Document:

EX-4.2

 Exhibit 4.2 

AMBRX, INC. 
 AMENDED AND
RESTATED REGISTRATION RIGHTS AGREEMENT 
 This Amended and Restated Registration Rights Agreement (this
“Agreement”) is made and entered into as of March 17, 2009 (the “Effective Date”) by and among Ambrx, Inc., a Delaware corporation (the “Company”) and the persons and
entities set forth on Schedule A attached hereto (the “Investors”). 
 This Agreement supersedes and replaces
that certain Amended and Restated Registration Rights Agreement, dated June 30, 2006 (the “Prior Agreement”), entered into by and among the Company and the other parties thereto. 

RECITALS 
 WHEREAS,
the Company and certain of the Investors are parties to the Prior Agreement; 
 WHEREAS, in order to induce the Company to enter into that
certain Series D-1 and D-2 Preferred Stock Purchase Agreement dated as of the date hereof (the “Purchase Agreement”) and to induce the Purchaser (as such term is defined in the Purchase Agreement) to invest in the Company
pursuant to the Purchase Agreement, the parties hereto desire to enter into this Agreement and to provide registration and other rights to the Investors; 

WHEREAS, the Prior Agreement provides that any amendment or waiver thereof shall be effective with the written consent of the Company and by
Investors holding at least two-thirds (2/3) of the Registrable Securities Then Outstanding (as such terms are defined in the Prior Agreement); and 

WHEREAS, the undersigned parties constitute Investors holding at least two-thirds (2/3) of the Registrable Securities Then Outstanding,
and, therefore, are entitled to bind all Holders of Registrable Securities (as such terms are defined in the Prior Agreement). 

 NOW, THEREFORE, in consideration of the foregoing recitals and the mutual promises hereinafter
set forth, the parties hereto agree as follows: 
 AGREEMENT 

1. REGISTRATION RIGHTS. 

1.1 Definitions. For purposes of this Section 1: 

(a) Registration. The terms “register,” “registered,” and
“registration” refer to a registration effected by preparing and filing a registration statement in compliance with the Securities Act of 1933, as amended (the “Securities Act”), and the declaration or
ordering of effectiveness of such registration statement. 
 (b) Registrable Securities. The term
“Registrable Securities” means: (i) any and all shares of the Company’s common stock (“Common Stock”) issued or issuable upon the conversion of the Company’s Series A Preferred
Stock, par value $0.001 per share (the “Series A Preferred”), Series B Preferred Stock, par value $0.001 per share (the “Series B Preferred”), Series C Preferred Stock, par value $0.001 per share (the
“Series C Preferred”), Series D-1 Preferred Stock, par value $0.001 per share (the “Series D-1 Preferred”) and Series D-2 Preferred Stock, par value $0.001 per share (the “Series D-2
Preferred”) and (ii) any shares of Common Stock issued as (or issuable upon the conversion or exercise of any warrant, right or other security which is issued as) a dividend or other distribution with respect to, in exchange for or
in replacement of, such shares of Common Stock described in clause (i) of this subsection. The term “Registrable Securities” shall exclude in all cases, however, any shares described by (i) or (ii) of this
subsection (b) that have been sold by a person in a transaction in which rights under this Section 1 are not assigned in accordance with this Agreement or any shares described by (i) or (ii) of this subsection (b) sold to
the public or sold pursuant to Rule 144 promulgated under the Securities Act. 
 (c) Registrable Securities Then Outstanding.
The term “Registrable Securities Then Outstanding” shall mean those shares of Common Stock which are Registrable Securities and (1) are then issued and outstanding or (2) are then issuable pursuant to the exercise
or conversion of then-outstanding and then-exercisable options, warrants or convertible securities. 
 (d) Holder. For purposes of
this Section 1 and Section 2 hereof, the term “Holder” or “Holders” means any person or persons owning Registrable Securities. 

  
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 (e) Form S-3. The term “Form S-3” means such form under the Securities Act as is in effect on the date hereof or any successor registration form under the Securities Act subsequently adopted by the SEC (as defined below)
which permits inclusion or incorporation of substantial information by reference to other documents filed by the Company with the SEC. 

(f) SEC. The term “SEC” means the United States Securities and Exchange Commission. 

1.2 Demand Registration. 

(a) Request by Holders. If the Company shall receive a written request from the Holders of at least fifty percent (50%) of the
Registrable Securities Then Outstanding, voting together as one class, not earlier than the earlier of (i) June 30, 2011 and (ii) six months after the effective date of the first registration statement filed by the Company covering an
underwritten offering of any of its securities to the general public (the “Initial Public Offering”), that the Company file a registration statement under the Securities Act covering the registration of Registrable Securities
pursuant to this Section 1.2, then the Company shall, within ten (10) business days of the receipt of such written request, give written notice of such request (“Request Notice”) to all Holders, and effect, as
soon as practicable, the registration under the Securities Act of all Registrable Securities which Holders request to be registered and included in such registration by written notice given by such Holders to the Company within twenty (20) days
after receipt of the Request Notice, subject to the limitations of this Section 1.2; provided that the Registrable Securities requested by all Holders to be registered pursuant to such request must have an anticipated aggregate public
offering price (before any underwriting discounts and commissions) of not less than $5,000,000. 
 (b) Underwriting. If the Holders
initiating the registration request under this Section 1.2 (“Initiating Holders”) intend to distribute the Registrable Securities covered by their request by means of an underwriting, then they shall so advise the
Company as a part of their request made pursuant to this Section 1.2 and the Company shall include such information in the Request Notice. In such event, the right of any Holder to include Registrable Securities in such registration shall be
conditioned upon such Holder’s participation in such underwriting and the inclusion of such Holder’s Registrable Securities in the underwriting (unless otherwise mutually agreed by such Holder and Initiating Holders holding a majority in
interest of the Registrable Securities to be included in such registration) to the extent provided herein. All Holders proposing to distribute their securities through such underwriting shall enter into an underwriting agreement in customary form
with the managing underwriter or underwriters selected for such underwriting by the Company (subject to the reasonable approval 

  
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of the Initiating Holders). Notwithstanding any other provision of this Section 1.2, if the underwriter(s) advise(s) the Company in writing that marketing factors require a limitation of the
number of securities to be underwritten, then the Company shall so advise all Holders of Registrable Securities that would otherwise be registered and underwritten pursuant hereto, and the number of Registrable Securities that may be included in the
underwriting shall be reduced as required by the underwriter(s) and allocated among the Holders of Registrable Securities on a pro rata basis according to the number of Registrable Securities held by each Holder requesting registration (including
the Initiating Holders); provided, however, that the number of shares of Registrable Securities to be included in such underwriting and registration shall not be reduced unless all other securities of the Company held by other
stockholders (that are not Registrable Securties) are first entirely excluded from the underwriting and registration. Any Registrable Securities excluded and withdrawn from such underwriting shall be withdrawn from the registration. 

(c) Maximum Number of Demand Registrations. The Company is obligated to effect only two (2) such registrations pursuant to this
Section 1.2 and shall not be obligated to effect such a registration during the six (6) month period after the effective date of the Initial Public Offering; provided that, a registration will count for purposes of this
Section 1.2 only if (i) all Registrable Securities requested to be registered under Section 1.2(a) are so registered, or (ii) the registration request is subsequently withdrawn at the request of the Holders of a majority of the
Registrable Securities to be registered unless at the time of such withdrawal, the Holders have learned of a material adverse change in the condition, business or prospects of the Company not known to the Holders at the time the written request of
such registration is made. 
 (d) Deferral. Notwithstanding the foregoing, if the Company shall furnish to Holders requesting the
filing of a registration statement pursuant to this Section 1.2 a certificate signed by the President or Chief Executive Officer of the Company stating that, in the good faith judgment of the board of directors of the Company (the
“Board of Directors”), it would be seriously detrimental to the Company and its stockholders for such registration statement to be filed and it is therefore essential to defer the filing of such registration statement, then
the Company shall have the right to defer such filing for a period of not more than ninety (90) days after receipt of the request of the Initiating Holders; provided, however, that the Company may not utilize this right more than
once in any twelve (12) month period. 

  
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 (e) Expenses. All registration and qualification fees, printers’ and accounting
fees, fees and disbursements of counsel for the Company and the reasonable fees and disbursements of one (1) counsel for the selling Holder or Holders (the “Registration Expenses”) shall be borne by the Company. Each
Holder participating in a registration pursuant to this Section 1.2 shall bear such Holder’s proportionate share (based on the total number of shares sold in such registration other than for the account of the Company) of any stock
transfer taxes and all discounts, commissions or other amounts payable to underwriters or brokers in connection with such offering (the “Selling Expenses”). Notwithstanding the foregoing, the Company shall not be required to
pay for any expenses of any registration proceeding begun pursuant to this Section 1.2 if the registration request is subsequently withdrawn at the request of the Holders of a majority of the Registrable Securities to be registered unless
(i) at the time of such withdrawal, the Holders have learned of a material adverse change in the condition, business or prospects of the Company not known to the Holders at the time their written request for such registration was made and have
withdrawn their request for registration with reasonable promptness after learning of such material adverse change or (ii) the Holders of a majority of the Registrable Securities to be registered agree to forfeit their right to one requested
registration pursuant to Section 1.2. 
 1.3 Piggyback Registrations. The Company shall notify all Holders of Registrable
Securities in writing at least thirty (30) days prior to filing any registration statement under the Securities Act for purposes of effecting a public offering of securities of the Company (including, but not limited to, registration statements
relating to secondary offerings of securities of the Company, but excluding registration statements relating to any registration under Section 1.2 or Section 1.4 of this Agreement or to any employee benefit plan or a corporate
reorganization) and will afford each such Holder an opportunity to include in such registration statement all or any part of the Registrable Securities then held by such Holder. Each Holder desiring to include in any such registration statement all
or any part of the Registrable Securities held by such Holder shall, within twenty (20) days after receipt of the above-described notice from the Company, notify the Company in writing, and in such notice shall inform the Company of the number
of Registrable Securities such Holder wishes to include in such registration statement. If a Holder decides not to include all of its Registrable Securities in any registration statement filed by the Company, such Holder shall nevertheless continue
to have the right to include any Registrable Securities in any subsequent registration statement or registration statements as may be filed by the Company with respect to offerings of its securities, all upon the terms and conditions set forth
herein. 

  
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 (a) Underwriting. If a registration statement under which the Company gives notice under
this Section 1.3 is for an underwritten offering, then the Company shall so advise the Holders of Registrable Securities. In such event, the right of any such Holder to include Registrable Securities in a registration pursuant to this
Section 1.3 shall be conditioned upon such Holder’s participation in such underwriting and the inclusion of such Holder’s Registrable Securities in the underwriting to the extent provided herein. All Holders proposing to distribute
their Registrable Securities through such underwriting shall enter into an underwriting agreement in customary form with the managing underwriter or underwriter(s) selected for such underwriting. Notwithstanding any other provision of this
Agreement, if the managing underwriter(s) determine(s) in good faith that marketing factors require a limitation of the number of shares to be underwritten, then the managing underwriter(s) may exclude shares (including Registrable Securities) from
the registration and the underwriting, and the number of shares that may be included in the registration and the underwriting shall be allocated, first, to the Company, second, to each of the Holders requesting inclusion of their
Registrable Securities in such registration statement on a pro rata basis based on the total number of Registrable Securities then held by each such Holder and third, to each other stockholder of the Company (other than a Holder). No such
reduction shall reduce the amount of securities of the selling Holders included in the registration below thirty percent (30%) of the total amount of securities included in such registration, unless such offering is the Initial Public Offering
and such registration does not include shares of any other selling stockholders, in which event any or all of the Registrable Securities of the Holders may be excluded in accordance with the immediately preceding sentence. If any Holder disapproves
of the terms of any such underwriting, such Holder may elect to withdraw therefrom by written notice to the Company and the underwriter, delivered at least ten (10) business days prior to the effective date of the registration statement. Any
Registrable Securities excluded or withdrawn from such underwriting shall be excluded and withdrawn from the registration. For any Holder which is a partnership, a limited liability company or corporation, the partners, retired partners, members and
retired members, and shareholders of such Holder, or the estates and family members of any such partners and retired partners and any trusts for the benefit of any of the foregoing persons shall be deemed to be a single “Holder,” and any
pro rata reduction with respect to such “Holder” shall be based upon the aggregate number of Registrable Securities owned by all entities and individuals included in such “Holder,” as defined in this sentence. In no event shall
any Registrable Securities be excluded from any registration unless all other stockholder’s securities (that are not Registrable Securities) have been first excluded. 

(b) Expenses. All Registration Expenses incurred in connection with a registration pursuant to this Section 1.3 shall be borne by
the Company. Each Holder participating in a registration pursuant to this Section 1.3 shall bear such Holder’s proportionate share (based on the total number of shares sold in such registration other than for the account of the Company) of
all Selling Expenses incurred in connection with a registration pursuant to this Section 1.3. 

  
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 1.4 Form S-3 Registration. In case the
Company shall receive from any Holder or Holders of Registrable Securities a written request or requests that the Company effect a registration on Form S-3 and any related qualification or compliance with
respect to all or a part of the Registrable Securities owned by such Holder or Holders, then the Company will: 
 (a) promptly give written
notice of the proposed registration and the Holder’s or Holders’ request therefor, and any related qualification or compliance, to all other Holders of Registrable Securities; and 

(b) as soon as practicable, effect such registration and all such qualifications and compliances as may be so-requested and as would permit
or facilitate the sale and distribution of all or such portion of such Holder’s or Holders’ Registrable Securities as are specified in such request, together with all or such portion of the Registrable Securities of any other Holder or
Holders joining in such request as are specified in a written request given within twenty (20) days after receipt of such written notice from the Company; provided, however, that the Company shall not be obligated to effect any
such registration, qualification or compliance pursuant to this Section 1.4: 
 (1) if
Form S-3 is not available for such offering by the Holders; 
 (2) if the Holders, together
with the holders of any other securities of the Company entitled to inclusion in such registration, propose to sell Registrable Securities and such other securities (if any) at an aggregate price to the public of less than One Million Five Hundred
Thousand Dollars ($1,500,000) (prior to underwriters’ commissions, discounts and expenses); 
 (3) if the Company shall furnish to the
Holders a certificate signed by the President or Chief Executive Officer of the Company stating that, in the good faith judgment of the Board of Directors, it would be seriously detrimental to the Company and its stockholders for such Form S-3 registration to be effected at such time, in which event the Company shall have the right to defer the filing of the Form S-3 registration statement no more
than once during any twelve (12) month period for a period of not more than ninety (90) days following receipt of the request of the Holder or Holders under this Section 1.4; provided, that the Company shall not effect any
registration for itself or any other stockholder during such 90-day period; 

  
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 (4) if the Company has, within the twelve (12) month period preceding the date of such
request, already effected two (2) registrations on Form S-3 for Holders pursuant to this Section 1.4; 

(5) within three (3) months of the effective date of any registration referenced to in Sections 1.2 or 1.3 above; or 

(6) in any particular jurisdiction in which the Company would be required to qualify to do business or to execute a general consent to
service of process in effecting such registration, qualification or compliance. 
 (c) Expenses. Subject to the foregoing, the
Company shall file a Form S-3 registration statement covering the Registrable Securities and other securities so requested to be registered pursuant to this Section 1.4 as soon as practicable after
receipt of the request(s) of the Holder(s) for such registration. All Registration Expenses incurred in connection with a Form S-3 Registration pursuant to this Section 1.4 shall be borne by the Company. Each Holder participating in a Form S-3 Registration pursuant to this Section 1.4 shall bear such Holder’s proportionate share (based on the total numbers of shares sold in such registration other than for the account of the Company) of all
Selling Expenses incurred in connection with each registration requested pursuant to this Section 1.4. 
 (d) Not Demand
Registration. Form S-3 registrations shall not be deemed to be demand registrations as described in Section 1.2 above. 

1.5 Obligations of the Company. Whenever required to effect the registration of any Registrable Securities under this Agreement, the
Company shall, as expeditiously as reasonably possible: 
 (a) prepare and file with the SEC a registration statement with respect to such
Registrable Securities and use commercially reasonable efforts to cause such registration statement to become effective as soon as practicable, and, upon the request of the Holders of a majority of the Registrable Securities registered thereunder,
keep such registration statement effective for up to the earlier of (i) one hundred twenty (120) days and (ii) until the distribution of the Registrable Securities covered by such registration statement has been completed; 

  
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 (b) prepare and file with the SEC such amendments and supplements to such registration statement
and the prospectus used in connection with such registration statement as may be necessary to comply with the provisions of the Securities Act with respect to the disposition of all securities covered by such registration statement; 

(c) furnish to the Holders such number of copies of a prospectus, including a preliminary prospectus, in conformity with the requirements of
the Securities Act, and such other documents as they may reasonably request in order to facilitate the disposition of the Registrable Securities owned by them that are included in such registration; 

(d) use its best efforts to register and qualify the securities covered by such registration statement under such other securities or Blue
Sky laws of such jurisdictions as shall be reasonably requested by the Holders, provided that the Company shall not be required in connection therewith or as a condition thereto to qualify to do business or to file a general consent to service of
process in any such states or jurisdictions; 
 (e) in the event of any underwritten public offering, enter into and perform its
obligations under an underwriting agreement, in usual and customary form, with the managing underwriter(s) of such offering (it being understood and agreed that, as a condition to the Company’s obligations under this clause (e), each
Holder participating in such underwriting shall also enter into and perform its obligations under such an agreement); 
 (f) notify each
Holder of Registrable Securities covered by such registration statement of the happening of any event as a result of which the registration statement, prospectus included in such registration statement, as then in effect, or other communication
(including oral communication) includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary to make the statements therein not misleading in the light of the circumstances then
existing; and 
 (g) furnish, at the request of any Holder requesting registration of Registrable Securities, on the date that such
Registrable Securities are delivered to the underwriters for sale, if such securities are being sold through underwriters, or, if such securities are not being sold through underwriters, on the date that the registration statement with respect to
such securities becomes effective, (i) an opinion, dated as of such date, of the counsel representing the Company for the purposes of such registration, in form and substance as is customarily given to underwriters in an underwritten public
offering and reasonably satisfactory to a majority in interest of the Holders requesting registration, addressed to the underwriters, if 

  
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any, and to the Holders requesting registration of Registrable Securities and (ii) a “comfort” letter dated as of such date, from the independent certified public accountants of
the Company, in form and substance as is customarily given by independent certified public accountants to underwriters in an underwritten public offering and reasonably satisfactory to a majority in interest of the Holders requesting registration,
addressed to the underwriters, if any, and to the Holders requesting registration of Registrable Securities. 
 1.6 Furnish
Information. It shall be a condition precedent to the obligations of the Company to take any action pursuant to Sections 1.2, 1.3 or 1.4 hereof that the selling Holders shall furnish to the Company such information regarding themselves, the
Registrable Securities held by them and the intended method of disposition of such securities as shall be required to timely effect the registration of their Registrable Securities. 

1.7 Delay of Registration. No Holder shall have any right to obtain or seek an injunction restraining or otherwise delaying any such
registration as the result of any controversy that might arise with respect to the interpretation or implementation of this Section 1. 

1.8 Indemnification. In the event any Registrable Securities are included in a registration statement under Sections 1.2, 1.3 or
1.4 hereof: 
 (a) By the Company. To the extent permitted by law, the Company will indemnify and hold harmless each Holder, the
partners, members, officers, directors, shareholders and attorneys of each Holder, any underwriter (as defined in the Securities Act) and each person, if any, who controls, is controlled by or is under common control with such Holder or underwriter
(an “Affiliate”) within the meaning of the Securities Act or the Securities Exchange Act of 1934, as amended, (the “Exchange Act”), against any losses, claims, damages, or liabilities (joint or
several) to which they may become subject under the Securities Act, the Exchange Act or other federal or state law, insofar as such losses, claims, damages, or liabilities (or actions in respect thereof) arise out of or are based upon any of the
following statements, omissions or violations (each a “Violation”): 
 (i) any untrue statement or alleged untrue
statement of a material fact contained in such registration statement, including any preliminary prospectus or final prospectus contained therein or any amendments or supplements thereto (including free writing prospectuses) and any other
communication, including oral communication; 
 (ii) the omission or alleged omission to state therein a material fact required to be
stated therein, or necessary to make the statements therein not misleading; or 

  
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 (iii) any violation or alleged violation by the Company of the Securities Act, the Exchange Act,
any federal or state securities law or any rule or regulation promulgated under the Securities Act, the Exchange Act or any federal or state securities law in connection with the offering covered by such registration statement; 

and the Company will reimburse each such Holder, partner, member, officer or director, attorneys of such Holder or underwriter or Affiliates of such Holder or
underwriter for any legal or other expenses reasonably incurred by them, as incurred, in connection with investigating or defending any such loss, claim, damage, liability or action; provided, however, that the indemnity agreement
contained in this subsection 1.8(a) shall not apply to amounts paid in settlement of any such loss, claim, damage, liability or action if such settlement is effected without the consent of the Company (which consent shall not be unreasonably
withheld), nor shall the Company be liable in any such case for any such loss, claim, damage, liability or action to the extent that it arises out of or is based upon a Violation which occurs in reliance upon and in conformity with written
information furnished expressly for use in connection with such registration by such Holder, partner, member, stockholder, officer, director, underwriter or Affiliate of such Holder or underwriter. 

(b) By Selling Holders. To the extent permitted by law, each selling Holder will severally and not jointly indemnify and hold harmless
the Company, each of its directors, each of its officers who have signed the registration statement, each of its attorneys, each person, if any, who controls the Company within the meaning of the Securities Act, any underwriter and any other Holder
selling Registrable Securities under such registration statement or any of such other Holder’s partners, directors or officers or any person who controls such Holder within the meaning of the Securities Act or the Exchange Act, against any
losses, claims, damages or liabilities (joint or several) to which the Company or any such director, officer, attorney, controlling person, underwriter or other such Holder, partner, member, shareholder or director, officer or Affiliate of such
other Holder may become subject under the Securities Act, the Exchange Act or other federal or state law, insofar as such losses, claims, damages or liabilities (or actions in respect thereto) arise out of or are based upon any Violation, in each
case to the extent (and only to the extent) that such Violation occurs in reliance upon and in conformity with written information furnished by such Holder expressly for use in connection with such registration; and each such Holder will reimburse
any legal or other expenses reasonably incurred by the Company or any such director, officer, attorney, controlling person, underwriter or other Holder, partner, member, shareholder, officer, director or Affiliate of such other Holder in connection
with investigating or defending any such loss, claim, damage, 

  
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liability or action; provided, however, that the indemnity agreement contained in this subsection 1.8(b) shall not apply to amounts paid in settlement of any such loss, claim,
damage, liability or action if such settlement is effected without the consent of the indemnifying Holder, which consent shall not be unreasonably withheld; and provided further, that the total amounts payable in indemnity by a Holder under
this Section 1.8(b) in respect of any Violation shall not exceed the net proceeds (after underwriting discounts and commissions) received by such Holder in the registered offering out of which such Violation arises. 

(c) Notice. Promptly after receipt by an indemnified party under this Section 1.8 of notice of the commencement of any action
(including any governmental action), such indemnified party will, if a claim in respect thereof is to be made against any indemnifying party under this Section 1.8, deliver to the indemnifying party a written notice of the commencement thereof
and the indemnifying party shall have the right to participate in, and, to the extent the indemnifying party so desires, jointly with any other indemnifying party similarly noticed, to assume the defense thereof with counsel mutually satisfactory to
the parties; provided, however, that an indemnified party shall have the right to retain its own counsel, with the fees and expenses to be paid by the indemnifying party, if representation of such indemnified party by the counsel
retained by the indemnifying party would be inappropriate due to actual or potential conflict of interests between such indemnified party and any other party represented by such counsel in such proceeding. The failure to deliver written notice to
the indemnifying party within a reasonable time of the commencement of any such action, if prejudicial to its ability to defend such action, shall relieve such indemnifying party of any liability to the indemnified party to the extent of such
prejudice under this Section 1.8, but the omission so to deliver written notice to the indemnifying party will not relieve it of any liability that it may have to any indemnified party otherwise than under this Section 1.8. 

(d) Contribution. In order to provide for just and equitable contribution to joint liability under the Securities Act in any case in
which either (i) any Holder exercising rights under this Agreement, or any Affiliate of any such Holder, makes a claim for indemnification pursuant to this Section 1.8 but it is judicially determined (by the entry of a final judgment or
decree by a court of competent jurisdiction and the expiration of time to appeal or the denial of the last right of appeal) that such indemnification may not be enforced in such case notwithstanding the fact that this Section 1.8 provides for
indemnification in such case, or (ii) contribution under the Securities Act may be required on the part of any such selling Holder or any such Affiliate in circumstances for which indemnification is provided under this Section 1.8; then,
and in each such case, the Company and such Holder will contribute to the 

  
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aggregate losses, claims, damages or liabilities to which they may be subject (after contribution from others) in such proportion so that such Holder is responsible for the portion represented by
the percentage that the public offering price of its Registrable Securities offered by and sold under the registration statement bears to the aggregate public offering price of all securities offered by and sold under such registration statement,
and the Company and other selling Holders are responsible for the remaining portion; provided, however, that, in any such case, (A) no such Holder will be required to contribute any amount in excess of the net proceeds of all such
Registrable Securities offered and sold by such Holder pursuant to such registration statement and (B) no person or entity guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) will be entitled
to contribution from any person or entity who was not guilty of such fraudulent misrepresentation. 
 (e) Survival. The obligations
of the Company and Holders under this Section 1.8 shall survive the completion of any offering of Registrable Securities in a registration statement, and the termination of the Company’s obligations under Section 1.11 below. 

1.9 “Market Stand-Off” Agreement. Each Holder hereby agrees that it shall not, to the extent requested by the Company or an
underwriter of securities of the Company, sell or otherwise transfer or dispose of or engage in any other transaction regarding any Registrable Securities or other shares of stock of the Company held by such Holder immediately before the effective
date of the first registration statement of the Company filed under the Securities Act (other than sales to donees or affiliates of the Holder who agree to be similarly bound) for up to one hundred ninety-eight (198) days following the
effective date of such registration statement; provided, however, that all executive officers and directors of the Company and all holders of 2% or more of the Company’s outstanding securities enter into similar agreements. 

In order to enforce the foregoing covenant, (i) the Company shall have the right to place restrictive legends on the certificates
representing the shares subject to this Section 1.9 and to impose stop transfer instructions with respect to the Registrable Securities and such other shares of stock of each Holder (and the shares or securities of every other person subject to
the foregoing restriction) until the end of such period and (ii) the Holder agrees to execute the form of agreement consistent with this Section 1.9 requested by the Company and/or underwriter. 

1.10 Rule 144 Reporting. With a view to making available the benefits of certain rules and regulations of the SEC, which may at
any time permit the sale of the Registrable Securities to the public without registration, after such time as a public market exists for the Common Stock of the Company, the Company agrees to: 

(a) make and keep public information available, as those terms are understood and defined in Rule 144 under the Securities Act, at all
times after the effective date of the Initial Public Offering; 

  
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 (b) use its best efforts to file with the SEC in a timely manner all reports and other documents
required of the Company under the Securities Act and the Exchange Act (at any time after it has become subject to such reporting requirements); and 

(c) as long as a Holder owns any Registrable Securities, to furnish to the Holder forthwith upon request a written statement by the Company
as to its compliance with the reporting requirements of said Rule 144 (at any time after ninety (90) days after the effective date of the Initial Public Offering), and of the Securities Act and the Exchange Act (at any time after it has
become subject to the reporting requirements of the Exchange Act), a copy of the most recent annual or quarterly report of the Company and such other reports and documents of the Company as a Holder may reasonably request in availing itself of any
rule or regulation of the SEC allowing a Holder to sell any such securities without registration (at any time after the Company has become subject to the reporting requirements of the Exchange Act). 

1.11 Termination of the Company’s Obligations Under this Section 1. The Company shall have no obligations pursuant to
Sections 1.2, 1.3 and 1.4 with respect to any Registrable Securities proposed to be sold by a Holder in a registration pursuant to Section 1.2, 1.3 or 1.4 upon the earliest to occur of (a) that time when, in the opinion of counsel to
the Company, all such Registrable Securities proposed to be sold by a Holder may be sold without registration under the Securities Act pursuant to Rule 144(k) under the Securities Act within any 90-day period, (b) five (5) years after
the date of the Initial Public Offering and (c) a Liquidation Event. “Liquidation Event” shall mean (i) the liquidation, dissolution, or winding up of the Company, whether voluntary or involuntary and
(ii) unless the Holders of at least seventy percent (70%) of the then outstanding shares of Series A Preferred, Series B Preferred, Series C Preferred, Series D-1 Preferred and Series D-2 Preferred, voting together as a single class, elect
otherwise, (A) any merger, reverse merger, consolidation, reorganization or similar transaction or series of related transactions, pursuant to which the stockholders of the Company of record as constituted immediately prior to such transaction
or series of related transactions do not hold, immediately after such transaction or series of related transactions, at least 50% of the voting power of the surviving entity; (B) any transaction or series of related transactions pursuant to
which 50% or more of the voting power of the Company is transferred (other than issuances of securities by the Company, the primary purposes of which are to raise capital for the Company as determined in good faith by a resolution duly adopted by
the Board of Directors of the 

  
 14 

 
Corporation) or (C) a sale, conveyance, lease, transfer or other disposition of or grant of an exclusive license to all or substantially all of the assets of the Company that constitutes a
“Liquidation Event” under the Company’s Amended and Restated Certificate of Incorporation (the “Certificate of Incorporation”) which results in payments by the Company of the amounts required to be paid under
Article IV, Section 3 of the Certificate of Incorporation. 
 1.12 Limitations on Subsequent Registration Rights. From and after
the date of this Agreement, the Company shall not, without the prior written consent of the Holders of two-thirds (2/3) of the Registrable Securities Then Outstanding, enter into any agreement with any holder or prospective holder of any
securities of the Company that provides such holder or prospective holder with registration rights superior to, equal to or in conflict with, or that could in any way diminish or otherwise impair, the registration rights provided to the Investors
pursuant to this Section 1. 
 2. ASSIGNMENT AND AMENDMENT. 

2.1 Assignment. Notwithstanding anything herein to the contrary, the registration rights of a Holder under Section 1 may be
assigned only to (i) a party who holds at least fifty thousand (50,000) shares of Registrable Securities (as adjusted for stock splits, stock dividends, recapitalization and the like) following such assignment or (ii)(A) a
shareholder, partner, limited partner, member, beneficiary, Affiliate or investment company of such Holder, including, without limitation, any assignment by Apposite Capital LLP to any entity within Mizuho Financial Holdings Group; (B) a
spouse, child, parent or beneficiary of the estate of such Holder or (C) a trust for the benefit of the persons set forth in (A) or (B); provided, however, that no party may be assigned any of the foregoing rights unless the
Company is given written notice by the assigning party at the time of such assignment stating the name and address of the assignee and identifying the securities of the Company as to which the rights in question are being assigned; provided
further, that any such assignee shall receive such assigned rights subject to all the terms and conditions of this Agreement, including without limitation the provisions of this Section 2; provided further, that in the case
of an assignee that is not an Affiliate of the transferring Holder, such assignee is not a competitor of the Company, as determined in good faith by the Board of Directors. 

2.2 Amendment of Rights; Waiver. Any provision of this Agreement may be amended and the observance thereof may be waived (either
generally or in a particular instance and either retroactively or prospectively), only with the written consent of the Company and Investors (and/or any of their permitted successors or assigns) holding two-thirds (2/3) of the Registrable
Securities Then Outstanding. Any amendment or waiver effected in accordance with this Section 2.2 shall be binding upon each Investor, each Holder, each permitted successor or assignee of such Investor or Holder and the Company. 

  
 15 

 3. GENERAL PROVISIONS. 

3.1 Notices. All notices and other communications required or permitted hereunder shall be in writing and may be given by any means
(e.g., mail, telecopier, electronic mail, hand delivery, messenger, overnight courier service, etc.) addressed as set forth on Schedule A attached hereto, or at such other address as the Holder may designate in the future. All such notices,
requests and other communications will be deemed given upon delivery at the Holder’s proper address. Any Holder from time to time may change its address, facsimile number or other information for the purpose of notices to that Holder by giving
prior written notice to the Company specifying such change. 
 3.2 Entire Agreement. This Agreement constitutes and contains the
entire agreement and understanding of the parties with respect to the subject matter hereof and supersedes any and all prior negotiations, correspondence, agreements, understandings, duties or obligations between the parties respecting the subject
matter hereof. 
 3.3 Governing Law. This Agreement shall be governed by and construed exclusively in accordance with the internal
laws of the State of California as applied to agreements among California residents entered into and to be performed entirely within California, excluding that body of law relating to conflict of laws and choice of law. 

3.4 Severability. If one or more provisions of this Agreement are held to be unenforceable under applicable law, then such provision(s)
shall be excluded from this Agreement and the balance of this Agreement shall be interpreted as if such provision(s) were so excluded and shall be enforceable in accordance with its terms. 

3.5 Third Parties. Nothing in this Agreement, express or implied, is intended to confer upon any person, other than the parties hereto
and their successors and assigns, any rights or remedies under or by reason of this Agreement. 
 3.6 Successors and Assigns. Subject
to the provisions of Section 2.1, the provisions of this Agreement shall inure to the benefit of, and shall be binding upon, the successors and permitted assigns of the parties hereto. 

  
 16 

 3.7 Captions. The captions to sections of this Agreement have been inserted for
identification and reference purposes only and shall not be used to construe or interpret this Agreement. 
 3.8 Counterparts. This
Agreement may be executed in counterparts and by facsimile, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. 

3.9 Costs and Attorneys’ Fees. In the event that any action, suit or other proceeding is instituted concerning or arising out of
this Agreement or any transaction contemplated hereunder, the prevailing party shall recover all of such party’s costs and attorneys’ fees incurred in each such action, suit or other proceeding, including any and all appeals or petitions
therefrom. 
 3.10 Adjustments for Stock Splits and Certain Other Changes. Wherever in this Agreement there is a reference to a
specific number of shares of Common Stock or preferred stock of the Company of any class or series, then, upon the occurrence of any subdivision, combination or stock dividend of such class or series of stock, the specific number of shares so
referenced in this Agreement shall automatically be proportionally adjusted to reflect the affect on the outstanding shares of such class or series of stock by such subdivision, combination or stock dividend. 

3.11 [Reserved] 
 3.12
Aggregation of Registrable Securities. All Registrable Securities held or acquired by Affiliates of Holders shall be aggregated together for the purpose of determining the availability of any rights under this Agreement. 

[The remainder of this page is intentionally left blank.] 

  
 17 

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date and year first above written. 
  

			
	 COMPANY:
  

AMBRX, INC.

		
	By:	 	/s/ Stephen W. Kaldor
	Name:	 	Stephen W. Kaldor, Ph.D.
	Title:	 	President and Chief Executive Officer

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first written above. 
  

			
	 INVESTORS:
  

TAVISTOCK BIO XXV, INC.

		
	By:	 	/s/ Shehan Dissanayake
		 	Name: Shehan Dissanayake, Ph.D.
		 	Title:
                                         
                           

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first written above. 
  

			
	 INVESTORS:
  

5AM VENTURES LLC, by its Manager
  

5AM Partners LLC

		
		 	/s/ John D. Diekman
		 	John D. Diekman, Managing Director
		
		 	 5AM CO-INVESTORS LLC, by its Manager
  

5AM Partners LLC

		
		 	/s/ John D. Diekman
		 	John D. Diekman, Managing Director

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first written above. 
  

			
	 INVESTORS:
 VERSANT VENTURE
CAPITAL II, L.P., BY ITS GENERAL PARTNER
 VERSANT VENTURES II, L.L.C.

		
	By:	 	/s/ Brian G. Atwood
		 	Name: Brian G. Atwood
		 	Title:   Managing Director
	
	 VERSANT SIDE FUND II, L.P., by its

General Partner
  

VERSANT VENTURES II, L.L.C.

		
	By:	 	/s/ Brian G. Atwood
		 	Name: Brian G. Atwood
		 	Title:   Managing Director
	
	 VERSANT AFFILIATES FUND II-A, L.P., by its

General Partner
  

VERSANT VENTURES II, L.L.C.

		
	By:	 	/s/ Brian G. Atwood
		 	Name: Brian G. Atwood
		 	Title:   Managing Director

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first written above. 
  

			
	 INVESTORS:
  

MAVERICK FUND, L.D.C.
  

By:   Maverick Capital, Ltd.,

Its:    Investment Advisor

		
	By:	 	/s/ John T. McLafferty
		
	Name:	 	John T. McLafferty
		
	Its:	 	Limited Partner and General Counsel
	  
 MAVERICK FUND USA, LTD.

 
 By:   Maverick Capital, Ltd.,

Its:    Investment Advisor

		
	By:	 	 /s/ John T. McLafferty

		
	Name:	 	John T. McLafferty
		
	Its:	 	Limited Partner and General Counsel
	  
 MAVERICK FUND II, LTD

 
 By:   Maverick Capital, Ltd.,

Its:    Investment Advisor

		
	By:	 	/s/ John T. McLafferty
		
	Name:	 	John T. McLafferty
		
	Its:	 	Limited Partner and General Counsel

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first set forth above. 
  

			
	 INVESTORS:
  

ROCHE FINANCE LTD.

		
	By:	 	/s/ A. Unierzinger
	Name:	 	A. Unierzinger
	Title:	 	Authorized Signatory

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first set forth above. 
  

			
	By:	 	 /s/ Peter Schultz

		 	 Peter Schultz

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first set forth above. 
  

			
	INVESTORS:
		
	By:	 	/s/ John W. Wallen, III
		 	John W. Wallen, III

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first set forth above. 
  

			
	 INVESTORS:
  

APPOSITE HEALTHCARE FUND, L.P.

		
	By:	 	/s/ Allan Marchington
		 	Name: Allan Marchington
		 	Title:   Partner

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first set forth above. 
  

			
	 INVESTORS:
  

GLYNN VENTURES V, L.P.
  

By:   John W. Glynn

Its:    General Partner

		
	By:	 	/s/ John W. Glynn
	  
 GLYNN VENTURES VI, L.P.

 
 By:   Glynn Management, LLC

Its:    General Partner

		
	By	 	/s/ Steven Rosston
		 	 Name: Steven Rosston
 Title:
  Managing Director

	  
 GLYNN PARTNERS, L.P.

 
 By:   Glynn Management, LLC

Its:    General Partner

		
	By	 	/s/ Steven Rosston
		 	 Name: Steven Rosston
 Title:
  Managing Director

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated Registration
Rights Agreement as of the date first set forth above. 
  

			
	 INVESTORS:
  

HEALTHCARE PRIVATE EQUITY LIMITED PARTNERSHIP
  

By:   Waverley Healthcare Private Equity Limited,
its general partner

		
	By:	 	/s/ William Blair
	Name:	 	William Blair
	Title:	 	Director, Adamant Venture under Power of
		 	Attorney to the General Partner

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 IN WITNESS WHEREOF, the parties hereto have executed this Amended and Restated
Registration Rights Agreement as of the date first set forth above. 
  

			
	 INVESTORS:
  

MERCK BV

		
	By:	 	/s/ Cedric Hyde
	Name:	 	Cedric Hyde
	Title:	 	Director

  

			
	MERCK BV
		
	By:	 	/s/ Glyn Harris
	Name:	 	Glyn Harris
	Title:	 	Director

  

COUNTERPART SIGNATURE PAGE TO THE 

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

 SCHEDULE A 

Investors 
  

																					
	 Purchaser
	 	Number of Shares of
Series A Preferred	 	 	Number of Shares of
Series B Preferred	 	 	Number of Shares of
Series C Preferred	 	 	Number of Shares of
Series D-1 Preferred	 	 	Number of Shares of
Series D-2 Preferred	 
	 Tavistock BIO XXV, Inc.

c/o Tavistock Life Sciences

9381 Judicial Drive, Suite 200

San Diego, CA 92121
	 	 	7,335,133	  	 	 	0	  	 	 	6,153,904	  	 	 	0	  	 	 	0	  
	 5 AM Ventures, LLC

c/o 5AM Ventures

3000 Sand Hill Road

Building 4, Suite 230

Menlo Park, CA 94025
	 	 	2,655,741	  	 	 	0	  	 	 	1,250,000	  	 	 	0	  	 	 	0	  
	 5 AM Co-Investors, LLC

c/o 5AM Ventures

3000 Sand Hill Road

Building 4, Suite 230

Menlo Park, CA 94025
	 	 	379,393	  	 	 	0	  	 	 	178,571	  	 	 	0	  	 	 	0	  
	 Versant Venture Capital II, L.P.

c/o Versant Ventures

3000 Sand Hill Road,

Bldg 4, Suite 210

Menlo Park, CA 94025
	 	 	2,788,817	  	 	 	0	  	 	 	2,339,714	  	 	 	0	  	 	 	0	  
	 Versant Side Fund II, L.P.

c/o Versant Ventures

3000 Sand Hill Road,

Bldg 4, Suite 210

Menlo Park, CA 94025
	 	 	24,925	  	 	 	0	  	 	 	20,911	  	 	 	0	  	 	 	0	  

																					
	 Purchaser
	 	Number of Shares of
Series A Preferred	 	 	Number of Shares of
Series B Preferred	 	 	Number of Shares of
Series C Preferred	 	 	Number of Shares of
Series D-1 Preferred	 	 	Number of Shares of
Series D-2 Preferred	 
	 Versant Affiliates Fund II-A, L.P.

c/o Versant Ventures

3000 Sand Hill Road,

Bldg 4, Suite 210

Menlo Park, CA 94025
	 	 	52,924	  	 	 	0	  	 	 	44,401	  	 	 	0	  	 	 	0	  
	 Aravis Venture I, L.P.

c/o Venture Associates AG

Lehfrauenweg 10

CH-8053 Zurich

Switzerland
	 	 	1,094,668	  	 	 	0	  	 	 	571,429	  	 	 	0	  	 	 	0	  
	 Maverick Fund, L.D.C.

300 Crescent Court

18th Floor

Dallas, TX 75201
	 	 	2,997,600	  	 	 	0	  	 	 	2,465,923	  	 	 	0	  	 	 	0	  
	 Maverick Fund USA, Ltd.

300 Crescent Court

18th Floor

Dallas, TX 75201
	 	 	1,463,700	  	 	 	0	  	 	 	1,007,429	  	 	 	0	  	 	 	0	  
	 Maverick Fund II, Ltd.

300 Crescent Court

18th Floor

Dallas, TX 75201
	 	 	2,205,366	  	 	 	0	  	 	 	2,119,733	  	 	 	0	  	 	 	0	  
	 CMEA Ventures Life Sciences 2000, L.P.

c/o CMEA Ventures

One Embarcadero Center

Suite 3250

San Francisco, CA 94111
	 	 	353,378	  	 	 	0	  	 	 	296,471	  	 	 	0	  	 	 	0	  
	 CMEA Ventures Life Sciences 2000,

Civil Law Partnership

c/o CMEA Ventures

One Embarcadero Center

Suite 3250

San Francisco, CA 94111
	 	 	21,249	  	 	 	0	  	 	 	17,827	  	 	 	0	  	 	 	0	  

																					
	 Purchaser
	 	Number of Shares of
Series A Preferred	 	 	Number of Shares of
Series B Preferred	 	 	Number of Shares of
Series C Preferred	 	 	Number of Shares of
Series D-1 Preferred	 	 	Number of Shares of
Series D-2 Preferred	 
	 CMEA Ventures VI, L.P

c/o CMEA Ventures

One Embarcadero Center

Suite 3250

San Francisco, CA 94111
	 	 	676,321	  	 	 	0	  	 	 	567,408	  	 	 	0	  	 	 	0	  
	 CMEA Ventures VI GmbH & Co. KG

c/o CMEA Ventures

One Embarcadero Center

Suite 3250

San Francisco, CA 94111
	 	 	15,718	  	 	 	0	  	 	 	13,187	  	 	 	0	  	 	 	0	  
	 Twilight Venture Partners, LLC

111 Monument Circle

Suite 4700

Indianapolis, IN 46204
	 	 	266,667	  	 	 	0	  	 	 	223,724	  	 	 	0	  	 	 	0	  
	 Alexandria Equities, LLC

c/o Alexandria Real Estate Equities, Inc.

385 E. Colorado Boulevard, Suite 299

Pasadena, CA 91101
	 	 	333,333	  	 	 	0	  	 	 	279,654	  	 	 	0	  	 	 	0	  
	 Roche Finance Ltd.

124 Grenzacherstrasse

Basel, Switzerland

4070
	 	 	0	  	 	 	2,380,952	  	 	 	1,997,530	  	 	 	0	  	 	 	0	  
	 Jerome Chao

109 Deanna Ct

Niskayuna, NY 12309-1333
	 	 	22,334	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 Erie Chao

36 Larned Road

Summit, NJ 07901
	 	 	22,333	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 James Chao

17 Country Club Lane

Scarborough, NY 10510
	 	 	22,333	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 T. Trust, Clyde T. Turner, Trustee

9511 Orient Express Ct.

Las Vegas, NV 89145
	 	 	80,000	  	 	 	0	  	 	 	123,048	  	 	 	0	  	 	 	0	  

																					
	 Purchaser
	 	Number of Shares of
Series A Preferred	 	 	Number of Shares of
Series B Preferred	 	 	Number of Shares of
Series C Preferred	 	 	Number of Shares of
Series D-1 Preferred	 	 	Number of Shares of
Series D-2 Preferred	 
	 Professor Peter B. Dervan

Dept of Chemistry

MC 164-30

California Institute of Technology

1200 E. California Blvd.

Pasadena, CA 91125
	 	 	66,666	  	 	 	0	  	 	 	55,930	  	 	 	0	  	 	 	0	  
	 Dr. Hsin-Soon Hsieh

218 Pines Bridge Road

Millwood, NY 10546
	 	 	20,001	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 Shirley and Steve Clifford

1020 East Moyamensing Avenue

Philadelphia, PA 19147-4321
	 	 	39,999	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 John and Pirkko Maguire as Trustees for

the Maguire Family Trust Dated April 23, 1989

4611 Rising Hill Court

Oakland, CA 94619
	 	 	183,667	  	 	 	0	  	 	 	156,886	  	 	 	0	  	 	 	0	  
	 Drs. Troy E. Wilson and Linda Hsieh-Wilson

575 Old Mill Road

San Marino, CA 91108
	 	 	213,334	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 Q Investments L.P.

3773 Howard Hughes Parkway

Suite 500 North

Las Vegas, NV 89109
	 	 	80,000	  	 	 	0	  	 	 	123,047	  	 	 	0	  	 	 	0	  
	 Peter Schultz

1650 La Jolla Rancho Road

La Jolla, California 92037
	 	 	200,000	  	 	 	0	  	 	 	167,793	  	 	 	0	  	 	 	0	  
	 Barbara A. Piette

8 Gracewood Park

Cambridge, MA 02138
	 	 	6,666	  	 	 	0	  	 	 	1,526	  	 	 	0	  	 	 	0	  
	 Isy Goldwasser, Trustee of the

Amangani Trust UDT dated July 19, 2001

3100 Central Expressway

Santa Clara, CA 95051
	 	 	133,333	  	 	 	0	  	 	 	111,861	  	 	 	0	  	 	 	0	  

																					
	 Purchaser
	 	Number of Shares of
Series A Preferred	 	 	Number of Shares of
Series B Preferred	 	 	Number of Shares of
Series C Preferred	 	 	Number of Shares of
Series D-1 Preferred	 	 	Number of Shares of
Series D-2 Preferred	 
	 John W. Wallen, III

c/o Ambrx, Inc.

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	20,000	  	 	 	0	  	 	 	5,714	  	 	 	0	  	 	 	0	  
	 Emil J. Banich, TTEE, Emil J. Banich

Living Trust, UAD 3-21-88

3 Prestiwick Ct.

Dearborn, MI 48120
	 	 	33,333	  	 	 	0	  	 	 	27,965	  	 	 	0	  	 	 	0	  
	 Dr. Thomas O. Daniel

c/o Ambrx, Inc.

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	0	  	 	 	0	  	 	 	36,959	  	 	 	0	  	 	 	0	  
	 Robert E. Daniel, Jr.

c/o Ambrx, Inc.

Attn: Dr. Thomas O. Daniel

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	5,000	  	 	 	0	  	 	 	3,871	  	 	 	0	  	 	 	0	  
	 Mary Ann Daniel

c/o Ambrx, Inc.

Attn: Dr. Thomas O. Daniel

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	10,000	  	 	 	0	  	 	 	7,742	  	 	 	0	  	 	 	0	  
	 Lyle Robert Daniel

c/o Ambrx, Inc.

Attn: Dr. Thomas O. Daniel

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	6,500	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 Corine Marie Daniel

c/o Ambrx, Inc.

Attn: Dr. Thomas O. Daniel

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	6,500	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  
	 Glen Robert Daugherty Trust

Dated December 27, 2002

4019 Goldfinch St. #117

San Diego, CA 92103
	 	 	133,333	  	 	 	0	  	 	 	0	  	 	 	0	  	 	 	0	  

																					
	 Purchaser
	 	Number of Shares of
Series A Preferred	 	 	Number of Shares of
Series B Preferred	 	 	Number of Shares of
Series C Preferred	 	 	Number of Shares of
Series D-1 Preferred	 	 	Number of Shares of
Series D-2 Preferred	 
	 Dr. Bruce E. Kimmel

c/o Ambrx, Inc.

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	0	  	 	 	0	  	 	 	8,571	  	 	 	0	  	 	 	0	  
	 Hazel M. Aker

c/o Ambrx, Inc.

10975 North Torrey Pines Rd.

La Jolla, CA 92037
	 	 	0	  	 	 	0	  	 	 	20,000	  	 	 	0	  	 	 	0	  
	 Apposite Healthcare Fund, L.P.

Bracken House

One Friday Street

London EC4M 9JA

United Kingdom
	 	 	0	  	 	 	0	  	 	 	6,742,857	  	 	 	0	  	 	 	0	  
	 Glynn Ventures V, L.P.

c/o Glynn Capital Management, LLC

Building 4, Suite 235

3000 Sand Hill Road

Menlo Park, CA 94025
	 	 	0	  	 	 	0	  	 	 	285,714	  	 	 	0	  	 	 	0	  
	 Glynn Ventures VI, L.P.

c/o Glynn Capital Management, LLC

Building 4, Suite 235

3000 Sand Hill Road

Menlo Park, CA 94025
	 	 	0	  	 	 	0	  	 	 	285,714	  	 	 	0	  	 	 	0	  
	 Glynn Partners, L.P.

c/o Glynn Capital Management, LLC

Building 4, Suite 235

3000 Sand Hill Road

Menlo Park, CA 94025
	 	 	0	  	 	 	0	  	 	 	571,429	  	 	 	0	  	 	 	0	  
	 Dow Employees’ Pension Plan

c/o Diamond Capital Management, Inc.

1320 Waldo Avenue

Dorinco 100

Midland, Michigan 48674
	 	 	0	  	 	 	0	  	 	 	857,143	  	 	 	0	  	 	 	0	  

																					
	 Purchaser
	 	Number of Shares of
Series A Preferred	 	 	Number of Shares of
Series B Preferred	 	 	Number of Shares of
Series C Preferred	 	 	Number of Shares of
Series D-1 Preferred	 	 	Number of Shares of
Series D-2 Preferred	 
	 Union Carbide Employees’ Pension Plan

c/o Diamond Capital Management, Inc.

1320 Waldo Avenue

Dorinco 100

Midland, Michigan 48674
	 	 	0	  	 	 	0	  	 	 	571,428	  	 	 	0	  	 	 	0	  
	 Healthcare Private Equity Limited Partnership

Edinburgh One

Morrison Street

Edinburgh EH3 8BE

United Kingdom
	 	 	0	  	 	 	0	  	 	 	1,714,286	  	 	 	0	  	 	 	0	  
	 Merck BV

Tupolevlaan 41-61

1119 NW Schiphol-Rijk

Netherlands
	 	 	0	  	 	 	0	  	 	 	0	  	 	 	3,649,635	  	 	 	*	  
	 Total
	 	 	23,970,265	  	 	 	2,380,952	  	 	 	31,427,300	  	 	 	3,649,635	  	 	 	*	  

  

	*	This schedule will be automatically updated to reflect the Series D-2 Preferred purchased upon consummation of the Second Closing.EX-10.2

 Exhibit 10.2 

AMBRX, INC. 
 2003 STOCK
OPTION PLAN 
 1. ESTABLISHMENT, PURPOSE AND TERM OF
PLAN. 
 1.1 Establishment. The Ambrx, Inc. 2003 Stock Option Plan (the
“Plan”) is hereby established effective as of May 1, 2003. 
 1.2 Purpose. The purpose of
the Plan is to advance the interests of the Participating Company Group and its stockholders by providing an incentive to attract, retain and reward persons performing services for the Participating Company Group and by motivating such persons to
contribute to the growth and profitability of the Participating Company Group. 
 1.3 Term of Plan. The Plan shall continue in effect
until the earlier of its termination by the Board or the date on which all of the shares of Stock available for issuance under the Plan have been issued and all restrictions on such shares under the terms of the Plan and the agreements evidencing
Options granted under the Plan have lapsed. However, all Options shall be granted, if at all, within ten (10) years from the earlier of the date the Plan is adopted by the Board or the date the Plan is duly approved by the stockholders of the
Company. 
 2. DEFINITIONS AND CONSTRUCTION. 

2.1 Definitions. Whenever used herein, the following terms shall have their respective meanings set forth below: 

(a) “Board” means the Board of Directors of the Company. If one or more Committees have been appointed by the Board
to administer the Plan, “Board” also means such Committee(s). 
 (b) “Code” means the
Internal Revenue Code of 1986, as amended, and any applicable regulations promulgated thereunder. 
 (c)
“Committee” means the Compensation Committee or other committee of the Board duly appointed to administer the Plan and having such powers as shall be specified by the Board. Unless the powers of the Committee have been
specifically limited, the Committee shall have all of the powers of the Board granted herein, including, without limitation, the power to amend or terminate the Plan at any time, subject to the terms of the Plan and any applicable limitations
imposed by law. 
 (d) “Company” means Ambrx, Inc., a Delaware corporation, or any successor corporation thereto.

 (e) “Consultant” means a person engaged to provide consulting or advisory services (other than as an Employee or
a Director) to a Participating Company, provided that the identity of such person, the nature of such services or the entity to which such 

 
services are provided would not preclude the Company from offering or selling securities to such person pursuant to the Plan in reliance on either the exemption from registration provided by Rule
701 under the Securities Act or, if the Company is required to file reports pursuant to Section 13 or 15(d) of the Exchange Act, registration on a Form S-8 Registration Statement under the Securities Act. 

(f) “Director” means a member of the Board or of the board of directors of any other Participating Company. 

(g) “Disability” means the inability of the Optionee, in the opinion of a qualified physician acceptable to the
Company, to perform the major duties of the Optionee’s position with the Participating Company Group because of the sickness or injury of the Optionee. 

(h) “Employee” means any person treated as an employee (including an Officer or a Director who is also treated as an
employee) in the records of a Participating Company and, with respect to any Incentive Stock Option granted to such person, who is an employee for purposes of Section 422 of the Code; provided, however, that neither service as a Director nor
payment of a director’s fee shall be sufficient to constitute employment for purposes of the Plan. The Company shall determine in good faith and in the exercise of its discretion whether an individual has become or has ceased to be an Employee
and the effective date of such individual’s employment or termination of employment, as the case may be. For purposes of an individual’s rights, if any, under the Plan as of the time of the Company’s determination, all such
determinations by the Company shall be final, binding and conclusive, notwithstanding that the Company or any court of law or governmental agency subsequently makes a contrary determination. 

(i) “Exchange Act” means the Securities Exchange Act of 1934, as amended. 

(j) “Fair Market Value” means, as of any date, the value of a share of Stock or other property as determined by the
Board, in its discretion, or by the Company, in its discretion, if such determination is expressly allocated to the Company herein, subject to the following: 

(i) If, on such date, the Stock is listed on a national or regional securities exchange or market system, the Fair Market Value of a share of
Stock shall be the closing price of a share of Stock (or the mean of the closing bid and asked prices of a share of Stock if the Stock is so quoted instead) as quoted on the Nasdaq National Market, The Nasdaq SmallCap Market or such other national
or regional securities exchange or market system constituting the primary market for the Stock, as reported in The Wall Street Journal or such other source as the Company deems reliable. If the relevant date does not fall on a day on which
the Stock has traded on such securities exchange or market system, the date on which the Fair Market Value shall be established shall be the last day on which the Stock was so traded prior to the relevant date, or such other appropriate day as shall
be determined by the Board, in its discretion. 

  
 2 

 (ii) If, on such date, the Stock is not listed on a national or regional securities exchange or
market system, the Fair Market Value of a share of Stock shall be as determined by the Board in good faith without regard to any restriction other than a restriction which, by its terms, will never lapse. 

(k) “Incentive Stock Option” means an Option intended to be (as set forth in the Option Agreement) and which
qualifies as an incentive stock option within the meaning of Section 422(b) of the Code. 
 (l) “Insider”
means an Officer, a Director of the Company or other person whose transactions in Stock are subject to Section 16 of the Exchange Act. 

(m) “Nonstatutory Stock Option” means an Option not intended to be (as set forth in the Option Agreement), or which
does not qualify as, an Incentive Stock Option. 
 (n) “Officer” means any person designated by the Board as an
officer of the Company. 
 (o) “Option” means a right to purchase Stock pursuant to the terms and conditions of the
Plan. An Option may be either an Incentive Stock Option or a Nonstatutory Stock Option. 
 (p) “Option Agreement”
means a written agreement between the Company and an Optionee setting forth the terms, conditions and restrictions of the Option granted to the Optionee and any shares acquired upon the exercise thereof. An Option Agreement may consist of a form of
“Notice of Grant of Stock Option” and a form of “Stock Option Agreement” incorporated therein by reference, or such other form or forms as the Board may approve from time to time. 

(q) “Optionee” means a person who has been granted one or more Options. 

(r) “Parent Corporation” means any present or future “parent corporation” of the Company, as defined in
Section 424(e) of the Code. 
 (s) “Participating Company” means the Company or any Parent Corporation or
Subsidiary Corporation. 
 (t) “Participating Company Group” means, at any point in time, all corporations
collectively which are then Participating Companies. 
 (u) “Rule 16b-3” means
Rule 16b-3 under the Exchange Act, as amended from time to time, or any successor rule or regulation. 

(v) “Securities Act” means the Securities Act of 1933, as amended. 

  
 3 

 (w) “Service” means an Optionee’s employment or service with the
Participating Company Group, whether in the capacity of an Employee, a Director or a Consultant. An Optionee’s Service shall not be deemed to have terminated merely because of a change in the capacity in which the Optionee renders Service to
the Participating Company Group or a change in the Participating Company for which the Optionee renders such Service, provided that there is no interruption or termination of the Optionee’s Service. Furthermore, an Optionee’s Service with
the Participating Company Group shall not be deemed to have terminated if the Optionee takes any military leave, sick leave, or other bona fide leave of absence approved by the Company; provided, however, that if any such leave exceeds ninety
(90) days, on the ninety-first (91st) day of such leave the Optionee’s Service shall be deemed to have terminated unless the Optionee’s right to return to Service with the Participating Company Group is guaranteed by statute or
contract. Notwithstanding the foregoing, unless otherwise designated by the Company or required by law, a leave of absence shall not be treated as Service for purposes of determining vesting under the Optionee’s Option Agreement. The
Optionee’s Service shall be deemed to have terminated either upon an actual termination of Service or upon the corporation for which the Optionee performs Service ceasing to be a Participating Company. Subject to the foregoing, the Company, in
its discretion, shall determine whether the Optionee’s Service has terminated and the effective date of such termination. 
 (x)
“Stock” means the common stock of the Company, as adjusted from time to time in accordance with Section 4.2. 

(y) “Subsidiary Corporation” means any present or future “subsidiary corporation” of the Company, as
defined in Section 424(f) of the Code. 
 (z) “Ten Percent Owner Optionee” means an Optionee who, at the time
an Option is granted to the Optionee, owns stock possessing more than ten percent (10%) of the total combined voting power of all classes of stock of a Participating Company within the meaning of Section 422(b)(6) of the Code. 

2.2 Construction. Captions and titles contained herein are for convenience only and shall not affect the meaning or interpretation of
any provision of the Plan. Except when otherwise indicated by the context, the singular shall include the plural and the plural shall include the singular. Use of the term “or” is not intended to be exclusive, unless the context clearly
requires otherwise. 
 3. ADMINISTRATION. 

3.1 Administration by the Board. The Plan shall be administered by the Board. All questions of interpretation of the Plan or of any
Option shall be determined by the Board, and such determinations shall be final and binding upon all persons having an interest in the Plan or such Option. 

3.2 Authority of Officers. Any Officer shall have the authority to act on behalf of the Company with respect to any matter, right,
obligation, determination or election that is the responsibility of or that is allocated to the Company herein, provided the Officer has apparent authority with respect to such matter, right, obligation, determination or election. 

  
 4 

 3.3 Powers of the Board. In addition to any other powers set forth in the Plan and subject
to the provisions of the Plan, the Board shall have the full and final power and authority, in its discretion: 
 (a) to determine the
persons to whom, and the time or times at which, Options shall be granted and the number of shares of Stock to be subject to each Option; 

(b) to designate Options as Incentive Stock Options or Nonstatutory Stock Options; 

(c) to determine the Fair Market Value of shares of Stock or other property; 

(d) to determine the terms, conditions and restrictions applicable to each Option (which need not be identical) and any shares acquired upon
the exercise thereof, including, without limitation, (i) the exercise price of the Option, (ii) the method of payment for shares purchased upon the exercise of the Option, (iii) the method for satisfaction of any tax withholding
obligation arising in connection with the Option or such shares, including by the withholding or delivery of shares of stock, (iv) the timing, terms and conditions of the exercisability of the Option or the vesting of any shares acquired upon
the exercise thereof, (v) the time of the expiration of the Option, (vi) the effect of the Optionee’s termination of Service with the Participating Company Group on any of the foregoing, and (vii) all other terms, conditions and
restrictions applicable to the Option or such shares not inconsistent with the terms of the Plan; 
 (e) to approve one or more forms of
Option Agreement; 
 (f) to amend, modify, extend, cancel or renew any Option or to waive any restrictions or conditions applicable to any
Option or any shares acquired upon the exercise thereof; 
 (g) to accelerate, continue, extend or defer the exercisability of any Option
or the vesting of any shares acquired upon the exercise thereof, including with respect to the period following an Optionee’s termination of Service with the Participating Company Group; 

(h) to prescribe, amend or rescind rules, guidelines and policies relating to the Plan, or to adopt supplements to, or alternative versions
of, the Plan, including, without limitation, as the Board deems necessary or desirable to comply with the laws of, or to accommodate the tax policy or custom of, foreign jurisdictions whose citizens may be granted Options; and 

(i) to correct any defect, supply any omission or reconcile any inconsistency in the Plan or any Option Agreement and to make all other
determinations and take such other actions with respect to the Plan or any Option as the Board may deem advisable to the extent not inconsistent with the provisions of the Plan or applicable law. 

  
 5 

 3.4 Administration with Respect to Insiders. With respect to participation by Insiders in
the Plan, at any time that any class of equity security of the Company is registered pursuant to Section 12 of the Exchange Act, the Plan shall be administered in compliance with the requirements, if any, of
Rule 16b-3. 
 3.5 Indemnification. In addition to such other rights of indemnification
as they may have as members of the Board or officers or employees of the Participating Company Group, members of the Board and any officers or employees of the Participating Company Group to whom authority to act for the Board or the Company is
delegated shall be indemnified by the Company against all reasonable expenses, including attorneys’ fees, actually and necessarily incurred in connection with the defense of any action, suit or proceeding, or in connection with any appeal
therein, to which they or any of them may be a party by reason of any action taken or failure to act under or in connection with the Plan, or any right granted hereunder, and against all amounts paid by them in settlement thereof (provided such
settlement is approved by independent legal counsel selected by the Company) or paid by them in satisfaction of a judgment in any such action, suit or proceeding, except in relation to matters as to which it shall be adjudged in such action, suit or
proceeding that such person is liable for gross negligence, bad faith or intentional misconduct in duties; provided, however, that within sixty (60) days after the institution of such action, suit or proceeding, such person shall offer to the
Company, in writing, the opportunity at its own expense to handle and defend the same. 
 4. SHARES
SUBJECT TO PLAN. 
 4.1 Maximum Number of Shares Issuable. Subject
to adjustment as provided in Section 4.2, the maximum aggregate number of shares of Stock that may be issued under the Plan shall be Four Million Three Hundred Twenty-five Thousand (4,325,000) and shall consist of authorized but unissued
or reacquired shares of Stock or any combination thereof. If an outstanding Option for any reason expires or is terminated or canceled or if shares of Stock are acquired upon the exercise of an Option subject to a Company repurchase option and are
repurchased by the Company at the Optionee’s exercise price, the shares of Stock allocable to the unexercised portion of such Option or such repurchased shares of Stock shall again be available for issuance under the Plan. However, except as
adjusted pursuant to Section 4.2, in no event shall more than Four Million Three Hundred Twenty-five Thousand (4,325,000) shares of Stock be available for issuance pursuant to the exercise of Incentive Stock Options (the
“ISO Share Issuance Limit”). Notwithstanding the foregoing, at any such time as the offer and sale of securities pursuant to the Plan is subject to compliance with Section 260.140.45 of Title 10 of the
California Code of Regulations (“Section 260.140.45”), the total number of shares of Stock issuable upon the exercise of all outstanding Options (together with options outstanding under any other stock option
plan of the Company) and the total number of shares provided for under any stock bonus or similar plan of the Company shall not exceed thirty percent (30%) (or such other higher percentage limitation as may be approved by the stockholders of
the Company pursuant to Section 260.140.45) of the then outstanding shares of the Company as calculated in accordance with the conditions and exclusions of Section 260.140.45. 

  
 6 

 4.2 Adjustments for Changes in Capital Structure. In the event of any stock dividend,
stock split, reverse stock split, recapitalization, combination, reclassification or similar change in the capital structure of the Company, appropriate adjustments shall be made in the number and class of shares subject to the Plan and to any
outstanding Options, in the ISO Share Issuance Limit set forth in Section 4.1, and in the exercise price per share of any outstanding Options. If a majority of the shares that are of the same class as the shares that are subject to outstanding
Options are exchanged for, converted into, or otherwise become (whether or not pursuant to an Ownership Change Event, as defined in Section 8.1) shares of another corporation (the “New Shares”), the Board
may unilaterally amend the outstanding Options to provide that such Options are exercisable for New Shares. In the event of any such amendment, the number of shares subject to, and the exercise price per share of, the outstanding Options shall be
adjusted in a fair and equitable manner as determined by the Board, in its discretion. Notwithstanding the foregoing, any fractional share resulting from an adjustment pursuant to this Section 4.2 shall be rounded down to the nearest whole
number, and in no event may the exercise price of any Option be decreased to an amount less than the par value, if any, of the stock subject to the Option. The adjustments determined by the Board pursuant to this Section 4.2 shall be final,
binding and conclusive. 
 5. ELIGIBILITY AND OPTION
LIMITATIONS. 
 5.1 Persons Eligible for Options. Options may be granted only to Employees,
Consultants, and Directors. For purposes of the foregoing sentence, “Employees,” “Consultants” and “Directors” shall include prospective Employees, prospective Consultants and prospective Directors to whom Options are
granted in connection with written offers of an employment or other service relationship with the Participating Company Group. Eligible persons may be granted more than one (1) Option. However, eligibility in accordance with this Section shall
not entitle any person to be granted an Option, or, having been granted an Option, to be granted an additional Option. 
 5.2 Option
Grant Restrictions. Any person who is not an Employee on the effective date of the grant of an Option to such person may be granted only a Nonstatutory Stock Option. An Incentive Stock Option granted to a prospective Employee upon the condition
that such person become an Employee shall be deemed granted effective on the date such person commences Service with a Participating Company, with an exercise price determined as of such date in accordance with Section 6.1. 

5.3 Fair Market Value Limitation. To the extent that options designated as Incentive Stock Options (granted under all stock option
plans of the Participating Company Group, including the Plan) become exercisable by an Optionee for the first time during any calendar year for Stock having a Fair Market Value greater than One Hundred Thousand Dollars ($100,000), the portions of
such options that exceed such amount shall be treated as Nonstatutory Stock Options. For purposes of this Section 5.3, options designated as Incentive Stock Options shall be taken into account in the order in which they were granted, and the
Fair Market Value of stock shall be determined as of the time the option with respect to such stock is granted. If the Code is amended to provide for a different limitation from that set forth in this Section 5.3, such different limitation
shall be deemed incorporated herein effective as of the date and with respect 

  
 7 

 
to such Options as required or permitted by such amendment to the Code. If an Option is treated as an Incentive Stock Option in part and as a Nonstatutory Stock Option in part by reason of the
limitation set forth in this Section 5.3, the Optionee may designate which portion of such Option the Optionee is exercising. In the absence of such designation, the Optionee shall be deemed to have exercised the Incentive Stock Option portion
of the Option first. Separate certificates representing each such portion shall be issued upon the exercise of the Option. 
 6.
TERMS AND CONDITIONS OF OPTIONS. 

Options shall be evidenced by Option Agreements specifying the number of shares of Stock covered thereby, in such form as the Board shall from
time to time establish. No Option or purported Option shall be a valid and binding obligation of the Company unless evidenced by a fully executed Option Agreement. Option Agreements may incorporate all or any of the terms of the Plan by reference
and shall comply with and be subject to the following terms and conditions: 
 6.1 Exercise Price. The exercise price for each Option
shall be established in the discretion of the Board; provided, however, that (a) the exercise price per share for an Incentive Stock Option shall not be less than the Fair Market Value of a share of Stock on the effective date of grant of the
Option, (b) the exercise price per share for a Nonstatutory Stock Option granted to a California resident shall not be less than eighty-five percent (85%) of the Fair Market Value of a share of Stock
on the effective date of grant of the Option, and (c) no Option granted to a Ten Percent Owner Optionee shall have an exercise price per share less than one hundred ten percent (110%) of the Fair Market Value of a share of Stock on the
effective date of grant of the Option. Notwithstanding the foregoing, an Option (whether an Incentive Stock Option or a Nonstatutory Stock Option) may be granted with an exercise price lower than the minimum exercise price set forth above if such
Option is granted pursuant to an assumption or substitution for another option in a manner qualifying under the provisions of Section 424(a) of the Code. 

6.2 Exercisability and Term of Options. Options shall be exercisable at such time or times, or upon such event or events, and subject
to such terms, conditions, performance criteria and restrictions as shall be determined by the Board and set forth in the Option Agreement evidencing such Option; provided, however, that (a) no Option shall be exercisable after the expiration
of ten (10) years after the effective date of grant of such Option, (b) no Incentive Stock Option granted to a Ten Percent Owner Optionee shall be exercisable after the expiration of five (5) years after the effective date of grant of
such Option, (c) no Option granted to a prospective Employee, prospective Consultant or prospective Director may become exercisable prior to the date on which such person commences Service with a Participating Company, and (d) with the
exception of an Option granted to an Officer, a Director or a Consultant, no Option granted to a California resident shall become exercisable at a rate less than twenty percent (20%) per year over a period of five (5) years from the
effective date of grant of such Option, subject to the Optionee’s continued Service. Subject to the foregoing, unless otherwise specified by the Board in the grant of an Option, any Option granted hereunder shall terminate ten (10) years
after the effective date of grant of the Option, unless earlier terminated in accordance with its provisions. 

  
 8 

 6.3 Payment of Exercise Price. 

(a) Forms of Consideration Authorized. Except as otherwise provided below, payment of the exercise price for the number of
shares of Stock being purchased pursuant to any Option shall be made (i) in cash, by check or cash equivalent, (ii) by tender to the Company, or attestation to the ownership, of shares of Stock owned by the Optionee having a Fair Market
Value not less than the exercise price, (iii) by delivery of a properly executed notice together with irrevocable instructions to a broker providing for the assignment to the Company of the proceeds of a sale or loan with respect to some or all
of the shares being acquired upon the exercise of the Option (including, without limitation, through an exercise complying with the provisions of Regulation T as promulgated from time to time by the Board of Governors of the Federal Reserve
System) (a “Cashless Exercise”), (iv) by such other consideration as may be approved by the Board from time to time to the extent permitted by applicable law, or (v) by any combination thereof. The
Board may at any time or from time to time, by approval of or by amendment to the standard forms of Option Agreement described in Section 7, or by other means, grant Options which do not permit all of the foregoing forms of consideration to be
used in payment of the exercise price or which otherwise restrict one or more forms of consideration. 
 (b) Limitations on Forms of
Consideration. 
 (i) Tender of Stock. Notwithstanding the foregoing, an Option may not be exercised by tender to the
Company, or attestation to the ownership, of shares of Stock to the extent such tender or attestation would constitute a violation of the provisions of any law, regulation or agreement restricting the redemption of the Company’s stock. Unless
otherwise provided by the Board, an Option may not be exercised by tender to the Company, or attestation to the ownership, of shares of Stock unless such shares either have been owned by the Optionee for more than six (6) months (and not used
for another Option exercise by attestation during such period) or were not acquired, directly or indirectly, from the Company. 
 (ii)
Cashless Exercise. The Company reserves, at any and all times, the right, in the Company’s sole and absolute discretion, to establish, decline to approve or terminate any program or procedures for the exercise of Options by means of a
Cashless Exercise. 
 (iii) Payment by Promissory Note. No promissory note shall be permitted if the exercise of an Option using a
promissory note would be a violation of any law. Any permitted promissory note shall be on such terms as the Board shall determine. The Board shall have the authority to permit or require the Optionee to secure any promissory note used to exercise
an Option with the shares of Stock acquired upon the exercise of the Option or with other collateral acceptable to the Company. Unless otherwise provided by the Board, if the Company at any time is subject to the regulations promulgated by the Board
of Governors of the Federal Reserve System or any other governmental entity affecting the extension of credit in connection with the Company’s securities, any promissory note shall comply with such applicable regulations, and the Optionee shall
pay the unpaid principal and accrued interest, if any, to the extent necessary to comply with such applicable regulations. 

  
 9 

 6.4 Tax Withholding. The Company shall have the right, but not the obligation, to deduct
from the shares of Stock issuable upon the exercise of an Option, or to accept from the Optionee the tender of, a number of whole shares of Stock having a Fair Market Value, as determined by the Company, equal to all or any part of the federal,
state, local and foreign taxes, if any, required by law to be withheld by the Participating Company Group with respect to such Option or the shares acquired upon the exercise thereof. Alternatively or in addition, in its discretion, the Company
shall have the right to require the Optionee, through payroll withholding, cash payment or otherwise, including by means of a Cashless Exercise, to make adequate provision for any such tax withholding obligations of the Participating Company Group
arising in connection with the Option or the shares acquired upon the exercise thereof. The Fair Market Value of any shares of Stock withheld or tendered to satisfy any such tax withholding obligations shall not exceed the amount determined by the
applicable minimum statutory withholding rates. The Company shall have no obligation to deliver shares of Stock or to release shares of Stock from an escrow established pursuant to the Option Agreement until the Participating Company Group’s
tax withholding obligations have been satisfied by the Optionee. 
 6.5 Repurchase Rights. Shares issued under the Plan may be
subject to a right of first refusal, one or more repurchase options, or other conditions and restrictions as determined by the Board in its discretion at the time the Option is granted. The Company shall have the right to assign at any time any
repurchase right it may have, whether or not such right is then exercisable, to one or more persons as may be selected by the Company. Upon request by the Company, each Optionee shall execute any agreement evidencing such transfer restrictions prior
to the receipt of shares of Stock hereunder and shall promptly present to the Company any and all certificates representing shares of Stock acquired hereunder for the placement on such certificates of appropriate legends evidencing any such transfer
restrictions. 
 6.6 Effect of Termination of Service. 

(a) Option Exercisability. Subject to earlier termination of the Option as otherwise provided herein and unless otherwise
provided by the Board in the grant of an Option and set forth in the Option Agreement, an Option shall be exercisable after an Optionee’s termination of Service only during the applicable time period determined in accordance with this
Section 6.6 and thereafter shall terminate: 
 (i) Disability. If the Optionee’s Service terminates because of the
Disability of the Optionee, the Option, to the extent unexercised and exercisable on the date on which the Optionee’s Service terminated, may be exercised by the Optionee (or the Optionee’s guardian or legal representative) at any time
prior to the expiration of twelve (12) months (or such longer period of time as determined by the Board, in its discretion) after the date on which the Optionee’s Service terminated, but in any event no later than the date of expiration of
the Option’s term as set forth in the Option Agreement evidencing such Option (the “Option Expiration Date”). 

(ii) Death. If the Optionee’s Service terminates because of the death of the Optionee, the Option, to the extent unexercised and
exercisable on the date on which the Optionee’s Service terminated, may be exercised by the Optionee’s legal representative or 

  
 10 

 
other person who acquired the right to exercise the Option by reason of the Optionee’s death at any time prior to the expiration of twelve (12) months (or such longer period of time as
determined by the Board, in its discretion) after the date on which the Optionee’s Service terminated, but in any event no later than the Option Expiration Date. The Optionee’s Service shall be deemed to have terminated on account of death
if the Optionee dies within three (3) months (or such longer period of time as determined by the Board, in its discretion) after the Optionee’s termination of Service. 

(iii) Termination After Change in Control. The Board may, in its discretion, provide in any Option Agreement that if the
Optionee’s Service ceases as a result of “Termination After Change in Control” (as defined in such Option Agreement), then (1) the Option, to the extent unexercised and exercisable on the date on which the Optionee’s Service
terminated, may be exercised by the Optionee (or the Optionee’s guardian or legal representative) at any time prior to the expiration of six (6) months (or such longer period of time as determined by the Board, in its discretion) after the
date on which the Optionee’s Service terminated, but in any event no later than the Option Expiration Date, and (2) the exercisability and vesting of the Option and any shares acquired upon the exercise thereof shall be accelerated
effective as of the date on which the Optionee’s Service terminated to such extent, if any, as shall have been determined by the Board, in its discretion, and set forth in the Option Agreement. 

(iv) Other Termination of Service. If the Optionee’s Service terminates for any reason, except Disability, death or Termination
After Change in Control, the Option, to the extent unexercised and exercisable by the Optionee on the date on which the Optionee’s Service terminated, may be exercised by the Optionee at any time prior to the expiration of three (3) months
(or such longer period of time as determined by the Board, in its discretion) after the date on which the Optionee’s Service terminated, but in any event no later than the Option Expiration Date. 

(b) Extension if Exercise Prevented by Law. Notwithstanding the foregoing, if the exercise of an Option within the applicable
time periods set forth in Section 6.6(a) is prevented by the provisions of Section 10 below, the Option shall remain exercisable until three (3) months (or such longer period of time as determined by the Board, in its discretion)
after the date the Optionee is notified by the Company that the Option is exercisable, but in any event no later than the Option Expiration Date. 

(c) Extension if Optionee Subject to Section 16(b). Notwithstanding the foregoing, if a sale within the applicable time
periods set forth in Section 6.6(a) of shares acquired upon the exercise of the Option would subject the Optionee to suit under Section 16(b) of the Exchange Act, the Option shall remain exercisable until the earliest to occur of
(i) the tenth (10th) day following the date on which a sale of such shares by the Optionee would no longer be subject to such suit, (ii) the one hundred and ninetieth (190th) day after the Optionee’s termination of Service,
or (iii) the Option Expiration Date. 

  
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 6.7 Transferability of Options. During the lifetime of the Optionee, an Option shall be
exercisable only by the Optionee or the Optionee’s guardian or legal representative. No Option shall be assignable or transferable by the Optionee, except by will or by the laws of descent and distribution. Notwithstanding the foregoing, to the
extent permitted by the Board, in its discretion, and set forth in the Option Agreement evidencing such Option, a Nonstatutory Stock Option shall be assignable or transferable subject to the applicable limitations, if any, described in
Section 260.140.41 of Title 10 of the California Code of Regulations, Rule 701 under the Securities Act, and the General Instructions to Form S-8 Registration Statement under the Securities Act. 

7. STANDARD FORMS OF OPTION AGREEMENT.

 7.1 Option Agreement. Unless otherwise provided by the Board at the time the Option is granted, an Option shall comply with and be
subject to the terms and conditions set forth in the applicable form of Option Agreement approved by the Board concurrently with its adoption of the Plan and as amended from time to time. 

7.2 Authority to Vary Terms. The Board shall have the authority from time to time to vary the terms of any standard form of Option
Agreement described in this Section 7 either in connection with the grant or amendment of an individual Option or in connection with the authorization of a new standard form or forms; provided, however, that the terms and conditions of any such
new, revised or amended standard form or forms of Option Agreement are not inconsistent with the terms of the Plan. 
 8.
CHANGE IN CONTROL. 
 8.1 Definitions. 

(a) An “Ownership Change Event” shall be deemed to have occurred if any of the following occurs
with respect to the Company: (i) the direct or indirect sale or exchange in a single or series of related transactions by the stockholders of the Company of more than fifty percent (50%) of the voting stock of the Company; (ii) a
merger or consolidation in which the Company is a party; (iii) the sale, exchange, or transfer of all or substantially all of the assets of the Company; or (iv) a liquidation or dissolution of the Company. 

(b) A “Change in Control” shall mean an Ownership Change Event or a series of related Ownership Change Events
(collectively, a “Transaction”) wherein the stockholders of the Company immediately before the Transaction do not retain immediately after the Transaction, in substantially the same proportions as their ownership of shares of
the Company’s voting stock immediately before the Transaction, direct or indirect beneficial ownership of more than fifty percent (50%) of the total combined voting power of the outstanding voting securities of the Company or, in the case
of a Transaction described in Section 8.1(a)(iii), the corporation or other business entity to which the assets of the Company were transferred (the “Transferee”), as the case may be. For purposes of the preceding
sentence, indirect beneficial ownership shall include, without limitation, an interest resulting from ownership of the voting securities of one or more corporations or other business entities which own the Company or the Transferee, as the case may
be, either directly or through one or more subsidiary corporations or other business entities. The Board shall have the right to determine whether multiple sales or exchanges of the voting securities of the Company or multiple Ownership Change
Events are related, and its determination shall be final, binding and conclusive. 

  
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 8.2 Effect of Change in Control on Options. In the event of a Change in Control, the
surviving, continuing, successor, or purchasing corporation or other business entity or parent thereof, as the case may be (the “Acquiring Corporation”), may, without the consent of any Optionee, either assume
the Company’s rights and obligations under outstanding Options or substitute for outstanding Options substantially equivalent options for the Acquiring Corporation’s stock. In the event the Acquiring Corporation elects not to assume or
substitute for outstanding Options in connection with a Change in Control, the exercisability and vesting of each such outstanding Option and any shares acquired upon the exercise thereof held by Optionees whose Service has not terminated prior to
such date shall be accelerated, effective as of the date ten (10) days prior to the date of the Change in Control, to such extent, if any, as shall have been determined by the Board, in its discretion, and set forth in the Option Agreement
evidencing such Option. The exercise or vesting of any Option and any shares acquired upon the exercise thereof that was permissible solely by reason of this Section 8.2 and the provisions of such Option Agreement shall be conditioned upon the
consummation of the Change in Control. Any Options which are neither assumed or substituted for by the Acquiring Corporation in connection with the Change in Control nor exercised as of the date of the Change in Control shall terminate and cease to
be outstanding effective as of the date of the Change in Control. Notwithstanding the foregoing, shares acquired upon exercise of an Option prior to the Change in Control and any consideration received pursuant to the Change in Control with respect
to such shares shall continue to be subject to all applicable provisions of the Option Agreement evidencing such Option except as otherwise provided in such Option Agreement. Furthermore, notwithstanding the foregoing, if the corporation the stock
of which is subject to the outstanding Options immediately prior to an Ownership Change Event described in Section 8.1(a)(i) constituting a Change in Control is the surviving or continuing corporation and immediately after such Ownership Change
Event less than fifty percent (50%) of the total combined voting power of its voting stock is held by another corporation or by other corporations that are members of an affiliated group within the meaning of Section 1504(a) of the Code
without regard to the provisions of Section 1504(b) of the Code, the outstanding Options shall not terminate unless the Board otherwise provides in its discretion. 

9. PROVISION OF INFORMATION. 

At least annually, copies of the Company’s balance sheet and income statement for the last completed fiscal year shall be made available
to each Optionee and purchaser of shares of Stock upon the exercise of an Option, to the extent required by the California Code of Regulations. The Company shall not be required to provide such information to key employees whose duties in connection
with the Company assure them access to equivalent information. Furthermore, the Company shall deliver to each Optionee such disclosures as are required in accordance with Rule 701 under the Securities Act. 

  
 13 

 10. COMPLIANCE WITH SECURITIES
LAWS. 
 The grant of Options and the issuance of shares of Stock upon
exercise of Options shall be subject to compliance with all applicable requirements of federal, state and foreign law with respect to such securities. Options may not be exercised if the issuance of shares of Stock upon exercise would constitute a
violation of any applicable federal, state or foreign securities laws or other law or regulations or the requirements of any stock exchange or market system upon which the Stock may then be listed. In addition, no Option may be exercised unless
(a) a registration statement under the Securities Act shall at the time of exercise of the Option be in effect with respect to the shares issuable upon exercise of the Option or (b) in the opinion of legal counsel to the Company, the
shares issuable upon exercise of the Option may be issued in accordance with the terms of an applicable exemption from the registration requirements of the Securities Act. The inability of the Company to obtain from any regulatory body having
jurisdiction the authority, if any, deemed by the Company’s legal counsel to be necessary to the lawful issuance and sale of any shares hereunder shall relieve the Company of any liability in respect of the failure to issue or sell such shares
as to which such requisite authority shall not have been obtained. As a condition to the exercise of any Option, the Company may require the Optionee to satisfy any qualifications that may be necessary or appropriate, to evidence compliance with any
applicable law or regulation and to make any representation or warranty with respect thereto as may be requested by the Company. 
 11.
TERMINATION OR AMENDMENT OF PLAN. 

The Board may terminate or amend the Plan at any time. However, subject to changes in applicable law, regulations or rules that would permit
otherwise, without the approval of the Company’s stockholders, there shall be (a) no increase in the maximum aggregate number of shares of Stock that may be issued under the Plan (except by operation of the provisions of Section 4.2),
(b) no change in the class of persons eligible to receive Incentive Stock Options, and (c) no other amendment of the Plan that would require approval of the Company’s stockholders under any applicable law, regulation or rule. No
termination or amendment of the Plan shall affect any then outstanding Option unless expressly provided by the Board. In any event, no termination or amendment of the Plan may adversely affect any then outstanding Option without the consent of the
Optionee, unless such termination or amendment is required to enable an Option designated as an Incentive Stock Option to qualify as an Incentive Stock Option or is necessary to comply with any applicable law, regulation or rule. 

12. STOCKHOLDER APPROVAL. 

The Plan or any increase in the maximum aggregate number of shares of Stock issuable thereunder as provided in Section 4.1 (the
“Authorized Shares”) shall be approved by the stockholders of the Company within twelve (12) months of the date of adoption thereof by the Board. Options granted prior to stockholder approval of the Plan or
in excess of the Authorized Shares previously approved by the stockholders shall become exercisable no earlier than the date of stockholder approval of the Plan or such increase in the Authorized Shares, as the case may be. 

  
 14 

 IN WITNESS WHEREOF, the undersigned Secretary of the Company certifies that the foregoing sets
forth the Ambrx, Inc. 2003 Stock Option Plan as duly adopted by the Board on May 1, 2003. 
  

	
	/s/ T. Knox Bell
	Secretary

  
 15 

 THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE NOT BEEN QUALIFIED WITH THE COMMISSIONER OF
CORPORATIONS OF THE STATE OF CALIFORNIA AND THE ISSUANCE OF SUCH SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE CONSIDERATION THEREFOR PRIOR TO SUCH QUALIFICATION IS UNLAWFUL, UNLESS THE SALE OF SECURITIES IS EXEMPT FROM QUALIFICATION BY
SECTION 25100, 25102, OR 25105 OF THE CALIFORNIA CORPORATIONS CODE. THE RIGHTS OF ALL PARTIES TO THIS AGREEMENT ARE EXPRESSLY CONDITIONED UPON SUCH QUALIFICATION BEING OBTAINED, UNLESS THE SALE IS SO EXEMPT. 

THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR
DISTRIBUTION THEREOF. NO SUCH SALE OR DISPOSITION MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE SECURITIES ACT OF
1933. 
 AMBRX, INC. 

STOCK OPTION AGREEMENT 

(Standard Vesting) 
 Ambrx, Inc.
has granted to the individual (the “Optionee”) named in the Notice of Grant of Stock Option (the “Notice”) to which this Stock Option Agreement (the “Option Agreement”) is attached an option
(the “Option”) to purchase certain shares of Stock upon the terms and conditions set forth in the Notice and this Option Agreement. The Option has been granted pursuant to and shall in all respects be subject to the terms and
conditions of the Ambrx, Inc. 2003 Stock Option Plan (the “Plan”), as amended to the Date of Option Grant, the provisions of which are incorporated herein by reference. By signing the Notice, the Optionee: (a) represents that
the Optionee has received copies of, and has read and is familiar with the terms and conditions of, the Notice, the Plan and this Option Agreement; (b) accepts the Option subject to all of the terms and conditions of the Notice, the Plan and
this Option Agreement; and (c) agrees to accept as binding, conclusive and final all decisions or interpretations of the Board upon any questions arising under the Notice, the Plan or this Option Agreement. 

1. DEFINITIONS AND CONSTRUCTION. 

1.1 Definitions. Unless otherwise defined herein, capitalized terms shall have the meanings assigned to such terms
in the Notice or the Plan. 
 1.2 Construction. Captions and titles contained herein are for convenience only and shall
not affect the meaning or interpretation of any provision of this Option Agreement. Except when otherwise indicated by the context, the singular shall include the plural and the plural shall include the singular. Use of the term “or” is
not intended to be exclusive, unless the context clearly requires otherwise. 

  
 1 

 2. TAX CONSEQUENCES. 

2.1 Tax Status of Option. This Option is intended to have the tax status designated in the Notice. 

(a) Incentive Stock Option. If the Notice so designates, this Option is intended to be an Incentive Stock
Option within the meaning of Section 422(b) of the Code, but the Company does not represent or warrant that this Option qualifies as such. The Optionee should consult with the Optionee’s own tax advisor regarding the tax effects of this
Option and the requirements necessary to obtain favorable income tax treatment under Section 422 of the Code, including, but not limited to, holding period requirements. (NOTE TO OPTIONEE: If the Option is exercised more than three
(3) months after the date on which you cease to be an Employee (other than by reason of your death or permanent and total disability as defined in Section 22(e)(3) of the Code), the Option will be treated as a Nonstatutory Stock Option and
not as an Incentive Stock Option to the extent required by Section 422 of the Code.) 
 (b) Nonstatutory Stock Option.
If the Notice so designates, this Option is intended to be a Nonstatutory Stock Option and shall not be treated as an Incentive Stock Option within the meaning of Section 422(b) of the Code. 

2.2 ISO Fair Market Value Limitation. If the Notice designates this Option as an Incentive Stock Option, then to the extent that
the Option (together with all Incentive Stock Options granted to the Optionee under all stock option plans of the Participating Company Group, including the Plan) becomes exercisable for the first time during any calendar year for shares having a
Fair Market Value greater than One Hundred Thousand Dollars ($100,000), the portion of such options which exceeds such amount will be treated as Nonstatutory Stock Options. For purposes of this Section 2.2, options designated as Incentive Stock
Options are taken into account in the order in which they were granted, and the Fair Market Value of stock is determined as of the time the option with respect to such stock is granted. If the Code is amended to provide for a different limitation
from that set forth in this Section 2.2, such different limitation shall be deemed incorporated herein effective as of the date required or permitted by such amendment to the Code. If the Option is treated as an Incentive Stock Option in part
and as a Nonstatutory Stock Option in part by reason of the limitation set forth in this Section 2.2, the Optionee may designate which portion of such Option the Optionee is exercising. In the absence of such designation, the Optionee shall be
deemed to have exercised the Incentive Stock Option portion of the Option first. Separate certificates representing each such portion shall be issued upon the exercise of the Option. (NOTE TO OPTIONEE: If the aggregate Exercise Price of the Option
(that is, the Exercise Price multiplied by the Number of Option Shares) plus the aggregate exercise price of any other Incentive Stock Options you hold (whether granted pursuant to the Plan or any other stock option plan of the Participating Company
Group) is greater than $100,000, you should contact the President of the Company to ascertain whether the entire Option qualifies as an Incentive Stock Option.) 

  
 2 

 3. ADMINISTRATION. 

All questions of interpretation concerning this Option Agreement shall be determined by the Board. All determinations by the Board shall be
final and binding upon all persons having an interest in the Option. Any Officer shall have the authority to act on behalf of the Company with respect to any matter, right, obligation, or election which is the responsibility of or which is allocated
to the Company herein, provided the Officer has apparent authority with respect to such matter, right, obligation, or election. 
 4.
EXERCISE OF THE OPTION. 
 4.1 Right to
Exercise. Except as otherwise provided herein, the Option shall be exercisable on and after the Initial Vesting Date and prior to the termination of the Option (as provided in Section 6) in an amount not to exceed the number of Vested
Shares less the number of shares previously acquired upon exercise of the Option, subject to the Company’s repurchase rights set forth in Sections 11 and 12. In no event shall the Option be exercisable for more shares than the Number of Option
Shares. 
 4.2 Method of Exercise. Exercise of the Option shall be by written notice to the Company which must
state the election to exercise the Option, the number of whole shares of Stock for which the Option is being exercised and such other representations and agreements as to the Optionee’s investment intent with respect to such shares as may be
required pursuant to the provisions of this Option Agreement. The written notice must be signed by the Optionee and must be delivered in person, by certified or registered mail, return receipt requested, by confirmed facsimile transmission, or by
such other means as the Company may permit, to the President of the Company, or other authorized representative of the Participating Company Group, prior to the termination of the Option as set forth in Section 6, accompanied by (i) full
payment of the aggregate Exercise Price for the number of shares of Stock being purchased and (ii) an executed copy, if required herein, of the then current form of escrow agreement referenced below. The Option shall be deemed to be exercised
upon receipt by the Company of such written notice, the aggregate Exercise Price, and, if required by the Company, such executed agreement. 

4.3 Payment of Exercise Price. 

(a) Forms of Consideration Authorized. Except as otherwise provided below, payment of the aggregate
Exercise Price for the number of shares of Stock for which the Option is being exercised shall be made (i) in cash, by check, or cash equivalent, (ii) by tender to the Company, or attestation to the ownership, of whole shares of Stock
owned by the Optionee having a Fair Market Value not less than the aggregate Exercise Price, (iii) by means of a Cashless Exercise, as defined in Section 4.3(b), or (iv) by any combination of the foregoing. 

(b) Limitations on Forms of Consideration. 

(i) Tender of Stock. Notwithstanding the foregoing, the Option may not be exercised by tender to the Company, or attestation to the
ownership, of shares of Stock to the extent such tender or attestation would constitute a violation of the provisions of any law, regulation or agreement restricting the redemption of the Company’s stock. The Option may not be exercised by
tender to the Company, or attestation to the ownership, of shares of Stock unless such shares either have been owned by the Optionee for more than six (6) months (and not used for another option exercise by attestation during such period) or
were not acquired, directly or indirectly, from the Company. 

  
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 (ii) Cashless Exercise. A “Cashless Exercise” means the delivery of a
properly executed notice together with irrevocable instructions to a broker in a form acceptable to the Company providing for the assignment to the Company of the proceeds of a sale or loan with respect to some or all of the shares of Stock acquired
upon the exercise of the Option pursuant to a program or procedure approved by the Company (including, without limitation, through an exercise complying with the provisions of Regulation T as promulgated from time to time by the Board of
Governors of the Federal Reserve System). The Company reserves, at any and all times, the right, in the Company’s sole and absolute discretion, to decline to approve or terminate any such program or procedure. 

4.4 Tax Withholding. At the time the Option is exercised, in whole or in part, or at any time thereafter as
requested by the Company, the Optionee hereby authorizes withholding from payroll and any other amounts payable to the Optionee, and otherwise agrees to make adequate provision for (including by means of a Cashless Exercise to the extent permitted
by the Company), any sums required to satisfy the federal, state, local and foreign tax withholding obligations of the Participating Company Group, if any, which arise in connection with the Option, including, without limitation, obligations arising
upon (i) the exercise, in whole or in part, of the Option, (ii) the transfer, in whole or in part, of any shares acquired upon exercise of the Option, (iii) the operation of any law or regulation providing for the imputation of
interest, or (iv) the lapsing of any restriction with respect to any shares acquired upon exercise of the Option. The Option is not exercisable unless the tax withholding obligations of the Participating Company Group are satisfied.
Accordingly, the Company shall have no obligation to deliver shares of Stock or to release shares of Stock from an escrow established pursuant to this Option Agreement until the tax withholding obligations of the Participating Company Group have
been satisfied by the Optionee. 
 4.5 Certificate Registration. Except in the event the Exercise Price is paid
by means of a Cashless Exercise, the certificate for the shares as to which the Option is exercised shall be registered in the name of the Optionee, or, if applicable, in the names of the heirs of the Optionee. 

4.6 Restrictions on Grant of the Option and Issuance of Shares. The grant of the Option and the issuance of shares
of Stock upon exercise of the Option shall be subject to compliance with all applicable requirements of federal, state or foreign law with respect to such securities. The Option may not be exercised if the issuance of shares of Stock upon exercise
would constitute a violation of any applicable federal, state or foreign securities laws or other law or regulations or the requirements of any stock exchange or market system upon which the Stock may then be listed. In addition, the Option may not
be exercised unless (i) a registration statement under the Securities Act shall at the time of exercise of the Option be in effect with respect to the shares issuable upon exercise of the Option or (ii) in the opinion of legal counsel to
the Company, the shares issuable upon exercise of the Option may be issued in accordance with the terms of an applicable exemption from the registration requirements of the Securities Act. THE OPTIONEE IS CAUTIONED THAT THE OPTION MAY NOT BE
EXERCISED UNLESS THE FOREGOING CONDITIONS ARE SATISFIED. ACCORDINGLY, THE 

  
 4 

 
OPTIONEE MAY NOT BE ABLE TO EXERCISE THE OPTION WHEN DESIRED EVEN THOUGH THE OPTION IS VESTED. The inability of the Company to obtain from any regulatory body having jurisdiction the authority,
if any, deemed by the Company’s legal counsel to be necessary to the lawful issuance and sale of any shares subject to the Option shall relieve the Company of any liability in respect of the failure to issue or sell such shares as to which such
requisite authority shall not have been obtained. As a condition to the exercise of the Option, the Company may require the Optionee to satisfy any qualifications that may be necessary or appropriate, to evidence compliance with any applicable law
or regulation and to make any representation or warranty with respect thereto as may be requested by the Company. 
 4.7 Fractional
Shares. The Company shall not be required to issue fractional shares upon the exercise of the Option. 
 5.
NONTRANSFERABILITY OF THE OPTION. 
 The Option may be
exercised during the lifetime of the Optionee only by the Optionee or the Optionee’s guardian or legal representative and may not be assigned or transferred in any manner except by will or by the laws of descent and distribution. Following the
death of the Optionee, the Option, to the extent provided in Section 7, may be exercised by the Optionee’s legal representative or by any person empowered to do so under the deceased Optionee’s will or under the then applicable laws
of descent and distribution. 
 6. TERMINATION OF THE
OPTION. 
 The Option shall terminate and may no longer be exercised after the first to occur of
(a) the Option Expiration Date, (b) the last date for exercising the Option following termination of the Optionee’s Service as described in Section 7, or (c) a Change in Control to the extent provided in Section 8. 

7. EFFECT OF TERMINATION OF SERVICE.

 7.1 Option Exercisability. 

(a) Disability. If the Optionee’s Service terminates because of the Disability of the Optionee, the Option, to the extent
unexercised and exercisable on the date on which the Optionee’s Service terminated, may be exercised by the Optionee (or the Optionee’s guardian or legal representative) at any time prior to the expiration of twelve (12) months after
the date on which the Optionee’s Service terminated, but in any event no later than the Option Expiration Date. 
 (b)
Death. If the Optionee’s Service terminates because of the death of the Optionee, the Option, to the extent unexercised and exercisable on the date on which the Optionee’s Service terminated, may be exercised by the
Optionee’s legal representative or other person who acquired the right to exercise the Option by reason of the Optionee’s death at any time prior to the expiration of twelve (12) months after the date on which the Optionee’s
Service terminated, but in any event no later than the Option Expiration Date. The Optionee’s Service shall be deemed to have terminated on account of death if the Optionee dies within three (3) months after the Optionee’s termination
of Service. 

  
 5 

 (c) Termination After Change in Control. If the Optionee’s Service ceases as
a result of Termination After Change in Control (as defined below), (i) the Option, to the extent unexercised and exercisable on the date on which the Optionee’s Service terminated, may be exercised by the Optionee (or the Optionee’s
guardian or legal representative) at any time prior to the expiration of six (6) months after the date on which the Optionee’s Service terminated, but in any event no later than the Option Expiration Date, and (ii) fifty percent
(50%) of the shares, if any, that are unvested as of the date of the Optionee’s termination of Service shall become immediately vested and exercisable. 

(d) Other Termination of Service. If the Optionee’s Service terminates for any reason, except Disability, death or
Termination After Change in Control, the Option, to the extent unexercised and exercisable by the Optionee on the date on which the Optionee’s Service terminated, may be exercised by the Optionee at any time prior to the expiration of three
(3) months (or such other longer period of time as determined by the Board, in its discretion) after the date on which the Optionee’s Service terminated, but in any event no later than the Option Expiration Date. 

7.2 Extension if Exercise Prevented by Law. Notwithstanding the foregoing, if the exercise of the Option within the applicable time
periods set forth in Section 7.1 is prevented by the provisions of Section 4.6, the Option shall remain exercisable until three (3) months after the date the Optionee is notified by the Company that the Option is exercisable, but in
any event no later than the Option Expiration Date. 
 7.3 Extension if Optionee Subject to Section 16(b). Notwithstanding the
foregoing, if a sale within the applicable time periods set forth in Section 7.1 of shares acquired upon the exercise of the Option would subject the Optionee to suit under Section 16(b) of the Exchange Act, the Option shall remain
exercisable until the earliest to occur of (i) the tenth (10th) day following the date on which a sale of such shares by the Optionee would no longer be subject to such suit, (ii) the one hundred and ninetieth (190th) day after
the Optionee’s termination of Service, or (iii) the Option Expiration Date. 
 7.4 Certain Definitions. 

(a) “Termination After Change in Control” shall mean either of the following events occurring within twelve (12) months
after a Change in Control: 
 (i) termination by the Participating Company Group of the Optionee’s Service with the Participating
Company Group for any reason other than for Cause (as defined below); or 
 (ii) the Optionee’s resignation for Good Reason (as defined
below) from all capacities in which the Optionee is then rendering Service to the Participating Company Group within a reasonable period of time following the event constituting Good Reason. 

Notwithstanding any provision herein to the contrary, Termination After Change in Control shall not include any termination of the Optionee’s Service
with the Participating Company Group that (1) is for Cause (as defined below); (2) is a result of the Optionee’s death or disability; (3) is a result of the Optionee’s voluntary termination of Service other than for Good
Reason; or (4) occurs prior to the effectiveness of a Change in Control. 

  
 6 

 (b) “Cause” shall mean any of the following: (i) the Optionee’s
theft, dishonesty, or falsification of any Participating Company documents or records; (ii) the Optionee’s improper use or disclosure of a Participating Company’s confidential or proprietary information; (iii) any action by the
Optionee which has a detrimental effect on a Participating Company’s reputation or business; (iv) the Optionee’s failure or inability to perform any reasonable assigned duties after written notice from a Participating Company of, and
a reasonable opportunity to cure, such failure or inability; (v) any material breach by the Optionee of any employment agreement between the Optionee and a Participating Company, which breach is not cured pursuant to the terms of such
agreement; or (vi) the Optionee’s conviction (including any plea of guilty or nolo contendere) of any criminal act which impairs the Optionee’s ability to perform his or her duties with a Participating Company. 

(c) “Good Reason” shall mean any one or more of the following: 

(i) without the Optionee’s express written consent, the assignment to the Optionee of any duties, or any limitation of the
Optionee’s responsibilities, substantially inconsistent with the Optionee’s positions, duties, responsibilities and status with the Participating Company Group immediately prior to the date of the Change in Control; 

(ii) without the Optionee’s express written consent, the relocation of the principal place of the Optionee’s Service to a location
that is more than fifty (50) miles from the Optionee’s principal place of Service immediately prior to the date of the Change in Control, or the imposition of travel requirements substantially more demanding of the Optionee than such
travel requirements existing immediately prior to the date of the Change in Control; 
 (iii) any failure by the Participating Company
Group to pay, or any material reduction by the Participating Company Group of, (1) the Optionee’s base salary in effect immediately prior to the date of the Change in Control (unless reductions comparable in amount and duration are
concurrently made for all other employees of the Participating Company Group with responsibilities, organizational level and title comparable to the Optionee’s), or (2) the Optionee’s bonus compensation, if any, in effect immediately
prior to the date of the Change in Control (subject to applicable performance requirements with respect to the actual amount of bonus compensation earned by the Optionee); or 

(iv) any failure by the Participating Company Group to (1) continue to provide the Optionee with the opportunity to participate, on
terms no less favorable than those in effect for the benefit of any employee or service provider group which customarily includes a person holding the employment or service provider position or a comparable position with the Participating Company
Group then held by the Optionee, in any benefit or compensation plans and programs, including, but not limited to, the Participating Company Group’s life, disability, health, dental, medical, savings, profit sharing, stock purchase and
retirement plans, if any, in which the Optionee was participating immediately prior to the date of the Change in Control, or their equivalent, or (2) provide the Optionee with all other 

  
 7 

 
fringe benefits (or their equivalent) from time to time in effect for the benefit of any employee or service provider group which customarily includes a person holding the employment or service
provider position or a comparable position with the Participating Company Group then held by the Optionee. 
 8. CHANGE
IN CONTROL. 
 8.1 Definitions. 

(a) An “Ownership Change Event” shall be deemed to have occurred if any of the following occurs with respect to the Company:
(i) the direct or indirect sale or exchange in a single or series of related transactions by the stockholders of the Company of more than fifty percent (50%) of the voting stock of the Company; (ii) a merger or consolidation in which
the Company is a party; (iii) the sale, exchange, or transfer of all or substantially all of the assets of the Company; or (iv) a liquidation or dissolution of the Company. 

(b) A “Change in Control” shall mean an Ownership Change Event or a series of related Ownership Change Events (collectively,
a “Transaction”) wherein the stockholders of the Company immediately before the Transaction do not retain immediately after the Transaction, in substantially the same proportions as their ownership of shares of the Company’s
voting stock immediately before the Transaction, direct or indirect beneficial ownership of more than fifty percent (50%) of the total combined voting power of the outstanding voting securities of the Company or, in the case of a Transaction
described in Section 8.1(a)(iii), the corporation or other business entity to which the assets of the Company were transferred (the “Transferee”), as the case may be. For purposes of the preceding sentence, indirect beneficial
ownership shall include, without limitation, an interest resulting from ownership of the voting securities of one or more corporations or other business entities which own the Company or the Transferee, as the case may be, either directly or through
one or more subsidiary corporations or other business entities. The Board shall have the right to determine whether multiple sales or exchanges of the voting securities of the Company or multiple Ownership Change Events are related, and its
determination shall be final, binding and conclusive. 
 8.2 Effect of Change in Control on Option. In the event of a Change in
Control, the surviving, continuing, successor, or purchasing corporation or other business entity or parent thereof, as the case may be (the “Acquiring Corporation”), may, without the consent of the Optionee, either assume the
Company’s rights and obligations under the Option or substitute for the Option a substantially equivalent option for the Acquiring Corporation’s stock. In the event the Acquiring Corporation elects not to assume the Company’s rights
and obligations under the Option or substitute for the Option in connection with the Change in Control, the Option, to the extent not previously exercised, shall terminate and cease to be outstanding effective as of the date of the Change in
Control. Notwithstanding the foregoing, shares acquired upon exercise of the Option prior to the Change in Control and any consideration received pursuant to the Change in Control with respect to such shares shall continue to be subject to all
applicable provisions of this Option Agreement except as otherwise provided herein. Furthermore, notwithstanding the foregoing, if the corporation the stock of which is subject to the Option immediately prior to an Ownership Change Event described
in Section 8.1(a)(i) 

  
 8 

 
constituting a Change in Control is the surviving or continuing corporation and immediately after such Ownership Change Event less than fifty percent (50%) of the total combined voting power
of its voting stock is held by another corporation or by other corporations that are members of an affiliated group within the meaning of Section 1504(a) of the Code without regard to the provisions of Section 1504(b) of the Code, the
Option shall not terminate unless the Board otherwise provides in its discretion. 
 9. ADJUSTMENTS FOR
CHANGES IN CAPITAL STRUCTURE. 
 In the event of any stock
dividend, stock split, reverse stock split, recapitalization, combination, reclassification, or similar change in the capital structure of the Company, appropriate adjustments shall be made in the number, Exercise Price and class of shares of stock
subject to the Option. If a majority of the shares which are of the same class as the shares that are subject to the Option are exchanged for, converted into, or otherwise become (whether or not pursuant to an Ownership Change Event) shares of
another corporation (the “New Shares”), the Board may unilaterally amend the Option to provide that the Option is exercisable for New Shares. In the event of any such amendment, the Number of Option Shares and the Exercise Price
shall be adjusted in a fair and equitable manner, as determined by the Board, in its discretion. Notwithstanding the foregoing, any fractional share resulting from an adjustment pursuant to this Section 9 shall be rounded down to the nearest
whole number, and in no event may the Exercise Price be decreased to an amount less than the par value, if any, of the stock subject to the Option. The adjustments determined by the Board pursuant to this Section 9 shall be final, binding and
conclusive. 
 10. RIGHTS AS A STOCKHOLDER, EMPLOYEE
OR CONSULTANT. 
 The Optionee shall have no rights as a stockholder with respect to any
shares covered by the Option until the date of the issuance of a certificate for the shares for which the Option has been exercised (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the
Company). No adjustment shall be made for dividends, distributions or other rights for which the record date is prior to the date such certificate is issued, except as provided in Section 9. If the Optionee is an Employee, the Optionee
understands and acknowledges that, except as otherwise provided in a separate, written employment agreement between a Participating Company and the Optionee, the Optionee’s employment is “at will” and is for no specified term. Nothing
in this Option Agreement shall confer upon the Optionee any right to continue in the Service of a Participating Company or interfere in any way with any right of the Participating Company Group to terminate the Optionee’s Service as an Employee
or Consultant, as the case may be, at any time. 
 11. RIGHT OF FIRST
REFUSAL. 
 11.1 Grant of Right of First Refusal. Except as provided in Section 11.7 below,
in the event the Optionee, the Optionee’s legal representative, or other holder of shares acquired upon exercise of the Option proposes to sell, exchange, transfer, pledge, or otherwise dispose of any shares acquired upon exercise of the Option
(the “Transfer Shares”) to any person or entity, including, without limitation, any stockholder of a Participating Company, the Company shall have the right to repurchase the Transfer Shares under the terms and subject to the
conditions set forth in this Section 11 (the “Right of First Refusal”). 

  
 9 

 11.2 Notice of Proposed Transfer. Prior to any proposed transfer of the Transfer Shares,
the Optionee shall deliver written notice (the “Transfer Notice”) to the Company describing fully the proposed transfer, including the number of Transfer Shares, the name and address of the proposed transferee (the “Proposed
Transferee”) and, if the transfer is voluntary, the proposed transfer price, and containing such information necessary to show the bona fide nature of the proposed transfer. In the event of a bona fide gift or involuntary transfer, the
proposed transfer price shall be deemed to be the Fair Market Value of the Transfer Shares, as determined by the Board in good faith. If the Optionee proposes to transfer any Transfer Shares to more than one Proposed Transferee, the Optionee shall
provide a separate Transfer Notice for the proposed transfer to each Proposed Transferee. The Transfer Notice shall be signed by both the Optionee and the Proposed Transferee and must constitute a binding commitment of the Optionee and the Proposed
Transferee for the transfer of the Transfer Shares to the Proposed Transferee subject only to the Right of First Refusal. 
 11.3 Bona
Fide Transfer. If the Company determines that the information provided by the Optionee in the Transfer Notice is insufficient to establish the bona fide nature of a proposed voluntary transfer, the Company shall give the Optionee written notice
of the Optionee’s failure to comply with the procedure described in this Section 11, and the Optionee shall have no right to transfer the Transfer Shares without first complying with the procedure described in this Section 11. The
Optionee shall not be permitted to transfer the Transfer Shares if the proposed transfer is not bona fide. 
 11.4 Exercise of Right of
First Refusal. If the Company determines the proposed transfer to be bona fide, the Company shall have the right to purchase all, but not less than all, of the Transfer Shares (except as the Company and the Optionee otherwise agree) at the
purchase price and on the terms set forth in the Transfer Notice by delivery to the Optionee of a notice of exercise of the Right of First Refusal within thirty (30) days after the date the Transfer Notice is delivered to the Company. The
Company’s exercise or failure to exercise the Right of First Refusal with respect to any proposed transfer described in a Transfer Notice shall not affect the Company’s right to exercise the Right of First Refusal with respect to any
proposed transfer described in any other Transfer Notice, whether or not such other Transfer Notice is issued by the Optionee or issued by a person other than the Optionee with respect to a proposed transfer to the same Proposed Transferee. If the
Company exercises the Right of First Refusal, the Company and the Optionee shall thereupon consummate the sale of the Transfer Shares to the Company on the terms set forth in the Transfer Notice within sixty (60) days after the date the
Transfer Notice is delivered to the Company (unless a longer period is offered by the Proposed Transferee); provided, however, that in the event the Transfer Notice provides for the payment for the Transfer Shares other than in cash, the Company
shall have the option of paying for the Transfer Shares by the present value cash equivalent of the consideration described in the Transfer Notice as reasonably determined by the Company. For purposes of the foregoing, cancellation of any
indebtedness of the Optionee to any Participating Company shall be treated as payment to the Optionee in cash to the extent of the unpaid principal and any accrued interest canceled. 

  
 10 

 11.5 Failure to Exercise Right of First Refusal. If the Company fails to exercise the
Right of First Refusal in full (or to such lesser extent as the Company and the Optionee otherwise agree) within the period specified in Section 11.4 above, the Optionee may conclude a transfer to the Proposed Transferee of the Transfer Shares
on the terms and conditions described in the Transfer Notice, provided such transfer occurs not later than ninety (90) days following delivery to the Company of the Transfer Notice. The Company shall have the right to demand further assurances
from the Optionee and the Proposed Transferee (in a form satisfactory to the Company) that the transfer of the Transfer Shares was actually carried out on the terms and conditions described in the Transfer Notice. No Transfer Shares shall be
transferred on the books of the Company until the Company has received such assurances, if so demanded, and has approved the proposed transfer as bona fide. Any proposed transfer on terms and conditions different from those described in the Transfer
Notice, as well as any subsequent proposed transfer by the Optionee, shall again be subject to the Right of First Refusal and shall require compliance by the Optionee with the procedure described in this Section 11. 

11.6 Transferees of Transfer Shares. All transferees of the Transfer Shares or any interest therein, other than the Company, shall be
required as a condition of such transfer to agree in writing (in a form satisfactory to the Company) that such transferee shall receive and hold such Transfer Shares or interest therein subject to all of the terms and conditions of this Option
Agreement, including this Section 11 providing for the Right of First Refusal with respect to any subsequent transfer. Any sale or transfer of any shares acquired upon exercise of the Option shall be void unless the provisions of this
Section 11 are met. 
 11.7 Transfers Not Subject to Right of First Refusal. The Right of First Refusal shall not apply to any
transfer or exchange of the shares acquired upon exercise of the Option if such transfer or exchange is in connection with an Ownership Change Event. If the consideration received pursuant to such transfer or exchange consists of stock of a
Participating Company, such consideration shall remain subject to the Right of First Refusal unless the provisions of Section 11.9 below result in a termination of the Right of First Refusal. 

11.8 Assignment of Right of First Refusal. The Company shall have the right to assign the Right of First Refusal at any time, whether
or not there has been an attempted transfer, to one or more persons as may be selected by the Company. 
 11.9 Early Termination of Right
of First Refusal. The other provisions of this Option Agreement notwithstanding, the Right of First Refusal shall terminate and be of no further force and effect upon (a) the occurrence of a Change in Control, unless the Acquiring
Corporation assumes the Company’s rights and obligations under the Option or substitutes a substantially equivalent option for the Acquiring Corporation’s stock for the Option, or (b) the existence of a public market for the class of
shares subject to the Right of First Refusal. A “public market” shall be deemed to exist if (i) such stock is listed on a national securities exchange (as that term is used in the Exchange Act) or (ii) such stock is traded
on the over-the-counter market and prices therefor are published daily on business days in a recognized financial journal. 

  
 11 

 12. VESTED SHARE REPURCHASE
OPTION. 
 12.1 Grant of Vested Share Repurchase Option. Except as provided in Section 12.4
below, in the event of the termination of the Optionee’s Service with the Participating Company Group at any time for Cause (as defined in Section 7.4(b)), the Company shall have the right to repurchase the shares acquired by the Optionee
pursuant to the Option which are Vested Shares (the “Repurchase Shares”) under the terms and subject to the conditions set forth in this Section 12 (the “Vested Share Repurchase Option”). 

12.2 Exercise of Vested Share Repurchase Option. The Company may exercise the Vested Share Repurchase Option by written notice to the
Optionee or other holder of the Repurchase Shares, as the case may be, during the Repurchase Period. The “Repurchase Period” shall be the period commencing at the time set forth in Section 12.1 above and ending on the later of
(a) the date ninety (90) days after the commencement of the Repurchase Period or (b) the date ninety (90) days after the Option is last exercised. If the Company fails to give notice during the Repurchase Period, the Vested Share
Repurchase Option shall terminate (unless the Company and the Optionee have extended the time for the exercise of the Vested Share Repurchase Option) unless and until there is a subsequent Repurchase Event. Notwithstanding a termination of the
Vested Share Repurchase Option, the remaining provisions of this Option Agreement shall remain in full force and effect, including, without limitation, the Right of First Refusal set forth in Section 11. The Vested Share Repurchase Option must
be exercised, if at all, for all of the Repurchase Shares, except as the Company and the Optionee otherwise agree. 
 12.3 Payment for
Repurchase Shares. The repurchase price per share being repurchased by the Company pursuant to the Vested Share Repurchase Option shall be an amount equal to the Fair Market Value of the shares determined as of the date of the Repurchase Event
by the Board in good faith. Payment by the Company to the Optionee shall be made in cash on or before the last day of the Repurchase Period. 

12.4 Transfers Not Subject to Vested Share Repurchase Option. The Vested Share Repurchase Option shall not apply to any transfer or
exchange of shares acquired upon exercise of the Option if such transfer or exchange is in connection with an Ownership Change Event. If the consideration received pursuant to such transfer or exchange consists of stock of a Participating Company,
such consideration will remain subject to the Vested Share Repurchase Option unless the provisions of Section 12.6 below result in a termination of the Vested Share Repurchase Option. 

12.5 Assignment of Vested Share Repurchase Option. The Company shall have the right to assign the Vested Share Repurchase Option at any
time, whether or not such option is then exercisable, to one or more persons as may be selected by the Company. 
 12.6 Early Termination
of Vested Share Repurchase Option. The other provisions of this Option Agreement notwithstanding, the Vested Share Repurchase Option shall terminate and be of no further force and effect upon (a) the occurrence of a Change in Control,
unless the Acquiring Corporation assumes the Company’s rights and obligations under the Option or substitutes a substantially equivalent option for the Acquiring Corporation’s stock for the Option, or (b) the existence of a public
market, as defined in Section 11.9, for the class of shares subject to the Vested Share Repurchase Option. 

  
 12 

 13. ESCROW. 

13.1 Establishment of Escrow. To ensure that shares subject to the Right of First Refusal or the Vested Share Repurchase Option will be
available for repurchase, the Company may require the Optionee to deposit the certificate evidencing the shares which the Optionee purchases upon exercise of the Option with an agent designated by the Company under the terms and conditions of an
escrow agreement approved by the Company. If the Company does not require such deposit as a condition of exercise of the Option, the Company reserves the right at any time to require the Optionee to so deposit the certificate in escrow. Upon the
occurrence of an Ownership Change Event or a change, as described in Section 9, in the character or amount of any of the outstanding stock of the corporation the stock of which is subject to the provisions of this Option Agreement, any and all
new, substituted or additional securities or other property to which the Optionee is entitled by reason of the Optionee’s ownership of shares of Stock acquired upon exercise of the Option that remain, following such Ownership Change Event or
change described in Section 9, subject to the Right of First Refusal or Vested Share Repurchase Option, shall be immediately subject to the escrow to the same extent as such shares of Stock immediately before such event. The Company shall bear
the expenses of the escrow. 
 13.2 Delivery of Shares to Optionee. As soon as practicable after the expiration of the Right of First
Refusal and the Vested Share Repurchase Option, but not more frequently than twice each calendar year, the escrow agent shall deliver to the Optionee the shares and any other property no longer subject to such restrictions. 

13.3 Notices and Payments. In the event the shares and any other property held in escrow are subject to the Company’s exercise of
the Right of First Refusal or the Vested Share Repurchase Option, the notices required to be given to the Optionee shall be given to the escrow agent, and any payment required to be given to the Optionee shall be given to the escrow agent. Within
thirty (30) days after payment by the Company, the escrow agent shall deliver the shares and any other property which the Company has purchased to the Company and shall deliver the payment received from the Company to the Optionee. 

14. STOCK DISTRIBUTIONS SUBJECT TO OPTION
AGREEMENT. 
 If, from time to time, there is any stock dividend, stock split or other change, as
described in Section 9, in the character or amount of any of the outstanding stock of the corporation the stock of which is subject to the provisions of this Option Agreement, then in such event any and all new, substituted or additional
securities to which the Optionee is entitled by reason of the Optionee’s ownership of the shares acquired upon exercise of the Option shall be immediately subject to the Right of First Refusal and Vested Share Repurchase Option with the same
force and effect as the shares subject to the Right of First Refusal and Vested Share Repurchase Option immediately before such event. 

  
 13 

 15. NOTICE OF SALES UPON
DISQUALIFYING DISPOSITION. 
 The Optionee shall dispose of the shares acquired
pursuant to the Option only in accordance with the provisions of this Option Agreement. In addition, if the Notice designates this Option as an Incentive Stock Option, the Optionee shall (a) promptly notify the President of the Company
if the Optionee disposes of any of the shares acquired pursuant to the Option within one (1) year after the date the Optionee exercises all or part of the Option or within two (2) years after the Date of Option Grant and (b) provide
the Company with a description of the circumstances of such disposition. Until such time as the Optionee disposes of such shares in a manner consistent with the provisions of this Option Agreement, unless otherwise expressly authorized by the
Company, the Optionee shall hold all shares acquired pursuant to the Option in the Optionee’s name (and not in the name of any nominee) for the one-year period immediately after the exercise of the Option and the two-year period immediately
after Date of Option Grant. At any time during the one-year or two-year periods set forth above, the Company may place a legend on any certificate representing shares acquired pursuant to the Option requesting the transfer agent for the
Company’s stock to notify the Company of any such transfers. The obligation of the Optionee to notify the Company of any such transfer shall continue notwithstanding that a legend has been placed on the certificate pursuant to the preceding
sentence. 
 16. LEGENDS. 

The Company may at any time place legends referencing the Right of First Refusal or the Vested Share Repurchase Option, and any applicable
federal, state or foreign securities law restrictions on all certificates representing shares of stock subject to the provisions of this Option Agreement. The Optionee shall, at the request of the Company, promptly present to the Company any and all
certificates representing shares acquired pursuant to the Option in the possession of the Optionee in order to carry out the provisions of this Section. Unless otherwise specified by the Company, legends placed on such certificates may include, but
shall not be limited to, the following: 
 16.1 “THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES, THE SALE IS MADE IN ACCORDANCE WITH RULE 144 OR RULE 701
UNDER THE ACT, OR THE COMPANY RECEIVES AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY, STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH
ACT.” 
 16.2 “THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A RIGHT OF FIRST REFUSAL OPTION AND VESTED SHARE
REPURCHASE OPTION IN FAVOR OF THE CORPORATION OR ITS ASSIGNEE SET FORTH IN AN AGREEMENT BETWEEN THE CORPORATION AND THE REGISTERED HOLDER, OR SUCH HOLDER’S PREDECESSOR IN INTEREST, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL OFFICE OF THIS
CORPORATION.” 

  
 14 

 16.3 “THE SHARES EVIDENCED BY THIS CERTIFICATE WERE ISSUED BY THE CORPORATION TO THE
REGISTERED HOLDER UPON EXERCISE OF AN INCENTIVE STOCK OPTION AS DEFINED IN SECTION 422 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (“ISO”). IN ORDER TO OBTAIN THE PREFERENTIAL TAX TREATMENT AFFORDED TO ISOs, THE SHARES
SHOULD NOT BE TRANSFERRED PRIOR TO [INSERT DISQUALIFYING DISPOSITION DATE HERE]. SHOULD THE REGISTERED HOLDER ELECT TO TRANSFER ANY OF THE SHARES PRIOR TO THIS DATE AND FOREGO ISO TAX TREATMENT, THE TRANSFER AGENT FOR THE SHARES SHALL NOTIFY THE
CORPORATION IMMEDIATELY. THE REGISTERED HOLDER SHALL HOLD ALL SHARES PURCHASED UNDER THE INCENTIVE STOCK OPTION IN THE REGISTERED HOLDER’S NAME (AND NOT IN THE NAME OF ANY NOMINEE) PRIOR TO THIS DATE OR UNTIL TRANSFERRED AS DESCRIBED
ABOVE.” 
 17. LOCK-UP AGREEMENT. 

The Optionee hereby agrees that in the event of any underwritten public offering of stock, including an initial public offering of stock, made
by the Company pursuant to an effective registration statement filed under the Securities Act, the Optionee shall not offer, sell, contract to sell, pledge, hypothecate, grant any option to purchase or make any short sale of, or otherwise dispose of
any shares of stock of the Company or any rights to acquire stock of the Company for such period of time from and after the effective date of such registration statement as may be established by the underwriter for such public offering; provided,
however, that such period of time shall not exceed one hundred eighty (180) days from the effective date of the registration statement to be filed in connection with such public offering. The foregoing limitation shall not apply to shares
registered in the public offering under the Securities Act. 
 18. RESTRICTIONS ON
TRANSFER OF SHARES. 
 No shares acquired upon exercise of the Option may
be sold, exchanged, transferred (including, without limitation, any transfer to a nominee or agent of the Optionee), assigned, pledged, hypothecated or otherwise disposed of, including by operation of law, in any manner which violates any of the
provisions of this Option Agreement and any such attempted disposition shall be void. The Company shall not be required (a) to transfer on its books any shares which will have been transferred in violation of any of the provisions set forth in
this Option Agreement or (b) to treat as owner of such shares or to accord the right to vote as such owner or to pay dividends to any transferee to whom such shares will have been so transferred. 

19. MISCELLANEOUS PROVISIONS. 

19.1 Binding Effect. Subject to the restrictions on transfer set forth herein, this Option Agreement shall inure to the benefit of and
be binding upon the parties hereto and their respective heirs, executors, administrators, successors and assigns. 
 19.2 Termination or
Amendment. The Board may terminate or amend the Plan or the Option at any time; provided, however, that except as provided in Section 8.2 in connection with a Change in Control, no such termination or amendment may adversely affect

  
 15 

 
the Option or any unexercised portion hereof without the consent of the Optionee unless such termination or amendment is necessary to comply with any applicable law or government regulation or is
required to enable the Option, if designated an Incentive Stock Option in the Notice, to qualify as an Incentive Stock Option. No amendment or addition to this Option Agreement shall be effective unless in writing. 

19.3 Notices. Any notice required or permitted hereunder shall be given in writing and shall be deemed effectively given (except to the
extent that this Option Agreement provides for effectiveness only upon actual receipt of such notice) upon personal delivery or upon deposit in the United States Post Office, by registered or certified mail, with postage and fees prepaid, addressed
to the other party at the address shown below that party’s signature or at such other address as such party may designate in writing from time to time to the other party. 

19.4 Integrated Agreement. The Notice, this Option Agreement and the Plan constitute the entire understanding and agreement of the
Optionee and the Participating Company Group with respect to the subject matter contained herein or therein and supersedes any prior agreements, understandings, restrictions, representations, or warranties among the Optionee and the Participating
Company Group with respect to such subject matter other than those as set forth or provided for herein or therein. To the extent contemplated herein or therein, the provisions of the Notice and the Option Agreement shall survive any exercise of the
Option and shall remain in full force and effect. 
 19.5 Applicable Law. This Option Agreement shall be governed by the laws of the
State of California as such laws are applied to agreements between California residents entered into and to be performed entirely within the State of California. 

19.6 Counterparts. The Notice may be executed in counterparts, each of which shall be deemed an original, but all of which together
shall constitute one and the same instrument. 

  
 16 

			
	     Incentive Stock Option	  	Optionee:
                                         
                       
	     Nonstatutory Stock Option	  	
		  	Date:
                                         
                   

 STOCK OPTION EXERCISE NOTICE 

(STANDARD VESTING) 
 Ambrx, Inc. 

Attention: Chief Business Officer 
  

 
  

Ladies and Gentlemen: 
 1. Option.
I was granted an option (the “Option”) to purchase shares of the common stock (the “Shares”) of Ambrx, Inc. (the “Company”) pursuant to the Company’s 2003 Stock Option Plan (the
“Plan”), my Notice of Grant of Stock Option (the “Notice”) and my Stock Option Agreement (the “Option Agreement”) as follows: 

 

							
	Grant Number:	  		 	                                    
                                
			
	Date of Option Grant:	  		 	                                    
                                
			
	Number of Option Shares:	  		 	                                    
                                
			
	Exercise Price per Share:	  		 	$                                    
                             

 2. Exercise of Option. I hereby elect to exercise the Option to purchase the following number of
Shares: 
  

							
	Total Shares Purchased:	  		 	                                    
                                
		
	Total Exercise Price (Total Shares X Price per Share)	 	$                                    
                             

 3. Payments. I enclose payment in full of the total exercise price for the Shares in the
following form(s), as authorized by my Option Agreement: 
  

							
	 ̈  Cash:	  		 	$                                    
                             
			
	 ̈  Check:	  		 	$                                    
                             
			
	 ̈  Tender of Company Stock:	  		 	Contact Plan Administrator

  
 17 

 4. Tax Withholding. I authorize payroll withholding and otherwise will make
adequate provision for the federal, state, local and foreign tax withholding obligations of the Company, if any, in connection with the Option. If I am exercising a Nonstatutory Stock Option, I enclose payment in full of my withholding taxes, if
any, as follows: 
 (Contact Plan Administrator for amount of tax due.) 

 

							
	 ̈  Cash:	  		 	$	 	 
				
	 ̈  Check:	  		 	$	 	 

 5. Optionee Information. 

 

							
	My address is:	  	 
		
		  	 

							
		
	My Social Security Number is: 	  	 

 6. Notice of Disqualifying Disposition. If the Option is an Incentive Stock Option, I agree that
I will promptly notify the President of the Company if I transfer any of the Shares within one (1) year from the date I exercise all or part of the Option or within two (2) years of the Date of Option Grant. 

7. Binding Effect. I agree that the Shares are being acquired in accordance with and subject to the terms, provisions and
conditions of the Option Agreement, including the Right of First Refusal and Vested Share Repurchase Option set forth therein, to all of which I hereby expressly assent. This Agreement shall inure to the benefit of and be binding upon my heirs,
executors, administrators, successors and assigns. If required by the Company, I agree to deposit the certificate(s) evidencing the Shares, along with a blank stock assignment separate from certificate executed by me, with an escrow agent designated
by the Company, to be held pursuant to the Company’s standard Joint Escrow Instructions. 
 8. Transfer. I understand and
acknowledge that the Shares have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), and that consequently the Shares must be held indefinitely unless they are subsequently registered under the
Securities Act, an exemption from such registration is available, or they are sold in accordance with Rule 144 or Rule 701 under the Securities Act. I further understand and acknowledge that the Company is under no obligation to register
the Shares. I understand that the certificate or certificates evidencing the Shares will be imprinted with legends which prohibit the transfer of the Shares unless they are registered or such registration is not required in the opinion of legal
counsel satisfactory to the Company. 
 I am aware that Rule 144 under the Securities Act, which permits limited public resale of
securities acquired in a nonpublic offering, is not currently available with respect to the Shares and, in any event, is available only if certain conditions are satisfied. I understand that any sale of the Shares that might be made in reliance upon
Rule 144 may only be made in limited amounts in accordance with the terms and conditions of such rule and that a copy of Rule 144 will be delivered to me upon request. 

  
 18 

 I understand that I am purchasing the Shares pursuant to the terms of the Plan, the Notice and my
Option Agreement, copies of which I have received and carefully read and understand. 
  

	
	Very truly yours,
	
	   

	(Signature)

 Receipt of the above is hereby acknowledged. 
  

			
	AMBRX, INC.
		
	By:	 	 
		
	Title:	 	 
		
	Dated:	 	 

  
 19

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