX, its Affiliates or its Sublicensees to a Third Party in such country, after such Licensed Product has been granted Regulatory Marketing Approval by
the competent Regulatory Authorities in such country or, if no such Regulatory Marketing Approval or similar approval is required, the date on which such Licensed Product is first commercially launched in such country. The foregoing notwithstanding,
“First Commercial Sale” shall not include: [***]. 
 1.56. “GAAP” means United States generally
accepted accounting principles, consistently applied. 
  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 7 

 1.57. “Generic Equivalent” means, with respect to any Licensed Product in a
given country, any biopharmaceutical product that is sold by a Third Party that is not a Sublicensee of CytomX or its Affiliates and such Third Party product (a) contains both (i) [***] or [***] that specifically binds to the Licensed
Target, and (ii) the same [***] and [***] as the relevant Licensed Product, or (b) (i) has been [***] as a [***] or [***] by FDA pursuant to [***] of [***] or any subsequent or superseding law, statute or regulation, (ii) has
been [***] as a [***] by the European Medicines Agency pursuant to [***], as may be amended, or any subsequent or superseding law, statute or regulation, or (iii) has otherwise [***] in reliance on the [***] of the [***] from another applicable
[***] where in the case of each of subclauses (i), (ii) or (iii) of clause (b) above, the [***] is the [***] for purposes of determining [***] or [***] of the Third Party product. 

1.58. “Governmental Authority” means any court, agency, department, authority or other instrumentality of any national, state,
county, city or other political subdivision. 
 1.59. “[***] Compounds” means [***]. 

1.60. “Immediate Patent Infringement Action” means an immediate patent infringement action pursuant to Section 351(1)(6)
of the PHSA. 
 1.61. [Reserved] 

1.62. “ImmunoGen Indemnified Party” is defined in Section 9.3 hereof. 

1.63. [Reserved] 
 1.64.
“ImmunoGen Program Technology” means any Program Technology (other than Joint Program Technology) the inventors of which are employees, agents or independent contractors of ImmunoGen or any of its Affiliates. Anything contained in
this Agreement to the contrary notwithstanding, any and all ImmunoGen Program Technology that is necessary or useful for Developing, Manufacturing, using or Commercializing Licensed Products and that claims, covers or is specifically directed to the
composition of, or any method of using or method of making any Licensed Product, Linker or Cytotoxic Compound comprised in a Licensed Product shall be included in the Licensed Intellectual Property. 

1.65. “ImmunoGen Proprietary Antibody Rights” means all Know-How (and associated Patent Rights) owned or Controlled by
ImmunoGen during the Term constituting or claiming (a) the composition of matter or method of use of, or method of making, an Antibody that was generated or in-licensed by ImmunoGen, whether or not patentable (an “ImmunoGen
Proprietary Antibody”), or (b) the composition of matter or method of use of, or method of making an ADC where the Antibody is an ImmunoGen Proprietary Antibody. For purposes of clarity, “ImmunoGen Proprietary Antibody
Rights” does not include any Program Technology that relates to Probodies Targeting the Licensed Target or any Patent Rights claiming such Program Technology. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 8 

 1.66. “ImmunoGen Proprietary Materials” means any chemical (including any
Cytotoxic Compounds), biological (including any Antibodies) and other tangible research materials Controlled by ImmunoGen and provided by ImmunoGen to CytomX under this Agreement. Subject to the last sentence of this definition, any mutant,
derivative, progeny or improvement of ImmunoGen Proprietary Materials shall be considered to be ImmunoGen Proprietary Materials. [***]. 

1.67. “ImmunoGen Technology Transfer Materials” means ImmunoGen information (including, without limitation, technical transfer
reports) as consistently provided by ImmunoGen to its other licensees of the Licensed Intellectual Property for the purpose of [***] and [***] with respect to ADCs, Cytotoxic Compounds and Linkers, as applicable, for use by CytomX for the purpose of
Developing, Manufacturing and Commercializing Licensed Products, including: (a) [***] and general properties; (b) an example of an ADC [***], including [***] and [***]; (c) an [***] for [***] and [***] and [***] of [***];
(d) information on [***] and [***]; (e) an [***] of [***]; (f) technical reports on [***] for Licensed Products developed by ImmunoGen under the Research Collaboration Agreement; and (g) a list of [***] and [***] and [***] for
[***] Licensed Products. 
 1.68. [Reserved] 

1.69. “Improvement” is defined in Section 1.141 hereof. 

1.70. “IND” means an Investigational New Drug Application, as defined in the FD&C Act, that is required to be filed with
the FDA before beginning clinical testing of a Licensed Product in human subjects, or an equivalent foreign filing. 
 1.71.
“Indemnified Party” is defined in Section 9.4.1 hereof. 
 1.72. “Indemnifying Party” is
defined in Section 9.4.1 hereof. 
 1.73. “Independent Patent Counsel” means an outside patent counsel
reasonably acceptable to both Parties who (and whose firm) is not at the time of the dispute, and was not at any time during the five (5)-year period preceding the dispute, performing legal services of any nature for either of the Parties or their
respective Affiliates (or, in the case of CytomX, its Sublicensees) and which did not, at any time, employ either of the Parties’ chief patent counsels (or persons with similar responsibilities). 

1.74. “Infringed Patent List” is defined in Section 5.5.3(e) hereof. 

1.75. “Infringement” is defined in Section 5.4.1 hereof. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 9 

 1.76. “Insolvency Event” means the occurrence of any of the following:
(a) a case is commenced by or against a Party under applicable bankruptcy, insolvency or similar laws, and is not dismissed within ninety (90) days, (b) a Party files for or is subject to the institution of bankruptcy, reorganization,
liquidation, receivership or similar proceedings, (c) a Party assigns all or a substantial portion of its assets for the benefit of creditors, (d) a receiver or custodian is appointed for a Party’s business, (e) a substantial
portion of a Party’s business is subject to attachment or similar process, or (f) anything analogous to any of the events described in the foregoing clauses (a) through (e) occurs under the laws of any applicable jurisdiction.

 1.77. “Joint Conjugation Probody Platform Improvements” means Conjugation Probody Platform Improvements the inventors of
which are jointly (a) employees, agents or independent contractors of CytomX or any of its Affiliates and (b) employees, agents or independent contractors of ImmunoGen or any of its Affiliates. 

1.78. “Joint Development Committee” or “JDC” is defined in Section 2.3.1 hereof. 

1.79. “Joint Patent Right” means any Patent Right comprised in the Joint Program Technology. 

1.80. [Reserved] 
 1.81.
“Joint Program Technology” means any Program Technology (other than Joint TAP Platform Improvements) the inventors of which are jointly (a) employees, agents or independent contractors of CytomX or any of its Affiliates
and (b) employees, agents or independent contractors of ImmunoGen or any of its Affiliates. 
 1.82. “Joint TAP Platform
Improvements” means TAP Platform Improvements the inventors of which are jointly (a) employees, agents or independent contractors of CytomX or any of its Affiliates and (b) employees, agents or independent contractors of
ImmunoGen or any of its Affiliates. 
 1.83. “Joint Unconjugated Probody Platform Improvements” means Unconjugated Probody
Platform Improvements the inventors of which are jointly (a) employees, agents or independent contractors of CytomX or any of its Affiliates and (b) employees, agents or independent contractors of ImmunoGen or any of its Affiliates.

 1.84. “Know-How” means any proprietary invention, discovery, data, information, process, method, technique, material,
technology, result or other know-how, whether or not patentable. 
 1.85. “Knowledge” is defined in Section 7.2
hereof. 
  
 ***Certain information contained herein has been omitted and filed
separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 10 

 1.86. “Liability” is defined in Section 9.2 hereof. 

1.87. “License Agreement” has the meaning ascribed to such term in the Research Collaboration Agreement. 

1.88. “Licensed Intellectual Property” means any Patent Right, Know-How or other intellectual property right that is owned or
Controlled by ImmunoGen or any Affiliate of ImmunoGen or that becomes owned or Controlled by ImmunoGen or any of its Affiliates at any time during the Term (including ImmunoGen’s one-half interest in Joint Program Technology and Joint TAP
Platform Improvements) that is necessary or useful for Developing, Manufacturing, using or Commercializing Licensed Products and that claims, covers or is specifically directed to the composition of, or any method of using or method of making any
Licensed Product, Linker or Cytotoxic Compound comprised in a Licensed Product, provided, however, that Licensed Intellectual Property shall expressly exclude any ImmunoGen Proprietary Antibody Rights. 

1.89. “Licensed Know-How” means any Know-How comprised in the Licensed Intellectual Property. 

1.90. “Licensed Patent Rights” means any Patent Rights comprised in the Licensed Intellectual Property. 

1.91. “Licensed Product” means any product that incorporates, is comprised of, or is otherwise derived from, a Target-Binding
Probody conjugated to a Cytotoxic Compound using a Linker. 
 1.92. “Licensed Target” means [***]. 

1.93. “Linker” means any compound or composition that is useful for linking a cytotoxic or cytostatic moiety, including,
without limitation, a Cytotoxic Compound, and a cell-binding moiety, including, without limitation, an Antibody or a Probody, together to form a conjugate of the cytotoxic or cytostatic moiety with the cell-binding moiety. 

1.94. “Loss of Market Exclusivity” with respect to any Licensed Product in any country, shall be deemed to have occurred only
if: (a) one or more Generic Equivalent(s) are being marketed by a Third Party (excluding any Sublicensee) in such country; and (b) Net Sales of such Licensed Product in that country during any Calendar Quarter following introduction of the
Generic Equivalent(s) have declined by at least [***] in that country relative to the average quarterly Net Sales of such Licensed Product in such country over [***] ending prior to the introduction of such Generic Equivalent(s) (the
“Baseline Net Sales”) and such decline in Net Sales is not primarily attributable to [***]. Anything contained in this Agreement to the contrary notwithstanding, a “Loss of Market Exclusivity” shall not be deemed to have
occurred if [***]. 
  
 ***Certain information contained herein has been omitted
and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 11 

 1.95. “Major EU Market Country” means any of [***]. 

1.96. “Manufacturing” or “Manufacture” means activities directed to making, producing, manufacturing,
processing, filling, finishing, packaging, labeling, quality assurance testing and release, shipping or storage of a product. 
 1.97.
“Marginal Royalty Rates” is defined in Section 4.2.1 hereof. 
 1.98. “Mask” means a peptide
linked to an Antibody that is capable of inhibiting the specific binding of the Antibody to its Target. 
 1.99. “Material
Breach” is defined in Section 8.3 hereof. 
 1.100. “[***] Compound” means [***]. 

1.101. “Milestone Payment” means any Development Milestone Payment or Sales Milestone Payment. 

1.102. “Monies” is defined in Section 5.4.2(g) hereof. 

1.103. “Negotiation Period” is defined in Section 5.5.3(e) hereof. 

1.104. “Net Sales” means, with respect to a Licensed Product, gross receipts from sales by CytomX and its Affiliates and
Sublicensees of such Licensed Product to Third Parties in the Territory, less in each case (a) bad debts, (b) sales returns and allowances actually paid, granted or accrued, including trade, quantity and cash discounts and any other
adjustments, including those granted on account of price adjustments, billing errors, rejected goods, damaged or defective goods, recalls, returns, rebates, chargeback rebates, reimbursements or similar payments granted or given to wholesalers or
other distributors, buying groups, health care insurance carriers, chain pharmacies, mass merchandisers, staff model HMO’s, pharmacy benefit managers or other institutions in respect of the purchase price, (c) adjustments actually paid,
granted or accrued arising from consumer discount programs or other similar programs, (d) customs or excise duties, sales tax, consumption tax, value added tax, and other taxes (except income taxes) or duties relating to sales, (e) any
payment made by CytomX, its Affiliates or Sublicensees in respect of sales to the United States government, any state government or any foreign government, or to any other Governmental Authority, or with respect to any government-subsidized program
or managed care organization, and (f) freight and freight insurance (to the extent that CytomX, its Affiliates or Sublicensees bears the cost of freight and freight insurance for the Licensed Product), in each case in accordance with GAAP, as
consistently applied by CytomX with respect to its overall operations. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 12 

 Net Sales shall not include sales or transfers among CytomX and its Affiliates
and Sublicensees where the Licensed Product is intended for subsequent sale to the end user. All the foregoing elements of Net Sales calculations shall be determined from the books and records of CytomX and its Sublicensees, maintained in accordance
with the CytomX Accounting Standards or, in the case of Sublicensees, such similar accounting principles, consistently applied. 

In the event a Licensed Product is sold as a component of a combination or bundled product that consists of a Licensed Product
together with another therapeutically active product, or screening or diagnostic product, for the same indication (a “Combination”), the Net Sales from the Combination, for the purposes of determining royalty payments hereunder, shall be
determined by multiplying the Net Sales of the Combination (as defined in the standard Net Sales definition above) by the fraction A/(A+B), where A is the weighted average per unit sale price of the Licensed Product when sold separately in finished
form in the country in which the Combination is sold in similar volumes and of the same class, purity, potency and dosage form, and B is the weighted average per unit sale price of the other product(s) included in the Combination when sold
separately in finished form in the country in which the Combination is sold in similar volumes and of the same class, purity, potency and dosage form. 

In the event that the weighted average per unit sale price of the Licensed Product can be determined but the weighted average
per unit sale price of the other product(s) included in the Combination cannot be determined, Net Sales for purposes of determining royalty payments shall be calculated by multiplying the Net Sales of the Combination (as defined in the standard Net
Sales definition above) by the fraction A/C, where A is the weighted average sale price of the Licensed Product when sold separately in finished form in the country in which the Combination is sold in similar volumes and of the same class, purity,
potency and dosage form, and C is the weighted average per unit sale price of the Combination. 
 In the event that the
weighted average per unit sale price of the other product(s) included in the Combination can be determined but the weighted average per unit sale price of the Licensed Product in similar volumes and of the same class purity, potency and dosage form
as in the Combination cannot be determined, Net Sales for purposes of determining royalty payments shall be calculated by multiplying Net Sales of the Combination (as defined in the standard Net Sales definition above) by a fraction determined by
the following formula: one (1) minus (B/C) where B is the weighted average per unit sale price of the other product(s) included in the Combination when sold separately in finished form in the country in which the Combination is sold in
similar volumes and of the same class, purity, potency and dosage form and C is the weighted average per unit sale price of the Combination. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 13 

 In the event that such average per unit sale price cannot be determined for the
Licensed Product, on the one hand, and all other product(s) included in the Combination, on the other, Net Sales for the purposes of determining royalty payments shall be mutually agreed upon by the Parties based on the relative value contributed by
each component, such agreement to be negotiated in good faith. 
 The weighted average per unit sale price for both the
Licensed Product, on the one hand, and all other product(s) included in the Combination, on the other, shall be calculated once each Calendar Year and such price shall be used during all applicable royalty reporting periods for the entire following
Calendar Year. When determining the weighted average per unit sale price of a Licensed Product, other product(s), or Combination, the weighted average per unit sale price shall be calculated by dividing sales dollars (translated into
U.S. Dollars using the CytomX Standard Exchange Rate Methodology) by the units sold during the twelve (12) months (or the number of months in which sales occurred in a partial Calendar Year) of the preceding Calendar Year for the
respective Licensed Product, other product(s), or Combination. In the initial Calendar Year, a forecasted weighted average per unit sale price will be used for the Licensed Product, other product(s), or Combination. Any over- or under-payment due to
a difference between the forecasted and actual weighted average per unit sale price will be paid or credited in the first royalty payment of the following Calendar Year. 

1.105. “Non-Disclosing Party” is defined in Section 6.3.2 hereof. 

1.106. “Notice of Dispute” is defined in Section 10.9.1 hereof. 

1.107. “Party” and “Parties” is defined in the introduction to this Agreement. 

1.108. “Patent Committee” is defined in Section 5.2.4 hereof. 

1.109. “Patent Rights” means any and all (a) patents, (b) pending patent applications, including all provisional
applications, substitutions, continuations, continuations-in-part, divisions and renewals, and all patents granted thereon, (c) all patents-of-addition, reissues, reexaminations and extensions or restorations by existing or future extension or
restoration mechanisms, including patent term extensions, supplementary protection certificates or the equivalent thereof, (d) inventor’s certificates, (e) any other form of government-issued right substantially similar to any of the
foregoing and (f) all United States and foreign counterparts of any of the foregoing. 
 1.110. “Payload” means a
therapeutic cytotoxic or cytostatic compound, including, without limitation, a Cytotoxic Compound. 
 1.111. “PDC” means a
compound that incorporates, is comprised of or is otherwise derived from, a Probody conjugated to a Payload using a Linker. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 14 

 1.112. “Permitted Third Party Service Providers” is defined in
Section 3.1.1 hereof. 
 1.113. “Person” means an individual, sole proprietorship, partnership, limited
partnership, limited liability partnership, corporation, limited liability company, business trust, joint stock company, trust, incorporated association, joint venture or similar entity or organization, including a government or political
subdivision or department or agency of a government. 
 1.114. “Phase 1 Clinical Study” means an initial study of a Licensed
Product in human subjects or patients with the endpoint of determining initial tolerance, safety, metabolism or pharmacokinetic information and clinical pharmacology of such product as and to the extent defined for the United States in 21 C.F.R.
§ 312.21(a), or its successor regulation, or the equivalent regulation in any other country. 
 1.115. “Phase 2 Clinical
Study” means a study of a Licensed Product in human patients that is intended to obtain information on the Licensed Product’s activity for an indication at a prescribed (or otherwise limited) dose and administration schedule, as well
as additional information on the Licensed Product’s safety and toxicity as and to the extent defined for the United States in 21 C.F.R. § 312.21(b), or its successor regulation, or the equivalent regulation in any other country.
Without limiting the generality of the foregoing, a clinical study shall be deemed to be a “Phase 2 Clinical Study” hereunder if such study has been designated by the sponsor as a Phase 2 [II] clinical trial on
www.clinicaltrials.gov (or any successor website maintained by the U.S. National Institutes of Health (or any successor agency of the U.S. Government)). 

1.116. “Phase 3 Clinical Study” means a study of a Licensed Product in human patients with a defined dose or a set of defined
doses of a Licensed Product designed to (a) ascertain efficacy and safety of such Licensed Product for its intended use; (b) define warnings, precautions and adverse reactions that are associated with the Licensed Product in the dosage
range to be prescribed; and (c) support preparing and submitting applications for Regulatory Marketing Approval to the competent Regulatory Authorities in a country of the world, as and to the extent defined for the United States in 21
C.F.R.§ 312.21(c), or its successor regulation, or the equivalent regulation in any other country. “Phase 3 Clinical Study” shall also include any other human clinical trial serving as a pivotal study from which the data are actually
submitted to the applicable Regulatory Authority in connection with a Regulatory Marketing Approval Application, whether or not such trial is called a “Phase 3” study. Without limiting the generality of the foregoing, a clinical study
shall be deemed to be a “Phase 3 Clinical Study” hereunder if such study has been designated by the sponsor as a Phase 3 [III] clinical trial on www.clinicaltrials.gov (or any successor website maintained by the U.S. National
Institutes of Health (or any successor agency of the U.S. Government)). 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 15 

 1.117. “PHSA” means the Public Health Services Act, as amended (42 U.S.C.
§ 201 et seq.). 
 1.118. “Pre-Market Notice” is defined in Section 5.5.4(b) hereof. 

1.119. “Probody” means an Antibody linked to a Substrate and a Mask that is claimed or covered by CytomX Technology. 

1.120. [Reserved] 
 1.121.
“Program Technology” means all Know-How (other than TAP Platform Improvements) that either Party or any of its Affiliates, Sublicensees or Permitted Third Party Service Providers (or any of their respective employees, agents or
independent contractors), alone or with others, makes, creates, develops, discovers, conceives or first actually reduces to practice pursuant to the Development, Manufacture, use or Commercialization of any Licensed Product, including any Patent
Rights related thereto. Program Technology also includes “Program Technology” (as defined in the Research Collaboration Agreement) that is necessary or useful for Developing, Manufacturing, using or Commercializing Licensed Products and
that claims, covers or is specifically directed to the composition of, or any method of using or method of making any Licensed Product, Linker or Cytotoxic Compound comprised in any Licensed Product. 

1.122. “Proposed Biosimilar Product” is defined in Section 5.5.1 hereof. 

1.123. “Proposed Patent List” is defined in Section 5.5.3(a) hereof. 

1.124. “Publishing Party” is defined in Section 6.3.2 hereof. 

1.125. “Receiving Party” is defined in Section 1.27 hereof. 

1.126. “Regulatory Approval” means any technical, medical, scientific or other license, registration, authorization or
approval of any Regulatory Authority (including any approval of a New Drug Application or Biologic License Application) necessary for the Development, Manufacture, use or Commercialization of a pharmaceutical product in any regulatory jurisdiction.

 1.127. “Regulatory Approval Application” means any application submitted to an appropriate Regulatory Authority seeking
any Regulatory Approval. 
 1.128. “Regulatory Authority” means the FDA or any counterpart of the FDA outside the United
States, or other national, supra-national, regional, state or local regulatory jurisdiction, any agency, department, bureau, commission, council or other governmental entity with authority over the Development, Manufacture, use or Commercialization
of a Licensed Product. 
  
 ***Certain information contained herein has been
omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 16 

 1.129. “Regulatory Marketing Approval” means, with respect to any pharmaceutical
product and any indication, Regulatory Approval (including any supplement thereto) to sell such pharmaceutical product for such indication, including, in any jurisdiction other than the United States, to the extent required for any sale in such
country, all pricing and reimbursement approvals to be obtained from the Regulatory Authority granting such Regulatory Approval or any affiliated Regulatory Authority. 

1.130. “Representatives” is defined in Section 1.27 hereof. 

1.131. “Research Collaboration Agreement” means that certain Research Collaboration Agreement effective as of January 8,
2014 by and between CytomX and ImmunoGen, as the same may be amended from time to time. 
 1.132. “Research Program” has the
meaning ascribed to such term in the Research Collaboration Agreement. 
 1.133. “Review Period” is defined in
Section 6.3.2 hereof. 
 1.134. “Royalty Term” means, on a Licensed Product-by-Licensed Product and
country-by-country basis, the period of time from the First Commercial Sale of such Licensed Product in such country until the later of (a) the expiration of the last Valid Claim that would, but for the license granted hereunder, be infringed
by the manufacture, use, sale, offer for sale or importation of such Licensed Product in such country or (b) the twelfth (12th) anniversary of the date of the First Commercial Sale of such Licensed Product in such country, but in the case
of (b), in no event later than the twentieth (20th) anniversary of the earlier of the date of the First Commercial Sale of such Licensed Product in the United States or the date of the First
Commercial Sale of such Licensed Product in any Major EU Market Country. Anything contained in this Agreement to the contrary notwithstanding, if the Licensed Product (or any component or intermediate thereof) was manufactured in a country where
such manufacture would, at the time of such manufacture, have infringed a Valid Claim within the Licensed Patent Rights in the country of manufacture in the absence of the license granted under Section 3.3.1 hereof, then the Royalty Term
in the country of sale of such Licensed Product, if otherwise expired pursuant to the first sentence of this Section, shall be extended or reinstated, as the case may be, but only with respect to sales of Licensed Products so manufactured. In
determining infringement of Valid Claims for purposes of this definition of Royalty Term, (i) any Valid Claim within the Licensed Patent Rights that is jointly owned by CytomX (or any of its Affiliates) with ImmunoGen (or any of its Affiliates)
shall be deemed to be owned solely by ImmunoGen or an Affiliate of ImmunoGen, and (ii) claims contained in patent applications that have not resulted in the issuance of a patent in a country will be disregarded for purposes of determining the
expiration of the Royalty Term for a Licensed Product in such country under this definition. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 17 

 1.135. “Sales Milestone” is defined in Section 4.1.2 hereof. 

1.136. “Sales Milestone Payment” is defined in Section 4.1.2 hereof. 

1.137. “Sales Threshold” is defined in Section 4.1.2 hereof. 

1.138. “Strain” is defined in Section 1.66 hereof. 

1.139. “Sublicensee” means any Third Party to whom CytomX or an Affiliate of CytomX grants or has granted, directly or
indirectly, a sublicense of rights licensed by ImmunoGen under this Agreement, in accordance with the provisions of this Agreement. 
 1.140.
“Substrate” means a moiety that is linked to the Antibody and to the Mask of a Probody and is capable of being cleaved, reduced or photolysed. 

1.141. “TAP Platform Improvements” means any enhancement, improvement or modification (each, an
“Improvement”) to the Licensed Intellectual Property that is (a) an Improvement to the [***] of or [***] of [***], (b) an Improvement to the [***] for [***] or [***] (including, for example, [***] or [***] that create
improvements in the [***] of such [***]), (c) an Improvement to the [***] of or [***] for [***], (d) an Improvement to any of the [***] used for [***] and [***] any [***] or [***], or (e) an Improvement to the [***] of [***] or [***].
[***], in and of themselves, will not be deemed to be TAP Platform Improvements, although the Parties acknowledge that TAP Platform Improvements may be incorporated into [***]. 

1.142. “Target” means a protein described by a unique UniProtKB/Swiss Prot accession number (and all fragments, mutations and
splice variants thereof) that is bound by an Antibody or a Probody. 
 1.143. “Target,” “Targeting” or
“Targeted” means, when used as a verb to describe the relationship between a molecule and a Target, where the molecule’s primary intended mechanism of action requires that it bind to the Target (or a portion thereof). 

1.144. “Target-Binding Probody” means a Probody that Targets the Licensed Target. [***] 

1.145. “Term” is defined in Section 8.1 hereof. 

1.146. “Territory” means the entire world. 

1.147. “Third Party” means any Person other than CytomX, ImmunoGen or their respective Affiliates. 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 18 

 1.148. “Third Party Claims” is defined in Section 9.2 hereof. 

1.149. “Third Party Payments” is defined in Section 4.2.3(a) hereof. 

1.150. “Unauthorized Use” is defined in Section 2.6.3 hereof. 

1.151. “Unconjugated Probody Platform Improvements” has the meaning ascribed to such term in the Research Collaboration
Agreement. 
 1.152. “Valid Claim” means, with respect to a particular country, (a) a claim of an issued and unexpired
patent right included within the Licensed Patent Rights that (i) has not been held permanently revoked, unenforceable or invalid by a decision of a court or other governmental authority of competent jurisdiction, which decision is unappealed or
unappealable within the time allowed for appeal, and (ii) has not been cancelled, withdrawn, abandoned, disclaimed or admitted to be invalid or unenforceable through reissue, disclaimer or otherwise; or (b) a bona fide claim of
a pending patent application included within the Licensed Patent Rights that has not been (i) cancelled, withdrawn or abandoned without being refiled in another application in the applicable jurisdiction or (ii) finally rejected by an
administrative agency action from which no appeal can be taken or that has not been appealed within the time allowed for appeal, provided that any claim in any patent application pending for more than seven (7) years from the earliest date on
which such patent application claims priority shall not be considered a Valid Claim for purposes of the Agreement from and after such seven (7) year date unless and until a patent containing such claim issues from such patent application and
solely if such patent issues while another Valid Claim covers the relevant Licensed Product in the relevant country. Anything contained in this Agreement to the contrary notwithstanding, a claim within an issued and unexpired patent within the
Licensed Patent Rights shall remain a Valid Claim for all purposes under this Agreement, notwithstanding a determination that such claim is unenforceable pursuant to the operation of the BPCIA, if such determination is exclusively caused by or
results solely from any act or omission by CytomX (or any of its Affiliates or Sublicensee) determined to have been made negligently or in bad faith in the performance of CytomX’s obligations under Section 5.5.3 hereof that results in
actual prejudice to ImmunoGen’s ability to preserve its rights in the Licensed Patent Rights and eliminate the infringement threatened by the Applicant (excluding any acts or omissions undertaken pursuant to the specific written instruction of
ImmunoGen). 
  

	2.	PRODUCT DEVELOPMENT, MANUFACTURING AND COMMERCIALIZATION. 

 2.1. General. CytomX
shall have sole authority over, responsibility for and control of (notwithstanding the formation of the JDC or its decisions and/or disputes among the membership of the JDC) the Development, Manufacture, use and Commercialization of 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 19 

 
the Licensed Products, and shall bear all costs associated with such Development, Manufacture, use and Commercialization. To the extent it has not already done so or is not required to do so
under the Research Collaboration Agreement, upon request by CytomX, ImmunoGen will provide CytomX and/or its designated Permitted Third Party Service Providers with the ImmunoGen Technology Transfer Materials. In addition, upon reasonable request by
CytomX, ImmunoGen shall use reasonable efforts to provide CytomX with technical advice to assist CytomX in its use of the ImmunoGen Technology Transfer Materials in connection with the Development and Manufacture of Licensed Products hereunder. 

2.2. Development Diligence. 

2.2.1. CytomX Diligence. CytomX will use Commercially Reasonable Efforts to Develop Licensed Products and to undertake investigations
and actions required to obtain Regulatory Marketing Approval in the Territory; provided that the obligations set forth in this Section shall cease upon the achievement of the first Regulatory Marketing Approval for any Licensed Product in any
country or other jurisdiction in the Territory. For avoidance of doubt, any actions taken by CytomX’s Affiliates or Sublicensees under this Agreement shall be treated as actions taken by CytomX in regard to satisfaction of the requirements of
this Section 2.2.1. Beginning on the sixth (6th) anniversary of the Effective Date and thereafter, CytomX will make non-refundable and non-creditable maintenance payments in the
amounts set forth below (the “Annual Maintenance Fees”) until the earlier of (a) the first filing of an IND in the U.S. or in any European Union country for any Licensed Product or (b) the termination of this
Agreement in accordance with its terms. The amounts of the Annual Maintenance Fee accruing as of each anniversary of the Effective Date, beginning with the sixth (6th) anniversary are as
follows: 
  

					
	 Anniversary of the Effective Date
	  	Maintenance Fee	 
	 Sixth (6th) anniversary
	  	$	[***	] 
	 Seventh (7th) anniversary
	  	$	[***	] 
	 Eighth (8th) anniversary and each anniversary thereafter
	  	 	[***	] 

 CytomX will pay the applicable Annual Maintenance Fee in accordance with Section 4.3 hereof within
[***] after the applicable anniversary of the Effective Date. Payment of Annual Maintenance Fees by CytomX shall not establish that CytomX has satisfied its due diligence obligations under this Section 2.2, and 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 20 

 
such payments shall be given no consideration or weight in determining whether CytomX has satisfied such due diligence obligations. Anything contained in this Agreement to the contrary
notwithstanding, CytomX shall have no obligation to pay Annual Maintenance Fees hereunder if the first filing of an IND in the U.S. or in any European Union country for any Licensed Product has occurred prior to the sixth (6th) anniversary of the Effective Date. 
 2.2.2. Exceptions to Diligence
Obligations. Notwithstanding any provision of this Agreement to the contrary, CytomX will be relieved from and will have no obligation to undertake any efforts with respect to any diligence obligation under Section 3.2.1 with respect
to a given Licensed Product (each, a “Diligence Obligation”) in the event that ImmunoGen materially breaches any of its Development or other obligations under this Agreement related to such Licensed Product upon which performance of
the applicable Diligence Obligation is dependent. 
 2.2.3. Remedies for Breach of Diligence Obligations. A material breach of any
Diligence Obligation by CytomX shall be deemed to be a Material Breach by CytomX hereunder. 
 2.3. Joint Development Committee. 

2.3.1. Formation of the Joint Development Committee. As soon as practicable after the Effective Date, CytomX and ImmunoGen shall
establish a “Joint Development Committee” (or “JDC”) to coordinate the sharing of safety data and minutes of meetings with Regulatory Authorities with regard to Licensed Products. The JDC shall also serve as a forum
to facilitate communications between the Parties regarding this Agreement. The JDC shall be comprised of two (2) representatives from each Party as appointed by such Party, with such representatives possessing appropriate expertise and
seniority. The JDC may change its size from time to time by mutual consent of its members. A Party may replace one or more of its representatives from time to time upon written notice to the other Party. The JDC shall exist until the expiration of
the Term or earlier termination of the Agreement, unless the Parties otherwise agree in writing, provided that CytomX may dissolve the JDC upon the achievement of the first Regulatory Marketing Approval for any Licensed Product in any country or
other jurisdiction in the Territory. 
 2.3.2. Chairperson and Secretary of the Joint Development Committee. CytomX shall designate a
chairperson of the JDC, and a secretary of the JDC shall be designated by agreement of the members of the JDC. CytomX may change the designation of the chairperson from time to time upon written notice to ImmunoGen. The chairperson or his or her
designee shall be responsible for 
  
 ***Certain information contained herein has
been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 21 

 
scheduling meetings of the JDC, preparing agendas for meetings and sending to all JDC members notices of all regular meetings and agendas for such meetings at least [***] Business Days
before such meetings. The chairperson shall solicit input from both Parties regarding matters to be included on the agenda, and any matter either Party desires to have included on the agenda shall be included for discussion. Nothing herein shall be
construed to prohibit the JDC from discussing or acting on matters not included on the applicable agenda. The secretary shall (a) record the minutes of the meeting, (b) circulate copies of meeting minutes to the Parties and each JDC member
promptly following the meeting for review, comment and approval by the JDC members and (c) finalize approved meeting minutes. The chairperson shall be a member of the JDC but the secretary need not be a member of the JDC. 

2.3.3. Meetings. The JDC shall meet at least three (3) times each Calendar Year (unless the Parties mutually agree in advance of
any scheduled meeting that there is no need for such meeting, in which case the next JDC meeting shall also be scheduled as agreed upon by the Parties) until it has been terminated in accordance with Section 2.3.1 hereof at dates and
times mutually agreed by the JDC. The initial meeting of the JDC shall be held within [***] days after the Effective Date. Either Party may call a special meeting of the JDC on [***] days written notice to the other Party’s members of the
JDC (or upon such shorter notice as exigent circumstances may require). Such written notice shall include an agenda for the special meeting. In-person meetings, including special meetings, of the JDC shall alternate between the offices of the
Parties, unless otherwise agreed upon by the members of the JDC. Meetings of the JDC may be held telephonically or by video conference; provided, however, that at least [***] meetings per year shall be held in-person. Meetings of the JDC shall be
effective only if at least one (1) representative of each Party is in attendance or participating in the meeting. Members of the JDC shall have the right to participate in at meetings held by telephone or video conference. In addition, the JDC
may act on any matter or issue without a meeting if it is documented in a written consent signed by each member of the JDC. 
 2.3.4.
Responsibilities of the Joint Development Committee. The JDC shall be responsible for (a) receiving and reviewing all safety data, relevant regulatory information and other related information obtained by either Party in connection with
the Development, Manufacture, use and Commercialization of Licensed Products; (b) facilitating communication between the Parties, (c) resolving Disputes between the Parties, such as Disputes about interpretation of this Agreement,
understanding that CytomX has sole authority over the Development, Manufacturing, use and Commercialization of Licensed Products; and (d) such other functions as expressly specified hereunder or as agreed by the Parties. At the 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 22 

 
time that the first Licensed Product enters a clinical trial, the Parties shall negotiate in good faith the terms of a separate written safety data exchange agreement that, among other things,
will govern the exchange of pharmacovigilance information. 
 2.3.5. Resolution by [***]. All resolution of Disputes by the JDC shall
be made by [***]. If the JDC cannot or does not reach [***] on a Dispute, then such Dispute shall be resolved in accordance with Section 10.9 hereof. 

2.4. Alliance Managers. In addition to the foregoing governance provisions, each of the Parties shall appoint a single individual to
serve as that Party’s alliance manager (“Alliance Manager”). The role of each Alliance Manager will be to participate and otherwise facilitate the relationship between the Parties as established by this Agreement. A Party may
replace its Alliance Manager from time to time upon written notice to the other Party. 
 2.5. Updates and Reports; Product Recalls.

 2.5.1. Development Updates. Upon the request of ImmunoGen, CytomX shall provide ImmunoGen with brief written reports, which
ImmunoGen may request no more frequently than [***] until satisfaction of CytomX’s obligations under Section 2.2.1 hereof, that shall summarize CytomX’s efforts to Develop the Licensed Products in the Field in the Territory in
sufficient detail to establish that CytomX is using Commercially Reasonable Efforts to Develop the Licensed Product, identify the applications for Regulatory Approval that CytomX or its Affiliates or Sublicensees have filed, sought or attempted to
obtain in the prior [***] period, and any they reasonably expect to file, seek or attempt to obtain in the following [***] period. The Parties agree that the minutes of the JDC meetings may serve as reports hereunder, to the extent such minutes
adequately address the above subject matter. 
 2.5.2. Correspondence for Licensed Products. To the extent reasonably practicable and
subject to any Third Party confidentiality obligations, CytomX shall provide ImmunoGen with copies of any material documents or correspondence pertaining to ImmunoGen’s manufacture or supply of Cytotoxic Compound or Licensed Product in drug
substance form and prepared for submission to any Regulatory Authority and any material documents or other correspondence received from any Regulatory Authority pertaining to ImmunoGen’s manufacture or supply of Cytotoxic Compound or Licensed
Product in drug substance form. ImmunoGen shall complete its review within [***] after receipt of the proposed submission. When requested in writing, ImmunoGen shall use commercially reasonable efforts to provide assistance to CytomX in obtaining
Regulatory Approvals for Licensed Products. 
  
 ***Certain information contained
herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 23 

 
Notwithstanding the foregoing, CytomX shall have the sole responsibility for, and ImmunoGen agrees that CytomX shall be the sole owner of, any Regulatory Approval for the Licensed Products. 

2.5.3. Product Recalls. In the event any Regulatory Authority issues or requests a recall or takes similar action with respect to a
Licensed Product that CytomX reasonably believes is or may be attributable to or otherwise relates to the Licensed Intellectual Property, or in the event either Party reasonably believes that an event, incident or circumstance has occurred that may
result in the need for such a recall, such Party shall promptly notify the other Party thereof by telephone, facsimile or email. Following such notification, CytomX shall decide and have control of whether to conduct a recall or market withdrawal
(except in the event of a recall or market withdrawal mandated by a Regulatory Authority, in which case it shall be required) or take such other corrective action in any country and the manner in which any such recall, market withdrawal or
corrective action shall be conducted, provided that CytomX shall keep ImmunoGen informed regarding any such recall, market withdrawal or corrective action as ImmunoGen from time to time may reasonably request, but only to the extent CytomX is
legally permitted to do so. CytomX shall bear all expenses of any such recall, market withdrawal or corrective action, including, without limitation, expenses of notification, destruction and return of the affected Licensed Product and any refund to
customers of the amounts paid for such Licensed Product. 
 2.5.4. Confidential Information. All reports, updates, product complaints
and other information provided by the Disclosing Party to the Receiving Party under this Agreement (including under this Section 2.5), shall be considered Confidential Information of the Disclosing Party, subject to the terms of
Article 7 hereof. 
 2.6. Transfer and Use of Proprietary Materials. 

2.6.1. Transfer and Use of ImmunoGen Proprietary Materials. From time to time during the Term, ImmunoGen may provide CytomX with
ImmunoGen Proprietary Materials for use in the Development and Manufacture of Licensed Products under this Agreement. ImmunoGen’s Proprietary Materials are provided by ImmunoGen on an “as-is” basis without representation or warranty
of any type, express or implied, including any representation or warranty of merchantability, non-infringement, title or fitness for a particular purpose, each of which is hereby disclaimed by ImmunoGen. In connection with the foregoing, CytomX
agrees that (a) it shall not use ImmunoGen’s Proprietary Materials provided under this Agreement for any purpose other than exercising its rights and performing its obligations hereunder; (b) it shall not use ImmunoGen Proprietary
Materials provided under this Agreement in any human subject; (c) it 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 24 

 
shall use ImmunoGen Proprietary Materials in compliance with all Applicable Laws; (d) it does not acquire any right, title or interest in or to ImmunoGen Proprietary Materials as a result of
such provision by ImmunoGen; and (e) upon expiration or termination of this Agreement for any reason, CytomX shall, if and as instructed by ImmunoGen, either destroy or return ImmunoGen Proprietary Materials provided under this Agreement that
are not the subject of a continuing license hereunder. CytomX shall be entitled to transfer ImmunoGen Proprietary Materials to any Affiliate, Sublicensee or Permitted Third Party Service Provider under terms obligating such Affiliate, Sublicensee or
Permitted Third Party Service Provider not to use or transfer such ImmunoGen Proprietary Materials except in compliance with the preceding sentence. 

2.6.2. Transfer and Use of CytomX Proprietary Materials. From time to time during the Term, CytomX may provide ImmunoGen with CytomX
Proprietary Materials. ImmunoGen shall use the CytomX Proprietary Materials solely in connection with conducting the specific activities for which such CytomX Proprietary Materials are provided to ImmunoGen, and for no other purpose. Without
limiting the generality of the foregoing, except as expressly set forth in this Agreement or in other written authorization by CytomX, ImmunoGen shall not make or attempt to make analogues, progeny or derivatives of, or modifications to, the CytomX
Proprietary Materials, using CytomX’s Confidential Information, and ImmunoGen shall not use the CytomX Proprietary Materials for the benefit of any Third Party or of its own internal research programs. ImmunoGen shall comply with all Applicable
Laws regarding the handling and use of the CytomX Proprietary Materials. ImmunoGen agrees to retain possession over the CytomX Proprietary Materials and not to provide the CytomX Proprietary Materials to any Third Party without CytomX’s prior
written consent. 
 2.6.3. Unauthorized Use of Confidential Information and Proprietary Materials. In the event that (a) CytomX
or any of its Affiliates or Sublicensees use ImmunoGen’s Confidential Information (including, without limitation, any Confidential Information within the Licensed Know-How) or ImmunoGen Proprietary Materials for any purpose other than in
connection with CytomX’s exercise of its rights and performance of its obligations hereunder or the Research Collaboration Agreement (if then in effect) or (b) ImmunoGen or any of its Affiliates uses CytomX’s Confidential Information
or CytomX Proprietary Materials for any purpose other than the purposes authorized herein or in any other License Agreement or the Research Collaboration Agreement (if then in effect) (in each case, an “Unauthorized Use”), the
results of such Unauthorized Use, and any discoveries or inventions that arise from such Unauthorized Use, whether patentable or not, shall belong solely and exclusively to the providing 

 
 ***Certain information contained herein has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 25 

 
Party. If required in order to perfect or enforce the providing Party’s ownership of such results, discoveries or inventions, each Party, on behalf of itself and its Affiliates (and in the
case of CytomX, its Sublicensees), each hereby assigns and agrees to assign to the providing Party all of its and their right, title and interest in and to all such results, discoveries or inventions made through such Unauthorized Use. Each Party
agrees to cooperate, and to cause its Affiliates (and in the case of CytomX, its Sublicensees) to cooperate, with the providing Party, and to execute and deliver any and all documents that the providing Party reasonably deems necessary, to perfect
and enforce its rights hereunder. 
 2.7. Services. If, during the Term, CytomX requests that ImmunoGen provide additional services
with respect to (a) process development, (b) analytical method development, or (c) manufacturing and supply of Licensed Product in drug substance form for any GLP toxicology studies, clinical studies, or commercial scale-up, but
excluding pivotal studies and commercial supply, or (d) any other tasks in connection with the Development, Manufacture, use or Commercialization of Licensed Products with respect to which the Parties may mutually agree, then the Parties shall
negotiate in good faith the terms of separate written agreements with respect to such activities. 
  

	3.	LICENSE GRANTS. 

 3.1. License Grants. 

3.1.1. Commercial License. Subject to the terms and conditions of this Agreement, ImmunoGen hereby grants to CytomX and its Affiliates
an exclusive (even as to ImmunoGen), non-transferable (except as expressly permitted in this Agreement), royalty-bearing license, including the right to grant sublicenses as described in Section 3.1.2 hereof, under the Licensed
Intellectual Property, to Develop, make, have made, use, sell, offer for sale, import and otherwise Commercialize Licensed Products in the Field in the Territory. CytomX and its Affiliates shall have the right to engage one or more Affiliates or
Third Parties (the latter being referred to herein as “Permitted Third Party Service Providers”) as subcontractors to perform designated functions in connection with its activities under this Agreement (including transferring
Licensed Know-How and ImmunoGen Proprietary Materials as may be necessary for such Permitted Third Party Service Providers to perform such designated functions); provided that (a) CytomX shall [***] and (b) CytomX shall [***]. 

3.1.2. Right to Sublicense. CytomX and its Affiliates shall have the right to grant sublicenses under the rights granted to them under
Section 3.1.1 hereof with respect to any Licensed Product to any Sublicensee, provided that (a) each such sublicense shall be consistent with the terms and conditions of this Agreement, (b) CytomX shall [***], (c) CytomX
and its Affiliates shall cause [***], (d) Cytomx shall [***]. 
  
 ***Certain
information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 26 

 3.2. Retained Rights and Covenants. 

3.2.1. [***] 
 3.2.2. [***] 

3.3. License to CytomX TAP Platform Improvements. CytomX, on behalf of itself and its Affiliates, hereby grants to ImmunoGen a
non-exclusive, sublicensable, perpetual, irrevocable, royalty-free worldwide license under CytomX’s interest in any CytomX TAP Platform Improvements, including, without limitation, any Patent Rights claiming such CytomX TAP Platform
Improvements, to exploit such CytomX TAP Platform Improvements (a) for any purpose in the Field other than developing, manufacturing, using or commercializing PDCs and (b) for any purpose outside of the Field. Nothing in this Agreement
shall be construed as obligating CytomX to [***] or any of its Affiliates or any Third Party [***]. 
 3.4. Section 365(n) of
Bankruptcy Code. All rights and licenses now or hereinafter granted by either Party to the other Party under or pursuant to any section of this Agreement, including the licensed granted in this Article 3, are rights to
“intellectual property” (as defined in Section 101(35A) of Title 11 of the United States Code, as amended (such Title 11, the “Bankruptcy Code”)). The Parties hereto acknowledge and agree that the payments
provided for under Article 4 hereof, other than royalty payments pursuant to Section 4.2 hereof, do not constitute royalties within the meaning of Section 365(n) of the Bankruptcy Code or relate to licenses of
intellectual property under this Agreement. 
 3.5. No Implied Rights. Except as expressly provided in this Agreement, neither Party
shall be deemed, by estoppel, implication or otherwise, to have granted the other Party any license or other right with respect to any intellectual property of such Party. 
  

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

  
 27 

	4.	PAYMENTS. 

 4.1. Milestone Payments. 

4.1.1. Development Milestones. Within [***] following the first occurrence of each event (each, a “Development
Milestone”) described below for the first Licensed Product that achieves such milestone, CytomX shall provide written notice to ImmunoGen identifying the Development Milestone achieved, and CytomX shall pay to ImmunoGen the amount set forth
below within [***] of receipt of ImmunoGen’s notice with respect to such Development Milestone (each such amount, a “Development Milestone Payment”) to be payable only once regardless of how many Licensed Products achieve such
Development Milestone. 
  

					
	 Development Milestone
	  	Payment	 
	 Dosing of first patient in a Phase 1 Clinical Study
	  	 	[***	] 
	 Dosing of first patient in a Phase 2 Clinical Study
	  	 	[***	] 
	 Dosing of first patient in a Phase 3 Clinical Study
	  	 	[***	] 
	 Date of filing of BLA
	  	 	[***	] 
	 Date of receipt of Regulatory Approval in [***]
	  	 	[***	] 
	 Date of receipt of Regulatory Marketing Approval in [***]
	  	 	[***	] 
	 Date of receipt of Regulatory Marketing Approval in [***]
	  	 	[***	] 

 If a clinical milestone is achieved and any previous clinical milestone has not yet been achieved for any
reason, notwithstanding anything herein to the contrary such previous milestone(s) shall be deemed to have been achieved and the corresponding Development Milestone Payment set forth in the table above shall be payable simultaneously with the
Development Milestone Payment for the achievement of the subsequent Milestone. All Development Milestone Payments shall be non-refundable and noncreditable. 

4.1.2. Sales Milestones. CytomX shall pay to ImmunoGen the following one-time payments (each, a “Sales Milestone
Payment”) when aggregate Annual Net Sales of a Licensed Product in the Territory in a Calendar Year first reach the respective threshold (a “Sales Threshold”) indicated below (each, a “Sales Milestone”):

  

					
	 Total Annual Net Sales
	  	Sales Milestone
Payment	 
	 Total Annual Net Sales at least equal 500,000,000
	  	 	[***	] 
	 Total Annual Net Sales at least equal 750,000,000
	  	 	[***	] 
	 Total Annual Net Sales at least equal 1,000,000,000
	  	 	[***	] 
	 Total Annual Net Sales at least equal 1,500,000,000
	  	 	[***	] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 28 

 Any Sales Milestone Payment with respect to any Calendar Year shall be payable within [***] of
the end of such Calendar Year in the United States. Each Sales Milestone Payment is payable a maximum of one time only, regardless of the number of times a Licensed Product achieves a particular Sales Threshold or the number of Licensed Products
that achieve a particular Sales Threshold. All Sales Milestone Payments shall be nonrefundable and noncreditable. 
 4.2. Royalties.

 4.2.1. Royalty Payments. With respect to each Licensed Product and subject to the provisions of Section 4.2.2 hereof,
CytomX shall pay ImmunoGen royalties in the amount of the applicable rates (“Marginal Royalty Rates”) set forth below of Annual Net Sales of such Licensed Product during the Royalty Term: 

 

					
	 Annual Net Sales
	  	Marginal Royalty Rate for
Licensed Products (% of
Annual Net Sales)	 
	 Annual Net Sales of such Licensed Product during a given Calendar Year [***]
	  	 	[***	]% 
	 Annual Net Sales of such Licensed Product during a given Calendar Year [***]
	  	 	[***	]% 
	 Annual Net Sales of such Licensed Product during a given Calendar Year [***]
	  	 	[***	]% 

 4.2.2. Marginal Royalty Rate Application. Each Marginal Royalty Rate set forth in the table above shall
apply only to that portion of the Annual Net Sales of a given Licensed Product in the Territory during a given Calendar Year that falls within the indicated range. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 29 

 4.2.3. Royalty Adjustments. 

(a) Third Party Royalty Offset. Subject to Section 4.2.3(e) hereof, if, with respect to a Calendar Quarter, CytomX or any
of its Affiliates or Sublicensees [***] to one or more Third Parties in consideration of a [***], in the [***] CytomX could [***] the Licensed Intellectual Property to [***] or [***] the [***] or [***] of any Licensed Product [***] owned or
exclusively licensed by such Third Party in any country (collectively, “Third Party Payments”), [***] then CytomX shall have the right to reduce the royalties otherwise due to ImmunoGen pursuant to Section 4.2.1,
4.2.3(c) or 4.2.3(d) hereof (but not the royalties otherwise due to ImmunoGen pursuant to Section 4.2.3(b) hereof) with respect to Net Sales in such country of such Licensed Products in such Calendar Quarter by an amount
equal to [***] of the amount of such Third Party Payments. [***] For the avoidance of doubt, the Parties agree and acknowledge that this Section 4.2.3(a) shall not apply with respect to royalties payable by a Party to any Third Party
under any agreement in existence as of the Effective Date. 
 (b) Valid Claim Coverage. 

(i) No Patent Coverage. Subject to Section 4.2.3(e) hereof, the royalty rates set forth in Sections 4.2.1,
4.2.3(c) and 4.2.3(d) hereof shall apply, on a country-by-country basis and Licensed Product-by-Licensed Product basis, to Net Sales of Licensed Products only where (A) such Licensed Product (or its manufacture, use, sale, offer
for sale or importation) in such country is Covered by a Valid Claim within the Licensed Patent Rights or (B) such Licensed Product (or any component or intermediate thereof) was manufactured in a country where the manufacture of such Licensed
Product (or such component or intermediate), was, at the time of its manufacture, Covered by a Valid Claim within the Licensed Patent Rights, regardless of the country in which such Licensed Product is sold. Subject to the other terms of this
Agreement (except for Section 4.2.3(a) hereof, which shall not apply), on a country-by-country and Licensed Product-by-Licensed Product basis where and as of and when the royalty rates under Sections 4.2.1, 4.2.3(c) and
4.2.3(d) hereof do not apply as a result of this Section 4.2.3(b)(i), the royalties payable with respect to Net Sales of such Licensed Product sold by CytomX, its Affiliates and its Sublicensees in such country shall be reduced by
[***] of the royalties otherwise owed to ImmunoGen pursuant to Section 4.2.1 or 4.2.3(d) hereof, as applicable, without giving effect to any royalty reduction provided in Section 4.2.3(c) hereof, using the methodology
outlined in Exhibit B attached hereto. The Parties 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 30 

 
hereby acknowledge and agree that such royalties shall be in consideration of the commercial advantage, know-how and background information gained from the unpatented Licensed Know-How,
including, without limitation, ImmunoGen’s Confidential Information and ImmunoGen Proprietary Materials. 
 (ii) Applicability of
Royalty Rates. For purposes of clarity, (A) if a Licensed Product (or its manufacture, use, sale, offer for sale or importation) is Covered by a Valid Claim in a country within the Territory such that royalties are paid by CytomX pursuant
to Section 4.2.1, 4.2.3(c) or 4.2.3(d) hereof and, prior to the expiration of the Royalty Term for such Licensed Product in such country, the Licensed Product (and its manufacture, use, sale, offer for sale or importation)
is no longer Covered by a Valid Claim in such country, CytomX shall pay ImmunoGen a royalty at the rate set forth in Section 4.2.1(b)(i) hereof for the portion of the Royalty Term during which no such Valid Claim Covers such Licensed
Product (or its manufacture, use, sale, offer for sale or importation) in such country; and (B) if a Licensed Product (or its manufacture, use, sale, offer for sale or importation) is not Covered by a Valid Claim in a country within the
Territory such that royalties are paid by CytomX pursuant to Section 4.2.1(b)(i) hereof and, prior to the expiration of the Royalty Term for such Licensed Product in such country, the Licensed Product (or its manufacture, use, sale,
offer for sale or importation) becomes Covered by a Valid Claim within the Licensed Patent Rights in such country, CytomX shall pay ImmunoGen a royalty at the rates set forth in Section 4.2.1, 4.2.3(c) or 4.2.3(d) hereof,
as applicable, for that portion of the Royalty Term during which such Valid Claim Covers such Licensed Product (or its manufacture, use, sale, offer for sale or importation) in such country. 

(iii) Definition of “Cover”. A Valid Claim within the Licensed Patent Rights “Covers” the Licensed Product
(or its manufacture, use, sale, offer for sale or importation) in a country if, but for the license granted under Section 3.1.1 hereof, the manufacture, use, sale, offer for sale or importation of the Licensed Product by CytomX or any of
its Affiliates or Sublicensees in such country would infringe such Valid Claim; provided, however, that in determining whether a Valid Claim within such Licensed Patent Rights “Covers” (as defined above) the Licensed Product (or its
manufacture, use, sale, offer for sale or importation), (A) any Valid Claim within the Licensed Patent Rights that is jointly owned by 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 31 

 
CytomX (or any of its Affiliates) with ImmunoGen (or any of its Affiliates) shall be deemed to be owned solely by ImmunoGen or an Affiliate of ImmunoGen and (B) any Valid Claim contained in
[***] within the Licensed Patent Rights that has not been (1) canceled, withdrawn or abandoned or (2) [***] shall be deemed to have been issued. 

(c) Loss of Market Exclusivity. Subject to Section 4.2.3(e) hereof, if, with respect to a Calendar Quarter, CytomX or any
of its Affiliates or Sublicensees experiences a Loss of Market Exclusivity for a Licensed Product in any country, then CytomX shall have the right to reduce the royalties otherwise due to ImmunoGen pursuant to Section 4.2.1 or
4.2.3(d) hereof (but not the royalties otherwise due to ImmunoGen under Section 4.2.3(b) hereof) with respect to Net Sales in such country of such Licensed Products in such Calendar Quarter as described below, in each case using a
methodology similar to that outlined in Exhibit B attached hereto. [***]. 
 (d) Effect of Challenge. In further
consideration of the grant by ImmunoGen of the license hereunder and except to the extent the following is unenforceable under the Applicable Laws of a particular jurisdiction where a patent application within the Licensed Patent Rights is pending
or a patent within the Licensed Patent Rights is issued, if CytomX, its Affiliates or Sublicensees initiates a Challenge or induces or assists a Third Party in initiating or prosecuting a Challenge (the Licensed Patent Rights subject to such
Challenge being referred to herein as the “Challenged Patent Rights”), then during the period that such Challenge is pending, the royalty rates set forth in Section 4.2.1 hereof shall be increased by [***] of annual Net Sales
(the “Challenge-Related Royalty Increase”) in the country(ies) in which the Challenged Patent Rights were pending or issued (each, a “Challenge Jurisdiction”) commencing on the date of such initiation or the date
CytomX, its Affiliates or Sublicensees first induces or provides assistance to such Third Party, as applicable, but only with respect to Net Sales of Licensed Products in the applicable Challenge Jurisdiction(s). If, following the final,
unappealable conclusion of a Challenge in a Challenge Jurisdiction, there remains one or more Valid Claims within the Challenged Patent Rights that would be infringed by the manufacture, use, sale, offer for sale or importation then (i) the
royalty rates set forth in Section 4.2.1 hereof shall be increased by [***] of annual Net Sales (which shall be in addition to the Challenge-Related Royalty Increase) in the applicable Challenge Jurisdiction, commencing upon the final,
unappealable conclusion of such Challenge and continuing for the remainder of the Royalty Term in the applicable Challenge Jurisdiction, and (ii) CytomX shall reimburse ImmunoGen for its costs 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 32 

 
and expenses (including, without limitation, reasonable attorneys’ and experts’ fees and expenses of litigation) incurred in responding to the Challenge. CytomX shall be required to pay
such reimbursement within [***] of receiving an invoice therefor from ImmunoGen, which shall set forth in reasonable detail the basis for the charges for which ImmunoGen is seeking reimbursement. If, following the final, unappealable conclusion of a
Challenge in a Challenge Jurisdiction, there remain no Valid Claims within the Challenged Patent Rights that would be infringed by the manufacture, use, sale, offer for sale or importation of Licensed Products by CytomX or any of its Affiliates or
Sublicensees in such Challenge Jurisdiction in the absence of the license granted under Section 3.1.1 hereof, then ImmunoGen shall reimburse CytomX for all amounts with respect to the Challenge-Related Royalty Increase actually paid by CytomX to
ImmunoGen with respect to the Challenge Jurisdiction (the “Clawback Amount”) as follows: [***]. 
 (e) Minimum Royalty
Rate. Anything contained in this Agreement to the contrary notwithstanding, none of the reductions to royalties provided in Sections 4.2.3(a), 4.2.3(b) and 4.2.3(c) hereof, shall, individually or in the aggregate, [***]
the royalties payable with respect to Net Sales of any Licensed Product sold by CytomX, its Affiliates and its Sublicensees in any country during the Royalty Term by [***] of the royalties otherwise owed to ImmunoGen pursuant to
Section 4.2.1 or 4.2.3(d), as applicable, without giving effect to any royalty reduction provided in Section 4.2.3(a), 4.2.3(b) or 4.2.3(c) hereof. 

4.3. Reports and Payments. 

4.3.1. Cumulative Royalties. The obligation to pay royalties under Section 4.2 shall be imposed only once with respect to a
single unit of a Licensed Product regardless of how many Valid Claims in Patent Rights included within the Licensed Intellectual Property would, but for this Agreement, be infringed by the use or sale of such Licensed Product in the country in which
such Licensed Product is used or sold. 
 4.3.2. Royalty Statements and Payments. Within [***] after the end of each Calendar Quarter,
CytomX shall deliver to ImmunoGen a report setting forth for such Calendar Quarter the following information, on a Licensed Product-by-Licensed Product basis: (a) the gross sales (if available) and the Net Sales of each Licensed Product
(specifying in reasonable detail the deductions to gross sales used to calculate Net Sales, (b) the basis for any adjustments to the royalty payable for the sale of each Licensed Product, (c) the applicable exchange rate to convert each
country’s currency to U.S. Dollars under Section 4.3.4 hereof and (d) 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 33 

 
the royalties due hereunder for the sale of each Licensed Product. No such reports shall be due for any Licensed Product before the First Commercial Sale of such Licensed Product in the
Territory. The total royalty due for the sale of Licensed Products during such Calendar Quarter shall be remitted at the time such report is delivered. 

4.3.3. No Set-Off; Taxes and Withholding. All payments made by CytomX to ImmunoGen hereunder shall be made without set-off or
counterclaim and free and clear of any taxes, duties, levies, fees or charges, except withholding taxes, if any. In the event any of the payments made pursuant to this Agreement become subject to withholding taxes under the Applicable Law of any
jurisdiction, CytomX shall deduct and withhold the amount of such taxes for the account of ImmunoGen, to the extent required by Applicable Law, such amounts payable to ImmunoGen shall be reduced by the amount of taxes deducted and withheld, and
CytomX shall pay the amounts of such taxes to the proper Governmental Authority in a timely manner and promptly transmit to ImmunoGen an official tax certificate or other evidence of such tax obligations together with proof of payment from the
relevant Governmental Authority of all amounts deducted and withheld sufficient to enable ImmunoGen to claim such payment of taxes. Any such withholding taxes required under Applicable Law to be paid or withheld shall be an expense of, and borne
solely by, ImmunoGen. CytomX will provide ImmunoGen with reasonable assistance to enable ImmunoGen to recover such taxes as permitted by Applicable Law. 

4.3.4. Currency. All amounts payable and calculations hereunder shall be in United States dollars, and all payments due under this
Agreement shall be made by wire transfer in immediately available funds to an account designated by the Party owed such payment. As applicable, Net Sales and any royalty deductions shall be converted into United States dollars in accordance with the
CytomX Standard Exchange Rate Methodology. 
 4.3.5. Overdue Payments. Subject to the other terms of this Agreement, any payments
hereunder not paid within the applicable time period set forth herein shall bear interest from the due date until paid in full, at a rate per annum equal to the lesser of (a) [***], or (b) the maximum interest rate permitted by applicable law in
regard to such payments, calculated in each case from the date such payment was due through to the date on which payment is actually made; provided, however, that with respect to any disputed payments, no interest shall be due until such dispute is
resolved and the interest that shall be payable thereon shall be based on the finally-resolved amount of such payment, calculated from the original date on which the disputed payment was due through the date on which payment is actually made. Such
payments when made shall be 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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accompanied by all interest so accrued. Such interest and the payment and acceptance thereof shall not negate or waive the right of ImmunoGen to any other remedy, legal or equitable, to which it
may be entitled because of the delinquency of the payment. 
 4.4. Maintenance of Records; Audits. 

4.4.1. Record Keeping. CytomX shall keep, and cause its Affiliates and Sublicensees to keep, accurate books of account and records in
connection with the sale of Licensed Products, in sufficient detail to permit accurate determination of all figures necessary for verification of royalties to be paid hereunder. CytomX shall maintain, and cause its Affiliates and Sublicensees to
maintain, such records for a period of at least [***] after the end of the Calendar Year in which they were generated. 
 4.4.2.
Audits. Upon [***] prior written notice from ImmunoGen, CytomX shall permit an independent certified public accounting firm of internationally recognized standing selected by ImmunoGen and reasonably acceptable to CytomX to examine, at
ImmunoGen’s sole expense, the relevant books and records of CytomX, its Affiliates and Sublicensees during the period covered by such examination, as may be reasonably necessary to verify the accuracy of the reports submitted by CytomX in
accordance with Section 4.3 hereof and the payment of royalties hereunder. An examination by ImmunoGen under this Section 4.4.2 shall occur not more than once in any Calendar Year and shall be limited to the pertinent books
and records for any Calendar Year ending not more than [***] before the date of the request. The accounting firm shall be provided access to such books and records at the facilities where such books and records are kept and such examination shall be
conducted during normal business hours. CytomX may require the accounting firm to sign a reasonable and customary non-disclosure agreement before providing the accounting firm access to CytomX’s facilities or records. Upon completion of the
audit, the accounting firm shall provide both ImmunoGen and CytomX a written report disclosing whether the reports submitted by CytomX are correct or incorrect, whether the royalties paid are correct or incorrect and, in each case, the specific
details concerning any discrepancies. CytomX and ImmunoGen shall each have the right to request a further determination by such accounting firm as to matters which such Party disputes within [***] following receipt of such report. The Party
initiating a dispute will provide the other Party and the accounting firm with a reasonably detailed statement of the grounds upon which it disputes any findings in the written report and the accounting firm shall undertake to complete such further
determination within [***] after the dispute notice is provided, which determination shall be limited to the disputed matters and provided to both 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 35 

 
Parties. The Parties shall use reasonable efforts, through the participation of finance representatives of both Parties, to resolve any dispute arising in relation to the audit by good faith
discussion. The results of any such audit, reflecting the accounting firm’s determination of any disputed matters, shall be binding on both Parties. 

4.4.3. Underpayments/Overpayments. If such accounting firm concludes that additional royalties were due to ImmunoGen, CytomX shall pay
the additional royalties (plus interest thereon at the rate provided in Section 4.3.5 hereof) within [***] of the date CytomX receives such accountant’s written report so concluding. If such underpayment exceeds [***] of the
royalties that were to be paid [***], CytomX also shall reimburse ImmunoGen for all reasonable charges of such accountants for conducting the audit. If such accounting firm concludes that CytomX overpaid royalties, ImmunoGen shall repay such amount
in full within [***] of the receipt of such accountant’s report, or, at CytomX’s option, it shall be entitled to offset all such overpayments against any outstanding or future amounts payable to ImmunoGen hereunder until CytomX has
received full credit for such overpayments. 
 4.4.4. Confidentiality. All financial information that is subject to review under this
Section 4.4 shall be deemed to be the Confidential Information of the audited Party subject to the provisions of Article 6 hereof. 
  

	5.	INTELLECTUAL PROPERTY. 

 5.1. Inventions. 

5.1.1. Ownership. All determinations of inventorship under this Agreement shall be made in accordance with the laws of the United
States. Determinations of ownership of intellectual property hereunder will be made in accordance with inventorship. 
 (a) ImmunoGen
Solely Owned Technology. As between the Parties, ImmunoGen shall be the sole owner of all Licensed Intellectual Property (other than Joint Program Technology and Joint TAP Platform Improvements included therein and any Joint Patent Rights). 

(b) CytomX Solely Owned Technology. As between the Parties, CytomX shall be the sole owner of all CytomX Program Technology and CytomX
TAP Platform Improvements and any Patent Rights claiming such CytomX Program Technology and CytomX TAP Platform Improvements. 
 (c)
Jointly Owned Technology. All Joint Program Technology and Joint TAP Platform Improvements (including, without limitation, all Joint Patent Rights) shall be jointly owned by the Parties, with each Party holding an undivided one-half interest
therein. Subject to the Parties’ other rights and obligations under this Agreement and any then-outstanding License Agreement, each Party shall be [***]. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 5.1.2. Disclosure. CytomX shall, no less than [***] before filing any initial Patent Right
disclosing CytomX TAP Platform Improvements or any Joint Program Technology or Joint TAP Platform Improvements or any other Patent Right that contains ImmunoGen’s Confidential Information, provide a copy of such disclosure to ImmunoGen.
ImmunoGen shall, no less than [***] before filing any initial Patent Right disclosing Joint Program Technology or Joint TAP Platform Improvements or any other Patent Right that contains CytomX’s Confidential Information, provide a copy of such
disclosure to CytomX. In each case, such disclosures to the other Party shall include all invention disclosures or other similar documents submitted to such Party by its, or its Affiliates’, employees, agents or independent contractors
describing such invention and the proposed inventorship of any new Patent Rights intended to be filed. The other Party shall promptly raise any issue regarding inventorship of any such Patent Rights, and the Parties agree to determine the correct
inventorship of any Patent Rights in accordance with Section 10.10.1 hereof. 
 5.2. Filing, Prosecution and Maintenance of
Patent Rights. 
 5.2.1. Cooperation. Without limiting any other rights and obligations of the Parties under this Agreement, the
Parties shall cooperate with respect to the timing, scope and filing of patent applications and patent claims relating to any Joint Program Technology to preserve and enhance the patent protection for Licensed Products, including the manufacture and
use thereof and to allow the Party owning the technology underlying an Improvement to have reasonable input to preserve and enhance its patent portfolio and patenting strategy. 

5.2.2. ImmunoGen Patent Rights. ImmunoGen, at its own expense, shall have the sole right, but not the obligation, to prepare, file,
prosecute and maintain, throughout the world, all Licensed Patent Rights (other than Licensed Patent Rights claiming Joint Program Technology or Joint TAP Platform Improvements). With respect to any Licensed Patent Rights disclosing or claiming
Program Technology (other than TAP Platform Improvements included in the Program Technology), ImmunoGen shall keep CytomX reasonably informed of the status of the filing, prosecution and maintenance of such Patent Rights and shall consider in good
faith any recommendations made by CytomX in regard to the filing, prosecution or maintenance of any such Patent Right. ImmunoGen shall 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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consult with CytomX in the filing, prosecution and maintenance of any ImmunoGen Patent Right related to Improvements to CytomX Technology and shall not unreasonably refuse to incorporate any
recommendations made by CytomX in regard to such filing, prosecution or maintenance. To the extent ImmunoGen decides not to file, prosecute or maintain any Licensed Patent Right that ImmunoGen reasonably believes covers or may cover the Development,
Manufacture, Commercialization or use of any Licensed Product (other than any such Patent Right owned or co-owned by a Third Party licensor or the filing of a new initial patent application) and except in the case in which the decision not to file,
prosecute or maintain such Patent Right is made by ImmunoGen in the ordinary course of filing continuation applications or as part of an overall strategy to optimize the scope or other aspects of the Licensed Intellectual Property, ImmunoGen shall
provide CytomX with [***] prior written notice to such effect (i.e., at least [***] prior to the date on which any such filing is intended or due or on which any other such action is due), in which event CytomX may elect to file or continue
prosecution or maintenance of such Patent Right, at CytomX’s expense, and ImmunoGen, upon CytomX’s written request received within such [***] period, shall execute such documents and perform such acts, at CytomX’s expense, as may be
reasonably necessary to permit CytomX to file, prosecute and maintain such Patent Right; provided that CytomX (a) shall keep ImmunoGen reasonably informed of the status of the filing, prosecution and maintenance of such Patent Rights,
(b) shall consider in good faith any recommendations made by ImmunoGen in regard to such filing, prosecution and maintenance of such Patent Right, and (c) shall not unreasonably refuse to incorporate any recommendations made by ImmunoGen
in regard to such filing, prosecution or maintenance. Any such Patent Right that is prosecuted or maintained by CytomX pursuant to this Section 5.2.2 (a) will continue to be owned by ImmunoGen, and (b) subject to the
Parties’ other rights and obligations under this Agreement, may be licensed by ImmunoGen to one or more Third Parties. For avoidance of doubt, “prosecution” as used in this Section 5.2 includes oppositions, nullity or
revocation actions, post-grant reviews and other patent office proceedings involving the referenced Patent Rights. 
 5.2.3. CytomX Patent
Rights. CytomX, at its own expense, shall have the sole right, but not the obligation, to prepare, file, prosecute and maintain, throughout the world, any Patent Rights comprised in the CytomX TAP Platform Improvements. CytomX shall consult with
ImmunoGen in the filing, prosecution and maintenance of any Patent Right related to CytomX TAP Platform Improvements (including, without limitation, keeping ImmunoGen reasonably informed of the status thereof), shall consider in good faith any
recommendations made by ImmunoGen in regard to such filing, prosecution or maintenance, and shall not unreasonably refuse to incorporate any recommendations made by 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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ImmunoGen in regard to such filing, prosecution or maintenance. Nothing contained in this Agreement shall be construed as obligating CytomX to file any patent application in any country or other
jurisdiction relating to CytomX TAP Platform Improvements. 
 5.2.4. Joint Patent Rights. If not already established under the
Research Collaboration Agreement, prior to either Party filing any Patent Right disclosing Joint Program Technology or Joint TAP Platform Improvements, the Parties shall establish a patent committee (the “Patent Committee”)
comprised of at least one (1) representative of each Party for the purpose of facilitating the preparation, filing, prosecution, maintenance and defense of Joint Patent Rights. As agreed upon by the Parties, meetings of the Patent Committee may
be face-to-face or may be conducted by teleconferences or videoconferences, from time to time as needed. The Patent Committee will be the forum through which the Parties coordinate their respective obligations to each other described in
Sections 5.2.2 and 5.2.3 hereof and in this Section. In the event the Parties conceive or generate any Joint Program Technology or Joint TAP Platform Improvements, the Parties shall promptly meet to discuss and determine, based on
mutual consent, whether to seek patent protection thereon, which Party will control filing, prosecution and maintenance of such patents and how to pay for the filing, prosecution and maintenance of such patents. It is presumed that CytomX will
control filing, prosecution and maintenance of Joint Patent Rights claiming Joint Program Technology or Joint Unconjugated Probody Platform Improvements, and that ImmunoGen will control filing, prosecution and maintenance of Joint Patent Rights
claiming Joint TAP Platform Improvements or Joint Conjugation Probody Platform Improvements. Neither Party will file any Joint Patent Right without the prior written consent of the other Party, which consent shall not be unreasonably withheld,
conditioned or delayed. The Party controlling filing and prosecution of any such Joint Patent Right (a) shall keep the other Party informed regarding each Patent Right, (b) shall consider in good faith any recommendations made by the other
Party in regard to the filing, prosecution or maintenance of any such Patent Right and (c) shall not unreasonably refuse to incorporate any recommendations made by the other Party in regard to such filing, prosecution or maintenance. 

5.2.5. Improper Patent Filings. Each Party agrees that, without the prior written consent of the other Party, neither it nor any of its
Affiliates will [***]. 
 5.2.6. Liability. Except for breaches of Section 5.2.5 hereof, to the extent that a Party is
obtaining, prosecuting or maintaining a Patent Right included in the Licensed Intellectual Property or Joint Patent Rights or otherwise exercising its rights under this Section 5.2, such Party, and its Affiliates, employees, agents or
representatives, shall not be liable to the other Party in respect of any act or omission on the part of any such Party, or its Affiliates, employees, agents or representatives, in connection with such activities undertaken in good faith. 

5.2.7. Extensions. The decision to file for a patent term extension and particulars thereof (including which patent(s) to extend) will
be made with the goal of obtaining the optimal patent term and scope of protection for Licensed Products. If a Party wishes to file for a patent term extension based on Patent Rights owned by the other Party, it will so notify the other Party, and
the Parties will meet to discuss and determine whether and how to proceed with such patent term extension. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 5.3. Joint Research Agreement. This Agreement shall be understood to be a joint research
agreement under 35 U.S.C. § 103(c)(3) entered into for the purpose of Developing Licensed Products. 
 5.4. Enforcement of
Patent Rights. 
 5.4.1. Notice. If either ImmunoGen or CytomX becomes aware of any infringement anywhere in the world of any
issued Patent Right within the Licensed Intellectual Property or Joint Patent Rights by any Third Party (an “Infringement”), such Party shall promptly notify the other Party in writing to that effect. 

5.4.2. Infringement of Certain Patent Rights. 

(a) In the event of any Infringement of a Patent Right included in the Licensed Intellectual Property (including, without limitation, Joint
Patent Rights included in the Joint TAP Platform Improvements and Joint Conjugation Probody Platform Improvements but excluding Joint Patent Rights included in the Joint Program Technology (other than Joint Conjugation Probody Platform
Improvements)), ImmunoGen shall have the first right to take action to obtain a discontinuance of Infringement or bring suit against a Third Party infringer of such Patent Right within [***] from the date of notice. 

(b) ImmunoGen shall bear all the expenses of any suit brought by it claiming infringement of any such Patent Right. CytomX shall reasonably
cooperate with ImmunoGen in any such suit and shall have the right to consult with ImmunoGen and to participate in and be represented by independent counsel in such litigation at its own expense. ImmunoGen shall incur no liability to CytomX as a
consequence of such litigation or any unfavorable decision resulting therefrom, including any decision holding any such Patent Right invalid or unenforceable, and ImmunoGen 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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shall not, without CytomX’s prior written consent (which consent shall not be unreasonably withheld, conditioned or delayed), enter into any settlement or consent decree that admits the
invalidity or unenforceability or limits the scope of any such Patent Right. 
 (c) If ImmunoGen has not obtained a discontinuance of such
Infringement by, or filed suit against, any such Third Party infringer within the [***] period set forth in subsection (a) above, then CytomX shall have the right, but not the obligation, to bring suit against such Third Party infringer, at
CytomX’s sole expense, under any Licensed Intellectual Property. ImmunoGen shall reasonably cooperate with CytomX in any such litigation, including being joined as a party, at CytomX’s expense, provided that ImmunoGen may, at its sole
discretion, elect to be represented by independent counsel in such litigation at its own expense. CytomX shall incur no liability to ImmunoGen as a consequence of such litigation or any unfavorable decision resulting therefrom, including any
decision holding any such ImmunoGen Patent Right invalid or unenforceable; and CytomX shall not, without ImmunoGen’s prior written consent (which ImmunoGen may withhold in its sole discretion), enter into any settlement or consent decree that
requires any payment by or admits or imparts any other liability to ImmunoGen or admits the invalidity or unenforceability or limits the scope of any such Patent Right. 

(d) In the event of any Infringement of a Joint Patent Right included in the Joint Program Technology (other than Joint Conjugation Probody
Platform Improvements), CytomX shall have the first right to take action to obtain a discontinuance of Infringement or bring suit against a Third Party infringer of such Patent Right within [***] from the date of notice. 

(e) CytomX shall bear all the expenses of any suit brought by it claiming infringement of any such Patent Right. ImmunoGen shall reasonably
cooperate with CytomX in any such suit and shall have the right to consult with CytomX and to participate in and be represented by independent counsel in such litigation at its own expense. CytomX shall incur no liability to ImmunoGen as a
consequence of such litigation or any unfavorable decision resulting therefrom, including any decision holding any such Patent Right invalid or unenforceable, and CytomX shall not, without ImmunoGen’s prior written consent, enter into any
settlement or consent decree that admits the invalidity or unenforceability or limits the scope of any such Patent Right. 
 (f) If CytomX
has not obtained a discontinuance of such Infringement by, or filed suit against, any such Third Party infringer within the [***] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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period set forth in subsection (d) above, then ImmunoGen shall have the right, but not the obligation, to bring suit against such Third Party infringer, at ImmunoGen’s sole expense,
under any CytomX TAP Platform Improvements. CytomX shall reasonably cooperate with ImmunoGen in any such litigation, including being joined as a party, at ImmunoGen’s expense, provided that CytomX may, at its sole discretion, elect to be
represented by independent counsel in such litigation at its own expense. ImmunoGen shall incur no liability to CytomX as a consequence of such litigation or any unfavorable decision resulting therefrom, including any decision holding any such
CytomX Patent Right invalid or unenforceable; and ImmunoGen shall not, without CytomX’s prior written consent (which CytomX may withhold in its sole discretion), enter into any settlement or consent decree that requires any payment by or admits
or imparts any other liability to CytomX or admits the invalidity or unenforceability or limits the scope of any such Patent Right 
 (g)
The enforcing Party shall keep the other Party reasonably informed of all material developments in connection with any such suit. Any recoveries obtained by either Party as a result of any proceeding against such a Third Party infringer
(“Monies”) shall be allocated as follows: 
 (i) the Monies will be distributed first to the controlling Party for its
out-of-pocket litigation costs and expenses incurred in connection with such litigation; then 
 (ii) the Monies will then be distributed to
the other Party for its out-of-pocket litigation costs and expenses incurred in connection with such litigation; then 
 (iii) [***]; or

 (iv) [***]; or 
 (v) [***];
then 
 (vi) [***]; or 
 (vii)
[***]. 
 (h) Other Infringement. For any infringement of Patent Rights owned by CytomX or licensed by CytomX from Third Parties,
CytomX retains the sole right (as between the Parties), but not the obligation, to enforce such Patent Rights. 
 (i) Infringement of
Joint Patent Rights. With respect to any notice of a Third Party infringer of any Joint Patent Right other than a Patent Right included in the Joint Program Technology or Joint TAP Platform Improvements, the Parties shall meet as soon as
reasonably practicable to 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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discuss such infringement and determine an appropriate course of action and the Parties’ respective rights and responsibilities with respect to any enforcement thereof. 

5.5. Response to Biosimilar Applicants. 

5.5.1. Notice. In the event that CytomX (a) receives a copy of a Biosimilar Application, whether or not such copy is provided under
any Applicable Laws (including the BPCIA, the United States Patient Protection and Affordable Care Act, implementing FDA regulations and guidance or similar foreign laws or regulations) applicable to the approval or manufacture of any biosimilar or
interchangeable biological product (a “Proposed Biosimilar Product”) for which a Licensed Product is a “reference product,” as such term is used in the BPCIA, or (b) otherwise becomes aware that such a Biosimilar
Application has been filed (such as in an instance described in Section 351(l)(9)(C) of the PHSA), then CytomX shall promptly provide ImmunoGen with written notice. 

5.5.2. Access to Confidential Information. Upon written request from ImmunoGen and to the extent permitted by Applicable Laws, CytomX
shall provide ImmunoGen with confidential access to those portions of the Biosimilar Application and such other information provided to CytomX by the Third Party that submitted the Biosimilar Application (the “Applicant”) that
describe the Linker and Payload of the Proposed Biosimilar Product or the method(s) of conjugating the cell-binding moiety of the Proposed Biosimilar Product to its Payload; provided, however, that prior to receiving the Biosimilar Application and
such confidential information, ImmunoGen shall provide notice to CytomX and the Applicant confirming its agreement to be subject to the confidentiality provisions in Section 351(l)(1)(B)(iii) of the PHSA. For purposes of clarity, the Parties
acknowledge and agree that ImmunoGen has retained a right to assert any patent within the Licensed Patent Rights and participate in litigation concerning any such patent. 

5.5.3. Proposed Patent List. 

(a) Preparation of Proposed Patent List. Not later than [***] days from the date of receipt by CytomX of a copy of a Biosimilar
Application and related manufacturing information, CytomX, with cooperation from ImmunoGen, shall prepare and provide ImmunoGen with a list (the “Proposed Patent List”) of (i) those patents within the Licensed Patent Rights
that CytomX reasonably believes would be infringed by the manufacture and/or sale of the Proposed Biosimilar Product and (ii) those patents within the Licensed Patent Rights, if any, that CytomX would be willing to sublicense to such Applicant
in accordance with the terms of 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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this Agreement. As soon as practicable following the date of receipt by ImmunoGen of the Proposed Patent List, ImmunoGen and CytomX shall discuss in good faith the patents within the Licensed
Patent Rights to be included on the Proposed Patent List and CytomX shall consider in good faith ImmunoGen’s proposals for changes to the Proposed Patent List with respect to the patents within the Licensed Patent Rights. Not later than the end
of the period specified by Applicable Laws, CytomX shall provide the Applicant with a copy of the Proposed Patent List; provided, however, that CytomX shall incorporate certain ImmunoGen requests in accordance with Section 5.5.3(d)
hereof. Notwithstanding the enforcement rights with respect to the Licensed Patent Rights set forth in Section 5.2.2 hereof, CytomX shall have the right to include any of the patents within the Licensed Patent Rights on the Proposed
Patent List to the extent that CytomX reasonably believes that a claim of patent infringement for such patent could be asserted by either ImmunoGen or CytomX; provided, however, that the right to control any suit or proceeding in which such a claim
is asserted shall be as set forth in Section 5.5.4 hereof. 
 (b) Disclosure of Applicant’s Response. Provided that
ImmunoGen has agreed to comply with the confidentiality provisions in Section 351(l)(1)(B)(iii) of the PHSA and to the extent permitted by Applicable Laws, CytomX shall provide to ImmunoGen the portion of the Applicant Response (as defined
below) pertaining to the Licensed Patent Rights no later than [***] days from the date of receipt by CytomX of a response from the Applicant with regard to any patent within the Licensed Patent Rights included on the Proposed Patent List,
including any response required by the BPCIA (the “Applicant Response”). 
 (c) Preparation of CytomX Response. Not
later than [***] days from the date of receipt by CytomX of the Applicant Response, CytomX, with cooperation and assistance from ImmunoGen, shall prepare and provide ImmunoGen with a proposed response with respect to the Licensed Patent Rights
(the “CytomX Response”) that (i) describes on a claim-by-claim basis, how each patent within the Licensed Patent Rights on the Proposed Patent List would be infringed by the commercial marketing of the Proposed Biosimilar
Product, and (ii) responds to Applicant’s claims, if any, that the patents within the Licensed Patent Rights on the Proposed Patent List are invalid or unenforceable. The CytomX Response shall include only the foregoing and shall not be
construed to include any proposed response to the Applicant relating to any patents other than the Licensed Patent Rights; further, any actual response to the Applicant under the BPCIA and all decisions relating to subsequent procedures

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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under the BPCIA with regard to any patent other than those included within the Licensed Patent Rights shall be within the sole discretion of CytomX. As soon as practicable following the date of
receipt by ImmunoGen of the proposed CytomX Response, the Parties shall discuss in good faith the statements in the proposed CytomX Response and CytomX shall consider in good faith ImmunoGen’s proposals for changes to the CytomX Response. Not
later than the end of the period specified by Applicable Laws, CytomX shall provide the Applicant with a copy of the CytomX Response; provided, however, that CytomX shall incorporate certain ImmunoGen requests in accordance with
Section 5.5.3(d) hereof. 
 (d) Inclusion of Licensed Patent Rights or Responsive Information. Provided that CytomX is
legally able under Applicable Law to provide ImmunoGen with a copy of the Biosimilar Application (and related manufacturing agreement) and ImmunoGen has provided notice to CytomX and Applicant confirming its agreement to be subject to the
confidentiality provisions of Section 351(l)(1)(B)(iii) of the PHSA, if ImmunoGen requests in writing to either (i) include a patent in the Proposed Patent List that was not included in CytomX’s initial Proposed Patent List provided
to ImmunoGen by CytomX pursuant to Section 5.5.3(a) hereof or (ii) include responsive information with respect to any patent within the Licensed Patent Rights in the CytomX Response that was not included in CytomX’s initial
CytomX Response provided to ImmunoGen pursuant to Section5.5.3(c) hereof, then, absent manifest error, CytomX shall include such patent in the Proposed Patent List and such responsive information in the CytomX Response provided to Applicant,
as applicable; provided, however, that ImmunoGen shall indemnify CytomX in accordance with Section 9.2 hereof to the extent any submissions requested by ImmunoGen are determined to have been made negligently or in bad faith. 

(e) Negotiation; ImmunoGen Rights. As soon as possible following the date on which CytomX provides the CytomX Response to the
Applicant, CytomX shall commence good faith negotiations with Applicant for a period of not more than [***] days (the “Negotiation Period”) in an effort to reach agreement on the patents on the Proposed Patent List (the
“Infringed Patent List”) that will be the subject to an Immediate Patent Infringement Action; provided, however, that if the Proposed Patent List includes both patents within the Licensed Patent Rights and patents that are not
within the Licensed Patent Rights, then CytomX shall not agree to the inclusion in the Infringed Patent List of any patents within the Licensed Patent Rights without the prior written consent of ImmunoGen, which consent shall not be unreasonably
withheld, 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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conditioned or delayed. If CytomX and Applicant fail to reach agreement under Section 351(l)(4)(A) of the PHSA on the Infringed Patent List, CytomX shall have the sole right to determine
under Section 351(l)(5)(B) of the PHSA which patents of those on the Proposed Patent List should be the subject of an Immediate Patent Infringement Action; provided, however, that if the Proposed Patent List [***], then CytomX shall [***].
Within [***] days following the exchange of such lists by CytomX and the Applicant, CytomX shall, to the extent legally permissible, provide ImmunoGen with a copy of the portion of the combined Infringed Patent List containing patents within
the Licensed Patent Rights that will be the subject of an Immediate Patent Infringement Action. 
 (f) Supplements to Proposed Patent
List. ImmunoGen shall provide CytomX with a copy of any U.S. patent within the Licensed Patent Rights that is issued after CytomX has provided the Proposed Patent List to the Applicant within [***] day after such issuance. As soon as
practicable following the date of receipt by CytomX of any such patent, ImmunoGen and CytomX shall discuss in good faith whether such patent would be infringed by the manufacture and/or sale of the Proposed Biosimilar Product. CytomX shall provide
the Applicant with a supplement to the Proposed Patent List to include such patent not later than [***] days after the issuance of such patent if CytomX reasonably believes that a claim of patent infringement for such patent could be asserted
by either ImmunoGen or CytomX or if ImmunoGen, absent manifest error, requests that CytomX supplement the Proposed Patent List to include such patent provided, however, that ImmunoGen shall indemnify CytomX in accordance with Section 9.2
hereof to the extent any supplement submissions requested by ImmunoGen are determined to have been made negligently or in bad faith. 

5.5.4. Claims, Suits and Proceedings. 

(a) Immediate Patent Infringement Action. With respect to any patents within the Licensed Patent Rights or any Patent Rights claiming
CytomX TAP Platform Improvements, Joint Program Technology or Joint TAP Platform Improvements that are to be the subject of an Immediate Patent Infringement Action, the Parties’ respective rights and obligations with respect to the litigation
of such patents (including rights to initiate, step in, participate in, settle and share amounts recovered pursuant to such Immediate Patent Infringement Action, and obligations to pay legal costs and expenses with respect to such Immediate Patent
Infringement Action) shall be as set forth in Section 5.4.2 hereof, except that the Party having 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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the first right to file a claim for Infringement against the Applicant with respect to any such patent subject to an Immediate Patent Infringement Action shall file such claim within
[***] days after agreement is reached as to the Infringed Patent List under Section 351(l)(4) or the exchange of the lists under Section 351(l)(5)(B) of the PHSA, as applicable. 

(b) Pre-Marketing Litigation. Either Party shall, within [***] days of receiving any notice of commercial marketing provided by
the Applicant pursuant to Section 351(l)(8)(A) of the PHSA (the “Premarket Notice”), notify the other Party. Thereafter, the Parties’ respective rights and obligations with respect to any litigation pursuant to
Section 351(l)(8)(B) of the PHSA (including rights to initiate, step in, participate in, settle and share amounts recovered pursuant to such action, and obligations to pay legal costs and expenses with respect to such action) shall be as set
forth in Section 5.4.2 hereof. 
 (c) Cooperation; Standing. If a Party with the right to initiate legal proceedings
under this Section 5.5.4 lacks standing to do so (or lacks the right under the BPCIA to do so) and the other Party has standing (or the sole right under the BPCIA) to initiate such legal proceedings, such Party with standing shall
initiate such legal proceedings at the request and expense of the other Party. 
 5.5.5. Invalidity or Unenforceability Defenses or
Actions. In the event that the Applicant asserts, as a defense or as a counterclaim in any infringement action under Section 5.5.4 hereof, that any of the Licensed Patent Rights or any Patent Rights claiming CytomX TAP Platform
Improvements, Joint Program Technology or Joint TAP Platform Improvements is invalid or unenforceable, then the Parties’ respective rights and obligations with respect to the response to such defense or the defense against such counterclaim, as
applicable, (including rights to initiate, step in, participate in, settle and share amounts recovered pursuant to such action, and obligations to pay legal costs and expenses with respect to such action) shall be as set forth in
Section 5.4.2 hereof; provided that for these purposes any such defense or counterclaim shall be deemed to be an Infringement. In all other cases, including any declaratory judgment action or similar action or claim filed by an Applicant
asserting that any of the Licensed Patent Rights or any Patent Rights claiming CytomX TAP Platform Improvements, Joint Program Technology or Joint TAP Platform Improvements is invalid or unenforceable (as in a declaratory judgment action brought by
the Applicant following the Premarket Notice), then the Parties’ respective rights and obligations with respect to such action (including rights to initiate, step in, participate in, settle and share amounts recovered pursuant to such action,
and obligations to pay legal costs and expenses with respect to such action) shall be as set forth in Section 5.4.2 hereof; provided that for these purposes any such case shall be deemed to be an Infringement. 

5.5.6. Changes in Applicable Law. The Parties have agreed to the provisions of this Section 5.5 on the basis of the BPCIA
and other applicable laws and regulations in effect as of the Effective Date. If there are any material changes to the BPCIA or other Applicable Laws that would affect these provisions, the Parties will discuss amendments to this
Section 5.5 in good faith. 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 5.6. Interference, Opposition, Revocation and Declaratory Judgment Actions. If the Parties
mutually determine that, based upon the review of a Third Party’s patent or patent application or other intellectual property rights, it may be desirable in connection with any Licensed Product to provoke or institute an interference,
opposition, revocation, post-grant review or other patent office proceedings or declaratory judgment action with respect thereto, then the Parties shall consult with one another and shall reasonably cooperate in connection with such an action. Each
Party shall retain all rights to control any actions initiated prior to the Effective Date. 
 5.7. Infringement of Third Party Patent
Rights. If the Development, Manufacture, use or Commercialization of any Licensed Product is alleged by a Third Party to infringe a Third Party’s patent or other intellectual property rights, the Party becoming aware of such allegation
shall promptly notify the other Party. CytomX shall have the right to take such action as it deems appropriate in response to such allegation, and shall be solely responsible for all damages, costs and expenses in connection therewith, subject to
Article 9 hereof. 
  

	6.	CONFIDENTIALITY 

 6.1. Confidentiality. Except to the extent expressly authorized
by this Agreement, the Parties agree that, during the Term and for [***] thereafter, each Party, in its capacity as the Receiving Party shall: (a) keep the Disclosing Party’s Confidential Information confidential; (b) not disclose, or
permit the disclosure of, the Disclosing Party’s Confidential Information; and (c) not use, or permit to be used, the Disclosing Party’s Confidential Information for any purpose, in each case, except for the performance of its
obligations or exercise of its rights under this Agreement, provided, however, that the foregoing obligations shall not apply, or shall cease to apply, to the extent that such Confidential Information (i) was already known by the Receiving
Party or its Affiliates (other than under an obligation of confidentiality to the Disclosing Party) at the time of disclosure by the Disclosing Party; (ii) was generally available to the public or otherwise part of the public domain at the time
of its disclosure to the Receiving Party; (iii) became generally available to the public or otherwise part of the public domain after its disclosure to the Receiving Party, other than through any act or omission of the Receiving Party or its
Affiliates or any of their respective Representatives in breach of its obligations under 

  
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this Agreement; (iv) was disclosed to the Receiving Party or its Affiliates, other than under an obligation of confidentiality, by a Third Party who had no obligation to the Disclosing Party
not to disclose such information to the Receiving Party ; or (v) was independently discovered or developed by or on behalf of the Receiving Party without the use of any Confidential Information of the Disclosing Party. 

6.2. Authorized Disclosure. 

6.2.1. Disclosure to Party Representatives. Notwithstanding the foregoing provisions of Section 6.1 hereof, the Receiving
Party may disclose Confidential Information belonging to the Disclosing Party to the Receiving Party’s Representatives who (a) have a need to know such Confidential Information in connection with the performance of the Receiving
Party’s obligations or the exercise of the Receiving Party’s rights under this Agreement and (b) have agreed in writing to non-disclosure and non-use provisions with respect to such Confidential Information that are at least as
restrictive as those set forth in this Article 6. 
 6.2.2. Disclosure to Third Parties. 

(a) Notwithstanding the foregoing provisions of Section 6.1 hereof, the Parties may disclose Confidential Information belonging to
the other Party: 
 (i) to Governmental Authorities to the extent reasonably necessary to obtain or maintain INDs or Regulatory Approvals
for any Licensed Product and in order to respond to inquiries, requests, investigations, orders or subpoenas of Governmental Authorities relating to this Agreement; 

(ii) to outside consultants, contractors, advisory boards, managed care organizations, and non-clinical and clinical investigators, in each
case to the extent reasonably necessary to Develop, Manufacture, use or Commercialize any Licensed Product under reasonable obligations of confidentiality; 

(iii) subject to Section 5.2 hereof, to the extent reasonably necessary, in connection with filing or prosecuting Patent Rights as
permitted by this Agreement; 
 (iv) to the extent reasonably necessary, in connection with prosecuting or defending litigation as permitted
by this Agreement; 

  
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 (v) regarding the existence of this Agreement, this Agreement itself or the material and
financial terms of this Agreement, (A) to its accountants, lawyers, and other advisers, and (B) to actual or potential investors, lenders, licensors, licensees, acquirers, investment bankers, or agents of the foregoing in connection with a
financing, licensing transaction, merger, or acquisition, in each case (A)-(B) under confidentiality obligations no less restrictive than those set forth in this Agreement, provided that ImmunoGen shall not disclose the identity of the Licensed
Target under clause (B) without the prior written consent of CytomX; 
 (vi) subject to Section 6.3.2 hereof, in connection
with or included in scientific presentations and publications relating to Licensed Products, including abstracts, posters, journal articles and the like, and posting results of and other information about clinical trials to clinicaltrials.gov or
PhRMA websites; and 
 (vii) to the extent necessary in order to enforce its rights under this Agreement. 

(b) In the event a Party deems it reasonably necessary to disclose Confidential Information belonging to the other Party pursuant to
Section 6.2.2(a)(i) hereof, the Disclosing Party shall to the extent possible give reasonable advance written notice of such disclosure to the other Party and take all reasonable measures to ensure confidential treatment of such
information. 
 (c) Data generated by CytomX using Licensed Products shall not be considered Confidential Information of ImmunoGen, and,
therefore, not subject to this Article 6. 
 6.2.3. SEC Filings and Other Disclosures. Notwithstanding any
provision of this Agreement to the contrary, either Party may disclose the existence or terms of this Agreement to the extent required, in the reasonable opinion of such Party’s legal counsel, to comply with Applicable Law. Notwithstanding the
foregoing, before disclosing this Agreement or any of the terms hereof pursuant to this Section 6.2.3, the Parties will consult with one another on the terms of this Agreement to be redacted in making any such disclosure. Further, if a
Party discloses this Agreement or any of the terms hereof in accordance with this Section 6.2.3, such Party shall, at its own expense, use Commercially Reasonable Efforts to seek such confidential treatment of confidential portions of
this Agreement and such other terms, as may be reasonably requested by the other Party. 

  
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 6.3. Public Announcements; Publications. 

6.3.1. Announcements. Except as may be expressly permitted under Section 6.2.3, neither Party will make any public
announcement regarding the existence or terms of this Agreement without the prior written approval of the other Party. For the sake of clarity, nothing in this Agreement shall prevent either Party from making any public disclosure relating to this
Agreement if the contents of such public disclosure have previously been made public other than through a breach of this Agreement by the issuing Party or its Affiliates. The Parties shall mutually agree to one or more press releases regarding the
signing of this Agreement following the Effective Date. The Parties agree that each Party may issue future announcements concerning CytomX’s achievement of any significant milestones, including the selection of a clinical candidate, under this
Agreement, provided that the content of any such announcement has been mutually agreed upon by the Parties. 
 6.3.2.
Publications. The Parties acknowledge that scientific publications and presentations must be strictly monitored to prevent any adverse effect from premature publication or dissemination of results of the activities hereunder. Each
Party (in such capacity the “Publishing Party”) agrees that, except as required by Applicable Laws, it shall not publish or present, or permit to be published or presented, any results of the Development, Manufacture, use or
Commercialization of a Licensed Product to the extent such results refer to, derive from or otherwise relate to the Licensed Intellectual Property (the “Covered Results”), without the prior review by and approval of the other Party
(in such capacity, the “Non-Disclosing Party”), which approval shall not be unreasonably withheld; provided that it shall not be deemed unreasonable for CytomX to withhold its consent to any request by ImmunoGen to publish or
disseminate Covered Results prior to the publication or dissemination of such Covered Results by CytomX. The Publishing Party shall submit to the Non-Disclosing Party for review and approval any proposed academic, scientific and medical publication
or public presentation which contains Covered Results or otherwise contains the Non-Disclosing Party’s Confidential Information; provided that the foregoing requirement shall apply to CytomX only to the extent any such proposed publication or
presentation would refer to, describe or otherwise disclose Confidential Information of ImmunoGen (including, without limitation, any non-public Licensed Intellectual Property). In addition, each Party shall submit to the other Party for review and
approval any proposed publication or public presentation relating to data generated under the Research Program. In both instances, such review and approval will be conducted for the purposes of preserving the value of the Licensed Intellectual
Property and determining whether any portion of the proposed publication or presentation containing the 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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Non-Disclosing Party’s Confidential Information should be modified or deleted. Written copies of such proposed publication or presentation required to be submitted hereunder shall be
submitted to the Non-Disclosing Party no later than [***] before submission for publication or presentation (the “Review Period”). The Non-Disclosing Party shall provide its comments with respect to such publications and
presentations within [***] after its receipt of such written copy, and the Publishing Party shall delete any Confidential Information of the Non-Disclosing Party upon request. The Review Period may be extended for an additional [***] in the event
the Non-Disclosing Party can, within [***] of receipt of the written copy, demonstrate reasonable need for such extension, including for the preparation and filing of patent applications. The Parties will each comply with standard academic practice
regarding authorship of scientific publications and recognition of contribution of other parties in any publication governed by this Section 6.3.2. 

6.3.3. Integration. As to the subject matter of this Agreement, this Article 6 supersedes any confidential disclosure
agreements between the Parties, including, without limitation, the Confidentiality Agreement and the confidentiality provisions of the Research Collaboration Agreement. Any confidential information of a Party disclosed under the Confidentiality
Agreement or the Research Collaboration Agreement relating to the subject matter of this Agreement shall be treated as Confidential Information of such Party hereunder, subject to the terms of this Article 6. 

 

	7.	REPRESENTATIONS AND WARRANTIES. 

 7.1. Mutual Representations and Warranties. Each
of CytomX and ImmunoGen hereby represents and warrants to the other that: 
 7.1.1. it is duly organized, validly existing and in good
standing under the laws of the jurisdiction of its organization; 
 7.1.2. the execution, delivery and performance of this Agreement by such
Party has been duly authorized by all requisite action under the provisions of its charter, bylaws and other organizational documents, and does not require any action or approval by any of its shareholders or other holders of its voting securities
or voting interests; 
 7.1.3. it has the power and authority to execute and deliver this Agreement and to perform its obligations hereunder;

 7.1.4. this Agreement has been duly executed and is a legal, valid and Binding Obligation on it, enforceable against it in accordance with
its terms; and 
 7.1.5. the execution, delivery and performance by such Party of this Agreement and its compliance with the terms and
provisions hereof does not and will not conflict with or result in a breach of or default under any Binding Obligation existing as of the Effective Date. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 7.2. Representations and Warranties of ImmunoGen. Except as set forth in a written
disclosure letter (the “Disclosure Letter”) delivered by ImmunoGen to CytomX within [***] after the Effective Date (which shall be deemed Confidential Information of ImmunoGen), ImmunoGen hereby represents and warrants to CytomX
that as of the Effective Date: 
 7.2.1. to its Knowledge, (a) the issued and unexpired patents within the Licensed Intellectual
Property are valid and enforceable patents and (b) ImmunoGen has received no written notice from a Third Party challenging or threatening to challenge the extent, validity or enforceability of any Licensed Patent Rights; 

7.2.2. to its Knowledge, ImmunoGen has received no written notice from a Third Party claiming that the use, practice or application of the
Licensed Intellectual Property pursuant to the license granted hereunder to CytomX will infringe the issued patents of any such Third Party (excluding, for clarity, any potential infringement that might arise solely as a result of the combination of
any Licensed Intellectual Property with any other technology or intellectual property); and 
 7.2.3. there is no (a) claim, demand,
suit, proceeding, arbitration, inquiry, investigation or other legal action of any nature, civil, criminal, regulatory or otherwise, pending or, to its Knowledge, threatened against ImmunoGen or any of its Affiliates or (b) judgment or
settlement against or owed by ImmunoGen or any of its Affiliates, in each case in connection with the Licensed Intellectual Property or relating to the transactions contemplated by this Agreement 

For purposes of this Section 7.2, “Knowledge” means the actual knowledge (without having conducted, or having any duty to
conduct, any specific inquiry) of the following ImmunoGen employees: (i) any “executive officer” (as defined in Rule 3b-7 promulgated under the Securities Exchange Act of 1934, as amended) [***]. 

7.3. Government Approvals. Each of CytomX and ImmunoGen shall cooperate with the other Party and use Commercially Reasonable
Efforts to make all registrations, filings and applications, to give all notices and to obtain as soon as practicable all governmental or other consents, transfers, approvals, orders, qualifications authorizations, permits and waivers, if any, and
to do all other things necessary or desirable for the consummation of the transactions as contemplated hereby. 

  
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 7.4. Further Covenants. In addition to the covenants made elsewhere in this
Agreement, ImmunoGen hereby covenants to CytomX that, from the Effective Date until expiration or termination of this Agreement, it will not (a) knowingly take any action that conflicts with the rights under the Licensed Intellectual Property
granted to CytomX under this Agreement or (b) knowingly fail to take any action that is reasonably necessary to avoid a conflict with the rights under the Licensed Intellectual Property granted to CytomX under this Agreement. 

7.5. Representation by Legal Counsel. Each Party hereto represents that it has been represented by legal counsel in connection
with this Agreement and acknowledges that it has participated in the drafting hereof. In interpreting and applying the terms and provisions of this Agreement, the Parties agree that no presumption shall exist or be implied against the Party which
drafted such terms and provisions. 
 7.6. Warranty Disclaimers. 

7.6.1. Except as expressly set forth in Section 7.1 or 7.2 hereof, nothing in this Agreement is or shall be construed as a
warranty or representation by ImmunoGen (a) as to the validity or scope of any patent application or patent within the Licensed Patent Rights or (b) that anything made, used, sold or otherwise disposed of under any license granted under
this Agreement is or will be free from infringement of patents, copyrights and other rights of Third Parties. 
 7.6.2. EXCEPT AS OTHERWISE
EXPRESSLY PROVIDED IN THIS AGREEMENT, NEITHER PARTY MAKES ANY REPRESENTATION OR EXTENDS ANY WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REPECT TO ANY TECHNOLOGY, GOODS, SERVICES, RIGHTS OR OTHER SUBJECT MATTER OF THIS AGREEMENT, INCLUDING,
WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. 
  

	8.	TERM AND TERMINATION. 

 8.1. Term. The term of this Agreement (the
“Term”) shall commence on the Effective Date and shall extend, unless this Agreement is terminated earlier in accordance with this Article 8, on a Licensed Product-by-Licensed Product and country-by-country basis, until
such time as the Royalty Term with respect to the sale of such Licensed Product in such country expires. Provided this Agreement has not been terminated prior thereto by ImmunoGen under Section 8.3, 8.4 or 8.5 hereof or by
CytomX under Section 8.2 or 8.4 hereof, following the expiration of the Royalty Term applicable to a Licensed Product in a country in accordance with Section 1.134 hereof, CytomX and its Affiliates shall have a fully
paid-up, irrevocable, freely transferable and sublicensable license under the relevant Licensed Intellectual Property, to make, have made, use, sell, offer for sale and import such Licensed Products in such country. 

  
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 8.2. Voluntary Termination by CytomX. CytomX shall have the right to terminate this
Agreement at any time prior to the achievement of the first Regulatory Marketing Approval for any Licensed Product in any country or other jurisdiction in the Territory, upon not less than ninety (90) days’ prior written notice to
ImmunoGen. 
 8.3. Termination by Either Party for Cause. Either Party may terminate this Agreement in its entirety at any time during
the Term by giving written notice to the other Party if the other Party commits a material breach of its obligations under this Agreement (a “Material Breach”), such notice to describe such Material Breach in reasonable detail, and
such Material Breach remains uncured for [***], measured from the date written notice of such breach is given to the breaching Party; provided, however, that if the nature of the asserted breach is such that more than [***] days are reasonably
required to cure, then the cure period shall be extended for a period not to exceed an additional [***] days so long as the Party seeking to cure the asserted breach is diligently pursuing such cure to completion. 

8.4. Termination on Insolvency. This Agreement may be terminated upon written notice by either Party at any time in the event of an
Insolvency Event of the other Party. 
 8.5. Termination for Material Breach of the Research Collaboration Agreement by CytomX.
ImmunoGen shall have the right to terminate this Agreement, effective upon thirty (30) days’ prior written notice to CytomX, in the event ImmunoGen has terminated the Research Collaboration Agreement due to the occurrence of a Material
Breach (as defined in the Research Collaboration Agreement) thereunder by CytomX which remains uncured as of the termination date of the Research Collaboration Agreement. 

8.6. Effects of Expiration or Termination. 

8.6.1. Effect of Termination by ImmunoGen under Section 8.3, 8.4 or 8.5 or by CytomX under Section 8.2. If ImmunoGen
terminates this Agreement pursuant to Section 8.3, 8.4 or 8.5 hereof, or CytomX terminates this Agreement pursuant to Section 8.2 hereof, then: 

(a) the license granted by ImmunoGen to CytomX and its Affiliates under Section 3.1.1 hereof shall immediately terminate, and
CytomX and its Affiliates shall discontinue the use of any Licensed Intellectual Property except, with respect to the Licensed Patent Rights, as otherwise permitted under [***] with respect to activities performed in the [***]; 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 (b) CytomX and its Affiliates and Sublicensees shall cease any Development and Commercialization
of Licensed Products in the Territory, subject to Section 8.6.3 hereof; and 
 (c) each Party shall promptly return or destroy
all of the other Party’s Confidential Information, provided that each Party may retain, subject to Article 6 hereof, (i) one (1) copy of the other Party’s Confidential Information in its archives solely for the
purpose of establishing the contents thereof and ensuring compliance with its obligations hereunder, (ii) any Confidential Information of the other Party contained in its laboratory notebooks or databases, and (iii) any Confidential
Information of the other Party to the extent reasonably required to exercise its rights and perform its obligations under any other then-outstanding License Agreement. 

8.6.2. Effect of Termination by CytomX under Section 8.3 or 8.4. If CytomX terminates this Agreement pursuant to
Section 8.3 or 8.4 hereof, then 
 (a) the license granted to CytomX by ImmunoGen pursuant to Section 3.1.1
hereof shall continue on the terms set forth herein, subject to CytomX’s continued payment of all milestone and royalty payments in accordance with this Agreement, and on a country-by-country and Licensed Product-by-Licensed Product basis, upon
the expiration of the Royalty Term applicable to a Licensed Product in country in accordance with Section 1.134 hereof and provided CytomX shall have paid to ImmunoGen all royalty amounts due to ImmunoGen with respect to Net Sales in
such country, CytomX and its Affiliates shall thereafter have a fully paid-up, irrevocable, freely transferable ad sublicensable license under the relevant Licensed Intellectual Property, to make, have made, use, sell, offer for sale and import such
Licensed Product in such country; 
 (b) ImmunoGen shall remain entitled to receive payments that accrued before the effective date of such
termination; and 
 (c) each Party shall promptly return or destroy all of the other Party’s Confidential Information, provided that
each Party may retain, subject to Article 6 hereof, (i) one (1) copy of the other Party’s Confidential Information in its archives solely for the purpose of establishing the contents thereof and ensuring compliance with
its obligations hereunder, (ii) any Confidential Information of the other Party contained in its laboratory notebooks or databases and (iii) any Confidential Information of the other Party to the extent reasonably required to exercise its
rights and perform its obligations under any then-outstanding License 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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Agreement. The foregoing notwithstanding, and subject to Article 6 hereof, CytomX may retain and use ImmunoGen’s Confidential Information with respect to the exercise of its
rights set forth in clause (a) above or necessary or useful to exercise any other of its rights under this Agreement that survive such termination. 

8.6.3. Treatment of Sublicensees on Termination. Notwithstanding the foregoing, ImmunoGen shall permit a Sublicensee of CytomX to become
its direct Sublicensee upon notification to ImmunoGen. 
 8.6.4. Satisfaction of Obligations During Notice Period. During the period
from providing a notice of termination through the termination of the Agreement, the Parties shall continue to perform their obligations under this Agreement. 

8.6.5. Pending Dispute Resolution. If a Party gives notice of termination and the other Party disputes whether such notice was proper,
then the issue of whether this Agreement has been terminated shall be resolved in accordance with Section 10.9 or 10.10 hereof, as applicable, and this Agreement shall remain in effect pending the resolution of such dispute. If as
a result of such dispute resolution process it is determined that the notice of termination was proper, then such termination shall be effective immediately. If as a result of such dispute resolution process it is determined that the notice of
termination was improper, then no termination shall have occurred and this Agreement shall remain in effect. Anything contained in this Agreement to the contrary notwithstanding, if the asserted breach is cured or shown to be non-existent within the
applicable cure period, the first notice of breach hereunder shall be deemed automatically withdrawn and of no effect. 
 8.7. Disposition
of Inventories of Products. Following termination of this Agreement by ImmunoGen pursuant to Section 8.3 or 8.4, CytomX and its Affiliates and Sublicensees shall have the right to continue to sell their existing inventories of
Licensed Product(s) that have received Regulatory Marketing Approval prior to such termination for a period [***] after the effective date of such termination or expiration and CytomX shall pay any milestones and royalties payable in connection with
such sales in accordance with Article 4 hereof. 
 8.8. Remedies. [***], the rights of the non-breaching Party set forth
in Section 8.6 hereof shall be the exclusive legal remedy to a Party arising from a Material Breach; provided, however, that (a) in addition to the foregoing legal remedy, the Parties may seek any and all equitable remedies,
including, without limitation, declarative and injunctive relief and specific performance in accordance with applicable law, and (b) nothing in this Section shall limit the Parties’ respective rights and obligations with respect to
(i) Unauthorized Use of the other Party’s Confidential Information or Proprietary Materials, (ii) unauthorized disclosure of the other Party’s Confidential Information or (iii) indemnification as set forth in
Article 9 hereof. 

  
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 8.9. Survival of Certain Obligations. Expiration or termination of this Agreement shall
not relieve the Parties of any obligation that accrued before such expiration or termination. The following provisions shall survive expiration or termination of this Agreement: Sections 2.5.2, 2.5.3, 2.5.4, 2.6 and
3.3, Articles 4, 5 and 6, Sections 7.6, 8.1, 8.6, 8.7 (for the period set forth therein), 8.8 and 8.9, and Articles 9 and 10. For avoidance of doubt,
any other Section that explicitly states it survives expiration or termination of this Agreement shall so survive. 
  

	9.	LIMITATION ON LIABILITY, INDEMNIFICATION AND INSURANCE. 

 9.1. No Consequential
Damages. Except with respect to liability arising from a breach of Article 6 hereof, in no event will either Party, its Affiliates or any of its or its Affiliates’ respective Representatives be liable under this Agreement for any
special, indirect, incidental, consequential or punitive or exemplary damages, whether in contract, warranty, tort, negligence, strict liability or otherwise, (a) including loss of profits or revenue suffered by either Party or any of its
respective Affiliates or Representatives or (b) cost of procurement of substitute goods, technology or services, even if either Party is informed in advance of the possibility of such damages and even if the remedies provided for in this
Agreement fail of their essential purpose. For purposes of clarity, a Party’s monetary liability under a Third Party Claim for such Third Party’s special, indirect, incidental or consequential damages or for any punitive or exemplary
damages payable in connection with such Third Party Claim, shall be deemed to be the direct damages of such Party for purposes of this Article 9. 

9.2. Indemnification by ImmunoGen. ImmunoGen will indemnify, defend and hold harmless CytomX, its Affiliates and each of its and their
respective employees, officers, directors and agents (each, a “CytomX Indemnified Party”) from and against any and all liability, loss, damage, expense (including reasonable attorneys’ fees and expenses) and cost (collectively,
a “Liability”) as a direct result of any Third Party claims, suits, actions, demands or judgments, including, without limitation, personal injury and product liability matters (collectively, “Third Party Claims”)
arising out of a Material Breach of this Agreement by ImmunoGen, except, in each case, to the extent any such Third Party Claim or Liability results from a Material Breach of this Agreement by CytomX, the Development, Manufacture, Commercialization
or use (including, without limitation, the production, manufacture, promotion, import, sale or use by any Person) of any Licensed Product by, on behalf of, or under the authority of, CytomX or any of its Affiliates, Sublicensees, subcontractors,
distributors or agents (other than an ImmunoGen Indemnified Party), or the negligence, recklessness or intentional acts of CytomX or any of its Affiliates, Sublicensees, subcontractors, distributors or agents; provided that with respect to any Third
Party Claim for which CytomX also has an obligation to indemnify 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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any ImmunoGen Indemnified Party pursuant to Section 9.3 hereof, ImmunoGen shall indemnify each CytomX Indemnified Party for its Liability to the extent of ImmunoGen’s responsibility,
relative to CytomX (or to Persons for whom CytomX is legally responsible), for the facts underlying the Third Party Claim. 
 9.3.
Indemnification by CytomX. CytomX will indemnify, defend and hold harmless ImmunoGen, its Affiliates, contractors, distributors and each of its and their respective employees, officers, directors and agents (each, a “ImmunoGen
Indemnified Party”) from and against any and all Liabilities as a direct result of any Third Party Claims arising out of: 
 (a) the
Development, Manufacture, Commercialization or use (including, without limitation, the production, manufacture, promotion, import, sale or use by any Person) of any Licensed Product by, on behalf of, or under the authority of, CytomX or any of its
Affiliates, Sublicensees, subcontractors, distributors or agents (other than by any ImmunoGen Indemnified Party); or 
 (b) a Material Breach
of this Agreement by CytomX; 
 except to the extent any such Third Party Claim or Liability results from a Material Breach of this Agreement
by ImmunoGen or the negligence, recklessness or intentional acts of ImmunoGen or any ImmunoGen Indemnified Party; provided that with respect to any Third Party Claim for which ImmunoGen also has an obligation to indemnify any CytomX Indemnified
Party pursuant to Section 9.2 hereof, CytomX shall indemnify each ImmunoGen Indemnified Party for its Liability to the extent of CytomX’s responsibility, relative to ImmunoGen (or to Persons for whom ImmunoGen is legally responsible), for
the facts underlying the Third Party Claim. 
 9.4. Procedure. 

9.4.1. Notice. Each Party will notify the other Party in writing in the event it becomes aware of a claim for which indemnification may
be sought hereunder. In the event that any Third Party asserts a claim or other proceeding (including any governmental investigation) with respect to any matter for which a Party (the “Indemnified Party”) is entitled to
indemnification hereunder, then the Indemnified Party shall promptly notify the Party obligated to indemnify the Indemnified Party (the “Indemnifying Party”) thereof; provided, however, that no delay on the part of the Indemnified
Party in notifying the Indemnifying Party shall relieve the Indemnifying Party from any obligation hereunder unless (and then only to the extent that) the Indemnifying Party is prejudiced thereby. 

9.4.2. Control. The Indemnifying Party shall have the right, at its sole cost and expense, exercisable by notice to the Indemnified
Party within ten (10) Business 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 59 

 
Days after receipt of notice from the Indemnified Party of the commencement of or assertion of any Third Party Claim, to assume direction and control of the defense, litigation, settlement,
appeal or other disposition of the Third Party Claim (including the right to settle the claim solely for monetary consideration) with counsel selected by the Indemnifying Party and reasonably acceptable to the Indemnified Party. The Indemnified
Party shall cooperate, and shall cause its Affiliates and agents to cooperate upon request of the Indemnifying Party, in the defense or prosecution of the Third Party Claim, including by furnishing such records, information and testimony and
attending such conferences, discovery proceedings, hearings, trials or appeals as may reasonably be requested by the Indemnifying Party. The Indemnified Party shall have the right to join in (including the right to conduct discovery, interview and
examine witnesses and participate in all settlement conferences), but not control, at its own expense, the defense of any Third Party Claim that the other Party is defending as provided in this Agreement. 

9.4.3. Settlement. Neither the Indemnifying Party nor the Indemnified Party shall enter into any compromise or settlement of a Third
Party Claim for which the right to indemnification hereunder has been asserted without the Indemnified Party’s prior written consent, which consent shall not be unreasonably withheld, conditioned or delayed; provided that the Indemnifying Party
may, without the Indemnified Party’s prior written consent, agree or consent to any settlement or other resolution of such Third Party Claim which requires solely money damages paid by the Indemnifying Party, and which includes as an
unconditional term thereof the giving by such claimant or plaintiff to the Indemnified Party of a release from all liability in respect of such Third Party Claim. Each of the Indemnifying Party and the Indemnified Party shall not make any admission
of liability in respect of any Third Party Claim without the prior written consent of the other Party, and the Indemnified Party shall use reasonable efforts to mitigate Liabilities arising from such Third Party Claim. 

9.5. Insurance. Each Party shall obtain and maintain, during the Term, commercial general liability insurance, including products
liability insurance, with reputable and financially secure insurance carriers (or pursuant to a program of self-insurance reasonably satisfactory to the other Party) to cover its indemnification obligations under Section 9.2 or
9.3 hereof with respect to bodily injury (including death) and damage to property, as applicable, in each case with limits of not less than $3,000,000 per occurrence and in the aggregate. Insurance (other than permitted self-insurance) shall
be procured with carriers having an A.M. Best Rating of A-VII or better. Any indemnification payment hereunder shall be made net of any insurance proceeds which the Indemnified Party is entitled to recover; provided, however, that if, following
the payment to the Indemnified Party of any amount under this Article 9, such Indemnified 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 60 

 
Party becomes entitled to recover any insurance proceeds in respect of the claim for which such indemnification payment was made, the Indemnified Party shall promptly pay an amount equal to the
amount of such proceeds (but not exceeding the amount of such indemnification payment) to the Indemnifying Party. 
  

	10.	MISCELLANEOUS. 

 10.1. Assignment. Neither Party may assign this Agreement without
the prior written consent of the other Party, which consent will not be unreasonably withheld, conditioned or delayed; provided, however, that such consent shall not be required in connection with any assignment of this Agreement to an Affiliate of
the assigned Party, or to a Third Party in connection with the transfer or sale of the business to which this Agreement relates, or to any successor Person resulting from any merger or consolidation of such Party with or into such Person, provided
that the assignee shall have agreed in writing to assume all of the assignor’s obligations hereunder, and provided, further, that the other Party shall be notified promptly after such assignment has been effected. This Agreement shall be
binding upon the successors and permitted assigns of the Parties and the name of a Party appearing herein shall be deemed to include the names of such Party’s successors and permitted assigns to the extent necessary to carry out the intent of
this Agreement. Any purported assignment not in accordance with this Section 10.1 shall be null and void. 
 10.2. Further
Actions. Each Party agrees to execute, acknowledge and deliver such further instruments, and to do all such other acts, as may be necessary or appropriate in order to carry out the purposes and intent of the Agreement. 

10.3. Force Majeure. Each Party shall be excused from the performance of its obligations under this Agreement to the extent that such
performance is prevented by force majeure (defined below) and the nonperforming Party promptly provides notice of the prevention to the other Party. Such excuse shall be continued so long as the condition constituting force majeure
continues and the nonperforming Party takes Commercially Reasonable Efforts to resume performance. For purposes of this Agreement, “force majeure” shall include conditions beyond the control of the Parties, including an act of God,
voluntary or involuntary compliance with any Applicable Law or order of any government, war, act of terror, civil commotion, labor strike or lock-out, epidemic, failure or default of public utilities or common carriers, or destruction of production
facilities or materials by fire, earthquake, storm or like catastrophe; provided that financial inability to pay in and of itself shall not be considered to be a force majeure event. 

10.4. Notices. Any notice or notification required or permitted to be provided pursuant to the terms and conditions of this Agreement
(including any notice of force majeure, breach, termination, change of address, etc.) shall be in writing and shall be deemed given upon receipt if delivered personally or by facsimile transmission (receipt verified),

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 61 

 
five (5) Business Days after deposited in the mail if mailed by certified mail (return receipt requested) postage prepaid, or on the next Business Day if sent by overnight delivery using a
nationally recognized express courier service and specifying next Business Day delivery (receipt verified), to the Parties at the following addresses or facsimile numbers (or at such other address or facsimile number for a Party as shall be
specified by like notice, provided, however, that notices of a change of address shall be effective only upon receipt thereof): 
 All
correspondence to ImmunoGen shall be addressed as follows: 
 ImmunoGen, Inc. 

830 Winter Street 
 Waltham, MA
02451 
 Attn: Vice President, Business Development 

Fax:  [***] 
 All
correspondence to CytomX shall be addressed as follows: 
 CytomX Therapeutics, Inc. 

343 Oyster Point Blvd., Suite 100 

South San Francisco, CA 94080-7014 

Attn: CEO 

Fax:  1-650-351-0353 

To help expedite the other Party’s awareness and response, copies of notices may be provided to the other Party by email but must be
supplemented by one of the following methods: (a) personal delivery, (b) first class certified mail with return receipt requested, or (c) next-day delivery by major international courier, with confirmation of delivery. Electronic
copies may be sent via email to [***] at CytomX and to [***] at ImmunoGen so long as such individuals remain employed by CytomX or ImmunoGen, respectively. 

10.5. Amendment. No amendment, modification or supplement of any provision of this Agreement shall be valid or effective unless made in
writing and signed by a duly authorized officer of the Party to be bound. 
 10.6. Waiver. No provision of this Agreement shall be
waived by any act, omission or knowledge of a Party or its agents or employees except by an instrument in writing expressly waiving such provision and signed by a duly authorized officer of the waiving Party. The waiver by either of the Parties of
any breach of any provision hereof by the other Party shall not be construed to be a waiver of any succeeding breach of such provision or a waiver of the provision itself. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 62 

 10.7. Severability. If any clause or portion thereof in this Agreement is for any reason
held to be invalid, illegal or unenforceable, the same shall not affect any other portion of this Agreement, as it is the intent of the Parties that this Agreement shall be construed in such fashion as to maintain its existence, validity and
enforceability to the greatest extent possible. In any such event, this Agreement shall be construed as if such clause or portion thereof had never been contained in this Agreement, and there shall be deemed substituted therefor such provision as
will most nearly carry out the intent of the Parties as expressed in this Agreement to the fullest extent permitted by Applicable Law. 

10.8. Descriptive Headings. The descriptive headings of this Agreement are for convenience only and shall be of no force or effect in
construing or interpreting any of the provisions of this Agreement. 
 10.9. Dispute Resolution. The Parties recognize that a
bona fide dispute as to certain matters may arise from time to time during the Term relating to either Party’s rights or obligations hereunder or otherwise relating to the validity, enforceability or performance of this Agreement,
including disputes relating to alleged breach or termination of this Agreement but excluding any disputes relating to Article 6 hereof or disputes relating to the determination of the validity, scope, infringement, enforceability,
inventorship or ownership of the Parties’ respective Patent Rights (hereinafter, a “Dispute”). In the event of the occurrence of any Dispute, the Parties shall follow the following procedures in an attempt to resolve the
dispute or disagreement: 
 10.9.1. The Party claiming that such a Dispute exists shall give notice in writing (a “Notice of
Dispute”) to the other Party of the nature of the Dispute. 
 10.9.2. Within [***] days of receipt of a Notice of Dispute, the
ImmunoGen Alliance Manager and the CytomX Alliance Manager shall meet in person or by teleconference and exchange written summaries reflecting, in reasonable detail, the nature and extent of the Dispute, and at this meeting they shall use their
reasonable endeavors to resolve the Dispute. 
 10.9.3. If the Alliance Managers are unable to resolve the Dispute during the meeting
described in Section 10.9.2 hereof or if for any reason such meeting does not take place within the period specified in Section 10.9.2 hereof, then the Dispute will be referred to the JDC which shall meet no later than [***]
days following the initial receipt of the Notice of Dispute and use reasonable endeavors to resolve the Dispute. 
 10.9.4. If the JDC is
unable to resolve the Dispute during the meeting described in Section 10.9.3 hereof or if for any reason such meeting does not take place within the period specified in Section 10.9.3 hereof, then the Chief Executive Officer
of ImmunoGen and the Chief Executive Officer of CytomX shall meet at a mutually agreed-upon time and location for the purpose of resolving such Dispute. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 63 

 10.9.5. If, within [***] days of initial receipt of the Notice of Dispute, the Dispute has
not been resolved, or if, for any reason, the meeting described in Section 10.9.4 hereof has not been held within [***] days of initial receipt of the Notice of Dispute, then the Parties agree that such Dispute shall be finally
resolved through binding arbitration to be administered by JAMS pursuant to its Comprehensive Arbitration Rules and Procedures and in accordance with the Expedited Procedures in those Rules, as specifically modified by the provisions of this
Section 10.9.5. 
 (a) Arbitration Panel. The arbitration shall be conducted by a panel of three (3) arbitrators.
Within [***] days after the initiation of the arbitration, each Party will nominate one person to act as arbitrator, and the two arbitrators so named will then jointly appoint the third arbitrator within [***] days of their appointment,
who will serve as chairman of the panel. All three (3) arbitrators must be independent Third Parties having at least [***] years of dispute resolution experience (which may include judicial experience) and/or legal or business experience
in the biotech or pharmaceutical industry. If either Party fails to nominate its arbitrator, or if the arbitrators selected by the Parties cannot agree on a person to be named as chairman within such [***] day period, JAMS will make the
necessary appointments for such arbitrator(s) or the chairman. Once appointed by a Party, such Party shall have no ex parte communication with its appointed arbitrator. 

(b) Location and Proceedings. The place of arbitration will be in the Borough of Manhattan, City of New York, NY or such other venue as
the Parties may mutually agree. The arbitration proceedings and all communications with respect thereto shall be in English. Any written evidence originally in another language will be submitted in English translation accompanied by the original or
a true copy thereof. The arbitrators have the power to decide all matters in Dispute, including any questions of whether or not such matters are subject to arbitration hereunder. The arbitration shall be governed by the Federal Arbitration Act,
9 U.S.C. §§1 et seq., and judgment upon the award rendered by the arbitrators may be entered in any court having competent jurisdiction thereof. 

(c) Limitation on Awards. Except for breaches of Article 6 hereof, the arbitrators shall have no authority to award any
special, indirect, incidental, consequential, punitive, exemplary or other similar damages. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 64 

 
Each Party shall bear its own costs and expenses (including attorneys’ fees and expert or consulting fees) incurred in connection with the arbitration. The Parties shall equally
(50/50) share the arbitrators’ fees and other administrative costs and expenses associated with the arbitration. 
 (d)
Confidentiality. The existence, content and results of any arbitration proceedings pursuant to this Section 10.9.5 shall be deemed the Confidential Information of both Parties. 

10.9.6. Notwithstanding any provision of this Agreement to the contrary, either Party may immediately initiate litigation in any court of
competent jurisdiction seeking any remedy at law or in equity, including the issuance of a preliminary, temporary or permanent injunction, to preserve or enforce its rights under this Agreement. 

10.10. Patent Disputes and Disputes Relating to Article 6. 

10.10.1. Inventorship. Any dispute, controversy or claim between the Parties involving the inventorship of any Program Technology that
is not resolved by mutual agreement of the Party’s respective chief patent counsels (or persons with similar responsibilities) within [***] days after the date the dispute is raised by one or both of the Parties shall be submitted to an
Independent Patent Counsel for resolution. Such Independent Patent Counsel’s determination of inventorship, absent manifest error, shall be final and binding on the Parties; provided, however, that any such determination with respect to a
patent application shall not preclude either Party from disputing inventorship with respect to any patents issuing from such patent application, which disputes shall be resolved in accordance with this Section. The Parties shall equally
(50/50) share the Independent Patent Counsel fees and expenses related to his determination of inventorship. 
 10.10.2. Other Patent
Disputes. Any dispute, controversy or claim between the Parties that involves the validity, scope, infringement, enforceability or ownership of the Parties’ respective Patent Rights (a) that are pending or issued in the United States
shall be subject to actions before the United States Patent and Trademark Office and/or submitted exclusively to the federal court located in the jurisdiction where the Party whose Patent Rights are the subject to such dispute, controversy or claim
resides (provided that if such Party does not reside in the United States, venue shall be the jurisdiction where such Party’s principal U.S. Affiliate resides) and (b) that are pending or issued in any other country (or region) shall be
brought before an appropriate regulatory or administrative body or court in that country (or region), and the Parties hereby consent to jurisdiction and venue in such courts and bodies. 

10.10.3. Disputes Relating to Article 6. Any dispute, controversy or claim between the Parties that relates to the enforcement of
Article 6 hereof shall be subject to action in any court of competent jurisdiction. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 65 

 10.11. Governing Law. This Agreement, and all claims arising under or in connection
therewith, shall be governed by and interpreted in accordance with the substantive laws of the State of New York, without regard to conflict of law principles thereof. 

10.12. Entire Agreement. This Agreement, including its Exhibits and Schedules, constitutes and contains the complete, final and
exclusive understanding and agreement of the Parties and cancels and supersedes any and all prior negotiations, correspondence, understandings and agreements, whether oral or written, between the Parties respecting the subject matter hereof and
thereof, including the Confidentiality Agreement. 
 10.13. Purpose and Scope. The Parties understand and agree that this Agreement is
limited to the activities, rights and obligations as expressly set forth herein. Nothing herein contained shall be deemed to create an employment, agency, joint venture or partnership relationship between the Parties hereto or any of their agents or
employees, or any other legal arrangement that would impose liability upon one Party for the act or failure to act of the other Party. Neither Party shall have any express or implied power to enter into any contracts or commitments or to incur any
liabilities in the name of, or on behalf of, the other Party, or to bind the other Party in any respect whatsoever. 
 10.14.
Counterparts. This Agreement may be executed in two or more counterparts, each of which shall be an original and both of which shall constitute together the same document. Counterparts may be signed and delivered by facsimile or PDF file,
each of which shall be binding when received by the applicable Party. 
 10.15. No Third Party Rights or Obligations. Except as set
forth in Article 9 hereof, no provision of this Agreement shall be deemed or construed in any way to result in the creation of any rights or obligation in any Person not a Party to this Agreement. However, either Party may decide, in its
sole discretion, to use one or more of its Affiliates to perform its obligations and duties hereunder, provided that such Party shall remain liable hereunder for the performance by any such Affiliates of any such obligations. 

10.16. Interpretation. The Parties hereto acknowledge and agree that: (a) each Party and its counsel reviewed and negotiated the
terms and provisions of this Agreement and have contributed to its revision; (b) the rule of construction to the effect that any ambiguities are resolved against the drafting Party shall not be employed in the interpretation of this Agreement;
and (c) the terms and provisions of this Agreement shall be construed fairly as to each Party hereto and not in a favor of or against any Party, regardless of which Party was generally responsible for the preparation of this Agreement. In
addition, unless the context otherwise requires, wherever used in this Agreement: 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 66 

 
(i) the singular shall include the plural, the plural the singular; (ii) the use of any gender shall be applicable to all genders; (iii) the word “or” is used in the
inclusive sense (and/or); (iv) the words “include” or “including” shall be construed as incorporating, also, “but not limited to” or “without limitation” (irrespective of whether the words are used in the
applicable instance); (v) the words “hereof,” “herein,” “hereby” and derivative or similar words refer to this Agreement as a whole and not to any particular provision of this Agreement; and (vi) all
references to “will” are interchangeable with the word “shall” and shall be understood to be imperative or mandatory in nature. 

[The remainder of this page has been intentionally left blank. The signature page follows.] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 67 

 IN WITNESS WHEREOF, duly authorized representatives of the Parties have duly executed this
Agreement to be effective as of the Effective Date. 
  

									
	IMMUNOGEN, INC.	 		 	CYTOMX THERAPEUTICS, INC.
					
	By:	 	  
	 		 	By:	 	  

					
	Name:	 		 		 	Name:	 	
					
	Title:	 		 		 	Title:	 	
					
	Date:	 		 		 	Date:	 	

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 EXHIBIT A 

Licensed Target 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 EXHIBIT B 

Royalty Rate Reduction Methodology 

[***]† 

 

	† 	Two pages of text have been omitted. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 EXHIBIT D 

Form of ImmunoGen License Agreement 

[See Attached 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 Exhibit D 

LICENSE AGREEMENT 

BETWEEN 
 IMMUNOGEN,
INC. 
 AND 

CYTOMX THERAPEUTICS, INC. 

            , 201     

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 TABLE OF CONTENTS 

 

									
	 	  	 	  	 	  	Page	 
			
	 1.
	  	 DEFINITIONS.
	  	 	1	  
			
	 2.
	  	 PRODUCT DEVELOPMENT, MANUFACTURING AND COMMERCIALIZATION.
	  	 	19	  
				
		  	2.1.	  	 General
	  	 	19	  
				
		  	2.2.	  	 Development Diligence
	  	 	20	  
				
		  	2.3.	  	 Joint Development Committee
	  	 	21	  
				
		  	2.4.	  	 Alliance Managers
	  	 	23	  
				
		  	2.5.	  	 Updates and Reports; Product Recalls
	  	 	23	  
				
		  	2.6.	  	 Transfer and Use of Proprietary Materials
	  	 	24	  
				
		  	2.7.	  	 Services
	  	 	25	  
			
	 3.
	  	 LICENSE GRANTS.
	  	 	26	  
				
		  	3.1.	  	 License Grants
	  	 	26	  
				
		  	3.2.	  	 Retained Rights and Covenants
	  	 	26	  
				
		  	3.3.	  	 License to ImmunoGen Probody Platform Improvements
	  	 	26	  
				
		  	3.4.	  	 Section 365(n) of Bankruptcy Code
	  	 	27	  
				
		  	3.5.	  	 No Implied Rights
	  	 	27	  
			
	 4.
	  	 PAYMENTS.
	  	 	27	  
				
		  	4.1.	  	 Milestone Payments
	  	 	27	  
				
		  	4.2.	  	 Royalties
	  	 	29	  
				
		  	4.3.	  	 Reports and Payments
	  	 	33	  

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 i 

									
				
		  	 4.4.
	  	 Maintenance of Records; Audits
	  	 	34	  
			
	 5.
	  	 INTELLECTUAL PROPERTY.
	  	 	36	  
				
		  	 5.1.
	  	 Inventions
	  	 	36	  
				
		  	 5.2.
	  	 Filing, Prosecution and Maintenance of Patent Rights
	  	 	37	  
				
		  	 5.3.
	  	 Joint Research Agreement
	  	 	40	  
				
		  	 5.4.
	  	 Enforcement of Patent Rights
	  	 	40	  
				
		  	 5.5.
	  	 Response to Biosimilar Applicants
	  	 	43	  
				
		  	 5.6.
	  	 Interference, Opposition, Revocation and Declaratory Judgment Actions
	  	 	48	  
				
		  	 5.7.
	  	 Infringement of Third Party Patent Rights
	  	 	48	  
			
	 6.
	  	 CONFIDENTIALITY.
	  	 	48	  
				
		  	 6.1.
	  	 Confidentiality
	  	 	48	  
				
		  	 6.2.
	  	 Authorized Disclosure
	  	 	49	  
				
		  	 6.3.
	  	 Public Announcements; Publications
	  	 	51	  
			
	 7.
	  	 REPRESENTATIONS AND WARRANTIES.
	  	 	52	  
				
		  	 7.1.
	  	 Mutual Representations and Warranties
	  	 	52	  
				
		  	 7.2.
	  	 Representations and Warranties of CytomX
	  	 	53	  
				
		  	 7.3.
	  	 Government Approvals
	  	 	54	  
				
		  	 7.4.
	  	 Further Covenants
	  	 	54	  
				
		  	 7.5.
	  	 Representation by Legal Counsel
	  	 	54	  
				
		  	 7.6.
	  	 Warranty Disclaimers
	  	 	54	  
			
	 8.
	  	 TERM AND TERMINATION.
	  	 	55	  
				
		  	 8.1.
	  	 Term
	  	 	55	  
				
		  	 8.2.
	  	 Voluntary Termination by ImmunoGen
	  	 	55	  

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 ii 

									
				
		  	 8.3.
	  	 Termination by Either Party for Cause
	  	 	55	  
				
		  	 8.4.
	  	 Termination on Insolvency
	  	 	55	  
				
		  	 8.5.
	  	 Termination for Material Breach of the Research Collaboration Agreement by ImmunoGen
	  	 	55	  
				
		  	 8.6.
	  	 Effects of Expiration or Termination
	  	 	55	  
				
		  	 8.7.
	  	 Disposition of Inventories of Products
	  	 	57	  
				
		  	 8.8.
	  	 Remedies
	  	 	58	  
				
		  	 8.9.
	  	 Survival of Certain Obligations
	  	 	58	  
			
	 9.
	  	 LIMITATION ON LIABILITY, INDEMNIFICATION AND INSURANCE.
	  	 	58	  
				
		  	 9.1.
	  	 No Consequential Damages
	  	 	58	  
				
		  	 9.2.
	  	 Indemnification by CytomX
	  	 	58	  
				
		  	 9.3.
	  	 Indemnification by ImmunoGen
	  	 	59	  
				
		  	 9.4.
	  	 Procedure
	  	 	59	  
				
		  	 9.5.
	  	 Insurance
	  	 	61	  
			
	 10.
	  	 MISCELLANEOUS.
	  	 	61	  
				
		  	 10.1.
	  	 Assignment
	  	 	61	  
				
		  	 10.2.
	  	 Further Actions
	  	 	61	  
				
		  	 10.3.
	  	 Force Majeure
	  	 	61	  
				
		  	 10.4.
	  	 Notices
	  	 	62	  
				
		  	 10.5.
	  	 Amendment
	  	 	63	  
				
		  	 10.6.
	  	 Waiver
	  	 	63	  
				
		  	 10.7.
	  	 Severability
	  	 	63	  
				
		  	 10.8.
	  	 Descriptive Headings
	  	 	63	  

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 iii 

									
				
		  	 10.9.
	  	 Dispute Resolution
	  	 	63	  
				
		  	 10.10.
	  	 Patent Disputes and Disputes Relating to Article 6
	  	 	65	  
				
		  	 10.11.
	  	 Governing Law
	  	 	66	  
				
		  	 10.12.
	  	 Entire Agreement
	  	 	66	  
				
		  	 10.13.
	  	 Purpose and Scope
	  	 	66	  
				
		  	 10.14.
	  	 Counterparts
	  	 	66	  
				
		  	 10.15.
	  	 No Third Party Rights or Obligations
	  	 	67	  
				
		  	 10.16.
	  	 Interpretation
	  	 	67	  

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 iv 

 EXHIBITS 

Exhibit A – Licensed Target 
 Exhibit B –
Royalty Rate Reduction Methodology 
 Schedule 1.120 – List of Cytotoxic Compound Patent Rights 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 v 

 LICENSE AGREEMENT 

This Research Collaboration and License Agreement (the “Agreement”) is entered into as of
                    1 (the “Effective Date”), by and between CytomX
Therapeutics, Inc., a corporation organized and existing under the laws of Delaware and having a place of business at 343 Oyster Point Blvd., Suite 100, South San Francisco, California, 94080 United States (“CytomX”) and
ImmunoGen, Inc., a corporation organized and existing under the laws of Massachusetts and having a place of business at 830 Winter Street, Waltham, Massachusetts, 02451 (“ImmunoGen”). CytomX and ImmunoGen may each be referred
to herein individually as a “Party” and collectively as the “Parties.” 
 WHEREAS, the
Parties have entered into a Research Collaboration Agreement, pursuant to which, among other things, CytomX granted to ImmunoGen the right to obtain a license to certain Know-How and related Patent Rights owned or Controlled by CytomX with respect
to certain Targets; and 
 WHEREAS, pursuant to the Research Collaboration Agreement, ImmunoGen has exercised an ImmunoGen
Option (as defined in the Research Collaboration Agreement), pursuant to which the Parties have agreed to enter into this Agreement setting forth the terms and conditions of an exclusive license from CytomX to ImmunoGen with respect to the Licensed
Target. 
 NOW THEREFORE, in consideration of the mutual promises and covenants set forth below and other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, the Parties hereby agree as follows: 
  

	1.	DEFINITIONS. 

 When used in this Agreement, the following capitalized
terms shall have the meanings set forth in this Article 1. 
 1.1. “ADC” means a compound that incorporates, is
comprised of or is otherwise derived from an Antibody (or other cell-binding moiety) conjugated to a Payload using a Linker, other than a PDC. 

1.2. “Affiliate” means, with respect to any Person, any other Person that controls, is controlled by or is under common
control with such Person. A Person shall be regarded as in control of another entity if it owns or controls at least fifty percent (50%) of the equity securities of the subject entity entitled to vote in the election of directors (or, in the

  

	1 	 Insert date of receipt by ImmunoGen of Option Exercise Notice with respect to the Licensed Target.

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 1 

 
case of an entity that is not a corporation, for the election of the corresponding managing authority), provided, however, that the term “Affiliate” shall not include subsidiaries or
other entities in which a Party or its Affiliates owns a majority of the ordinary voting power necessary to elect a majority of the board of directors or other managing authority, but is restricted from electing such majority by contract or
otherwise, until such time as such restrictions are no longer in effect. A Person shall be deemed an Affiliate only so long as it satisfies the foregoing definition. 

1.3. “Alliance Manager” is defined in Section 2.4 hereof. 

1.4. “Annual Maintenance Fees” is defined in Section 2.2.1 hereof. 

1.5. “Annual Net Sales” means, with respect to any Licensed Product in a Calendar Year during the applicable Royalty Term for
such Licensed Product, the aggregate Net Sales by a Party, its Affiliates and its Sublicensees from the sale of such Licensed Product in the Territory during such Calendar Year. 

1.6. “Antibody” means a molecule which comprises or contains: (a) one or more immunoglobulin variable domains; or
(b) fragments, variants, modifications or derivatives of such immunoglobulin variable domains irrespective of origin or source, including but not limited to antigen binding portions including Fab, Fab’, F(ab’)2, Fv, dAb and CDR
fragments, single chain antibodies (scFv), chimeric antibodies, monospecific antibodies, diabodies and polypeptides (including humanized versions thereof) that contain at least a portion of an immunoglobulin that is sufficient to confer specific
antigen binding to the polypeptide. For clarity, as used in this Agreement, the term “Antibody” shall not include Probodies or PDCs. 

1.7. “Applicable Law” means the laws, statutes, rules, regulations, guidelines, or other requirements that may be in effect
from time to time and apply to a particular activity contemplated hereby, including any such laws, statutes, rules, regulations, guidelines or other requirements of the FDA or the EMA or any applicable securities regulatory authorities or national
securities exchanges or securities listing organizations. 
 1.8. “Applicant” is defined in Section 5.5.2
hereof. 
 1.9. “Applicant Response” is defined in Section 5.5.3(b) hereof. 

1.10. “Bankruptcy Code” is defined in Section 3.4 hereof. 

1.11. “Baseline Net Sales” is defined in Section 1.94 hereof. 

1.12. “Binding Obligation” means, with respect to a Party (a) any oral or written agreement or arrangement that binds or
legally affects such Party’s operations or property, 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 2 

 
including any assignment, license agreement, loan agreement, guaranty, or financing agreement; (b) the provisions of such Party’s charter, bylaws or other organizational documents or
(c) any order, writ, injunction, decree or judgment of any court or Governmental Authority entered against such Party or by which any of such Party’s operations or property are bound. 

1.13. “Biosimilar Application” means an application submitted to the FDA under subsection (k) of the PHSA or a similar
application submitted under a similar regulatory scheme to another Regulatory Authority. 
 1.14. “BLA” means a Biologics
License Application (as that term is used in Title 21 of the United States Code of Federal Regulations) filed with the FDA seeking Regulatory Approval to market and sell any Licensed Product in the United States for a particular indication. 

1.15. “BPCIA” means the Biologics Price Competition and Innovation Act of 2009. 

1.16. “Business Day” means a day other than a Saturday, a Sunday or other day on which banking institutions in Boston,
Massachusetts or San Francisco, California are required to be closed or are actually closed with legal authorization. 
 1.17.
“Calendar Quarter” means the respective periods of three (3) consecutive calendar months ending on March 31, June 30, September 30 or December 31, for so long as this Agreement is in effect. 

1.18. “Calendar Year” means each successive period of twelve (12) calendar months commencing on January 1 and ending
on December 31. 
 1.19. “Challenge” means any challenge to the [***], or [***] of any of the Licensed Patent Rights,
including without limitation: (a) filing a declaratory judgment action in which any of the Licensed Patent Rights is alleged to be invalid or unenforceable; (b) citing prior art pursuant to 35 U.S.C. §122 or §301, filing a
request for re-examination of any of the Licensed Patent Rights pursuant to 35 U.S.C. §302 or §311, filing a [***] of the Licensed Patent Rights pursuant to [***], or filing a [***] of the Licensed Patent Rights pursuant to [***]; or
(c) filing or commencing any re-examination, opposition, cancellation, nullity or similar proceeding against any of the Licensed Patent Rights in any country. 

1.20. “Challenge Jurisdiction” is defined in Section 4.2.3(d) hereof. 

1.21. “Challenged Patent Rights” is defined in Section 4.2.3(d) hereof. 

1.22. “Challenge-Related Royalty Increase” is defined in Section 4.2.3 (d) hereof. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 3 

 1.23. “Clawback Amount” is defined in Section 4.2.3(d) hereof. 

1.24. “Combination” is defined in Section 1.104 hereof. 

1.25. “Commercialization” or “Commercialize” means activities with respect to a Licensed Product relating to
commercialization in the Field in the Territory, including pre-launch and launch activities, pricing and reimbursement activities, marketing, promoting, detailing, distributing, offering for sale and selling such Licensed Product, importing and
exporting such Licensed Product for sale, conducting post-marketing human clinical trials, reporting of adverse events in patients and interacting with Regulatory Authorities regarding any of the foregoing. Commercialization shall not include any
activities related to Manufacturing or Development. When used as a verb, “Commercialize” means to engage in Commercialization and “Commercialized” has a corresponding meaning. 

1.26. “Commercially Reasonable Efforts” means, with respect to the efforts to be expended by a Party with respect to any
objective, those reasonable, good faith efforts to accomplish such objective as such Party would normally use to accomplish a similar objective under similar circumstances. With respect to any efforts relating to the Development of a Licensed
Product by ImmunoGen, [***] or with respect to [***] in the [***], ImmunoGen will be deemed to have exercised Commercially Reasonable Efforts if it has exercised those efforts normally used by ImmunoGen, in the [***], with respect to a [***] or
[***], as applicable, [***] or [***] ImmunoGen, or to which ImmunoGen [***], which [***] is of [***], and is [***] in its [***] or [***] as [***], taking into account [***] in effect [***]. It is expressly understood that, so long as this Agreement
may be terminated by ImmunoGen [***] pursuant to Section 8.2 hereof, [***] the [***] of a [***] shall be deemed to be [***]. Further, to the extent that the performance of ImmunoGen’s obligations hereunder is [***] by [***] to [***], the
impact of such [***] will be taken into account in determining whether ImmunoGen has used its Commercially Reasonable Efforts to perform [***]. 

1.27. “Confidential Information” of a Party means (a) with respect to ImmunoGen, the identity of the Licensed Target, and
(b) with respect to each Party, all Know-How or other information, including proprietary information and materials (whether or not patentable) regarding such Party’s technology, products, business or objectives, that is communicated in any
way or form by or on behalf of such Party (in such capacity, the “Disclosing Party”) to the other Party (in such capacity, the “Receiving Party”) or to 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 4 

 
any of the Receiving Party’s or its Affiliates’ employees, consultants or subcontractors (collectively, “Representatives”), either prior to or after the Effective Date
of this Agreement (including any information disclosed pursuant to the Confidentiality Agreement), and whether or not such Know-How or other information is identified as confidential at the time of disclosure. The terms and conditions of this
Agreement shall be deemed to be the Confidential Information of each Party. Confidential Information within the CytomX Program Technology shall be deemed to be the Confidential Information of CytomX. Confidential Information within the ImmunoGen
Program Technology shall be deemed to be the Confidential Information of ImmunoGen. Confidential Information within the Joint Program Technology shall be deemed to be the Confidential Information of each Party. Certain other information is
designated as Confidential Information throughout this Agreement and is included in this definition. 
 1.28. “Confidentiality
Agreement” means that certain Mutual Confidential Disclosure Agreement between the Parties effective as of March 21, 2013. 

1.29. “Conjugation Probody Platform Improvements” is defined in Section 1.120 hereof. 

1.30. “Control” or “Controlled” means, with respect to any (a) item of information, including Know-How,
(b) intellectual property right, or (c) Proprietary Material, the possession (whether by ownership interest or license, other than pursuant to this Agreement) by a Party of the ability to grant to the other Party access to or a license
under such item, right or material, as provided herein, without violating the terms of any agreement or other arrangements with any Third Party. 

1.31. “Covered Results” is defined in Section 6.3.2 hereof. 

1.32. “Cover(s)” is defined in Section 4.2.3(b)(iii) hereof. 

1.33. [Reserved] 
 1.34.
“CytomX Indemnified Party” is defined in Section 9.3 hereof. 
 1.35. “CytomX Program
Technology” means any Program Technology (other than Joint Program Technology) the inventors of which are employees, agents or independent contractors of CytomX or any of its Affiliates. Anything contained in this Agreement to the contrary
notwithstanding, any and all CytomX Program Technology that is necessary or useful for Developing, Manufacturing, using or Commercializing Licensed Products and that claims, covers or is specifically directed to the composition of, or any method of
using or method of making any Licensed Product or Probody comprised in a Licensed Product shall be included in the Licensed Intellectual Property. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 5 

 1.36. “CytomX Proprietary Materials” means biological materials (including any
Probodies, Masks or Substrates) and other tangible research materials Controlled by CytomX and provided by CytomX to ImmunoGen under this Agreement. Without prejudice to any intellectual property rights in and to Probodies, any tangible Probodies
produced by or for ImmunoGen or any of its Affiliates, Sublicensees or Permitted Third Party Service Providers using any hybridoma or genetic sequencing information provided by CytomX in connection with the Development, Manufacture, use and
Commercialization of Licensed Products shall not be deemed to be CytomX Proprietary Materials for purposes of this Agreement. 
 1.37.
[Reserved] 
 1.38. [Reserved] 

1.39. [Reserved] 
 1.40.
“CytomX Technology” means any Patent Right, Know-How or other intellectual property right that is Controlled by CytomX or any Affiliate of CytomX or that comes into the Control of CytomX at any time during the Term of this Agreement
and is actually used by CytomX in Developing Licensed Products under this Agreement or is otherwise necessary for Developing, Manufacturing, using or Commercializing Licensed Products and that claims, covers or is specifically directed to the
composition of, or any method of using or method of making or any Tools for Developing, any Probody, Mask or Substrate. 
 1.41.
“Cytotoxic Compound” means [***] Compounds and [***] Compounds. 
 1.42. “Deemed Royalty Portion” is
defined in Section 5.4.2(g)(iii) hereof. 
 1.43. “Develop” or “Development” means, with
respect to a Licensed Product, all pre-clinical, non-clinical and clinical research and drug development activities with respect to such Licensed Product relating to research and development in connection with seeking, obtaining or maintaining any
Regulatory Approval for such Licensed Product, including research, toxicology, pharmacology and other similar efforts, test method development and stability testing, manufacturing process development, formulation development, delivery system
development, quality assurance and quality control development, statistical analysis, clinical studies (including pre- and post-approval studies), development of diagnostic assays in connection with clinical studies, and all activities directed to
obtaining any Regulatory Approval, including any marketing, pricing or reimbursement approval. When used as a verb, “Develop” means to engage in Development and “Developed” has a corresponding meaning. 

1.44. “Development Milestone” is defined in Section 4.1.1 hereof. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 6 

 1.45. “Development Milestone Payment” is defined in Section 4.1.1
hereof. 
 1.46. “Diligence Obligation” is defined in Section 2.2.2 hereof. 

1.47. “Disclosing Party” is defined in Section 1.27 hereof. 

1.48. “Disclosure Letter” is defined in Section 7.2 hereof. 

1.49. “Dispute” is defined in Section 10.9 hereof. 

1.50. “Effective Date” is defined in the introduction to this Agreement. 

1.51. “EMA” means the European Medicines Agency, or any successor agency thereto. 

1.52. “Field” means all human therapeutic, prophylactic and diagnostic uses. 

1.53. “FD&C Act” means the United States Federal Food, Drug, and Cosmetic Act (21 U.S.C. § 301 et seq.), as amended,
and the rules and regulations promulgated thereunder. 
 1.54. “FDA” means the United States Food and Drug Administration or
any successor agency thereto. 
 1.55. “First Commercial Sale” means, with respect to any Licensed Product and any country
of the world, the first sale of such Licensed Product under this Agreement by ImmunoGen, its Affiliates or its Sublicensees to a Third Party in such country, after such Licensed Product has been granted Regulatory Marketing Approval by the competent
Regulatory Authorities in such country or, if no such Regulatory Marketing Approval or similar approval is required, the date on which such Licensed Product is first commercially launched in such country. The foregoing notwithstanding, “First
Commercial Sale” shall not include: [***]. 
 1.56. “GAAP” means United States generally accepted accounting
principles, consistently applied. 
 1.57. “Generic Equivalent” means, with respect to any Licensed Product in a given
country, any biopharmaceutical product that is sold by a Third Party that is not a Sublicensee of ImmunoGen or its Affiliates and such Third Party product (a) contains both (i) [***] or [***] that specifically binds to the Licensed Target,
and (ii) the same [***] and [***] as the relevant Licensed Product, or (b) (i) has been [***] as a [***] or [***] by FDA pursuant to Section 351(k) of the PHSA or any subsequent or superseding law, statute or regulation,
(ii) has been [***] as a [***] by the European Medicines Agency pursuant to [***], as may be amended, or any subsequent or superseding law, statute or regulation, or (iii) has otherwise [***] in reliance on the prior approval of the

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 7 

 
[***] from another applicable [***] where in the case of each of subclauses (i), (ii) or (iii) of clause (b) above, the [***] is the [***] for purposes of determining [***] or [***] of
the Third Party product. 
 1.58. “Governmental Authority” means any court, agency, department, authority or other
instrumentality of any national, state, county, city or other political subdivision. 
 1.59. “[***] Compounds” means [***].

 1.60. “Immediate Patent Infringement Action” means an immediate patent infringement action pursuant to Section 351(1)(6)
of the PHSA. 
 1.61. “ImmunoGen Accounting Standards” means GAAP, as generally and consistently applied throughout
ImmunoGen’s organization. Beginning upon the First Commercial Sale of a Licensed Product and thereafter during the Term as long as ImmunoGen has an obligation to pay royalties under Section 4.2 hereof, ImmunoGen shall promptly
notify CytomX in the event it changes the accounting principles pursuant to which its records are maintained, it being understood and agreed that only internationally recognized accounting principles may be used (e.g., GAAP, IFRS
(International Financial Reporting Standards), etc.). 
 1.62. “ImmunoGen Indemnified Party” is defined in
Section 9.2 hereof. 
 1.63. “ImmunoGen Probody Platform Improvements” means any Probody Platform Improvement
(other than a Joint Probody Platform Improvements) the inventors of which (alone or with others) are employees of, or others obligated to assign inventions to, ImmunoGen or any of its Affiliates, Sublicensees or Permitted Third Party Service
Providers pursuant to the Development, Manufacture, use and Commercialization of any Licensed Product. 
 1.64. “ImmunoGen Program
Technology” means any Program Technology (other than Joint Program Technology) the inventors of which (alone or with others) are employees of, or others obligated to assign inventions to, ImmunoGen or any of its Affiliates, Sublicensees or
Permitted Third Party Service Providers. 
 1.65. [Reserved] 

1.66. “ImmunoGen Proprietary Materials” means any chemical (including any Cytotoxic Compounds), biological (including any
Antibodies) and other tangible research materials Controlled by ImmunoGen and provided by ImmunoGen to CytomX under this Agreement. Subject to the last sentence of this definition, any mutant, derivative, progeny or improvement of ImmunoGen
Proprietary Materials shall be considered to be ImmunoGen Proprietary Materials. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 8 

 1.67. “ImmunoGen Response” is defined in Section 5.5.3(c) hereof.

 1.68. “ImmunoGen Standard Exchange Rate Methodology” means, with respect to amounts invoiced in U.S. Dollars, all such
amounts shall be expressed in U.S. Dollars. With respect to amounts invoiced in a currency other than U.S. Dollars, all such amounts shall be expressed both in the currency in which the amount was invoiced and in the U.S. Dollar equivalent. The
U.S. Dollar equivalent shall be calculated using ImmunoGen’s then-current standard exchange rate methodology, which is in accordance with the ImmunoGen Accounting Standards applied in its external reporting for the conversion of foreign
currency sales into U.S. Dollars or, in the case of Sublicensees, such similar methodology, consistently applied. 
 1.69.
“Improvement” is defined in Section 1.120 hereof. 
 1.70. “IND” means an Investigational New
Drug Application, as defined in the FD&C Act, that is required to be filed with the FDA before beginning clinical testing of a Licensed Product in human subjects, or an equivalent foreign filing. 

1.71. “Indemnified Party” is defined in Section 9.4.1 hereof. 

1.72. “Indemnifying Party” is defined in Section 9.4.1 hereof. 

1.73. “Independent Patent Counsel” means an outside patent counsel reasonably acceptable to both Parties who (and whose firm)
is not at the time of the dispute, and was not at any time during the five (5)-year period preceding the dispute, performing legal services of any nature for either of the Parties or their respective Affiliates (or, in the case of ImmunoGen, its
Sublicensees) and which did not, at any time, employ either of the Parties’ chief patent counsels (or persons with similar responsibilities). 

1.74. “Infringed Patent List” is defined in Section 5.5.3(e) hereof. 

1.75. “Infringement” is defined in Section 5.4.1 hereof. 

1.76. “Insolvency Event” means the occurrence of any of the following: (a) a case is commenced by or against a Party
under applicable bankruptcy, insolvency or similar laws, and is not dismissed within ninety (90) days, (b) a Party files for or is subject to the institution of bankruptcy, reorganization, liquidation, receivership or similar proceedings,
(c) a Party assigns all or a substantial portion of its assets for the benefit of creditors, (d) a receiver or custodian is appointed for a Party’s business, (e) a substantial portion of a Party’s business is subject to
attachment or similar process, or (f) anything analogous to any of the events described in the foregoing clauses (a) through (e) occurs under the laws of any applicable jurisdiction. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 9 

 1.77. “Joint Conjugation Probody Platform Improvements” means Conjugation
Probody Platform Improvements the inventors of which are jointly (a) employees, agents or independent contractors of CytomX or any of its Affiliates and (b) employees, agents or independent contractors of ImmunoGen or any of its
Affiliates. 
 1.78. “Joint Development Committee” or “JDC” is defined in Section 2.3.1 hereof.

 1.79. “Joint Patent Right” means any Patent Right comprised in the Joint Program Technology. 

1.80. “Joint Probody Platform Improvements” means Probody Platform Improvements the inventors of which are jointly
(a) employees, agents or independent contractors of CytomX or any of its Affiliates and (b) employees, agents or independent contractors of ImmunoGen or any of its Affiliates. 

1.81. “Joint Program Technology” means any Program Technology (other than Joint Probody Platform Improvements) the inventors
of which are jointly (a) employees, agents or independent contractors of CytomX or any of its Affiliates and (b) employees, agents or independent contractors of ImmunoGen or any of its Affiliates. 

1.82. [Reserved] 
 1.83.
“Joint Unconjugated Probody Platform Improvements” means Unconjugated Probody Platform Improvements the inventors of which are jointly (a) employees, agents or independent contractors of CytomX or any of its Affiliates
and (b) employees, agents or independent contractors of ImmunoGen or any of its Affiliates. 
 1.84. “Know-How”
means any proprietary invention, discovery, data, information, process, method, technique, material, technology, result or other know-how, whether or not patentable. 

1.85. “Knowledge” is defined in Section 7.2 hereof. 

1.86. “Liability” is defined in Section 9.2 hereof. 

1.87. “License Agreement” has the meaning ascribed to such term in the Research Collaboration Agreement. 

1.88. “Licensed Intellectual Property” means any Patent Right, Know-How or other intellectual property right that is owned or
Controlled by CytomX or any Affiliate of CytomX or that becomes owned or Controlled by CytomX or any of its Affiliates at any time during the Term (including CytomX’s one-half interest in Joint Program Technology and Joint Probody Platform
Improvements) that is necessary or useful for 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 10 

 
Developing, Manufacturing, using or Commercializing Licensed Products and that claims, covers or is specifically directed to the composition of, or any method of using or method of making any
Licensed Product or Probody comprised in a Licensed Product. 
 1.89. “Licensed Know-How” means any Know-How comprised in
the Licensed Intellectual Property. 
 1.90. “Licensed Patent Rights” means any Patent Rights comprised in the Licensed
Intellectual Property. 
 1.91. “Licensed Product” means any product that incorporates, is comprised of, or is otherwise
derived from, a Target-Binding Probody conjugated to a Cytotoxic Compound using a Linker. 
 1.92. “Licensed Target” means
the Target set forth in Exhibit A attached hereto and incorporated herein by reference. 
 1.93. “Linker” means any
compound or composition that is useful for linking a cytotoxic or cytostatic moiety, including, without limitation, a Cytotoxic Compound, and a cell-binding moiety, including, without limitation, an Antibody or a Probody, together to form a
conjugate of the cytotoxic or cytostatic moiety with the cell-binding moiety. 
 1.94. “Loss of Market Exclusivity” with
respect to any Licensed Product in any country, shall be deemed to have occurred only if: (a) one or more Generic Equivalent(s) are being marketed by a Third Party (excluding any Sublicensee) in such country; and (b) Net Sales of such
Licensed Product in that country during any Calendar Quarter following introduction of the Generic Equivalent(s) have declined by at least [***] in that country relative to the average quarterly Net Sales of such Licensed Product in such country
over [***] ending prior to the introduction of such Generic Equivalent(s) (the “Baseline Net Sales”) and such decline in Net Sales is not primarily attributable to [***]. Anything contained in this Agreement to the contrary
notwithstanding, a “Loss of Market Exclusivity” shall not be deemed to have occurred if [***]. 
 1.95. “Major EU Market
Country” means any of [***]. 
 1.96. “Manufacturing” or “Manufacture” means activities directed
to making, producing, manufacturing, processing, filling, finishing, packaging, labeling, quality assurance testing and release, shipping or storage of a product. 

1.97. “Marginal Royalty Rates” is defined in Section 4.2.1 hereof. 

1.98. “Mask” means a peptide linked to an Antibody that is capable of inhibiting the specific binding of the Antibody to its
Target. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 11 

 1.99. “Material Breach” is defined in Section 8.3 hereof. 

1.100. “[***] Compound” means [***]. 

1.101. “Milestone Payment” means any Development Milestone Payment or Sales Milestone Payment. 

1.102. “Monies” is defined in Section 5.4.2(g) hereof. 

1.103. “Negotiation Period” is defined in Section 5.5.3(e) hereof. 

1.104. “Net Sales” means, with respect to a Licensed Product, gross receipts from sales by ImmunoGen and its Affiliates and
Sublicensees of such Licensed Product to Third Parties in the Territory, less in each case (a) bad debts, (b) sales returns and allowances actually paid, granted or accrued, including trade, quantity and cash discounts and any other
adjustments, including those granted on account of price adjustments, billing errors, rejected goods, damaged or defective goods, recalls, returns, rebates, chargeback rebates, reimbursements or similar payments granted or given to wholesalers or
other distributors, buying groups, health care insurance carriers, chain pharmacies, mass merchandisers, staff model HMO’s, pharmacy benefit managers or other institutions in respect of the purchase price, (c) adjustments actually paid,
granted or accrued arising from consumer discount programs or other similar programs, (d) customs or excise duties, sales tax, consumption tax, value added tax, and other taxes (except income taxes) or duties relating to sales, (e) any
payment made by ImmunoGen, its Affiliates or Sublicensees in respect of sales to the United States government, any state government or any foreign government, or to any other Governmental Authority, or with respect to any government-subsidized
program or managed care organization, and (f) freight and freight insurance (to the extent that ImmunoGen, its Affiliates or Sublicensees bears the cost of freight and freight insurance for the Licensed Product), in each case in accordance with
GAAP, as consistently applied by ImmunoGen with respect to its overall operations. 
 Net Sales shall not include sales or
transfers among ImmunoGen and its Affiliates and Sublicensees where the Licensed Product is intended for subsequent sale to the end user. All the foregoing elements of Net Sales calculations shall be determined from the books and records of
ImmunoGen and its Sublicensees, maintained in accordance with the ImmunoGen Accounting Standards or, in the case of Sublicensees, such similar accounting principles, consistently applied. 

In the event a Licensed Product is sold as a component of a combination or bundled product that consists of a Licensed Product
together with another therapeutically active product, or screening or diagnostic product, for the same indication (a “Combination”), the Net Sales from the Combination, for the purposes of determining royalty payments hereunder, shall be
determined by multiplying the Net Sales of the 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 12 

 
Combination (as defined in the standard Net Sales definition above) by the fraction A/(A+B), where A is the weighted average per unit sale price of the Licensed Product when sold separately in
finished form in the country in which the Combination is sold in similar volumes and of the same class, purity, potency and dosage form, and B is the weighted average per unit sale price of the other product(s) included in the Combination when sold
separately in finished form in the country in which the Combination is sold in similar volumes and of the same class, purity, potency and dosage form. 

In the event that the weighted average per unit sale price of the Licensed Product can be determined but the weighted average
per unit sale price of the other product(s) included in the Combination cannot be determined, Net Sales for purposes of determining royalty payments shall be calculated by multiplying the Net Sales of the Combination (as defined in the standard Net
Sales definition above) by the fraction A/C, where A is the weighted average sale price of the Licensed Product when sold separately in finished form in the country in which the Combination is sold in similar volumes and of the same class, purity,
potency and dosage form, and C is the weighted average per unit sale price of the Combination. 
 In the event that the
weighted average per unit sale price of the other product(s) included in the Combination can be determined but the weighted average per unit sale price of the Licensed Product in similar volumes and of the same class purity, potency and dosage form
as in the Combination cannot be determined, Net Sales for purposes of determining royalty payments shall be calculated by multiplying Net Sales of the Combination (as defined in the standard Net Sales definition above) by a fraction determined by
the following formula: one (1) minus (B/C) where B is the weighted average per unit sale price of the other product(s) included in the Combination when sold separately in finished form in the country in which the Combination is sold in similar
volumes and of the same class, purity, potency and dosage form and C is the weighted average per unit sale price of the Combination. 

In the event that such average per unit sale price cannot be determined for the Licensed Product, on the one hand, and all
other product(s) included in the Combination, on the other, Net Sales for the purposes of determining royalty payments shall be mutually agreed upon by the Parties based on the relative value contributed by each component, such agreement to be
negotiated in good faith. 
 1.105. The weighted average per unit sale price for both the Licensed Product, on the one hand, and all other
product(s) included in the Combination, on the other, shall be calculated once each Calendar Year and such price shall be used during all applicable royalty reporting periods for the entire following Calendar Year. When determining the weighted
average per unit sale price of a Licensed Product, other product(s), or Combination, the weighted average per unit sale price shall be calculated by dividing 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 13 

 
sales dollars (translated into U.S. Dollars using the ImmunoGen Standard Exchange Rate Methodology) by the units sold during the twelve (12) months (or the number of months in which sales
occurred in a partial Calendar Year) of the preceding Calendar Year for the respective Licensed Product, other product(s), or Combination. In the initial Calendar Year, a forecasted weighted average per unit sale price will be used for the Licensed
Product, other product(s), or Combination. Any over- or under-payment due to a difference between the forecasted and actual weighted average per unit sale price will be paid or credited in the first royalty payment of the following Calendar Year.

 1.106. “Non-Disclosing Party” is defined in Section 6.3.2 hereof. 

1.107. “Notice of Dispute” is defined in Section 10.9.1 hereof. 

1.108. “Party” and “Parties” is defined in the introduction to this Agreement. 

1.109. “Patent Committee” is defined in Section 5.2.4 hereof. 

1.110. “Patent Rights” means any and all (a) patents, (b) pending patent applications, including all provisional
applications, substitutions, continuations, continuations-in-part, divisions and renewals, and all patents granted thereon, (c) all patents-of-addition, reissues, reexaminations and extensions or restorations by existing or future extension or
restoration mechanisms, including patent term extensions, supplementary protection certificates or the equivalent thereof, (d) inventor’s certificates, (e) any other form of government-issued right substantially similar to any of the
foregoing and (f) all United States and foreign counterparts of any of the foregoing. 
 1.111. “Payload” means a
therapeutic cytotoxic or cytostatic compound, including, without limitation, a Cytotoxic Compound. 
 1.112. “PDC” means a
compound that incorporates, is comprised of or is otherwise derived from, a Probody conjugated to a Payload using a Linker. 
 1.113.
“Permitted Third Party Service Providers” is defined in Section 3.1.1 hereof. 
 1.114.
“Person” means an individual, sole proprietorship, partnership, limited partnership, limited liability partnership, corporation, limited liability company, business trust, joint stock company, trust, incorporated association, joint
venture or similar entity or organization, including a government or political subdivision or department or agency of a government. 
 1.115.
“Phase 1 Clinical Study” means an initial study of a Licensed Product in human subjects or patients with the endpoint of determining initial tolerance, safety, metabolism or pharmacokinetic information and clinical pharmacology of
such product as and to the extent defined for the United States in 21 C.F.R. § 312.21(a), or its successor regulation, or the equivalent regulation in any other country. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 14 

 1.116. “Phase 2 Clinical Study” means a study of a Licensed Product in human
patients that is intended to obtain information on the Licensed Product’s activity for an indication at a prescribed (or otherwise limited) dose and administration schedule, as well as additional information on the Licensed Product’s
safety and toxicity as and to the extent defined for the United States in 21 C.F.R. § 312.21(b), or its successor regulation, or the equivalent regulation in any other country. Without limiting the generality of the foregoing, a clinical
study shall be deemed to be a “Phase 2 Clinical Study” hereunder if such study has been designated by the sponsor as a Phase 2 [II] clinical trial on www.clinicaltrials.gov (or any successor website maintained by the U.S. National
Institutes of Health (or any successor agency of the U.S. Government)). 
 1.117. “Phase 3 Clinical Study” means a study of
a Licensed Product in human patients with a defined dose or a set of defined doses of a Licensed Product designed to (a) ascertain efficacy and safety of such Licensed Product for its intended use; (b) define warnings, precautions and adverse
reactions that are associated with the Licensed Product in the dosage range to be prescribed; and (c) support preparing and submitting applications for Regulatory Marketing Approval to the competent Regulatory Authorities in a country of the
world, as and to the extent defined for the United States in 21 C.F.R.§ 312.21(c), or its successor regulation, or the equivalent regulation in any other country. “Phase 3 Clinical Study” shall also include any other human clinical
trial serving as a pivotal study from which the data are actually submitted to the applicable Regulatory Authority in connection with a Regulatory Marketing Approval Application, whether or not such trial is called a “Phase 3” study.
Without limiting the generality of the foregoing, a clinical study shall be deemed to be a “Phase 3 Clinical Study” hereunder if such study has been designated by the sponsor as a Phase 3 [III] clinical trial on
www.clinicaltrials.gov (or any successor website maintained by the U.S. National Institutes of Health (or any successor agency of the U.S. Government)). 

1.118. “PHSA” means the Public Health Services Act, as amended (42 U.S.C. § 201 et seq.). 

1.119. “Pre-Market Notice” is defined in Section 5.5.4(b) hereof. 

1.120. “Probody” means an Antibody linked to a Substrate and a Mask that is claimed or covered by CytomX Technology. 

1.121. “Probody Platform Improvements” means any Patent Right, Know-How or other intellectual property right that is an
enhancement, improvement or modification (each, an “Improvement”) to the CytomX Technology invented by either Party or any of its Affiliates (or by a Third Party on behalf of either Party or its Affiliates) that is an

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 15 

 
Improvement to the composition of, or any method of using or method of making or any Tools for developing, any unconjugated Probody, Mask or Substrate (collectively, “Unconjugated Probody
Platform Improvements”). Probody Platform Improvements also include Improvements (a) to any of the analytical methods used for making, releasing and characterizing any Agreement PDCs that are necessary because of the presence of a Mask
and/or Substrate, or (b) consisting of conjugation chemistry or conjugation methods that are necessary because of the presence of a Mask and/or Substrate (collectively, “Conjugation Probody Platform Improvements”). Licensed Products
and ImmunoGen Probodies, in and of themselves, will not be considered to be Probody Platform Improvements, although the Parties acknowledge that Probody Platform Improvements may be incorporated into Licensed Products and ImmunoGen Probodies. [***]

 1.122. “Program Technology” means all Know-How (other than Probody Platform Improvements) that either Party or any of its
Affiliates, Sublicensees or Permitted Third Party Service Providers (or any of their respective employees, agents or independent contractors), alone or with others, makes, creates, develops, discovers, conceives or first actually reduces to practice
pursuant to the Development, Manufacture, use or Commercialization of any Licensed Product, including any Patent Rights related thereto. Program Technology also includes “Program Technology” (as defined in the Research Collaboration
Agreement) that is necessary or useful for Developing, Manufacturing, using or Commercializing Licensed Products and that claims, covers or is specifically directed to the composition of, or any method of using or method of making any Target-Binding
Antibody, Licensed Product, Linker or Cytotoxic Compound comprised in any Licensed Product. 
 1.123. “Proposed Biosimilar
Product” is defined in Section 5.5.1 hereof. 
 1.124. “Proposed Patent List” is defined in
Section 5.5.3(a) hereof. 
 1.125. “Publishing Party” is defined in Section 6.3.2 hereof. 

1.126. “Receiving Party” is defined in Section 1.27 hereof. 

1.127. “Regulatory Approval” means any technical, medical, scientific or other license, registration, authorization or
approval of any Regulatory Authority (including any approval of a New Drug Application or Biologic License Application) necessary for the Development, Manufacture, use or Commercialization of a pharmaceutical product in any regulatory jurisdiction.

 1.128. “Regulatory Approval Application” means any application submitted to an appropriate Regulatory Authority seeking
any Regulatory Approval. 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 1.129. “Regulatory Authority” means the FDA or any counterpart of the FDA
outside the United States, or other national, supra-national, regional, state or local regulatory jurisdiction, any agency, department, bureau, commission, council or other governmental entity with authority over the Development, Manufacture, use or
Commercialization of a Licensed Product. 
 1.130. “Regulatory Marketing Approval” means, with respect to any pharmaceutical
product and any indication, Regulatory Approval (including any supplement thereto) to sell such pharmaceutical product for such indication, including, in any jurisdiction other than the United States, to the extent required for any sale in such
country, all pricing and reimbursement approvals to be obtained from the Regulatory Authority granting such Regulatory Approval or any affiliated Regulatory Authority. 

1.131. “Representatives” is defined in Section 1.27 hereof. 

1.132. “Research Collaboration Agreement” means that certain Research Collaboration Agreement effective as of January 8,
2014 by and between CytomX and ImmunoGen, as the same may be amended from time to time. 
 1.133. “Research Program” has the
meaning ascribed to such term in the Research Collaboration Agreement. 
 1.134. “Review Period” is defined in
Section 6.3.2 hereof. 
 1.135. “Royalty Term” means, on a Licensed Product-by-Licensed Product and
country-by-country basis, the period of time from the First Commercial Sale of such Licensed Product in such country until the later of (a) the expiration of the last Valid Claim that would, but for the license granted hereunder, be infringed
by the manufacture, use, sale, offer for sale or importation of such Licensed Product in such country or (b) the twelfth (12th) anniversary of the date of the First Commercial Sale of
such Licensed Product in such country, but in the case of (b), in no event later than the twentieth (20th) anniversary of the earlier of the date of the First Commercial Sale of such Licensed
Product in the United States or the date of the First Commercial Sale of such Licensed Product in any Major EU Market Country. Anything contained in this Agreement to the contrary notwithstanding, if the Licensed Product (or any component or
intermediate thereof) was manufactured in a country where such manufacture would, at the time of such manufacture, have infringed a Valid Claim within the Licensed Patent Rights in the country of manufacture in the absence of the license granted
under Section 3.3.1 hereof, then the Royalty Term in the country of sale of such Licensed Product, if otherwise expired pursuant to the first sentence of this Section, shall be extended or reinstated, as the case may be, but only with
respect to sales of Licensed Products so manufactured. In determining infringement of Valid Claims for purposes of this definition of Royalty Term, (i) any Valid Claim within the Licensed Patent Rights that is jointly owned by

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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CytomX (or any of its Affiliates) with CytomX (or any of its Affiliates) shall be deemed to be owned solely by CytomX or an Affiliate of CytomX, and (ii) claims contained in patent
applications that have not resulted in the issuance of a patent in a country will be disregarded for purposes of determining the expiration of the Royalty Term for a Licensed Product in such country under this definition. 

1.136. “Sales Milestone” is defined in Section 4.1.2 hereof. 

1.137. “Sales Milestone Payment” is defined in Section 4.1.2 hereof. 

1.138. “Sales Threshold” is defined in Section 4.1.2 hereof. 

1.139. [Reserved] 
 1.140.
“Sublicensee” means any Third Party to whom ImmunoGen or an Affiliate of ImmunoGen grants or has granted, directly or indirectly, a sublicense of rights licensed by CytomX under this Agreement, in accordance with the provisions of
this Agreement. 
 1.141. “Substrate” means a moiety that is linked to the Antibody and to the Mask of a Probody and is
capable of being cleaved, reduced or photolysed. 
 1.142. [Reserved] 

1.143. “Target” means a protein described by a unique UniProtKB/Swiss Prot accession number (and all fragments, mutations and
splice variants thereof) that is bound by an Antibody or a Probody. 
 1.144. “Target,” “Targeting” or
“Targeted” means, when used as a verb to describe the relationship between a molecule and a Target, where the molecule’s primary intended mechanism of action requires that it bind to the Target (or a portion thereof). 

1.145. “Target-Binding Probody” means a Probody that Targets the Licensed Target. [***] 

1.146. “Term” is defined in Section 8.1 hereof. 

1.147. “Territory” means the entire world. 

1.148. “Third Party” means any Person other than CytomX, ImmunoGen or their respective Affiliates. 

1.149. “Third Party Claims” is defined in Section 9.2 hereof. 

1.150. “Third Party Payments” is defined in Section 4.2.3(a) hereof. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 1.151. “Unauthorized Use” is defined in Section 2.6.3 hereof. 

1.152. “Unconjugated Probody Platform Improvements” is defined in Section 1.120 hereof. 

1.153. “Valid Claim” means, with respect to a particular country, (a) a claim of an issued and unexpired patent right
included within the Licensed Patent Rights that (i) has not been held permanently revoked, unenforceable or invalid by a decision of a court or other governmental authority of competent jurisdiction, which decision is unappealed or unappealable
within the time allowed for appeal, and (ii) has not been cancelled, withdrawn, abandoned, disclaimed or admitted to be invalid or unenforceable through reissue, disclaimer or otherwise; or (b) a bona fide claim of a pending patent
application included within the Licensed Patent Rights that has not been (i) cancelled, withdrawn or abandoned without being refiled in another application in the applicable jurisdiction or (ii) finally rejected by an administrative agency
action from which no appeal can be taken or that has not been appealed within the time allowed for appeal, provided that any claim in any patent application pending for more than seven (7) years from the earliest date on which such patent
application claims priority shall not be considered a Valid Claim for purposes of the Agreement from and after such seven (7) year date unless and until a patent containing such claim issues from such patent application and solely if such
patent issues while another Valid Claim covers the relevant Licensed Product in the relevant country. Anything contained in this Agreement to the contrary notwithstanding, a claim within an issued and unexpired patent within the Licensed Patent
Rights shall remain a Valid Claim for all purposes under this Agreement, notwithstanding a determination that such claim is unenforceable pursuant to the operation of the BPCIA, if such determination is exclusively caused by or results solely from
any act or omission by ImmunoGen (or any of its Affiliates or Sublicensee) determined to have been made negligently or in bad faith in the performance of ImmunoGen’s obligations under Section 5.5.3 hereof that results in actual prejudice
to CytomX’s ability to preserve its rights in the Licensed Patent Rights and eliminate the infringement threatened by the Applicant (excluding any acts or omissions undertaken pursuant to the specific written instruction of CytomX. 

 

	2.	PRODUCT DEVELOPMENT, MANUFACTURING AND COMMERCIALIZATION. 

 2.1. General.
ImmunoGen shall have sole authority over, responsibility for and control of (notwithstanding the formation of the JDC or its decisions and/or disputes among the membership of the JDC) the Development, Manufacture, use and Commercialization of the
Licensed Products, and shall bear all costs associated with such Development, Manufacture, use and Commercialization. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 2.2. Development Diligence. 

2.2.1. ImmunoGen Diligence. ImmunoGen will use Commercially Reasonable Efforts to Develop Licensed Products and to undertake
investigations and actions required to obtain Regulatory Marketing Approval in the Territory; provided that the obligations set forth in this Section shall cease upon the achievement of the first Regulatory Marketing Approval for any Licensed
Product in any country or other jurisdiction in the Territory. For avoidance of doubt, any actions taken by ImmunoGen’s Affiliates or Sublicensees under this Agreement shall be treated as actions taken by ImmunoGen in regard to satisfaction of
the requirements of this Section 2.2.1. Beginning on the sixth (6th) anniversary of the Effective Date and thereafter, ImmunoGen will make non-refundable and non-creditable
maintenance payments in the amounts set forth below (the “Annual Maintenance Fees”) until the earlier of (a) the first filing of an IND in the U.S. or in any European Union country for any Licensed Product or (b) the
termination of this Agreement in accordance with its terms. The amounts of the Annual Maintenance Fee accruing as of each anniversary of the Effective Date, beginning with the sixth
(6th) anniversary are as follows: 
  

					
	 Anniversary of the Effective Date
	  	Maintenance Fee	 
	 Sixth (6th) anniversary
	  	 	[***	] 
	 Seventh (7th) anniversary
	  	 	[***	] 
	 Eighth(8th) anniversary and each anniversary thereafter
	  	 	[***	] 

 ImmunoGen will pay the applicable Annual Maintenance Fee in accordance with Section 4.3 hereof
within [***] after the applicable anniversary of the Effective Date. Payment of Annual Maintenance Fees by ImmunoGen shall not establish that ImmunoGen has satisfied its due diligence obligations under this Section 2.2, and such payments
shall be given no consideration or weight in determining whether ImmunoGen has satisfied such due diligence obligations. Anything contained in this Agreement to the contrary notwithstanding, ImmunoGen shall have no obligation to pay Annual
Maintenance Fees hereunder if the first filing of an IND in the U.S. or in any European Union country for any Licensed Product has occurred prior to the sixth (6th) anniversary of the
Effective Date. 
 2.2.2. Exceptions to Diligence Obligations. Notwithstanding any provision of this Agreement to the contrary,
ImmunoGen will be relieved from and will have no obligation to undertake any efforts with respect to any diligence obligation 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 20 

 
under Section 3.2.1 with respect to a given Licensed Product (each, a “Diligence Obligation”) in the event that CytomX materially breaches any of its Development or
other obligations under this Agreement related to such Licensed Product upon which performance of the applicable Diligence Obligation is dependent. 

2.2.3. Remedies for Breach of Diligence Obligations. A material breach of any Diligence Obligation by ImmunoGen shall be deemed to be a
Material Breach by ImmunoGen hereunder. 
 2.3. Joint Development Committee. 

2.3.1. Formation of the Joint Development Committee. As soon as practicable after the Effective Date, CytomX and ImmunoGen shall
establish a “Joint Development Committee” (or “JDC”) to coordinate the sharing of safety data and minutes of meetings with Regulatory Authorities with regard to Licensed Products. The JDC shall also serve as a forum
to facilitate communications between the Parties regarding this Agreement. The JDC shall be comprised of two (2) representatives from each Party as appointed by such Party, with such representatives possessing appropriate expertise and
seniority. The JDC may change its size from time to time by mutual consent of its members. A Party may replace one or more of its representatives from time to time upon written notice to the other Party. The JDC shall exist until the expiration of
the Term or earlier termination of the Agreement, unless the Parties otherwise agree in writing, provided that ImmunoGen may dissolve the JDC upon the achievement of the first Regulatory Marketing Approval for any Licensed Product in any country or
other jurisdiction in the Territory. 
 2.3.2. Chairperson and Secretary of the Joint Development Committee. ImmunoGen shall designate
a chairperson of the JDC, and a secretary of the JDC shall be designated by agreement of the members of the JDC. ImmunoGen may change the designation of the chairperson from time to time upon written notice to CytomX. The chairperson or his or her
designee shall be responsible for scheduling meetings of the JDC, preparing agendas for meetings and sending to all JDC members notices of all regular meetings and agendas for such meetings at least [***] Business Days before such meetings. The
chairperson shall solicit input from both Parties regarding matters to be included on the agenda, and any matter either Party desires to have included on the agenda shall be included for discussion. Nothing herein shall be construed to prohibit the
JDC from discussing or acting on matters not included on the applicable agenda. The secretary shall (a) record the minutes of the meeting, (b) circulate copies of meeting minutes to the Parties and each JDC member promptly following the
meeting for review, comment and approval by the JDC members and (c) finalize approved meeting minutes. The chairperson shall be a member of the JDC but the secretary need not be a member of the JDC. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 2.3.3. Meetings. The JDC shall meet at least three (3) times each Calendar Year
(unless the Parties mutually agree in advance of any scheduled meeting that there is no need for such meeting, in which case the next JDC meeting shall also be scheduled as agreed upon by the Parties) until it has been terminated in accordance with
Section 2.3.1 hereof at dates and times mutually agreed by the JDC. The initial meeting of the JDC shall be held within [***] days after the Effective Date. Either Party may call a special meeting of the JDC on [***] days written notice
to the other Party’s members of the JDC (or upon such shorter notice as exigent circumstances may require). Such written notice shall include an agenda for the special meeting. In-person meetings, including special meetings, of the JDC shall
alternate between the offices of the Parties, unless otherwise agreed upon by the members of the JDC. Meetings of the JDC may be held telephonically or by video conference; provided, however, that at least [***] meetings per year shall be held
in-person. Meetings of the JDC shall be effective only if at least one (1) representative of each Party is in attendance or participating in the meeting. Members of the JDC shall have the right to participate in at meetings held by telephone or
video conference. In addition, the JDC may act on any matter or issue without a meeting if it is documented in a written consent signed by each member of the JDC. 

2.3.4. Responsibilities of the Joint Development Committee. The JDC shall be responsible for (a) receiving and reviewing all safety
data, relevant regulatory information and other related information obtained by either Party in connection with the Development, Manufacture, use and Commercialization of Licensed Products; (b) facilitating communication between the Parties,
(c) resolving Disputes between the Parties, such as Disputes about interpretation of this Agreement, understanding that ImmunoGen has sole authority over the Development, Manufacturing, use and Commercialization of Licensed Products; and
(d) such other functions as expressly specified hereunder or as agreed by the Parties. At the time that the first Licensed Product enters a clinical trial, the Parties shall negotiate in good faith the terms of a separate written safety data
exchange agreement that, among other things, will govern the exchange of pharmacovigilance information. 
 2.3.5. Resolution by [***].
All resolution of Disputes by the JDC shall be made by [***]. If the JDC cannot or does not reach [***] on a Dispute, then such Dispute shall be resolved in accordance with Section 10.9 hereof. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 2.4. Alliance Managers. In addition to the foregoing governance provisions, each of the
Parties shall appoint a single individual to serve as that Party’s alliance manager (“Alliance Manager”). The role of each Alliance Manager will be to participate and otherwise facilitate the relationship between the Parties as
established by this Agreement. A Party may replace its Alliance Manager from time to time upon written notice to the other Party. 
 2.5.
Updates and Reports; Product Recalls. 
 2.5.1. Development Updates. Upon the request of CytomX, ImmunoGen shall provide CytomX
with brief written reports, which CytomX may request no more frequently than [***] until satisfaction of ImmunoGen’s obligations under Section 2.2.1 hereof, that shall summarize ImmunoGen’s efforts to Develop the Licensed
Products in the Field in the Territory in sufficient detail to establish that ImmunoGen is using Commercially Reasonable Efforts to Develop the Licensed Product, identify the applications for Regulatory Approval that ImmunoGen or its Affiliates or
Sublicensees have filed, sought or attempted to obtain in the prior [***] period, and any they reasonably expect to file, seek or attempt to obtain in the following [***] period. The Parties agree that the minutes of the JDC meetings may serve as
reports hereunder, to the extent such minutes adequately address the above subject matter. 
 2.5.2. [Reserved] 

2.5.3. Product Recalls. In the event any Regulatory Authority issues or requests a recall or takes similar action with respect to a
Licensed Product that ImmunoGen reasonably believes is or may be attributable to or otherwise relates to the Licensed Intellectual Property, or in the event either Party reasonably believes that an event, incident or circumstance has occurred that
may result in the need for such a recall, such Party shall promptly notify the other Party thereof by telephone, facsimile or email. Following such notification, ImmunoGen shall decide and have control of whether to conduct a recall or market
withdrawal (except in the event of a recall or market withdrawal mandated by a Regulatory Authority, in which case it shall be required) or take such other corrective action in any country and the manner in which any such recall, market withdrawal
or corrective action shall be conducted, provided that ImmunoGen shall keep CytomX informed regarding any such recall, market withdrawal or corrective action as CytomX from time to time may reasonably request, but only to the extent ImmunoGen is
legally permitted to do so. ImmunoGen shall bear all expenses of any such recall, market withdrawal or corrective action, including, without limitation, expenses of notification, destruction and return of the affected Licensed Product and any refund
to customers of the amounts paid for such Licensed Product. 
 2.5.4. Confidential Information. All reports, updates, product
complaints and other information provided by the Disclosing Party to the Receiving Party under this Agreement (including under this Section 2.5), shall be considered Confidential Information of the Disclosing Party, subject to the terms
of Article 7 hereof. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 2.6. Transfer and Use of Proprietary Materials. 

2.6.1. Transfer and Use of CytomX Proprietary Materials. From time to time during the Term, CytomX may provide ImmunoGen with CytomX
Proprietary Materials for use in the Development and Manufacture of Licensed Products under this Agreement. CytomX’s Proprietary Materials are provided by CytomX on an “as-is” basis without representation or warranty of any type,
express or implied, including any representation or warranty of merchantability, non-infringement, title or fitness for a particular purpose, each of which is hereby disclaimed by CytomX. In connection with the foregoing, ImmunoGen agrees that
(a) it shall not use CytomX’s Proprietary Materials provided under this Agreement for any purpose other than exercising its rights and performing its obligations hereunder; (b) it shall not use CytomX Proprietary Materials provided
under this Agreement in any human subject; (c) it shall use CytomX Proprietary Materials in compliance with all Applicable Laws; (d) it does not acquire any right, title or interest in or to CytomX Proprietary Materials as a result of such
provision by CytomX; and (e) upon expiration or termination of this Agreement for any reason, ImmunoGen shall, if and as instructed by CytomX, either destroy or return CytomX Proprietary Materials provided under this Agreement that are not the
subject of a continuing license hereunder. ImmunoGen shall be entitled to transfer CytomX Proprietary Materials to any Affiliate, Sublicensee or Permitted Third Party Service Provider under terms obligating such Affiliate, Sublicensee or Permitted
Third Party Service Provider not to use or transfer such CytomX Proprietary Materials except in compliance with the preceding sentence. 

2.6.2. Transfer and Use of ImmunoGen Proprietary Materials. From time to time during the Term, ImmunoGen may provide CytomX with
ImmunoGen Proprietary Materials. CytomX shall use the ImmunoGen Proprietary Materials solely in connection with conducting the specific activities for which such ImmunoGen Proprietary Materials are provided to CytomX, and for no other purpose.
Without limiting the generality of the foregoing, except as expressly set forth in this Agreement or in other written authorization by ImmunoGen, CytomX shall not make or attempt to make analogues, progeny or derivatives of, or

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 24 

 
modifications to, the ImmunoGen Proprietary Materials, using ImmunoGen’s Confidential Information, and CytomX shall not use the ImmunoGen Proprietary Materials for the benefit of any Third
Party or of its own internal research programs. CytomX shall comply with all Applicable Laws regarding the handling and use of the ImmunoGen Proprietary Materials. CytomX agrees to retain possession over the ImmunoGen Proprietary Materials and not
to provide the ImmunoGen Proprietary Materials to any Third Party without ImmunoGen’s prior written consent. 
 2.6.3. Unauthorized
Use of Confidential Information and Proprietary Materials. In the event that (a) ImmunoGen or any of its Affiliates or Sublicensees use CytomX’s Confidential Information (including, without limitation, any Confidential Information
within the Licensed Know-How) or CytomX Proprietary Materials for any purpose other than in connection with ImmunoGen’s exercise of its rights and performance of its obligations hereunder or the Research Collaboration Agreement (if then in
effect) or (b) CytomX or any of its Affiliates uses ImmunoGen’s Confidential Information or ImmunoGen Proprietary Materials for any purpose other than the purposes authorized herein or in any other License Agreement or the Research
Collaboration Agreement (if then in effect) (in each case, an “Unauthorized Use”), the results of such Unauthorized Use, and any discoveries or inventions that arise from such Unauthorized Use, whether patentable or not, shall
belong solely and exclusively to the providing Party. If required in order to perfect or enforce the providing Party’s ownership of such results, discoveries or inventions, each Party, on behalf of itself and its Affiliates (and in the case of
ImmunoGen, its Sublicensees), each hereby assigns and agrees to assign to the providing Party all of its and their right, title and interest in and to all such results, discoveries or inventions made through such Unauthorized Use. Each Party agrees
to cooperate, and to cause its Affiliates (and in the case of ImmunoGen, its Sublicensees) to cooperate, with the providing Party, and to execute and deliver any and all documents that the providing Party reasonably deems necessary, to perfect and
enforce its rights hereunder. 
 2.7. Services. If, during the Term, ImmunoGen requests that CytomX provide additional services with
respect to (a) the creation of new Probodies Targeting the Licensed Target or (b) any other tasks in connection with the Development, Manufacture, use or Commercialization of Licensed Products with respect to which the Parties may mutually
agree, then the Parties shall negotiate in good faith the terms of separate written agreements with respect to such activities. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 25 

	3.	LICENSE GRANTS. 

 3.1. License Grants. 

3.1.1. Commercial License. Subject to the terms and conditions of this Agreement, CytomX hereby grants to ImmunoGen and its Affiliates
an exclusive (even as to CytomX), non-transferable (except as expressly permitted in this Agreement), royalty-bearing license, including the right to grant sublicenses as described in Section 3.1.2 hereof, under the Licensed Intellectual
Property, to Develop, make, have made, use, sell, offer for sale, import and otherwise Commercialize Licensed Products in the Field in the Territory. ImmunoGen and its Affiliates shall have the right to engage one or more Affiliates or Third Parties
(the latter being referred to herein as “Permitted Third Party Service Providers”) as subcontractors to perform designated functions in connection with its activities under this Agreement (including transferring Licensed Know-How
and CytomX Proprietary Materials as may be necessary for such Permitted Third Party Service Providers to perform such designated functions); provided that (a) ImmunoGen shall [***] and (b) ImmunoGen shall [***]. 

3.1.2. Right to Sublicense. ImmunoGen and its Affiliates shall have the right to grant sublicenses under the rights granted to them
under Section 3.1.1 hereof with respect to any Licensed Product to any Sublicensee, provided that (a) each such sublicense shall be consistent with the terms and conditions of this Agreement, (b) ImmunoGen shall [***],
(c) ImmunoGen and its Affiliates shall cause [***], (d) ImmunoGen shall [***]. 
 3.2. Retained Rights and Covenants. 

3.2.1. [***] 
 3.2.2. [***] 

3.3. License to ImmunoGen Probody Platform Improvements. ImmunoGen, on behalf of itself and its Affiliates, hereby grants to CytomX a
non-exclusive, sublicensable, perpetual, irrevocable, royalty-free worldwide license under ImmunoGen’s interest in any ImmunoGen Probody Platform Improvements, including, without limitation, any Patent Rights claiming such ImmunoGen Probody
Platform Improvements, to exploit such ImmunoGen Probody Platform Improvements (a) for any purpose in the Field other than developing, manufacturing, using or commercializing PDCs having a Payload that is a Cytotoxic Compound2 and (b) for any purpose outside of the Field. Nothing in this Agreement shall be construed as obligating ImmunoGen to [***] or any of its Affiliates or any Third Party [***]. 

 

	2 	[***] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 26 

 3.4. Section 365(n) of Bankruptcy Code. All rights and licenses now or hereinafter
granted by either Party to the other Party under or pursuant to any section of this Agreement, including the licensed granted in this Article 3, are rights to “intellectual property” (as defined in Section 101(35A) of
Title 11 of the United States Code, as amended (such Title 11, the “Bankruptcy Code”)). The Parties hereto acknowledge and agree that the payments provided for under Article 4 hereof, other than royalty
payments pursuant to Section 4.2 hereof, do not constitute royalties within the meaning of Section 365(n) of the Bankruptcy Code or relate to licenses of intellectual property under this Agreement. 

3.5. No Implied Rights. Except as expressly provided in this Agreement, neither Party shall be deemed, by estoppel, implication or
otherwise, to have granted the other Party any license or other right with respect to any intellectual property of such Party. 
  

	4.	PAYMENTS. 

 4.1. Milestone Payments. 

4.1.1. Development Milestones. Within [***] following the first occurrence of each event (each, a “Development
Milestone”) described below for the first Licensed Product that achieves such milestone, ImmunoGen shall provide written notice to CytomX identifying the Development Milestone achieved, and ImmunoGen shall pay to CytomX the amount set forth
below within [***] of receipt of CytomX’s notice with respect to such Development Milestone (each such amount, a “Development Milestone Payment”) to be payable only once regardless of how many Licensed Products achieve such
Development Milestone. 
  

					
	 Development Milestone
	  	Payment	 
	 Dosing of first patient in a Phase 1 Clinical Study
	  	 	[***	] 
	 Dosing of first patient in a Phase 2 Clinical Study*
	  	 	[***	] 
	 Dosing of first patient in a Phase 3 Clinical Study
	  	 	[***	] 
	 Date of filing of BLA
	  	 	[***	] 
	 Date of receipt of Regulatory Approval in [***]
	  	 	[***	] 
	 Date of receipt of Regulatory Marketing Approval in [***]
	  	 	[***	] 
	 Date of receipt of Regulatory Marketing Approval in [***]
	  	 	[***	] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 27 

 If a clinical milestone is achieved and any previous clinical milestone has not yet been achieved
for any reason, notwithstanding anything herein to the contrary such previous milestone(s) shall be deemed to have been achieved and the corresponding Development Milestone Payment set forth in the table above shall be payable simultaneously with
the Development Milestone Payment for the achievement of the subsequent Milestone. All Development Milestone Payments shall be non-refundable and noncreditable. 

4.1.2. Sales Milestones. ImmunoGen shall pay to CytomX the following one-time payments (each, a “Sales Milestone
Payment”) when aggregate Annual Net Sales of a Licensed Product in the Territory in a Calendar Year first reach the respective threshold (a “Sales Threshold”) indicated below (each, a “Sales Milestone”):

  

					
	 Total Annual Net Sales
	  	Sales Milestone
Payment	 
	 Total Annual Net Sales at least equal [***]
	  	 	[***	] 
	 Total Annual Net Sales at least equal [***]
	  	 	[***	] 
	 Total Annual Net Sales at least equal [***]
	  	 	[***	] 
	 Total Annual Net Sales at least equal [***]
	  	 	[***	] 

 Any Sales Milestone Payment with respect to any Calendar Year shall be payable within [***] of the end of such
Calendar Year in the United States. Each Sales Milestone Payment is payable a maximum of one time only, regardless of the number of times a Licensed Product achieves a particular Sales Threshold or the number of Licensed Products that achieve a
particular Sales Threshold. All Sales Milestone Payments shall be nonrefundable and noncreditable. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 28 

 4.2. Royalties. 

4.2.1. Royalty Payments. With respect to each Licensed Product and subject to the provisions of Section 4.2.2 hereof,
ImmunoGen shall pay CytomX royalties in the amount of the applicable rates (“Marginal Royalty Rates”) set forth below of Annual Net Sales of such Licensed Product during the Royalty Term: 

 

					
	 Annual Net Sales
	  	Marginal Royalty Rate for
Licensed Products (% of
Annual Net Sales)	 
	 Annual Net Sales of such Licensed Product during a given Calendar Year [***]
	  	 	[***	]% 
	 Annual Net Sales of such Licensed Product during a given Calendar Year [***]
	  	 	[***	]% 
	 Annual Net Sales of such Licensed Product during a given Calendar Year [***]
	  	 	[***	]% 

 4.2.2. Marginal Royalty Rate Application. Each Marginal Royalty Rate set forth in the table above shall
apply only to that portion of the Annual Net Sales of a given Licensed Product in the Territory during a given Calendar Year that falls within the indicated range. 

4.2.3. Royalty Adjustments. 

(a) Third Party Royalty Offset. Subject to Section 4.2.3(e) hereof, if, with respect to a Calendar Quarter, ImmunoGen or
any of its Affiliates or Sublicensees [***] to one or more Third Parties in consideration of a [***], in the absence of which ImmunoGen could not practice the Licensed Intellectual Property to [***] or [***] the [***] or [***] of the [***] portion
of any Licensed Product [***] owned or exclusively licensed by such Third Party in any country (collectively, “Third Party Payments”), [***] then ImmunoGen shall have the right to reduce the royalties otherwise due to CytomX
pursuant to Section 4.2.1, 4.2.3(c) or 4.2.3(d) hereof (but not the royalties otherwise due to CytomX pursuant to Section 4.2.3(b) hereof) with respect to Net Sales in such country of such Licensed Products in
such Calendar Quarter by an amount equal to [***] of the amount of such Third Party Payments. [***] For the avoidance of doubt, the Parties agree and acknowledge that this Section 4.2.3(a) shall not apply with respect to royalties
payable by a Party to any Third Party under any agreement in existence as of the Effective Date. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 29 

 (b) Valid Claim Coverage. 

(i) No Patent Coverage. Subject to Section 4.2.3(e) hereof, the royalty rates set forth in Sections 4.2.1,
4.2.3(c) and 4.2.3(d) hereof shall apply, on a country-by-country basis and Licensed Product-by-Licensed Product basis, to Net Sales of Licensed Products only where (A) such Licensed Product (or its manufacture, use, sale, offer
for sale or importation) in such country is Covered by a Valid Claim within the Licensed Patent Rights or (B) such Licensed Product (or any component or intermediate thereof) was manufactured in a country where the manufacture of such Licensed
Product (or such component or intermediate), was, at the time of its manufacture, Covered by a Valid Claim within the Licensed Patent Rights, regardless of the country in which such Licensed Product is sold. Subject to the other terms of this
Agreement (except for Section 4.2.3(a) hereof, which shall not apply), on a country-by-country and Licensed Product-by-Licensed Product basis where and as of and when the royalty rates under Sections 4.2.1, 4.2.3(c) and
4.2.3(d) hereof do not apply as a result of this Section 4.2.3(b)(i), the royalties payable with respect to Net Sales of such Licensed Product sold by ImmunoGen, its Affiliates and its Sublicensees in such country shall be reduced
by [***] of the royalties otherwise owed to CytomX pursuant to Section 4.2.1 or 4.2.3(d) hereof, as applicable, without giving effect to any royalty reduction provided in Section 4.2.3(c) hereof, using the methodology
outlined in Exhibit B attached hereto. The Parties hereby acknowledge and agree that such royalties shall be in consideration of the commercial advantage, know-how and background information gained from the unpatented Licensed Know-How,
including, without limitation, CytomX’s Confidential Information and CytomX Proprietary Materials. 
 (ii) Applicability of Royalty
Rates. For purposes of clarity, (A) if a Licensed Product (or its manufacture, use, sale, offer for sale or importation) is Covered by a Valid Claim in a country within the Territory such that royalties are paid by ImmunoGen pursuant to
Section 4.2.1, 4.2.3(c) or 4.2.3(d) hereof and, prior to the expiration of the Royalty Term for such Licensed Product in such country, the Licensed Product (and its manufacture, use, sale,

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 30 

 
offer for sale or importation) is no longer Covered by a Valid Claim in such country, ImmunoGen shall pay CytomX a royalty at the rate set forth in Section 4.2.1(b)(i) hereof for the
portion of the Royalty Term during which no such Valid Claim Covers such Licensed Product (or its manufacture, use, sale, offer for sale or importation) in such country; and (B) if a Licensed Product (or its manufacture, use, sale, offer for
sale or importation) is not Covered by a Valid Claim in a country within the Territory such that royalties are paid by ImmunoGen pursuant to Section 4.2.1(b)(i) hereof and, prior to the expiration of the Royalty Term for such Licensed
Product in such country, the Licensed Product (or its manufacture, use, sale, offer for sale or importation) becomes Covered by a Valid Claim within the Licensed Patent Rights in such country, ImmunoGen shall pay CytomX a royalty at the rates set
forth in Section 4.2.1, 4.2.3(c) or 4.2.3(d) hereof, as applicable, for that portion of the Royalty Term during which such Valid Claim Covers such Licensed Product (or its manufacture, use, sale, offer for sale or
importation) in such country. 
 (iii) Definition of “Cover”. A Valid Claim within the Licensed Patent Rights
“Covers” the Licensed Product (or its manufacture, use, sale, offer for sale or importation) in a country if, but for the license granted under Section 3.1.1 hereof, the manufacture, use, sale, offer for sale or
importation of the Licensed Product by ImmunoGen or any of its Affiliates or Sublicensees in such country would infringe such Valid Claim; provided, however, that in determining whether a Valid Claim within such Licensed Patent Rights
“Covers” (as defined above) the Licensed Product (or its manufacture, use, sale, offer for sale or importation), (A) any Valid Claim within the Licensed Patent Rights that is jointly owned by ImmunoGen (or any of its
Affiliates) with CytomX (or any of its Affiliates) shall be deemed to be owned solely by CytomX or an Affiliate of CytomX and (B) any Valid Claim contained in [***] within the Licensed Patent Rights that has not been (1) canceled,
withdrawn or abandoned or (2) [***] shall be deemed to have been issued. 
 (c) Loss of Market Exclusivity. Subject to
Section 4.2.3(e) hereof, if, with respect to a Calendar Quarter, ImmunoGen or any of its Affiliates or Sublicensees experiences a Loss of Market Exclusivity for a Licensed Product in any country, then ImmunoGen shall have the right to
reduce the royalties otherwise due to CytomX pursuant to Section 4.2.1 or 4.2.3(d) 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 31 

 
hereof (but not the royalties otherwise due to CytomX under Section 4.2.3(b) hereof) with respect to Net Sales in such country of such Licensed Products in such Calendar Quarter as
described below, in each case using a methodology similar to that outlined in Exhibit B attached hereto. [***] 
 (d) Effect
of Challenge. In further consideration of the grant by CytomX of the license hereunder and except to the extent the following is unenforceable under the Applicable Laws of a particular jurisdiction where a patent application within the Licensed
Patent Rights is pending or a patent within the Licensed Patent Rights is issued, if CytomX, its Affiliates or Sublicensees initiates a Challenge or induces or assists a Third Party in initiating or prosecuting a Challenge (the Licensed Patent
Rights subject to such Challenge being referred to herein as the “Challenged Patent Rights”), then during the period that such Challenge is pending, the royalty rates set forth in Section 4.2.1 hereof shall be increased
by [***] of annual Net Sales (the “Challenge-Related Royalty Increase”) in the country(ies) in which the Challenged Patent Rights were pending or issued (each, a “Challenge Jurisdiction”) commencing on the date of
such initiation or the date ImmunoGen, its Affiliates or Sublicensees first induces or provides assistance to such Third Party, as applicable, but only with respect to Net Sales of Licensed Products in the applicable Challenge Jurisdiction(s). If,
following the final, unappealable conclusion of a Challenge in a Challenge Jurisdiction, there remains one or more Valid Claims within the Challenged Patent Rights that would be infringed by the manufacture, use, sale, offer for sale or importation
then (i) the royalty rates set forth in Section 4.2.1 hereof shall be increased by [***] of annual Net Sales (which shall be in addition to the Challenge-Related Royalty Increase) in the applicable Challenge Jurisdiction, commencing
upon the final, unappealable conclusion of such Challenge and continuing for the remainder of the Royalty Term in the applicable Challenge Jurisdiction, and (ii) ImmunoGen shall reimburse CytomX for its costs and expenses (including, without
limitation, reasonable attorneys’ and experts’ fees and expenses of litigation) incurred in responding to the Challenge. ImmunoGen shall be required to pay such reimbursement within [***] of receiving an invoice therefor from CytomX, which
shall set forth in reasonable detail the basis for the charges for which CytomX is seeking reimbursement. If, following the final, unappealable conclusion of a Challenge in a Challenge Jurisdiction, there remain no Valid Claims within the Challenged
Patent Rights that would be infringed by the manufacture, use, sale, offer for sale or importation of Licensed Products by ImmunoGen or any of its Affiliates or Sublicensees in such Challenge Jurisdiction in the absence of the license granted under
Section 3.1.1 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 32 

 
hereof, then CytomX shall reimburse ImmunoGen for all amounts with respect to the Challenge-Related Royalty Increase actually paid by ImmunoGen to CytomX with respect to the Challenge
Jurisdiction (the “Clawback Amount”) as follows: [***]. 
 (e) Minimum Royalty Rate. Anything contained in this
Agreement to the contrary notwithstanding, none of the reductions to royalties provided in Sections 4.2.3(a), 4.2.3(b) and 4.2.3(c) hereof, shall, individually or in the aggregate, [***] the royalties payable with respect
to Net Sales of any Licensed Product sold by ImmunoGen, its Affiliates and its Sublicensees in any country during the Royalty Term by [***] of the royalties otherwise owed to CytomX pursuant to Section 4.2.1 or 4.2.3(d), as
applicable, without giving effect to any royalty reduction provided in Section 4.2.3(a), 4.2.3(b) or 4.2.3(c) hereof. 

4.3. Reports and Payments. 

4.3.1. Cumulative Royalties. The obligation to pay royalties under Section 4.2 shall be imposed only once with respect to a
single unit of a Licensed Product regardless of how many Valid Claims in Patent Rights included within the Licensed Intellectual Property would, but for this Agreement, be infringed by the use or sale of such Licensed Product in the country in which
such Licensed Product is used or sold. 
 4.3.2. Royalty Statements and Payments. Within [***] after the end of each Calendar Quarter,
ImmunoGen shall deliver to CytomX a report setting forth for such Calendar Quarter the following information, on a Licensed Product-by-Licensed Product basis: (a) the gross sales (if available) and the Net Sales of each Licensed Product
(specifying in reasonable detail the deductions to gross sales used to calculate Net Sales, (b) the basis for any adjustments to the royalty payable for the sale of each Licensed Product, (c) the applicable exchange rate to convert each
country’s currency to U.S. Dollars under Section 4.3.4 hereof and (d) the royalties due hereunder for the sale of each Licensed Product. No such reports shall be due for any Licensed Product before the First Commercial
Sale of such Licensed Product in the Territory. The total royalty due for the sale of Licensed Products during such Calendar Quarter shall be remitted at the time such report is delivered. 

4.3.3. No Set-Off; Taxes and Withholding. All payments made by ImmunoGen to CytomX hereunder shall be made without set-off or
counterclaim and free and clear of any taxes, duties, levies, fees or charges, except withholding taxes, if any. In the event any of the payments made pursuant to this Agreement become 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 33 

 
subject to withholding taxes under the Applicable Law of any jurisdiction, ImmunoGen shall deduct and withhold the amount of such taxes for the account of CytomX, to the extent required by
Applicable Law, such amounts payable to CytomX shall be reduced by the amount of taxes deducted and withheld, and ImmunoGen shall pay the amounts of such taxes to the proper Governmental Authority in a timely manner and promptly transmit to CytomX
an official tax certificate or other evidence of such tax obligations together with proof of payment from the relevant Governmental Authority of all amounts deducted and withheld sufficient to enable CytomX to claim such payment of taxes. Any such
withholding taxes required under Applicable Law to be paid or withheld shall be an expense of, and borne solely by, CytomX. ImmunoGen will provide CytomX with reasonable assistance to enable CytomX to recover such taxes as permitted by Applicable
Law. 
 4.3.4. Currency. All amounts payable and calculations hereunder shall be in United States dollars, and all payments due under
this Agreement shall be made by wire transfer in immediately available funds to an account designated by the Party owed such payment. As applicable, Net Sales and any royalty deductions shall be converted into United States dollars in accordance
with the ImmunoGen Standard Exchange Rate Methodology. 
 4.3.5. Overdue Payments. Subject to the other terms of this Agreement, any
payments hereunder not paid within the applicable time period set forth herein shall bear interest from the due date until paid in full, at a rate per annum equal to the lesser of (a) [***], or (b) the maximum interest rate permitted by
applicable law in regard to such payments, calculated in each case from the date such payment was due through to the date on which payment is actually made; provided, however, that with respect to any disputed payments, no interest shall be due
until such dispute is resolved and the interest that shall be payable thereon shall be based on the finally-resolved amount of such payment, calculated from the original date on which the disputed payment was due through the date on which payment is
actually made. Such payments when made shall be accompanied by all interest so accrued. Such interest and the payment and acceptance thereof shall not negate or waive the right of CytomX to any other remedy, legal or equitable, to which it may be
entitled because of the delinquency of the payment. 
 4.4. Maintenance of Records; Audits. 

4.4.1. Record Keeping. ImmunoGen shall keep, and cause its Affiliates and Sublicensees to keep, accurate books of account and records in
connection with the sale of Licensed Products, in sufficient detail to permit accurate determination 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 34 

 
of all figures necessary for verification of royalties to be paid hereunder. ImmunoGen shall maintain, and cause its Affiliates and Sublicensees to maintain, such records for a period of at least
[***] after the end of the Calendar Year in which they were generated. 
 4.4.2. Audits. Upon [***] prior written notice from CytomX,
ImmunoGen shall permit an independent certified public accounting firm of internationally recognized standing selected by CytomX and reasonably acceptable to ImmunoGen to examine, at CytomX’s sole expense, the relevant books and records of
ImmunoGen, its Affiliates and Sublicensees during the period covered by such examination, as may be reasonably necessary to verify the accuracy of the reports submitted by ImmunoGen in accordance with Section 4.3 hereof and the payment
of royalties hereunder. An examination by CytomX under this Section 4.4.2 shall occur not more than once in any Calendar Year and shall be limited to the pertinent books and records for any Calendar Year ending not more than [***] before
the date of the request. The accounting firm shall be provided access to such books and records at the facilities where such books and records are kept and such examination shall be conducted during normal business hours. ImmunoGen may require the
accounting firm to sign a reasonable and customary non-disclosure agreement before providing the accounting firm access to ImmunoGen’s facilities or records. Upon completion of the audit, the accounting firm shall provide both CytomX and
ImmunoGen a written report disclosing whether the reports submitted by ImmunoGen are correct or incorrect, whether the royalties paid are correct or incorrect and, in each case, the specific details concerning any discrepancies. ImmunoGen and CytomX
shall each have the right to request a further determination by such accounting firm as to matters which such Party disputes within [***] following receipt of such report. The Party initiating a dispute will provide the other Party and the
accounting firm with a reasonably detailed statement of the grounds upon which it disputes any findings in the written report and the accounting firm shall undertake to complete such further determination within [***] after the dispute notice is
provided, which determination shall be limited to the disputed matters and provided to both Parties. The Parties shall use reasonable efforts, through the participation of finance representatives of both Parties, to resolve any dispute arising in
relation to the audit by good faith discussion. The results of any such audit, reflecting the accounting firm’s determination of any disputed matters, shall be binding on both Parties. 

4.4.3. Underpayments/Overpayments. If such accounting firm concludes that additional royalties were due to CytomX, ImmunoGen shall pay
the additional royalties (plus interest thereon at the rate provided in Section 4.3.5 hereof) within [***] of the date ImmunoGen receives such accountant’s written report so 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 35 

 
concluding. If such underpayment exceeds [***] of the royalties that were to be paid [***], ImmunoGen also shall reimburse CytomX for all reasonable charges of such accountants for conducting the
audit. If such accounting firm concludes that ImmunoGen overpaid royalties, CytomX shall repay such amount in full within [***] of the receipt of such accountant’s report, or, at ImmunoGen’s option, it shall be entitled to offset all such
overpayments against any outstanding or future amounts payable to CytomX hereunder until ImmunoGen has received full credit for such overpayments. 

4.4.4. Confidentiality. All financial information that is subject to review under this Section 4.4 shall be deemed to be the
Confidential Information of the audited Party subject to the provisions of Article 6 hereof. 
  

	5.	INTELLECTUAL PROPERTY. 

 5.1. Inventions. 

5.1.1. Ownership. All determinations of inventorship under this Agreement shall be made in accordance with the laws of the United
States. Determinations of ownership of intellectual property hereunder will be made in accordance with inventorship. 
 (a) CytomX Solely
Owned Technology. As between the Parties, CytomX shall be the sole owner of all Licensed Intellectual Property (other than Joint Program Technology and Joint Probody Platform Improvements included therein and any Joint Patent Rights). 

(b) ImmunoGen Solely Owned Technology. As between the Parties, ImmunoGen shall be the sole owner of all ImmunoGen Program Technology
and ImmunoGen Probody Platform Improvements and any Patent Rights claiming such ImmunoGen Program Technology and ImmunoGen Probody Platform Improvements. 

(c) Jointly Owned Technology. All Joint Program Technology and Joint Probody Platform Improvements (including, without limitation, all
Joint Patent Rights) shall be jointly owned by the Parties, with each Party holding an undivided one-half interest therein. Subject to the Parties’ other rights and obligations under this Agreement and any then-outstanding License Agreement,
each Party shall be [***]. 
 5.1.2. Disclosure. ImmunoGen shall, no less than [***] before filing any initial Patent Right disclosing
ImmunoGen Probody Platform Improvements or any Joint Program Technology or Joint Probody Platform Improvements or any other Patent 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 36 

 
Right that contains CytomX’s Confidential Information, provide a copy of such disclosure to CytomX. CytomX shall, no less than [***] before filing any initial Patent Right disclosing Joint
Program Technology or Joint Probody Platform Improvements or any other Patent Right that contains ImmunoGen’s Confidential Information, provide a copy of such disclosure to ImmunoGen. In each case, such disclosures to the other Party shall
include all invention disclosures or other similar documents submitted to such Party by its, or its Affiliates’, employees, agents or independent contractors describing such invention and the proposed inventorship of any new Patent Rights
intended to be filed. The other Party shall promptly raise any issue regarding inventorship of any such Patent Rights, and the Parties agree to determine the correct inventorship of any Patent Rights in accordance with Section 10.10.1
hereof. 
 5.2. Filing, Prosecution and Maintenance of Patent Rights. 

5.2.1. Cooperation. Without limiting any other rights and obligations of the Parties under this Agreement, the Parties shall cooperate
with respect to the timing, scope and filing of patent applications and patent claims relating to any Joint Program Technology to preserve and enhance the patent protection for Licensed Products, including the manufacture and use thereof and to
allow the Party owning the technology underlying an Improvement to have reasonable input to preserve and enhance its patent portfolio and patenting strategy. 

5.2.2. CytomX Patent Rights. CytomX, at its own expense, shall have the sole right, but not the obligation, to prepare, file, prosecute
and maintain, throughout the world, all Licensed Patent Rights (other than Licensed Patent Rights claiming Joint Program Technology or Joint Probody Platform Improvements). With respect to any Licensed Patent Rights disclosing or claiming Program
Technology (other than Probody Platform Improvements included in the Program Technology), CytomX shall keep ImmunoGen reasonably informed of the status of the filing, prosecution and maintenance of such Patent Rights and shall consider in good faith
any recommendations made by ImmunoGen in regard to the filing, prosecution or maintenance of any such Patent Right. CytomX shall consult with ImmunoGen in the filing, prosecution and maintenance of any CytomX Patent Right related to Improvements to
ImmunoGen Technology and shall not unreasonably refuse to incorporate any recommendations made by ImmunoGen in regard to such filing, prosecution or maintenance. To the extent CytomX decides not to file, prosecute or maintain any Licensed Patent
Right that CytomX reasonably believes covers or may cover the Development, Manufacture, Commercialization or use of any Licensed Product (other than any such Patent Right owned or co-owned by a Third Party licensor or the filing of a new initial
patent application) and except in the case in which the decision not to file, 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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prosecute or maintain such Patent Right is made by CytomX in the ordinary course of filing continuation applications or as part of an overall strategy to optimize the scope or other aspects of
the Licensed Intellectual Property, CytomX shall provide ImmunoGen with [***] prior written notice to such effect (i.e., at least [***] prior to the date on which any such filing is intended or due or on which any other such action is due),
in which event ImmunoGen may elect to file or continue prosecution or maintenance of such Patent Right, at ImmunoGen’s expense, and CytomX, upon ImmunoGen’s written request received within such [***] period, shall execute such documents
and perform such acts, at ImmunoGen’s expense, as may be reasonably necessary to permit ImmunoGen to file, prosecute and maintain such Patent Right; provided that ImmunoGen (a) shall keep CytomX reasonably informed of the status of the
filing, prosecution and maintenance of such Patent Rights, (b) shall consider in good faith any recommendations made by CytomX in regard to such filing, prosecution and maintenance of such Patent Right, and (c) shall not unreasonably
refuse to incorporate any recommendations made by CytomX in regard to such filing, prosecution or maintenance. Any such Patent Right that is prosecuted or maintained by ImmunoGen pursuant to this Section 5.2.2 (a) will continue to
be owned by CytomX, and (b) subject to the Parties’ other rights and obligations under this Agreement, may be licensed by CytomX to one or more Third Parties. For avoidance of doubt, “prosecution” as used in this
Section 5.2 includes oppositions, nullity or revocation actions, post-grant reviews and other patent office proceedings involving the referenced Patent Rights. 

5.2.3. ImmunoGen Patent Rights. ImmunoGen, at its own expense, shall have the sole right, but not the obligation, to prepare, file,
prosecute and maintain, throughout the world, any Patent Rights comprised in the ImmunoGen Probody Platform Improvements. ImmunoGen shall consult with CytomX in the filing, prosecution and maintenance of any Patent Right related to ImmunoGen Probody
Platform Improvements (including, without limitation, keeping CytomX reasonably informed of the status thereof), shall consider in good faith any recommendations made by CytomX in regard to such filing, prosecution or maintenance, and shall not
unreasonably refuse to incorporate any recommendations made by CytomX in regard to such filing, prosecution or maintenance. Nothing contained in this Agreement shall be construed as obligating ImmunoGen to file any patent application in any country
or other jurisdiction relating to ImmunoGen Probody Platform Improvements. 
 5.2.4. Joint Patent Rights. If not already established
under the Research Collaboration Agreement, prior to either Party filing any Patent Right disclosing Joint Program Technology or Joint Probody Platform Improvements, the Parties shall establish a patent committee (the “Patent
Committee”) comprised of at 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 38 

 
least one (1) representative of each Party for the purpose of facilitating the preparation, filing, prosecution, maintenance and defense of Joint Patent Rights. As agreed upon by the
Parties, meetings of the Patent Committee may be face-to-face or may be conducted by teleconferences or videoconferences, from time to time as needed. The Patent Committee will be the forum through which the Parties coordinate their respective
obligations to each other described in Sections 5.2.2 and 5.2.3 hereof and in this Section. In the event the Parties conceive or generate any Joint Program Technology or Joint Probody Platform Improvements, the Parties shall promptly
meet to discuss and determine, based on mutual consent, whether to seek patent protection thereon, which Party will control filing, prosecution and maintenance of such patents and how to pay for the filing, prosecution and maintenance of such
patents. It is presumed that ImmunoGen will control filing, prosecution and maintenance of Joint Patent Rights claiming Joint Program Technology or Joint Conjugation Probody Platform Improvements, and that CytomX will control filing, prosecution and
maintenance of Joint Patent Rights claiming Joint Unconjugated Probody Platform Improvements. Neither Party will file any Joint Patent Right without the prior written consent of the other Party, which consent shall not be unreasonably withheld,
conditioned or delayed. The Party controlling filing and prosecution of any such Joint Patent Right (a) shall keep the other Party informed regarding each Patent Right, (b) shall consider in good faith any recommendations made by the other
Party in regard to the filing, prosecution or maintenance of any such Patent Right and (c) shall not unreasonably refuse to incorporate any recommendations made by the other Party in regard to such filing, prosecution or maintenance. 

5.2.5. Improper Patent Filings. Each Party agrees that, without the prior written consent of the other Party, neither it nor any
of its Affiliates will [***]. 
 5.2.6. Liability. Except for breaches of Section 5.2.5 hereof, to the extent that a Party
is obtaining, prosecuting or maintaining a Patent Right included in the Licensed Intellectual Property or Joint Patent Rights or otherwise exercising its rights under this Section 5.2, such Party, and its Affiliates, employees, agents or
representatives, shall not be liable to the other Party in respect of any act or omission on the part of any such Party, or its Affiliates, employees, agents or representatives, in connection with such activities undertaken in good faith. 

5.2.7. Extensions. The decision to file for a patent term extension and particulars thereof (including which patent(s) to extend)
will be made with the goal of obtaining the optimal patent term and scope of protection for Licensed Products. If a Party wishes to file for a patent term extension based on Patent Rights owned by the other Party, it will so notify the other Party,
and the Parties will meet to discuss and determine whether and how to proceed with such patent term extension. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 39 

 5.3. Joint Research Agreement. This Agreement shall be understood to be a joint
research agreement under 35 U.S.C. § 103(c)(3) entered into for the purpose of Developing Licensed Products. 
 5.4.
Enforcement of Patent Rights.  
 5.4.1. Notice. If either CytomX or ImmunoGen becomes aware of any infringement
anywhere in the world of any issued Patent Right within the Licensed Intellectual Property or Joint Patent Rights by any Third Party (an “Infringement”), such Party shall promptly notify the other Party in writing to that effect.

 5.4.2. Infringement of Certain Patent Rights. 

(a) In the event of any Infringement of a Patent Right included in the Licensed Intellectual Property (including, without limitation, Joint
Patent Rights included in the Joint Unconjugated Probody Platform Improvements but excluding Joint Patent Rights included in the Joint Program Technology (other than Joint Unconjugated Probody Platform Improvements)), CytomX shall have the first
right to take action to obtain a discontinuance of Infringement or bring suit against a Third Party infringer of such Patent Right within [***] from the date of notice. 

(b) CytomX shall bear all the expenses of any suit brought by it claiming infringement of any such Patent Right. ImmunoGen shall reasonably
cooperate with CytomX in any such suit and shall have the right to consult with CytomX and to participate in and be represented by independent counsel in such litigation at its own expense. CytomX shall incur no liability to ImmunoGen as a
consequence of such litigation or any unfavorable decision resulting therefrom, including any decision holding any such Patent Right invalid or unenforceable, and CytomX shall not, without ImmunoGen’s prior written consent (which consent shall
not be unreasonably withheld, conditioned or delayed), enter into any settlement or consent decree that admits the invalidity or unenforceability or limits the scope of any such Patent Right. 

(c) If CytomX has not obtained a discontinuance of such Infringement by, or filed suit against, any such Third Party infringer within the
[***] period set forth in subsection (a) above, then ImmunoGen shall have the right, but not the obligation, to bring suit against such Third Party 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 40 

 
infringer, at ImmunoGen’s sole expense, under any Licensed Intellectual Property. CytomX shall reasonably cooperate with ImmunoGen in any such litigation, including being joined as a party,
at ImmunoGen’s expense, provided that CytomX may, at its sole discretion, elect to be represented by independent counsel in such litigation at its own expense. ImmunoGen shall incur no liability to CytomX as a consequence of such litigation or
any unfavorable decision resulting therefrom, including any decision holding any such CytomX Patent Right invalid or unenforceable; and ImmunoGen shall not, without CytomX’s prior written consent (which CytomX may withhold in its sole
discretion), enter into any settlement or consent decree that requires any payment by or admits or imparts any other liability to CytomX or admits the invalidity or unenforceability or limits the scope of any such Patent Right. 

(d) In the event of any Infringement of a Joint Patent Right included in the Joint Program Technology (other than Joint Unconjugated Probody
Platform Improvements), ImmunoGen shall have the first right to take action to obtain a discontinuance of Infringement or bring suit against a Third Party infringer of such Patent Right within [***] from the date of notice. 

(e) ImmunoGen shall bear all the expenses of any suit brought by it claiming infringement of any such Patent Right. CytomX shall reasonably
cooperate with ImmunoGen in any such suit and shall have the right to consult with ImmunoGen and to participate in and be represented by independent counsel in such litigation at its own expense. ImmunoGen shall incur no liability to CytomX as a
consequence of such litigation or any unfavorable decision resulting therefrom, including any decision holding any such Patent Right invalid or unenforceable, and ImmunoGen shall not, without CytomX’s prior written consent, enter into any
settlement or consent decree that admits the invalidity or unenforceability or limits the scope of any such Patent Right. 
 (f) If
ImmunoGen has not obtained a discontinuance of such Infringement by, or filed suit against, any such Third Party infringer within the [***] period set forth in subsection (d) above, then CytomX shall have the right, but not the obligation, to
bring suit against such Third Party infringer, at CytomX’s sole expense, under any ImmunoGen Probody Platform Improvements. ImmunoGen shall reasonably cooperate with CytomX in any such litigation, including being joined as a party, at
CytomX’s expense, provided that ImmunoGen may, at its sole discretion, elect to be represented by independent counsel in such litigation at its own 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 41 

 
expense. CytomX shall incur no liability to ImmunoGen as a consequence of such litigation or any unfavorable decision resulting therefrom, including any decision holding any such ImmunoGen Patent
Right invalid or unenforceable; and CytomX shall not, without ImmunoGen’s prior written consent (which ImmunoGen may withhold in its sole discretion), enter into any settlement or consent decree that requires any payment by or admits or imparts
any other liability to ImmunoGen or admits the invalidity or unenforceability or limits the scope of any such Patent Right 
 (g) The
enforcing Party shall keep the other Party reasonably informed of all material developments in connection with any such suit. Any recoveries obtained by either Party as a result of any proceeding against such a Third Party infringer
(“Monies”) shall be allocated as follows: 
 (i) the Monies will be distributed first to the controlling Party for its
out-of-pocket litigation costs and expenses incurred in connection with such litigation; then 
 (ii) the Monies will then be distributed to
the other Party for its out-of-pocket litigation costs and expenses incurred in connection with such litigation; then 
 (iii) [***]; or

 (iv) [***]; or 
 (v) [***];
then 
 (vi) [***]; or 
 (vii)
[***]. 
 (h) Other Infringement. For any infringement of Patent Rights owned by ImmunoGen or licensed by ImmunoGen from Third
Parties, ImmunoGen retains the sole right (as between the Parties), but not the obligation, to enforce such Patent Rights. 
 (i)
Infringement of Joint Patent Rights. With respect to any notice of a Third Party infringer of any Joint Patent Right other than a Patent Right included in the Joint Program Technology or Joint Probody Platform Improvements, the Parties shall
meet as soon as reasonably practicable to discuss such infringement and determine an appropriate course of action and the Parties’ respective rights and responsibilities with respect to any enforcement thereof. 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 5.5. Response to Biosimilar Applicants. 

5.5.1. Notice. In the event that ImmunoGen (a) receives a copy of a Biosimilar Application, whether or not such copy is provided
under any Applicable Laws (including the BPCIA, the United States Patient Protection and Affordable Care Act, implementing FDA regulations and guidance or similar foreign laws or regulations) applicable to the approval or manufacture of any
biosimilar or interchangeable biological product (a “Proposed Biosimilar Product”) for which a Licensed Product is a “reference product,” as such term is used in the BPCIA, or (b) otherwise becomes aware that such a
Biosimilar Application has been filed (such as in an instance described in Section 351(l)(9)(C) of the PHSA), then ImmunoGen shall promptly provide CytomX with written notice. 

5.5.2. Access to Confidential Information. Upon written request from CytomX and to the extent permitted by Applicable Laws, ImmunoGen
shall provide CytomX with confidential access to those portions of the Biosimilar Application and such other information provided to ImmunoGen by the Third Party that submitted the Biosimilar Application (the “Applicant”) that
describe the Linker and Payload of the Proposed Biosimilar Product or the method(s) of conjugating the cell-binding moiety of the Proposed Biosimilar Product to its Payload; provided, however, that prior to receiving the Biosimilar Application and
such confidential information, CytomX shall provide notice to ImmunoGen and the Applicant confirming its agreement to be subject to the confidentiality provisions in Section 351(l)(1)(B)(iii) of the PHSA. For purposes of clarity, the Parties
acknowledge and agree that CytomX has retained a right to assert any patent within the Licensed Patent Rights and participate in litigation concerning any such patent. 

5.5.3. Proposed Patent List. 

(a) Preparation of Proposed Patent List. Not later than [***] days from the date of receipt by ImmunoGen of a copy of a Biosimilar
Application and related manufacturing information, ImmunoGen, with cooperation from CytomX, shall prepare and provide CytomX with a list (the “Proposed Patent List”) of (i) those patents within the Licensed Patent Rights that
ImmunoGen reasonably believes would be infringed by the manufacture and/or sale of the Proposed Biosimilar Product and (ii) those patents within the Licensed Patent Rights, if any, that ImmunoGen would be willing to sublicense to such Applicant
in accordance with the terms of 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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this Agreement. As soon as practicable following the date of receipt by CytomX of the Proposed Patent List, CytomX and ImmunoGen shall discuss in good faith the patents within the Licensed Patent
Rights to be included on the Proposed Patent List and ImmunoGen shall consider in good faith CytomX’s proposals for changes to the Proposed Patent List with respect to the patents within the Licensed Patent Rights. Not later than the end of the
period specified by Applicable Laws, ImmunoGen shall provide the Applicant with a copy of the Proposed Patent List; provided, however, that ImmunoGen shall incorporate certain CytomX requests in accordance with Section 5.5.3(d) hereof.
Notwithstanding the enforcement rights with respect to the Licensed Patent Rights set forth in Section 5.2.2 hereof, ImmunoGen shall have the right to include any of the patents within the Licensed Patent Rights on the Proposed Patent
List to the extent that ImmunoGen reasonably believes that a claim of patent infringement for such patent could be asserted by either CytomX or ImmunoGen; provided, however, that the right to control any suit or proceeding in which such a claim is
asserted shall be as set forth in Section 5.5.4 hereof. 
 (b) Disclosure of Applicant’s Response. Provided that
CytomX has agreed to comply with the confidentiality provisions in Section 351(l)(1)(B)(iii) of the PHSA and to the extent permitted by Applicable Laws, ImmunoGen shall provide to CytomX the portion of the Applicant Response (as defined below)
pertaining to the Licensed Patent Rights no later than [***] days from the date of receipt by ImmunoGen of a response from the Applicant with regard to any patent within the Licensed Patent Rights included on the Proposed Patent List, including
any response required by the BPCIA (the “Applicant Response”). 
 (c) Preparation of ImmunoGen Response. Not later
than [***] days from the date of receipt by ImmunoGen of the Applicant Response, ImmunoGen, with cooperation and assistance from CytomX, shall prepare and provide CytomX with a proposed response with respect to the Licensed Patent Rights (the
“ImmunoGen Response”) that (i) describes on a claim-by-claim basis, how each patent within the Licensed Patent Rights on the Proposed Patent List would be infringed by the commercial marketing of the Proposed Biosimilar
Product, and (ii) responds to Applicant’s claims, if any, that the patents within the Licensed Patent Rights on the Proposed Patent List are invalid or unenforceable. The ImmunoGen Response shall include only the foregoing and shall not be
construed to include any proposed response to the Applicant relating to any patents other than the Licensed Patent Rights; further, any actual 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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response to the Applicant under the BPCIA and all decisions relating to subsequent procedures under the BPCIA with regard to any patent other than those included within the Licensed Patent Rights
shall be within the sole discretion of ImmunoGen. As soon as practicable following the date of receipt by CytomX of the proposed ImmunoGen Response, the Parties shall discuss in good faith the statements in the proposed ImmunoGen Response and
ImmunoGen shall consider in good faith CytomX’s proposals for changes to the ImmunoGen Response. Not later than the end of the period specified by Applicable Laws, ImmunoGen shall provide the Applicant with a copy of the ImmunoGen Response;
provided, however, that ImmunoGen shall incorporate certain CytomX requests in accordance with Section 5.5.3(d) hereof. 
 (d)
Inclusion of Licensed Patent Rights or Responsive Information. Provided that ImmunoGen is legally able under Applicable Law to provide CytomX with a copy of the Biosimilar Application (and related manufacturing agreement) and CytomX has
provided notice to ImmunoGen and Applicant confirming its agreement to be subject to the confidentiality provisions of Section 351(l)(1)(B)(iii) of the PHSA, if CytomX requests in writing to either (i) include a patent in the Proposed
Patent List that was not included in ImmunoGen’s initial Proposed Patent List provided to CytomX by ImmunoGen pursuant to Section 5.5.3(a) hereof or (ii) include responsive information with respect to any patent within the
Licensed Patent Rights in the ImmunoGen Response that was not included in ImmunoGen’s initial ImmunoGen Response provided to CytomX pursuant to Section5.5.3(c) hereof, then, absent manifest error, ImmunoGen shall include such patent in
the Proposed Patent List and such responsive information in the ImmunoGen Response provided to Applicant, as applicable; provided, however, that CytomX shall indemnify ImmunoGen in accordance with Section 9.2 hereof to the extent any
submissions requested by CytomX are determined to have been made negligently or in bad faith. 
 (e) Negotiation; CytomX Rights. As
soon as possible following the date on which ImmunoGen provides the ImmunoGen Response to the Applicant, ImmunoGen shall commence good faith negotiations with Applicant for a period of not more than [***] days (the “Negotiation
Period”) in an effort to reach agreement on the patents on the Proposed Patent List (the “Infringed Patent List”) that will be the subject to an Immediate Patent Infringement Action; provided, however, that if the Proposed
Patent List includes both patents within the Licensed Patent Rights and patents that are not within the Licensed Patent Rights, then 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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ImmunoGen shall not agree to the inclusion in the Infringed Patent List of any patents within the Licensed Patent Rights without the prior written consent of CytomX, which consent shall not be
unreasonably withheld, conditioned or delayed. If ImmunoGen and Applicant fail to reach agreement under Section 351(l)(4)(A) of the PHSA on the Infringed Patent List, ImmunoGen shall have the sole right to determine under
Section 351(l)(5)(B) of the PHSA which patents of those on the Proposed Patent List should be the subject of an Immediate Patent Infringement Action; provided, however, that if the Proposed Patent List [***], then ImmunoGen shall [***]. Within
[***] days following the exchange of such lists by ImmunoGen and the Applicant, ImmunoGen shall, to the extent legally permissible, provide CytomX with a copy of the portion of the combined Infringed Patent List containing patents within the
Licensed Patent Rights that will be the subject of an Immediate Patent Infringement Action. 
 (f) Supplements to Proposed Patent
List. CytomX shall provide ImmunoGen with a copy of any U.S. patent within the Licensed Patent Rights that is issued after ImmunoGen has provided the Proposed Patent List to the Applicant within [***] day after such issuance. As soon
as practicable following the date of receipt by ImmunoGen of any such patent, CytomX and ImmunoGen shall discuss in good faith whether such patent would be infringed by the manufacture and/or sale of the Proposed Biosimilar Product. ImmunoGen shall
provide the Applicant with a supplement to the Proposed Patent List to include such patent not later than [***] days after the issuance of such patent if ImmunoGen reasonably believes that a claim of patent infringement for such patent could be
asserted by either CytomX or ImmunoGen or if CytomX, absent manifest error, requests that ImmunoGen supplement the Proposed Patent List to include such patent provided, however, that CytomX shall indemnify ImmunoGen in accordance with
Section 9.2 hereof to the extent any supplement submissions requested by CytomX are determined to have been made negligently or in bad faith. 

5.5.4. Claims, Suits and Proceedings. 

(a) Immediate Patent Infringement Action. With respect to any patents within the Licensed Patent Rights or any Patent Rights claiming
ImmunoGen Probody Platform Improvements, Joint Program Technology or Joint Probody Platform Improvements that are to be the subject of an Immediate Patent Infringement Action, the Parties’ respective rights and obligations with respect to the
litigation of such patents (including rights 

  
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 46 

 
to initiate, step in, participate in, settle and share amounts recovered pursuant to such Immediate Patent Infringement Action, and obligations to pay legal costs and expenses with respect to
such Immediate Patent Infringement Action) shall be as set forth in Section 5.4.2 hereof, except that the Party having the first right to file a claim for Infringement against the Applicant with respect to any such patent subject to an
Immediate Patent Infringement Action shall file such claim within [***] days after agreement is reached as to the Infringed Patent List under Section 351(l)(4) or the exchange of the lists under Section 351(l)(5)(B) of the PHSA, as
applicable. 
 (b) Pre-Marketing Litigation. Either Party shall, within [***] days of receiving any notice of commercial
marketing provided by the Applicant pursuant to Section 351(l)(8)(A) of the PHSA (the “Premarket Notice”), notify the other Party. Thereafter, the Parties’ respective rights and obligations with respect to any litigation
pursuant to Section 351(l)(8)(B) of the PHSA (including rights to initiate, step in, participate in, settle and share amounts recovered pursuant to such action, and obligations to pay legal costs and expenses with respect to such action) shall
be as set forth in Section 5.4.2 hereof. 
 (c) Cooperation; Standing. If a Party with the right to initiate legal
proceedings under this Section 5.5.4 lacks standing to do so (or lacks the right under the BPCIA to do so) and the other Party has standing (or the sole right under the BPCIA) to initiate such legal proceedings, such Party with standing
shall initiate such legal proceedings at the request and expense of the other Party. 
 5.5.5. Invalidity or Unenforceability Defenses or
Actions. In the event that the Applicant asserts, as a defense or as a counterclaim in any infringement action under Section 5.5.4 hereof, that any of the Licensed Patent Rights or any Patent Rights claiming ImmunoGen Probody
Platform Improvements, Joint Program Technology or Joint Probody Platform Improvements is invalid or unenforceable, then the Parties’ respective rights and obligations with respect to the response to such defense or the defense against such
counterclaim, as applicable, (including rights to initiate, step in, participate in, settle and share amounts recovered pursuant to such action, and obligations to pay legal costs and expenses with respect to such action) shall be as set forth in
Section 5.4.2 hereof; provided that for these purposes any such defense or counterclaim shall be deemed to be an Infringement. In all other cases, including any declaratory judgment action or similar action or claim filed by an Applicant
asserting that any of the Licensed Patent Rights or any Patent Rights claiming ImmunoGen Probody Platform 

  
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Improvements, Joint Program Technology or Joint Probody Platform Improvements is invalid or unenforceable (as in a declaratory judgment action brought by the Applicant following the Premarket
Notice), then the Parties’ respective rights and obligations with respect to such action (including rights to initiate, step in, participate in, settle and share amounts recovered pursuant to such action, and obligations to pay legal costs and
expenses with respect to such action) shall be as set forth in Section 5.4.2 hereof; provided that for these purposes any such case shall be deemed to be an Infringement. 

5.5.6. Changes in Applicable Law. The Parties have agreed to the provisions of this Section 5.5 on the basis of the BPCIA
and other applicable laws and regulations in effect as of the Effective Date. If there are any material changes to the BPCIA or other Applicable Laws that would affect these provisions, the Parties will discuss amendments to this
Section 5.5 in good faith. 
 5.6. Interference, Opposition, Revocation and Declaratory Judgment Actions. If the
Parties mutually determine that, based upon the review of a Third Party’s patent or patent application or other intellectual property rights, it may be desirable in connection with any Licensed Product to provoke or institute an interference,
opposition, revocation, post-grant review or other patent office proceedings or declaratory judgment action with respect thereto, then the Parties shall consult with one another and shall reasonably cooperate in connection with such an action. Each
Party shall retain all rights to control any actions initiated prior to the Effective Date. 
 5.7. Infringement of Third Party Patent
Rights. If the Development, Manufacture, use or Commercialization of any Licensed Product is alleged by a Third Party to infringe a Third Party’s patent or other intellectual property rights, the Party becoming aware of such
allegation shall promptly notify the other Party. ImmunoGen shall have the right to take such action as it deems appropriate in response to such allegation, and shall be solely responsible for all damages, costs and expenses in connection therewith,
subject to Article 9 hereof. 
  

	6.	CONFIDENTIALITY 

 6.1. Confidentiality. Except to the extent expressly
authorized by this Agreement, the Parties agree that, during the Term and for [***] thereafter, each Party, in its capacity as the Receiving Party shall: (a) keep the Disclosing Party’s Confidential Information confidential; (b) not
disclose, or permit the disclosure of, the Disclosing Party’s Confidential Information; and (c) not use, or permit to be used, the Disclosing Party’s Confidential Information for any purpose, in each case, except for the performance
of its obligations or exercise of its rights under this Agreement, provided, however, that the foregoing obligations shall not apply, or shall cease to apply, to the extent that such 

  
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Confidential Information (i) was already known by the Receiving Party or its Affiliates (other than under an obligation of confidentiality to the Disclosing Party) at the time of disclosure
by the Disclosing Party; (ii) was generally available to the public or otherwise part of the public domain at the time of its disclosure to the Receiving Party; (iii) became generally available to the public or otherwise part of the public
domain after its disclosure to the Receiving Party, other than through any act or omission of the Receiving Party or its Affiliates or any of their respective Representatives in breach of its obligations under this Agreement; (iv) was disclosed
to the Receiving Party or its Affiliates, other than under an obligation of confidentiality, by a Third Party who had no obligation to the Disclosing Party not to disclose such information to the Receiving Party ; or (v) was independently
discovered or developed by or on behalf of the Receiving Party without the use of any Confidential Information of the Disclosing Party. 

6.2. Authorized Disclosure.  

6.2.1. Disclosure to Party Representatives. Notwithstanding the foregoing provisions of Section 6.1 hereof, the Receiving
Party may disclose Confidential Information belonging to the Disclosing Party to the Receiving Party’s Representatives who (a) have a need to know such Confidential Information in connection with the performance of the Receiving
Party’s obligations or the exercise of the Receiving Party’s rights under this Agreement and (b) have agreed in writing to non-disclosure and non-use provisions with respect to such Confidential Information that are at least as
restrictive as those set forth in this Article 6. 
 6.2.2. Disclosure to Third Parties. 

(a) Notwithstanding the foregoing provisions of Section 6.1 hereof, the Parties may disclose Confidential Information belonging to
the other Party: 
 (i) to Governmental Authorities to the extent reasonably necessary to obtain or maintain INDs or Regulatory Approvals
for any Licensed Product and in order to respond to inquiries, requests, investigations, orders or subpoenas of Governmental Authorities relating to this Agreement; 

(ii) to outside consultants, contractors, advisory boards, managed care organizations, and non-clinical and clinical investigators, in each
case to the extent reasonably necessary to Develop, Manufacture, use or Commercialize any Licensed Product under reasonable obligations of confidentiality; 

  
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 (iii) subject to Section 5.2 hereof, to the extent reasonably necessary, in
connection with filing or prosecuting Patent Rights as permitted by this Agreement; 
 (iv) to the extent reasonably necessary, in
connection with prosecuting or defending litigation as permitted by this Agreement; 
 (v) regarding the existence of this Agreement, this
Agreement itself or the material and financial terms of this Agreement, (A) to its accountants, lawyers, and other advisers, and (B) to actual or potential investors, lenders, licensors, licensees, acquirers, investment bankers, or agents
of the foregoing in connection with a financing, licensing transaction, merger, or acquisition, in each case (A)-(B) under confidentiality obligations no less restrictive than those set forth in this Agreement, provided that CytomX shall not
disclose the identity of the Licensed Target under clause (B) without the prior written consent of ImmunoGen; 
 (vi) subject to
Section 6.3.2 hereof, in connection with or included in scientific presentations and publications relating to Licensed Products, including abstracts, posters, journal articles and the like, and posting results of and other information
about clinical trials to clinicaltrials.gov or PhRMA websites; and 
 (vii) to the extent necessary in order to enforce its rights under
this Agreement. 
 (b) In the event a Party deems it reasonably necessary to disclose Confidential Information belonging to the other Party
pursuant to Section 6.2.2(a)(i) hereof, the Disclosing Party shall to the extent possible give reasonable advance written notice of such disclosure to the other Party and take all reasonable measures to ensure confidential treatment of
such information. 
 (c) Data generated by ImmunoGen using Licensed Products shall not be considered Confidential Information of CytomX,
and, therefore, not subject to this Article 6. 
 6.2.3. SEC Filings and Other Disclosures. Notwithstanding any
provision of this Agreement to the contrary, either Party may disclose the existence or terms of this Agreement to the extent required, in the reasonable opinion of such Party’s legal counsel, to comply with Applicable Law. Notwithstanding the
foregoing, before disclosing this Agreement or any of the terms hereof pursuant to this 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 50 

 
Section 6.2.3, the Parties will consult with one another on the terms of this Agreement to be redacted in making any such disclosure. Further, if a Party discloses this Agreement or
any of the terms hereof in accordance with this Section 6.2.3, such Party shall, at its own expense, use Commercially Reasonable Efforts to seek such confidential treatment of confidential portions of this Agreement and such other terms,
as may be reasonably requested by the other Party. 
 6.3. Public Announcements; Publications. 

6.3.1. Announcements. Except as may be expressly permitted under Section 6.2.3, neither Party will make any public
announcement regarding the existence or terms of this Agreement without the prior written approval of the other Party. For the sake of clarity, nothing in this Agreement shall prevent either Party from making any public disclosure relating to this
Agreement if the contents of such public disclosure have previously been made public other than through a breach of this Agreement by the issuing Party or its Affiliates. The Parties shall mutually agree to one or more press releases regarding the
signing of this Agreement following the Effective Date. The Parties agree that each Party may issue future announcements concerning ImmunoGen’s achievement of any significant milestones, including the selection of a clinical candidate, under
this Agreement, provided that the content of any such announcement has been mutually agreed upon by the Parties. 
 6.3.2.
Publications. The Parties acknowledge that scientific publications and presentations must be strictly monitored to prevent any adverse effect from premature publication or dissemination of results of the activities hereunder. Each Party (in
such capacity the “Publishing Party”) agrees that, except as required by Applicable Laws, it shall not publish or present, or permit to be published or presented, any results of the Development, Manufacture, use or Commercialization
of a Licensed Product to the extent such results refer to, derive from or otherwise relate to the Licensed Intellectual Property (the “Covered Results”), without the prior review by and approval of the other Party (in such capacity,
the “Non-Disclosing Party”), which approval shall not be unreasonably withheld; provided that it shall not be deemed unreasonable for ImmunoGen to withhold its consent to any request by CytomX
to publish or disseminate Covered Results prior to the publication or dissemination of such Covered Results by ImmunoGen. The Publishing Party shall submit to the Non-Disclosing Party for review and approval
any proposed academic, scientific and medical publication or public presentation which contains Covered Results or otherwise contains the Non-Disclosing Party’s Confidential Information; provided that the foregoing requirement shall apply to
ImmunoGen only to the extent any such proposed 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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publication or presentation would refer to, describe or otherwise disclose Confidential Information of CytomX (including, without limitation, any non-public Licensed Intellectual Property). In
addition, each Party shall submit to the other Party for review and approval any proposed publication or public presentation relating to data generated under the Research Program. In both instances, such review and approval will be conducted for the
purposes of preserving the value of the Licensed Intellectual Property and determining whether any portion of the proposed publication or presentation containing the Non-Disclosing Party’s Confidential Information should be modified or deleted.
Written copies of such proposed publication or presentation required to be submitted hereunder shall be submitted to the Non-Disclosing Party no later than [***] before submission for publication or presentation (the “Review
Period”). The Non-Disclosing Party shall provide its comments with respect to such publications and presentations within [***] after its receipt of such written copy, and the Publishing Party shall delete any Confidential Information of the
Non-Disclosing Party upon request. The Review Period may be extended for an additional [***] in the event the Non-Disclosing Party can, within [***] of receipt of the written copy, demonstrate reasonable need for such extension, including for the
preparation and filing of patent applications. The Parties will each comply with standard academic practice regarding authorship of scientific publications and recognition of contribution of other parties in any publication governed by this
Section 6.3.2. 
 6.3.3. Integration. As to the subject matter of this Agreement, this Article 6 supersedes
any confidential disclosure agreements between the Parties, including, without limitation, the Confidentiality Agreement and the confidentiality provisions of the Research Collaboration Agreement. Any confidential information of a Party disclosed
under the Confidentiality Agreement or the Research Collaboration Agreement relating to the subject matter of this Agreement shall be treated as Confidential Information of such Party hereunder, subject to the terms of this Article 6.

  

	7.	REPRESENTATIONS AND WARRANTIES. 

 7.1. Mutual Representations and Warranties. Each
of CytomX and ImmunoGen hereby represents and warrants to the other that: 
 7.1.1. it is duly organized, validly existing and in good
standing under the laws of the jurisdiction of its organization; 
 7.1.2. the execution, delivery and performance of this Agreement by such
Party has been duly authorized by all requisite action under the provisions of its charter, 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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bylaws and other organizational documents, and does not require any action or approval by any of its shareholders or other holders of its voting securities or voting interests; 

7.1.3. it has the power and authority to execute and deliver this Agreement and to perform its obligations hereunder; 

7.1.4. this Agreement has been duly executed and is a legal, valid and Binding Obligation on it, enforceable against it in accordance with its
terms; and 
 7.1.5. the execution, delivery and performance by such Party of this Agreement and its compliance with the terms and provisions
hereof does not and will not conflict with or result in a breach of or default under any Binding Obligation existing as of the Effective Date. 

7.2. Representations and Warranties of CytomX. Except as set forth in a written disclosure letter (the “Disclosure
Letter”) delivered by CytomX to ImmunoGen within [***] days after the Effective Date (which shall be deemed Confidential Information of CytomX), CytomX hereby represents and warrants to ImmunoGen that as of the Effective Date: 

7.2.1. to its Knowledge, (a) the issued and unexpired patents within the Licensed Intellectual Property are valid and enforceable patents
and (b) CytomX has received no written notice from a Third Party challenging or threatening to challenge the extent, validity or enforceability of any Licensed Patent Rights; 

7.2.2. to its Knowledge, CytomX has received no written notice from a Third Party claiming that the use, practice or application of the
Licensed Intellectual Property pursuant to the license granted hereunder to ImmunoGen will infringe the issued patents of any such Third Party (excluding, for clarity, any potential infringement that might arise solely as a result of the combination
of any Licensed Intellectual Property with any other technology or intellectual property); and 
 7.2.3. there is no (a) claim, demand,
suit, proceeding, arbitration, inquiry, investigation or other legal action of any nature, civil, criminal, regulatory or otherwise, pending or, to its Knowledge, threatened against CytomX or any of its Affiliates or (b) judgment or settlement
against or owed by CytomX or any of its Affiliates, in each case in connection with the Licensed Intellectual Property or relating to the transactions contemplated by this Agreement 

For purposes of this Section 7.2, “Knowledge” means the actual knowledge (without having conducted, or having any
duty to conduct, any specific inquiry) of its Chief Executive Officer, President, any Vice President or other officer who is in charge of a principal business unit or function or who performs a policy-making function, and its Senior Director, Head
of Intellectual Property (or person with similar responsibilities). 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 7.3. Government Approvals. Each of CytomX and ImmunoGen shall cooperate with the other
Party and use Commercially Reasonable Efforts to make all registrations, filings and applications, to give all notices and to obtain as soon as practicable all governmental or other consents, transfers, approvals, orders, qualifications
authorizations, permits and waivers, if any, and to do all other things necessary or desirable for the consummation of the transactions as contemplated hereby. 

7.4. Further Covenants. In addition to the covenants made elsewhere in this Agreement, CytomX hereby covenants to ImmunoGen that, from
the Effective Date until expiration or termination of this Agreement, it will not (a) knowingly take any action that conflicts with the rights under the Licensed Intellectual Property granted to ImmunoGen under this Agreement or
(b) knowingly fail to take any action that is reasonably necessary to avoid a conflict with the rights under the Licensed Intellectual Property granted to ImmunoGen under this Agreement. 

7.5. Representation by Legal Counsel. Each Party hereto represents that it has been represented by legal counsel in connection with this
Agreement and acknowledges that it has participated in the drafting hereof. In interpreting and applying the terms and provisions of this Agreement, the Parties agree that no presumption shall exist or be implied against the Party which drafted such
terms and provisions. 
 7.6. Warranty Disclaimers. 

7.6.1. Except as expressly set forth in Section 7.1 or 7.2 hereof, nothing in this Agreement is or shall be construed as a
warranty or representation by CytomX (a) as to the validity or scope of any patent application or patent within the Licensed Patent Rights or (b) that anything made, used, sold or otherwise disposed of under any license granted under this
Agreement is or will be free from infringement of patents, copyrights and other rights of Third Parties. 
 7.6.2. EXCEPT AS OTHERWISE
EXPRESSLY PROVIDED IN THIS AGREEMENT, NEITHER PARTY MAKES ANY REPRESENTATION OR EXTENDS ANY WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REPECT TO ANY TECHNOLOGY, GOODS, SERVICES, RIGHTS OR OTHER SUBJECT MATTER OF THIS AGREEMENT, INCLUDING,
WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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	8.	TERM AND TERMINATION. 

 8.1. Term. The term of this Agreement (the
“Term”) shall commence on the Effective Date and shall extend, unless this Agreement is terminated earlier in accordance with this Article 8, on a Licensed Product-by-Licensed Product and country-by-country basis, until
such time as the Royalty Term with respect to the sale of such Licensed Product in such country expires. Provided this Agreement has not been terminated prior thereto by CytomX under Section 8.3, 8.4 or 8.5 hereof or by
ImmunoGen under Section 8.2 or 8.4 hereof, following the expiration of the Royalty Term applicable to a Licensed Product in a country in accordance with Section 1.134 hereof, ImmunoGen and its Affiliates shall have a
fully paid-up, irrevocable, freely transferable and sublicensable license under the relevant Licensed Intellectual Property, to make, have made, use, sell, offer for sale and import such Licensed Products in such country. 

8.2. Voluntary Termination by ImmunoGen. ImmunoGen shall have the right to terminate this Agreement at any time prior to the achievement
of the first Regulatory Marketing Approval for any Licensed Product in any country or other jurisdiction in the Territory, upon not less than ninety (90) days’ prior written notice to CytomX. 

8.3. Termination by Either Party for Cause. Either Party may terminate this Agreement in its entirety at any time during the Term by
giving written notice to the other Party if the other Party commits a material breach of its obligations under this Agreement (a “Material Breach”), such notice to describe such Material Breach in reasonable detail, and such
Material Breach remains uncured for [***] days, measured from the date written notice of such breach is given to the breaching Party; provided, however, that if the nature of the asserted breach is such that more than [***] days are
reasonably required to cure, then the cure period shall be extended for a period not to exceed an additional [***] days so long as the Party seeking to cure the asserted breach is diligently pursuing such cure to completion. 

8.4. Termination on Insolvency. This Agreement may be terminated upon written notice by either Party at any time in the event of an
Insolvency Event of the other Party. 
 8.5. Termination for Material Breach of the Research Collaboration Agreement by ImmunoGen.
CytomX shall have the right to terminate this Agreement, effective upon thirty (30) days’ prior written notice to ImmunoGen, in the event CytomX has terminated the Research Collaboration Agreement due to the occurrence of a Material Breach
(as defined in the Research Collaboration Agreement) thereunder by ImmunoGen which remains uncured as of the termination date of the Research Collaboration Agreement. 

8.6. Effects of Expiration or Termination. 

8.6.1. Effect of Termination by CytomX under Section 8.3, 8.4 or 8.5 or by ImmunoGen under Section 8.2. If CytomX terminates
this Agreement pursuant to Section 8.3, 8.4 or 8.5 hereof, or ImmunoGen terminates this Agreement pursuant to Section 8.2 hereof, then: 

(a) the license granted by CytomX to ImmunoGen and its Affiliates under Section 3.1.1 hereof shall immediately terminate, and
ImmunoGen and its Affiliates shall discontinue the use of any Licensed Intellectual Property except, with respect to the Licensed Patent Rights, as otherwise permitted under [***] with respect to activities performed [***]; 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 (b) ImmunoGen and its Affiliates and Sublicensees shall cease any Development and
Commercialization of Licensed Products in the Territory, subject to Section 8.6.3 hereof; and 
 (c) each Party shall promptly
return or destroy all of the other Party’s Confidential Information, provided that each Party may retain, subject to Article 6 hereof, (i) one (1) copy of the other Party’s Confidential Information in its archives
solely for the purpose of establishing the contents thereof and ensuring compliance with its obligations hereunder, (ii) any Confidential Information of the other Party contained in its laboratory notebooks or databases, and (iii) any
Confidential Information of the other Party to the extent reasonably required to exercise its rights and perform its obligations under any other then-outstanding License Agreement. 

8.6.2. Effect of Termination by ImmunoGen under Section 8.3 or 8.4. If ImmunoGen terminates this Agreement pursuant to
Section 8.3 or 8.4 hereof, then 
 (a) the license granted to ImmunoGen by CytomX pursuant to Section 3.1.1
hereof shall continue on the terms set forth herein, subject to ImmunoGen’s continued payment of all milestone and royalty payments in accordance with this Agreement, and on a country-by-country and Licensed Product-by-Licensed Product basis,
upon the expiration of the Royalty Term applicable to a Licensed Product in country in accordance with Section 1.134 hereof and provided ImmunoGen shall have paid to CytomX all royalty amounts due to CytomX with respect to Net Sales in
such country, ImmunoGen and its Affiliates shall thereafter have a fully paid-up, irrevocable, freely transferable ad sublicensable license under the relevant Licensed Intellectual Property, to make, have made, use, sell, offer for sale and import
such Licensed Product in such country; 
 (b) CytomX shall remain entitled to receive payments that accrued before the effective date of
such termination; and 
 (c) each Party shall promptly return or destroy all of the other Party’s Confidential Information, provided
that each Party may retain, subject to Article 6 hereof, (i) one (1) copy of the other Party’s Confidential Information in its archives solely for the purpose of establishing the contents thereof and ensuring compliance
with its obligations hereunder, (ii) any Confidential Information of the other Party contained in its laboratory notebooks or databases and (iii) any Confidential Information of the other Party to the extent reasonably required to exercise
its rights and perform its obligations under any then-outstanding License Agreement. The foregoing notwithstanding, and subject to Article 6 hereof, ImmunoGen may retain and use CytomX’s Confidential Information with respect to the
exercise of its rights set forth in clause (a) above or necessary or useful to exercise any other of its rights under this Agreement that survive such termination. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 8.6.3. Treatment of Sublicensees on Termination. Notwithstanding the foregoing, CytomX
shall permit a Sublicensee of ImmunoGen to become its direct Sublicensee upon notification to CytomX. 
 8.6.4. Satisfaction of
Obligations During Notice Period. During the period from providing a notice of termination through the termination of the Agreement, the Parties shall continue to perform their obligations under this Agreement. 

8.6.5. Pending Dispute Resolution. If a Party gives notice of termination and the other Party disputes whether such notice was proper,
then the issue of whether this Agreement has been terminated shall be resolved in accordance with Section 10.9 or 10.10 hereof, as applicable, and this Agreement shall remain in effect pending the resolution of such dispute. If as
a result of such dispute resolution process it is determined that the notice of termination was proper, then such termination shall be effective immediately. If as a result of such dispute resolution process it is determined that the notice of
termination was improper, then no termination shall have occurred and this Agreement shall remain in effect. Anything contained in this Agreement to the contrary notwithstanding, if the asserted breach is cured or shown to be non-existent within the
applicable cure period, the first notice of breach hereunder shall be deemed automatically withdrawn and of no effect. 
 8.7. Disposition
of Inventories of Products. Following termination of this Agreement by CytomX pursuant to Section 8.3 or 8.4, ImmunoGen and its Affiliates and Sublicensees shall have the right to continue to sell their existing inventories of
Licensed Product(s) that have received Regulatory Marketing Approval prior to such termination for a period [***] after the effective date of such termination or expiration and ImmunoGen shall pay any milestones and royalties payable in connection
with such sales in accordance with Article 4 hereof. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 8.8. Remedies. [***], the rights of the non-breaching Party set forth in
Section 8.6 hereof shall be the exclusive legal remedy to a Party arising from a Material Breach; provided, however, that (a) in addition to the foregoing legal remedy, the Parties may seek any and all equitable remedies, including,
without limitation, declarative and injunctive relief and specific performance in accordance with applicable law, and (b) nothing in this Section shall limit the Parties’ respective rights and obligations with respect to
(i) Unauthorized Use of the other Party’s Confidential Information or Proprietary Materials, (ii) unauthorized disclosure of the other Party’s Confidential Information or (iii) indemnification as set forth in
Article 9 hereof. 
 8.9. Survival of Certain Obligations. Expiration or termination of this Agreement shall not relieve
the Parties of any obligation that accrued before such expiration or termination. The following provisions shall survive expiration or termination of this Agreement: Sections 2.5.2, 2.5.3, 2.5.4, 2.6 and 3.3,
Articles 4, 5 and 6, Sections 7.6, 8.1, 8.6, 8.7 (for the period set forth therein), 8.8 and 8.9, and Articles 9 and 10. For avoidance of doubt, any other
Section that explicitly states it survives expiration or termination of this Agreement shall so survive. 
  

	9.	LIMITATION ON LIABILITY, INDEMNIFICATION AND INSURANCE. 

 9.1. No Consequential
Damages. Except with respect to liability arising from a breach of Article 6 hereof, in no event will either Party, its Affiliates or any of its or its Affiliates’ respective Representatives be liable under this Agreement for any
special, indirect, incidental, consequential or punitive or exemplary damages, whether in contract, warranty, tort, negligence, strict liability or otherwise, (a) including loss of profits or revenue suffered by either Party or any of its
respective Affiliates or Representatives or (b) cost of procurement of substitute goods, technology or services, even if either Party is informed in advance of the possibility of such damages and even if the remedies provided for in this
Agreement fail of their essential purpose. For purposes of clarity, a Party’s monetary liability under a Third Party Claim for such Third Party’s special, indirect, incidental or consequential damages or for any punitive or exemplary
damages payable in connection with such Third Party Claim, shall be deemed to be the direct damages of such Party for purposes of this Article 9. 

9.2. Indemnification by CytomX. CytomX will indemnify, defend and hold harmless ImmunoGen, its Affiliates and each of its and their
respective employees, officers, directors and agents (each, a “ImmunoGen Indemnified Party”) from and against any and all liability, loss, damage, expense (including reasonable attorneys’ fees and expenses) and cost
(collectively, a “Liability”) as a direct result of any Third Party claims, suits, 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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actions, demands or judgments, including, without limitation, personal injury and product liability matters (collectively, “Third Party Claims”) arising out of a Material Breach
of this Agreement by CytomX, except, in each case, to the extent any such Third Party Claim or Liability results from a Material Breach of this Agreement by ImmunoGen, the Development, Manufacture, Commercialization or use (including, without
limitation, the production, manufacture, promotion, import, sale or use by any Person) of any Licensed Product by, on behalf of, or under the authority of, ImmunoGen or any of its Affiliates, Sublicensees, subcontractors, distributors or agents
(other than an CytomX Indemnified Party), or the negligence, recklessness or intentional acts of ImmunoGen or any of its Affiliates, Sublicensees, subcontractors, distributors or agents; provided that with respect to any Third Party Claim for which
ImmunoGen also has an obligation to indemnify any CytomX Indemnified Party pursuant to Section 9.3 hereof, CytomX shall indemnify each ImmunoGen Indemnified Party for its Liability to the extent of CytomX’s responsibility, relative to
ImmunoGen (or to Persons for whom ImmunoGen is legally responsible), for the facts underlying the Third Party Claim. 
 9.3.
Indemnification by ImmunoGen. ImmunoGen will indemnify, defend and hold harmless CytomX, its Affiliates, contractors, distributors and each of its and their respective employees, officers, directors and agents (each, a “CytomX
Indemnified Party”) from and against any and all Liabilities as a direct result of any Third Party Claims arising out of: 
 (a) the
Development, Manufacture, Commercialization or use (including, without limitation, the production, manufacture, promotion, import, sale or use by any Person) of any Licensed Product by, on behalf of, or under the authority of, ImmunoGen or any of
its Affiliates, Sublicensees, subcontractors, distributors or agents (other than by any CytomX Indemnified Party); or 
 (b) a Material
Breach of this Agreement by ImmunoGen; 
 except to the extent any such Third Party Claim or Liability results from a Material Breach of this
Agreement by CytomX or the negligence, recklessness or intentional acts of CytomX or any CytomX Indemnified Party; provided that with respect to any Third Party Claim for which CytomX also has an obligation to indemnify any ImmunoGen Indemnified
Party pursuant to Section 9.2 hereof, ImmunoGen shall indemnify each CytomX Indemnified Party for its Liability to the extent of ImmunoGen’s responsibility, relative to CytomX (or to Persons for whom CytomX is legally responsible), for the
facts underlying the Third Party Claim. 
 9.4. Procedure. 

9.4.1. Notice. Each Party will notify the other Party in writing in the event it becomes aware of a claim for which indemnification may
be sought hereunder. In 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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the event that any Third Party asserts a claim or other proceeding (including any governmental investigation) with respect to any matter for which a Party (the “Indemnified
Party”) is entitled to indemnification hereunder, then the Indemnified Party shall promptly notify the Party obligated to indemnify the Indemnified Party (the “Indemnifying Party”) thereof; provided, however, that no delay
on the part of the Indemnified Party in notifying the Indemnifying Party shall relieve the Indemnifying Party from any obligation hereunder unless (and then only to the extent that) the Indemnifying Party is prejudiced thereby. 

9.4.2. Control. The Indemnifying Party shall have the right, at its sole cost and expense, exercisable by notice to the Indemnified
Party within ten (10) Business Days after receipt of notice from the Indemnified Party of the commencement of or assertion of any Third Party Claim, to assume direction and control of the defense, litigation, settlement, appeal or other
disposition of the Third Party Claim (including the right to settle the claim solely for monetary consideration) with counsel selected by the Indemnifying Party and reasonably acceptable to the Indemnified Party. The Indemnified Party shall
cooperate, and shall cause its Affiliates and agents to cooperate upon request of the Indemnifying Party, in the defense or prosecution of the Third Party Claim, including by furnishing such records, information and testimony and attending such
conferences, discovery proceedings, hearings, trials or appeals as may reasonably be requested by the Indemnifying Party. The Indemnified Party shall have the right to join in (including the right to conduct discovery, interview and examine
witnesses and participate in all settlement conferences), but not control, at its own expense, the defense of any Third Party Claim that the other Party is defending as provided in this Agreement. 

9.4.3. Settlement. Neither the Indemnifying Party nor the Indemnified Party shall enter into any compromise or settlement of a Third
Party Claim for which the right to indemnification hereunder has been asserted without the Indemnified Party’s prior written consent, which consent shall not be unreasonably withheld, conditioned or delayed; provided that the Indemnifying Party
may, without the Indemnified Party’s prior written consent, agree or consent to any settlement or other resolution of such Third Party Claim which requires solely money damages paid by the Indemnifying Party, and which includes as an
unconditional term thereof the giving by such claimant or plaintiff to the Indemnified Party of a release from all liability in respect of such Third Party Claim. Each of the Indemnifying Party and the Indemnified Party shall not make any admission
of liability in respect of any Third Party Claim without the prior written consent of the other Party, and the Indemnified Party shall use reasonable efforts to mitigate Liabilities arising from such Third Party Claim. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 9.5. Insurance. Each Party shall obtain and maintain, during the Term, commercial general
liability insurance, including products liability insurance, with reputable and financially secure insurance carriers (or pursuant to a program of self-insurance reasonably satisfactory to the other Party) to cover its indemnification obligations
under Section 9.2 or 9.3 hereof with respect to bodily injury (including death) and damage to property, as applicable, in each case with limits of not less than $3,000,000 per occurrence and in the aggregate. Insurance (other than
permitted self-insurance) shall be procured with carriers having an A.M. Best Rating of A-VII or better. Any indemnification payment hereunder shall be made net of any insurance proceeds which the Indemnified Party is entitled to recover;
provided, however, that if, following the payment to the Indemnified Party of any amount under this Article 9, such Indemnified Party becomes entitled to recover any insurance proceeds in respect of the claim for which such
indemnification payment was made, the Indemnified Party shall promptly pay an amount equal to the amount of such proceeds (but not exceeding the amount of such indemnification payment) to the Indemnifying Party. 

 

	10.	MISCELLANEOUS. 

 10.1. Assignment. Neither Party may assign this Agreement without
the prior written consent of the other Party, which consent will not be unreasonably withheld, conditioned or delayed; provided, however, that such consent shall not be required in connection with any assignment of this Agreement to an Affiliate of
the assigned Party, or to a Third Party in connection with the transfer or sale of the business to which this Agreement relates, or to any successor Person resulting from any merger or consolidation of such Party with or into such Person, provided
that the assignee shall have agreed in writing to assume all of the assignor’s obligations hereunder, and provided, further, that the other Party shall be notified promptly after such assignment has been effected. This Agreement shall be
binding upon the successors and permitted assigns of the Parties and the name of a Party appearing herein shall be deemed to include the names of such Party’s successors and permitted assigns to the extent necessary to carry out the intent of
this Agreement. Any purported assignment not in accordance with this Section 10.1 shall be null and void. 
 10.2. Further
Actions. Each Party agrees to execute, acknowledge and deliver such further instruments, and to do all such other acts, as may be necessary or appropriate in order to carry out the purposes and intent of the Agreement. 

10.3. Force Majeure. Each Party shall be excused from the performance of its obligations under this Agreement to the extent that such
performance is prevented by force majeure (defined below) and the nonperforming Party promptly provides notice of the prevention to the other Party. Such excuse shall be continued so long as the condition constituting force majeure
continues and the nonperforming Party takes Commercially Reasonable Efforts to resume performance. For purposes of this Agreement, “force  

  
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majeure” shall include conditions beyond the control of the Parties, including an act of God, voluntary or involuntary compliance with any Applicable Law or order of any government,
war, act of terror, civil commotion, labor strike or lock-out, epidemic, failure or default of public utilities or common carriers, or destruction of production facilities or materials by fire, earthquake, storm or like catastrophe; provided that
financial inability to pay in and of itself shall not be considered to be a force majeure event. 
 10.4. Notices. Any notice
or notification required or permitted to be provided pursuant to the terms and conditions of this Agreement (including any notice of force majeure, breach, termination, change of address, etc.) shall be in writing and shall be deemed given
upon receipt if delivered personally or by facsimile transmission (receipt verified), five (5) Business Days after deposited in the mail if mailed by certified mail (return receipt requested) postage prepaid, or on the next Business Day if sent
by overnight delivery using a nationally recognized express courier service and specifying next Business Day delivery (receipt verified), to the Parties at the following addresses or facsimile numbers (or at such other address or facsimile number
for a Party as shall be specified by like notice, provided, however, that notices of a change of address shall be effective only upon receipt thereof): 

All correspondence to ImmunoGen shall be addressed as follows: 

ImmunoGen, Inc. 
 830 Winter
Street 
 Waltham, MA 02451 

Attn: Vice President, Business Development 

Fax: [***] 
 All correspondence
to CytomX shall be addressed as follows: 
 CytomX Therapeutics, Inc. 

343 Oyster Point Blvd., Suite 100 

South San Francisco, CA 94080-7014 

Attn: CEO 
 Fax: 1-650-351-0353

 To help expedite the other Party’s awareness and response, copies of notices may be provided to the other Party by email but must be
supplemented by one of the following methods: (a) personal delivery, (b) first class certified mail with return receipt requested, or (c) next-day delivery by major international courier, with confirmation of delivery. Electronic
copies may be sent via email to [***] at CytomX and to [***] at ImmunoGen so long as such individuals remain employed by CytomX or ImmunoGen, respectively. 

  
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contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
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 10.5. Amendment. No amendment, modification or supplement of any provision of this
Agreement shall be valid or effective unless made in writing and signed by a duly authorized officer of the Party to be bound. 
 10.6.
Waiver. No provision of this Agreement shall be waived by any act, omission or knowledge of a Party or its agents or employees except by an instrument in writing expressly waiving such provision and signed by a duly authorized officer of the
waiving Party. The waiver by either of the Parties of any breach of any provision hereof by the other Party shall not be construed to be a waiver of any succeeding breach of such provision or a waiver of the provision itself. 

10.7. Severability. If any clause or portion thereof in this Agreement is for any reason held to be invalid, illegal or unenforceable,
the same shall not affect any other portion of this Agreement, as it is the intent of the Parties that this Agreement shall be construed in such fashion as to maintain its existence, validity and enforceability to the greatest extent possible. In
any such event, this Agreement shall be construed as if such clause or portion thereof had never been contained in this Agreement, and there shall be deemed substituted therefor such provision as will most nearly carry out the intent of the Parties
as expressed in this Agreement to the fullest extent permitted by Applicable Law. 
 10.8. Descriptive Headings. The descriptive
headings of this Agreement are for convenience only and shall be of no force or effect in construing or interpreting any of the provisions of this Agreement. 

10.9. Dispute Resolution. The Parties recognize that a bona fide dispute as to certain matters may arise from time to time
during the Term relating to either Party’s rights or obligations hereunder or otherwise relating to the validity, enforceability or performance of this Agreement, including disputes relating to alleged breach or termination of this Agreement
but excluding any disputes relating to Article 6 hereof or disputes relating to the determination of the validity, scope, infringement, enforceability, inventorship or ownership of the Parties’ respective Patent Rights (hereinafter,
a “Dispute”). In the event of the occurrence of any Dispute, the Parties shall follow the following procedures in an attempt to resolve the dispute or disagreement: 

10.9.1. The Party claiming that such a Dispute exists shall give notice in writing (a “Notice of Dispute”) to the other Party
of the nature of the Dispute. 
 10.9.2. Within [***] days of receipt of a Notice of Dispute, the ImmunoGen Alliance Manager and the
CytomX Alliance Manager shall meet in person or by teleconference and exchange written summaries reflecting, in reasonable detail, the nature and extent of the Dispute, and at this meeting they shall use their reasonable endeavors to resolve the
Dispute. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 63 

 10.9.3. If the Alliance Managers are unable to resolve the Dispute during the meeting described
in Section 10.9.2 hereof or if for any reason such meeting does not take place within the period specified in Section 10.9.2 hereof, then the Dispute will be referred to the JDC which shall meet no later than [***] days
following the initial receipt of the Notice of Dispute and use reasonable endeavors to resolve the Dispute. 
 10.9.4. If the JDC is unable
to resolve the Dispute during the meeting described in Section 10.9.3 hereof or if for any reason such meeting does not take place within the period specified in Section 10.9.3 hereof, then the Chief Executive Officer of
ImmunoGen and the Chief Executive Officer of CytomX shall meet at a mutually agreed-upon time and location for the purpose of resolving such Dispute. 

10.9.5. If, within [***] days of initial receipt of the Notice of Dispute, the Dispute has not been resolved, or if, for any reason, the
meeting described in Section 10.9.4 hereof has not been held within [***] days of initial receipt of the Notice of Dispute, then the Parties agree that such Dispute shall be finally resolved through binding arbitration to be
administered by JAMS pursuant to its Comprehensive Arbitration Rules and Procedures and in accordance with the Expedited Procedures in those Rules, as specifically modified by the provisions of this Section 10.9.5. 

(a) Arbitration Panel. The arbitration shall be conducted by a panel of three (3) arbitrators. Within [***] days after the
initiation of the arbitration, each Party will nominate one person to act as arbitrator, and the two arbitrators so named will then jointly appoint the third arbitrator within [***] days of their appointment, who will serve as chairman of the
panel. All three (3) arbitrators must be independent Third Parties having at least [***] years of dispute resolution experience (which may include judicial experience) and/or legal or business experience in the biotech or pharmaceutical
industry. If either Party fails to nominate its arbitrator, or if the arbitrators selected by the Parties cannot agree on a person to be named as chairman within such [***] day period, JAMS will make the necessary appointments for such
arbitrator(s) or the chairman. Once appointed by a Party, such Party shall have no ex parte communication with its appointed arbitrator. 

(b) Location and Proceedings. The place of arbitration will be in the Borough of Manhattan, City of New York, NY or such other venue as
the 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 64 

 
Parties may mutually agree. The arbitration proceedings and all communications with respect thereto shall be in English. Any written evidence originally in another language will be submitted in
English translation accompanied by the original or a true copy thereof. The arbitrators have the power to decide all matters in Dispute, including any questions of whether or not such matters are subject to arbitration hereunder. The arbitration
shall be governed by the Federal Arbitration Act, 9 U.S.C. §§1 et seq., and judgment upon the award rendered by the arbitrators may be entered in any court having competent jurisdiction thereof. 

(c) Limitation on Awards. Except for breaches of Article 6 hereof, the arbitrators shall have no authority to award any
special, indirect, incidental, consequential, punitive, exemplary or other similar damages. Each Party shall bear its own costs and expenses (including attorneys’ fees and expert or consulting fees) incurred in connection with the arbitration.
The Parties shall equally (50/50) share the arbitrators’ fees and other administrative costs and expenses associated with the arbitration. 

(d) Confidentiality. The existence, content and results of any arbitration proceedings pursuant to this Section 10.9.5
shall be deemed the Confidential Information of both Parties. 
 10.9.6. Notwithstanding any provision of this Agreement to the contrary,
either Party may immediately initiate litigation in any court of competent jurisdiction seeking any remedy at law or in equity, including the issuance of a preliminary, temporary or permanent injunction, to preserve or enforce its rights under this
Agreement. 
 10.10. Patent Disputes and Disputes Relating to Article 6. 

10.10.1. Inventorship. Any dispute, controversy or claim between the Parties involving the inventorship of any Program Technology that
is not resolved by mutual agreement of the Party’s respective chief patent counsels (or persons with similar responsibilities) within [***] days after the date the dispute is raised by one or both of the Parties shall be submitted to an
Independent Patent Counsel for resolution. Such Independent Patent Counsel’s determination of inventorship, absent manifest error, shall be final and binding on the Parties; provided, however, that any such determination with respect to a
patent application shall not preclude either Party from disputing inventorship with respect to any patents issuing from such patent application, which disputes shall be resolved in accordance with this Section. The Parties shall equally
(50/50) share the Independent Patent Counsel fees and expenses related to his determination of inventorship. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 65 

 10.10.2. Other Patent Disputes. Any dispute, controversy or claim between the Parties that
involves the validity, scope, infringement, enforceability or ownership of the Parties’ respective Patent Rights (a) that are pending or issued in the United States shall be subject to actions before the United States Patent and Trademark
Office and/or submitted exclusively to the federal court located in the jurisdiction where the Party whose Patent Rights are the subject to such dispute, controversy or claim resides (provided that if such Party does not reside in the United States,
venue shall be the jurisdiction where such Party’s principal U.S. Affiliate resides) and (b) that are pending or issued in any other country (or region) shall be brought before an appropriate regulatory or administrative body or court in
that country (or region), and the Parties hereby consent to jurisdiction and venue in such courts and bodies. 
 10.10.3. Disputes
Relating to Article 6. Any dispute, controversy or claim between the Parties that relates to the enforcement of Article 6 hereof shall be subject to action in any court of competent jurisdiction. 

10.11. Governing Law. This Agreement, and all claims arising under or in connection therewith, shall be governed by and interpreted in
accordance with the substantive laws of the State of New York, without regard to conflict of law principles thereof. 
 10.12. Entire
Agreement. This Agreement, including its Exhibits and Schedules, constitutes and contains the complete, final and exclusive understanding and agreement of the Parties and cancels and supersedes any and all prior negotiations, correspondence,
understandings and agreements, whether oral or written, between the Parties respecting the subject matter hereof and thereof, including the Confidentiality Agreement. 

10.13. Purpose and Scope. The Parties understand and agree that this Agreement is limited to the activities, rights and obligations as
expressly set forth herein. Nothing herein contained shall be deemed to create an employment, agency, joint venture or partnership relationship between the Parties hereto or any of their agents or employees, or any other legal arrangement that would
impose liability upon one Party for the act or failure to act of the other Party. Neither Party shall have any express or implied power to enter into any contracts or commitments or to incur any liabilities in the name of, or on behalf of, the other
Party, or to bind the other Party in any respect whatsoever. 
 10.14. Counterparts. This Agreement may be executed in two or more
counterparts, each of which shall be an original and both of which shall constitute together the same document. Counterparts may be signed and delivered by facsimile or PDF file, each of which shall be binding when received by the applicable Party.

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 66 

 10.15. No Third Party Rights or Obligations. Except as set forth in Article 9
hereof, no provision of this Agreement shall be deemed or construed in any way to result in the creation of any rights or obligation in any Person not a Party to this Agreement. However, either Party may decide, in its sole discretion, to use one or
more of its Affiliates to perform its obligations and duties hereunder, provided that such Party shall remain liable hereunder for the performance by any such Affiliates of any such obligations. 

10.16. Interpretation. The Parties hereto acknowledge and agree that: (a) each Party and its counsel reviewed and negotiated the
terms and provisions of this Agreement and have contributed to its revision; (b) the rule of construction to the effect that any ambiguities are resolved against the drafting Party shall not be employed in the interpretation of this Agreement;
and (c) the terms and provisions of this Agreement shall be construed fairly as to each Party hereto and not in a favor of or against any Party, regardless of which Party was generally responsible for the preparation of this Agreement. In
addition, unless the context otherwise requires, wherever used in this Agreement: (i) the singular shall include the plural, the plural the singular; (ii) the use of any gender shall be applicable to all genders; (iii) the word
“or” is used in the inclusive sense (and/or); (iv) the words “include” or “including” shall be construed as incorporating, also, “but not limited to” or “without limitation” (irrespective of
whether the words are used in the applicable instance); (v) the words “hereof,” “herein,” “hereby” and derivative or similar words refer to this Agreement as a whole and not to any particular provision of
this Agreement; and (vi) all references to “will” are interchangeable with the word “shall” and shall be understood to be imperative or mandatory in nature. 

[The remainder of this page has been intentionally left blank. The signature page follows.] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  
 67 

 IN WITNESS WHEREOF, duly authorized representatives of the Parties have duly executed this
Agreement to be effective as of the Effective Date. 
  

									
	IMMUNOGEN, INC.	 		 	CYTOMX THERAPEUTICS, INC.
					
	By:	 	  
	 		 	By:	 	  

					
	Name:	 		 		 	Name:	 	
					
	Title:	 		 		 	Title:	 	
					
	Date:	 		 		 	Date:	 	

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  

 EXHIBIT A 

Licensed Target 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

  

 EXHIBIT B 

Royalty Rate Reduction
Methodology† 

[***] 
  

	† 	Two pages of text have been omitted. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 SCHEDULE 1.120 

List of Cytotoxic Compound Patent Rights 

[See Attached] 
 [***]† 

  
 †Nine pages of text have been omitted. 

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

 EXHIBIT E 

Form of Work Plan 
 [See
Attached 

[***]† 

† Five pages of text have been
omitted. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 EXHIBIT F 

Representatives to the Joint Research Committee 

ImmunoGen Representatives 

[***] 
 CytomX
Representatives 
 [***] 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 SCHEDULE 1.104 

List of Cytotoxic Compound Patent Rights 

[See Attached] 
 [***]† 

  
 †Nine pages of text have been omitted. 

***Certain information contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has
been requested with respect to the omitted portions. 

 FIRST AMENDMENT TO RESEARCH COLLABORATION AGREEMENT 

This First Amendment to Research Collaboration Agreement (the “First Amendment”) is made effective as of the date of
the last signature below by and between ImmunoGen, Inc., a Massachusetts corporation (“ImmunoGen”), with its principal place of business being 830 Winter Street, Waltham, Massachusetts 02451, USA, and CytomX
Therapeutics, Inc., a Delaware corporation (“CytomX”), with its principal place of business being 343 Oyster Point Blvd., Suite 100, South San Francisco, California 94080. ImmunoGen and CytomX are herein sometimes
referred to as a “Party” and collectively as the “Parties.” 
 WHEREAS, ImmunoGen and CytomX
are parties to that certain Research Collaboration Agreement dated as of January 8, 2014 (the “RCA”); and 

WHEREAS, the Parties desire to amend the RCA to provide CytomX with the ability to evaluate a second Replacement Target, as set forth in this
First Amendment; and 
 NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Parties agree and covenant as follows. 
 1. Target Replacement Right.
Section 2.1.2 of the RCA is amended by adding the following to the end thereof: 
 “Anything contained in this Agreement to the
contrary notwithstanding, CytomX shall have the right to replace its first Replacement Target with another single Replacement Target, exercisable upon written notice to ImmunoGen and payment to ImmunoGen of a fee in the amount of [***] (the
“Expanded Access Fee”) at any time after CytomX has replaced its initial Research Program Targets with a Replacement Target but on or prior to the Replacement Target Cut-Off Date; provided that CytomX may not replace its first
Replacement Target once it has exercised its Option with respect to such first Replacement Target. Any such second Replacement Target for CytomX may not be a Target that is or was previously a Research Program Target of ImmunoGen, and availability
of any such second Replacement Target shall be subject to Section 2.1.3 hereof. Payment of the Expanded Access Fee by CytomX to ImmunoGen shall be made in U.S. Dollars without set-off or counterclaim and free and clear of any taxes,
duties, levies, fees or charges. The Expansion Fee shall be non-refundable and non-creditable.” 
 2. Miscellaneous.
Capitalized terms used and not otherwise defined herein shall have the respective meanings ascribed to them in the RCA. The RCA remains in full force and effect, as amended by this First Amendment. References in the RCA to “Agreement” mean
the RCA as amended by this First Amendment. 

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 

 IN WITNESS WHEREOF, the Parties have caused this First Amendment to Research Collaboration
Agreement to be executed by their duly authorized representatives. 
  

									
	IMMUNOGEN, INC.	 		 	CYTOMX THERAPEUTICS, INC.
					
	By:	 	 /s/ Peter Williams
	 		 	By:	 	 /s/ Sean McCarthy

					
	Name:	 	 Peter Williams
	 		 	Name:	 	 Sean McCarthy

					
	Title:	 	 Vice President
	 		 	Title:	 	 CEO

					
	Date:	 	 4/3/15
	 		 	Date:	 	 4/1/15

  
 ***Certain information
contained herein has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.

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