Document:

Plain English Warrant Agreement - Triplepoint Capital LLC

 Exhibit 4.6 
 THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE HEREUNDER HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (the “1933 ACT”), OR ANY APPLICABLE STATE SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR
SALE, PLEDGED, OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY IN FORM AND SUBSTANCE TO YOU THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE 1933 ACT, OR ANY
APPLICABLE STATE SECURITIES LAWS 
 PLAIN ENGLISH WARRANT AGREEMENT 
 This is a PLAIN ENGLISH WARRANT AGREEMENT dated March 7, 2007 by and between BAYHILL THERAPEUTICS, INC., a Delaware corporation, and TRIPLEPOINT CAPITAL LLC, a Delaware limited liability company.

 The words “We”, “Us”, or “Our” refer to the warrant holder, which is TRIPLEPOINT CAPITAL LLC. The words “You” or
“Your” refers to the issuer, which is BAYHILL THERAPEUTICS, INC., and not to any individual. The words “The Parties” refers to both TRIPLEPOINT CAPITAL LLC and BAYHILL THERAPEUTICS, INC. This Plain English Warrant Agreement may
be referred to as the “Warrant Agreement”. 
 The Parties have entered into a Plain English Growth Capital Loan and Security Agreement dated as of
February 28, 2007, which may be referred to as the “Loan Agreement”. 
 In consideration of such Loan Agreement, the Parties agree to the
following mutual agreements and conditions set forth below: 
  

					
	WARRANT INFORMATION
			
	 Effective Date
	 	 Warrant Number
	 	 Loan Facility Number

	March 7, 2007	 	462-W-01	 	Gl-462

 Warrant Coverage 
 Subject to adjustment per Section I, the Warrant Coverage percentage is 5%. 
 Subject to
Section 1, the initial Warrant Coverage is $250,000 (5% of $5,000,000); the Warrant Coverage shall be increased by an additional 5% of each Advance in excess of initial Advances totaling $5,000,000 under the Loan Agreement. Subject to
Section 1, for avoidance of doubt, if We lend You Advances in the aggregate amount of $10,000,000, We will be entitled to aggregate Warrant Coverage not in excess of $500,000 (5% of $10,000,000), consisting of the initial Warrant Coverage of
$250,000 and additional Warrant Coverage of $250,000 (5% of $5,000,000). 
  

					
	 Number of Shares
	 	 Price Per Share
	 	 Type of Stock

	192,307; this number may increase based upon Your utilization of the facility set forth in the Loan Agreement, as set forth under the caption “Warrant Coverage,” or may
decrease pursuant to the terms of Section 1 of this Warrant Agreement under the caption “What You Agree to Grant Us.”	 	$1.30, subject to adjustment per the terms of Section 1 of this Warrant Agreement under the caption “What You Agree to Grant Us.”	 	Series B Preferred Stock

 1 

					
	OUR CONTACT INFORMATION
			
	 Name
	 	 Address For Notices
	 	 Contact Person

	TriplePoint Capital LLC	 	 2420 Sand Hill Road, Ste. 101
 Menlo Park, CA 94025
 Tel: (650) 854-2090
 Fax: (650) 854-2094
	 	 Sajal Srivastava, COO
 Tel: (650) 233-2102
 Fax: (650) 854-2094
 email: sks@triplepointcapital.com

	
	YOUR CONTACT INFORMATION
			
	 Customer Name
	 	 Address For Notices
	 	 Contact Person

	Bayhill Therapeutics, Inc.	 	 3400 West Bayshore Road
 Palo Alto, CA 94303
	 	 Mark Schwartz, Pres. & CEO
 Tel: (650) 320-2800
 Fax: (650) 320-2815
 email: mwschwartz@bayhilltx.com

 1. WHAT YOU AGREE TO GRANT US. 
 You grant to Us and We are entitled, upon the terms and subject to the conditions set forth in this Warrant Agreement, to subscribe for and to purchase from You 192,307 fully paid and non-assessable shares of Your
Series B Preferred Stock at a purchase price per share equal to the “Exercise Price” as defined below. 
 In addition, as set forth in the section
entitled “Warrant Coverage” above, for each Advance under the Loan Agreement in excess of initial Advances totaling $5,000,000, You grant to Us and We are entitled, upon the terms and subject to the conditions set forth in this Warrant
Agreement, to subscribe for and to purchase from You an additional number of fully paid and non-assessable shares of Your Series B Preferred Stock at a purchase price per share equal to the Exercise Price. The total number of additional shares of
Your Series B Preferred Stock shall be calculated as the quotient of (x) the product of (a) the amount of the Advances under the Loan Agreement in excess of initial Advances totaling $5,000,000 and (b) five percent (5%) and
(y) $1.30, with such quotient rounded down to the nearest whole share of Series B Preferred Stock. 
 The “Exercise Price” shall equal $1.30
or, in the event the per share price of Your next round of preferred stock equity financing is less than $1.30, then the Exercise Price shall equal to the product of (a) $1.217 and (b) the conversion price of a share of Series B Preferred
Stock as determined pursuant to the weighted-average antidilution protection accorded to all holders of Series B Preferred Stock in Your Amended and Restated Certificate of Incorporation, as amended from time to time, with such exercise price
rounded up to the nearest whole cent. In either event, the Number of Shares shall be determined by the quotient of (x) the Warrant Coverage and (y) $1.30, and shall not exceed 384,614. 
 Notwithstanding the above, in the event all outstanding principal and interest under the Loan Agreement is indefeasibly paid in full on or before May 5, 2009, and
We have not previously exercised Our rights under this Warrant Agreement, then the Warrant Coverage percentage shall be reduced by one percent (1%) to equal a total Warrant Coverage percentage of four percent (4%) and the Warrant Coverage
and Number of Shares shall be adjusted accordingly. 
 Your Series B Preferred Stock is sometimes referred to in this Warrant Agreement as “Warrant
Stock”. 
 The number and purchase price of such shares are subject to adjustment as provided in Section 4 hereof. 
 The Parties agree that this Warrant Agreement to purchase the Warrant Stock has a fair market value equal to $100 and that $100 of the issue price of the investment will
be allocable to the Warrant Agreement and the balance shall be allocable to the Loan Agreement for income tax purposes and the original issue discount on the Loan Agreement shall be considered to be zero. 
 2 

 2. WHEN ARE WE ENTITLED TO PURCHASE YOUR WARRANT STOCK. 
 Term. The term of this Warrant Agreement and our right to purchase Warrant Stock will begin the Effective
Date, and shall continue until the later of (i) the seventh (7th) anniversary of the Effective Date or (ii) the second (2nd) anniversary of the effective date of Your initial public offering pursuant to a registration statement under the 1933 Act (“Your IPO”).

 Early Termination Upon Certain Merger Events. Our right to purchase the Warrant Stock shall be automatically and fully exercised
(without surrender of the Warrant Agreement) upon the occurrence of a Merger Event (as defined below in Section 4), in which You are not the surviving corporation, provided that, upon consummation of the Merger Event, the consideration payable
to Us pursuant to such exercise and on account of the Warrant Stock consists of: 
 (i) cash; or 
 (ii) cash and/ or stock that is traded on a recognized public exchange or on the NASDAQ Global Market at a price per share equal to or greater than one
and one half (1.5) times the Exercise Price per share (as adjusted). 
 No less than ten (10) business days prior to any Merger Event, You shall
provide Us with written notice of the proposed Merger Event together with a copy of the proposed merger agreement and information concerning Your expected capitalization immediately prior to the Merger Event. Upon consummation of the Merger Event,
You shall promptly provide Us with (a) a copy of the executed merger agreement, (b) any other documents in connection therewith, (c) information concerning Your capitalization immediately prior to the Merger Event, and, (d) upon
request, by Us any other information reasonably necessary to an informed evaluation of Our rights under this Agreement. 
 In such a Merger Event, if the
consideration to be received by Us does not consist of (i) cash or (ii) cash and/or stock that is traded on a recognized public exchange or on the Nasdaq Global Market or is less than one and one half (1.5) times the Exercise Price
per share and We have not elected to exercise Our rights under this Warrant Agreement, then You may, at Your sole discretion, pay Us a sum equal to one (1) times the Exercise Price for each share exercisable under this Warrant Agreement in
exchange for the cancellation of this Warrant Agreement upon the consummation of the Merger Event. 
 Other Termination. Notwithstanding any
provisions of this Warrant Agreement to the contrary, this Warrant Agreement shall terminate and shall not be exercisable for any shares of Your Series B Preferred Stock if We default in lending You any portion of the Commitment Amount (as defined
in the Loan Agreement) pursuant to the terms of the Loan Agreement upon Your provision of an Advance Request (as defined in the Loan Agreement) (such a default, a “TriplePoint Default”). Further, upon a TriplePoint Default, We shall
surrender any shares of Your Series B Preferred Stock acquired upon exercise of this Warrant Agreement, or any shares of Your Common Stock issued upon conversion of shares of Your Series B Preferred Stock. However, this paragraph shall not apply to
Warrant Coverage earned on Advance Requests previously funded under the Loan Agreement (“Previous Advances”) and this Warrant Agreement shall continue in full force and effect with regard to the Warrant Coverage earned on those Previous
Advances and We shall not be required to surrender any shares of Series B Preferred Stock acquired upon exercise of this Warrant Agreement, or any shares of Your Common Stock issued upon conversion of shares of Your Series B Preferred Stock, in each
case provided that such exercise or conversion is related to the Previous Advances. 
 3. HOW WE MAY PURCHASE YOUR WARRANT STOCK. 
 We may exercise Our purchase rights, in whole or in part, at any time, or from time to time, prior to the expiration of the term of this Warrant Agreement, by giving You
a completed and executed Notice of Exercise in the form attached as Exhibit I. Promptly upon receipt of the Notice of Exercise and in any event no later than twenty-one (21) days after you have received Our Notice of Exercise and
payment of the aggregate Exercise Price for the shares purchased, You will issue to Us a certificate for the number of shares of Warrant Stock that We have purchased and You will execute the Acknowledgment of Exercise in the form attached
hereto as Exhibit II indicating the number of shares which will be available to Us for future purchases, if any. 
 3 

 We may pay for the Warrant Stock by either (i) cash or check, or (ii) by the net issuance method as
determined below. If We elect the Net Issuance method, You will issue Warrant Stock using the following formula: 
  

					
		  		  	 X = Y(A-B)
   A

			
	Where:	  	X  =	  	the number of shares of Warrant Stock to be issued to Us.
		  	Y  =	  	the number of shares of Warrant Stock We request to be exercised under this Warrant Agreement.
		  	A  =	  	the fair market value of one share of Warrant Stock.
		  	B  =	  	the Exercise Price.

 For purposes of the above calculation, the current fair market value of Warrant Stock shall mean with respect to
each share of Warrant Stock: 
 If the exercise is in connection with Your IPO, and if Your registration statement relating to such public offering has
been declared effective by the Securities and Exchange Commission, referred to herein as the SEC, then the fair market value per share shall be the product of (x) the initial “Price to Public” specified in the final prospectus of the
offering and (y) the number of shares of Common Stock into which each share of Warrant Stock is convertible at the time of such exercise; 
 If this
Warrant Agreement is exercised after, and not in connection with Your IPO, and: 
  

	•	 	 if traded on a securities exchange, the fair market value shall be the product of (x) the average of the closing prices over a five (5) day period ending
three (3) days before the day the current fair market value of the securities is being determined and (y) the number of shares of Common Stock into which each share of Warrant Stock is convertible at the time of such exercise; or

  

	•	 	 if actively traded over-the-counter, the fair market value shall be the product of (x) the average of the average of the closing bid and asked prices
quoted on the NASDAQ system (or similar system) over the five (5) day period ending three (3) days before the day the current fair market value of the securities is being determined and (y) the number of shares of Common Stock into
which each share of Warrant Stock is convertible at the time of such exercise; 

  

	•	 	 if at any time Your Common Stock is not listed on any securities exchange or quoted in the NASDAQ system or the over-the-counter market, the current fair market
value of Warrant Stock shall be the product of (x) the fair market value of a share of Your Common Stock (the highest price per share which You could obtain from a willing buyer (not a current employee or director) for shares of Common Stock
sold, from authorized but unissued shares), as determined in good faith by Your Board of Directors and (y) the number of shares of Common Stock into which each share of Warrant Stock is convertible at the time of such exercise, unless You shall
become subject to a Merger Event pursuant to which You are not the surviving party, in which case the fair market value of Warrant Stock shall be deemed to be the value received by the holders of Your Warrant Stock on a common equivalent basis
pursuant to such Merger Event. 

  

	•	 	 During the term of this Warrant Agreement, You will at all times from and after the Effective Date have authorized and reserved a sufficient number of shares of
(a) Warrant Stock to provide for the exercise of our rights to purchase Warrant Stock, and (b) Common Stock to provide for the conversion of the Warrant Stock. 

 If We elect to exercise part of the Warrant Agreement, You will promptly issue to Us an amended Warrant Agreement stating the remaining number of shares that are
available. All other terms and conditions of that amended Warrant Agreement shall be identical to those contained in this Warrant Agreement. 
 If at the end
of the term of this Warrant Agreement, the fair market value of one share of Warrant Stock (or other security issuable upon the exercise hereof) as determined in accordance herewith is greater than the Exercise Price in effect on such date, then
this Warrant Agreement shall automatically be deemed on and as of such date to be converted pursuant hereto as to all shares of Warrant Stock (or such other securities) for which it shall not previously have been exercised or converted pursuant to
the net issuance method, and You shall promptly deliver a certificate representing the shares of Warrant Stock (or such other securities) issued upon such conversion to Us. 
 4 

 4. WHEN WILL THE NUMBER OF SHARES AND EXERCISE PRICE CHANGE. 
  

	•	 	 If You are Acquired. Subject to Section 2, if at any time: (i) there is a reorganization of Your stock (other than a reclassification,
exchange or subdivision of Your stock otherwise provided for in this Warrant Agreement); (ii) You merge or consolidate with or into another entity, whether or not You are the surviving entity; (iii) You sell or convey, or grant an
exclusive licenses with respect to, all or substantially all of Your assets to any other person; or (iv) there occurs any transaction or series of related transactions that result in the transfer of fifty percent (50%) or more of the
outstanding voting power of the capital stock of You (each of the foregoing events are referred to as a “Merger Event”), then this Warrant Agreement shall be assumed or an equivalent warrant substituted by the successor or surviving
corporation or a parent of the successor or surviving corporation. 

  

	•	 	 If You Reclassify Your Stock. If at any time You combine, reclassify, exchange or subdivide Your securities or otherwise, change any of the securities as to
which purchase rights under this Warrant Agreement exist into the same or a different number of securities of any other class or classes, this Warrant Agreement will thereafter represent the right to acquire such number and kind of securities as
would have been issuable as the result of such change with respect to the securities which were subject to the purchase rights under this Warrant Agreement immediately prior to such combination, reclassification, exchange, subdivision or other
change. 

  

	•	 	 If You Subdivide or Combine Your Shares. If at any time You combine or subdivide Your Series B Preferred Stock, the Exercise Price will be
proportionately decreased in the case of a subdivision, or proportionately increased in the case of a combination. 

  

	•	 	 If You Pay Stock Dividends. If at any time You pay a dividend payable in, or make any other distribution (except any distribution specifically provided for
in the above paragraphs) of Your stock, then the Exercise Price shall be adjusted, from and after the record date of such dividend or distribution, to that price determined by multiplying the Exercise Price in effect immediately prior to such record
date by a fraction (i) the numerator of which shall be the total number of all shares of Your stock outstanding immediately prior to such dividend or distribution, on an as-converted to Common Stock basis, and (ii) the denominator of which
shall be the total number of all shares of Your stock outstanding immediately after such dividend or distribution, on an as-converted to Common Stock basis. We will thereafter be entitled to purchase, at the Exercise Price resulting from such
adjustment, the number of shares of Warrant Stock (calculated to the nearest whole share) obtained by multiplying the Exercise Price in effect immediately prior to such adjustment by the number of shares of Warrant Stock issuable upon the exercise
hereof immediately prior to such adjustment and dividing the product thereof by the Exercise Price resulting from such adjustment. 

  

	•	 	 If You Change the Antidilution Rights of the Warrant Stock or Issue New Preferred or Convertible Stock. All antidilution rights applicable to the Warrant
Stock purchasable under this Warrant Agreement are as set forth in Your Certificate of Incorporation, as amended through the Effective Date. You will promptly provide Us with any restatement, amendment, modification or waiver of Your Certificate of
Incorporation. You will provide Us with any written notices relating to such andilution rights provided to holders of Your Series B Preferred Stock. 

 5. WE CAN TRANSFER THIS PLAIN ENGLISH WARRANT AGREEMENT. 
 Subject to the terms and conditions contained in Section 7, We (or any successor transferee) may transfer in whole or in part this Warrant Agreement and all its rights. You will record the transfer on Your books when You receive Our
Notice of Transfer in the form attached hereto as Exhibit III, and Our payment of all transfer taxes and other governmental charges involved in such transfer. So long as You have not assigned Your assets for the benefit of Your creditors, have
entered (voluntarily or involuntarily) a bankruptcy proceeding, liquidated or taken any action for the purpose of the foregoing. You may refuse to transfer
this Warrant Agreement or any Warrant Stock to any person who directly competes with You (as determined in good faith by You) unless Your stock is publicly traded. 
 5 

 6. REPRESENTATIONS, WARRANTIES, AND COVENANTS FROM YOU. 
  

	•	 	 Reservation of Warrant Stock. The Warrant Stock issuable upon exercise of Our rights under this Warrant Agreement will be duly and validly reserved and when
issued in accordance with the provisions of this Warrant Agreement will be validly issued, fully paid and non-assessable, and will be free of any taxes, liens, charges or encumbrances of any nature whatsoever; provided, however, that the Warrant
Stock issuable pursuant to this Warrant Agreement may be subject to restrictions on transfer under state and/or Federal securities laws. Upon Our exercise, You will issue to Us certificates for shares of Warrant Stock without charging Us any tax, or
other cost incurred by You in connection with such exercise and the related issuance of shares of Warrant Stock. You will not be required to pay any tax, which may be payable in respect of any transfer involved and the issuance and delivery of any
certificate in a name other than TriplePoint Capital LLC. 

  

	•	 	 Due Authority. Your execution and delivery of this Warrant Agreement and the performance of Your obligations hereunder, including the issuance to Us of the
right to acquire the shares of Warrant Stock, have been duly authorized by all necessary corporate action on Your part and this Warrant Agreement is not inconsistent with Your Certificate of Incorporation or Bylaws, does not contravene any law or
governmental rule, regulation or order applicable to it, do not and will not contravene any provision of, or constitute a default under, any indenture, mortgage, contract or other instrument to which You are a party or by which You are bound, and
this Warrant Agreement constitutes a legal, valid and binding agreement, enforceable in accordance with its respective terms, subject to laws of general application relating to bankruptcy, insolvency and the relief of debtors and the rules of law or
principles at equity governing specific performance, injunctive relief and other equitable remedies. 

  

	•	 	 Consents and Approvals. No consent or approval of, giving of notice to, registration with, or taking of any other action in respect of any state, Federal or
other governmental authority or agency is required with respect to execution, delivery and Your performance of Your obligations under this Warrant Agreement, except for the filing of any required notices pursuant to federal and state securities
laws, which filings will be effective by the times required thereby. 

  

	•	 	 Issued Securities. All of Your issued and outstanding shares of Common Stock, Warrant Stock or any other securities have been duly authorized and validly
issued and are fully paid and non-assessable. All outstanding shares of Common Stock and Warrant Stock were issued in full compliance with all federal and state securities laws. In addition as of the Effective Date: 

 Your authorized capital consists of (A) 76,384,500 shares of Common Stock, of which 3,033,512 shares of Common Stock are issued and outstanding, (B) 14,912,500
shares of Series A Preferred Stock, of which 14,550,000 shares are issued and outstanding, and (C) 49,472,000 shares of Series B Preferred Stock, of which 48,018,373 shares are issued and outstanding. 
 You have reserved 6,000,000 shares of Common Stock for issuance under Your 2002 Equity Incentive Plan, under which 5,280,969 options have been granted. Except as
otherwise provided in this Warrant Agreement, as noted above and pursuant to outstanding warrants to purchase 362,499 shares of Your Series A Preferred Stock there are no other options, warrants, conversion privileges or other rights presently
outstanding to purchase or otherwise acquire any authorized but unissued shares of Your capital stock or other of Your securities. 
 Except as set forth in
the Amended and Restated Investor Rights Agreement, dated October 4, 2004, by and among You and the Investors (as defined therein), as amended, referred to herein as the Investors’ Rights Agreement, Your stockholders do not have preemptive
rights to purchase new issuances of Your capital stock. 
  

	•	 	 Other Commitments to Register Securities. Except as set forth in this Warrant Agreement and the Investors’ Rights Agreement, You are not,
pursuant to the terms of any other agreement currently in existence, under any obligation to register under the 1933 Act any of Your presently outstanding securities or any of Your securities which may hereafter be issued.

 6 

	•	 	 Exempt Transaction. Subject to the accuracy of Our representations in Section 7 hereof, the issuance of the Warrant Stock upon exercise of this Warrant
Agreement will constitute a transaction exempt from (i) the registration requirements of Section 5 of the 1933 Act, in reliance upon Section 4(2) thereof, and (ii) the qualification requirements of the applicable state securities
laws. 

  

	•	 	 Compliance with Rule 144. We may sell the Warrant Stock issuable hereunder in compliance with Rule 144 promulgated by the SEC. Within ten (10) business
days of Our request, You agree to furnish Us, a written statement confirming Your compliance, as applicable, with the filing requirements of the Securities and Exchange Commission as set forth in such Rule 144, as may be amended.

 7. OUR REPRESENTATIONS AND COVENANTS TO YOU. 
  

	•	 	 Investment Purpose. The right to acquire Warrant Stock or the Warrant Stock issuable upon exercise of Our rights contained herein and the Common Stock
issuable upon conversion of the Warrant Stock will be acquired for investment purposes and not with a view to the sale or distribution of any part thereof, and We have no present intention of selling or engaging in any public distribution of the
same in violation of the 1933 Act. 

  

	•	 	 Private Issue. We understand (i) that this Warrant Agreement, the Warrant Stock issuable upon exercise of this Warrant Agreement and the Common Stock
issuable upon conversion of the Warrant Stock are not registered under the 1933 Act or qualified under applicable state securities laws on the ground that the issuance contemplated by this Warrant Agreement will be exempt from the registration and
qualifications requirements thereof, and (ii) that Your reliance on such exemption is predicated on the representations set forth in this Section 7. 

  

	•	 	 Disposition of Our Rights. In no event will We make a disposition of any of Our rights to acquire Warrant Stock or Warrant Stock issuable upon exercise of
such rights or the Common Stock issuable upon conversion of the Warrant Stock unless and until (i) We shall have notified You in writing of the proposed disposition, and (ii) the transferee agrees to be bound in writing to the applicable
terms and conditions of this Warrant Agreement, and (iii) if You request, We shall have furnished You with an opinion of counsel satisfactory in form and substance to You and Your counsel to the effect that (A) appropriate action necessary
for compliance with the 1933 Act has been taken, or (B) an exemption from the registration requirements of the 1933 Act is available. Notwithstanding the foregoing, the restrictions imposed upon the transferability of any of Our rights to
acquire Warrant Stock or Warrant Stock issuable on the exercise of such rights or the Common Stock issuable upon conversion of the Warrant Stock do not apply to transfers from the beneficial owner of any of the aforementioned securities to its
nominee or from such nominee to its beneficial owner, and shall terminate as to any particular share of Warrant Stock when (1) such security shall have been effectively registered under the 1933 Act and sold by the holder thereof in accordance
with such registration, (2) such security shall have been sold without registration in compliance with Rule 144 under the 1933 Act, or (3) a letter shall have been issued to You at Our request by the staff of the SEC or a ruling shall have
been issued to You at Our request by the SEC stating that no action shall be recommended by such staff or taken by the SEC, as the case may be, if such security is transferred without registration under the 1933 Act in accordance with the conditions
set forth in such letter or ruling and such letter or ruling specifies that no subsequent restrictions on transfer are required. Whenever the restrictions imposed hereunder shall terminate, as hereinabove provided, the holder of a share of Warrant
Stock then outstanding as to which such restrictions have terminated shall be entitled to receive from You, without expense to such holder, one or more new certificates for the Warrant or for such shares of Warrant Stock not bearing any restrictive
legend referring to 1933 Act registration or exemption. 

  

	•	 	 Financial Risk. We have such knowledge and experience in financial and business matters and knowledge of Your business affairs and financial condition as to
be capable of evaluating the merits and risks of Our investment, and have the ability to bear the economic risks of Our investment. 

 7 

	•	 	 Risk of No Registration. We understand that if You do not register with the SEC pursuant to Section 12 of the Securities Exchange Act of 1934 (the
“1934 Act”), or file reports pursuant to Section 15(d) of the 1934 Act, or if a registration statement covering the securities under the 1933 Act is not in effect when We desire to sell (i) the rights to purchase Warrant Stock
pursuant to this Warrant Agreement, or (ii) the Warrant Stock issuable upon exercise of this Warrant Agreement, or (iii) the Common Stock issuable upon conversion of the Warrant Stock, We may be required to hold such securities for an
indefinite period. We also understand that any sale of Our right to purchase Warrant Stock or Warrant Stock or Common Stock issuable upon conversion of the Warrant Stock, which might be made by us in reliance upon Rule 144 under the 1933 Act may be
made only in accordance with the terms and conditions of that Rule. 

  

	•	 	 Accredited Investor. We are an “accredited investor” within the meaning of Rule 501 of Regulation D of the 1933 Act, as presently in effect.

  

	•	 	 Market Standoff. We agree in connection with any registration of Your securities (other than a registration of securities in a Rule 145 transaction or
with respect to an employee benefit plan), upon request of the underwriters managing any underwritten offering of Your securities, not to sell, make any short sale of, loan, pledge or otherwise hypothecate or encumber, grant any option for the
purchase of, or otherwise dispose of any of Your securities without the prior written consent of such underwriters, as the case may be, for such period of time (not to exceed one hundred eighty (180) days from the effective date of such
registration in the case of Your IPO (or such longer period, not to exceed eighteen (18) days after the expiration of the one hundred eighty (180)-day period, as the case may be, as the underwriters or You shall request in order to facilitate
compliance with NASD Rule 2711)) as may be requested by such managing underwriter(s) and to execute a lock-up agreement in the form provided by such managing underwriters relating to such market standoff. You may impose stock-transfer instructions
with respect to any of Your securities subject to the foregoing restriction until the end of such period. Your underwriters are intended third-party beneficiaries of this “Market Stand-Off” section and shall have the right, power and
authority to enforce the provisions hereof as though they were a party hereto. The obligations described in this section shall apply only if all executive officers and directors of You, and all holders of at least one percent (1%) of Your then
outstanding securities (calculated on a fully diluted basis) enter into similar agreements. 

 8. NOTICES YOU AGREE TO PROVIDE
US. 
 You agree to give Us at least twenty (20) days prior written notice before the effective date of any of the following events: 

 

	•	 	 If You Pay a dividend or distribution declaration upon your stock. 

  

	•	 	 If You offer for subscription pro-rata to the existing stockholders additional stock or other rights. 

  

	•	 	 If You consummate a Merger Event. 

  

	•	 	 If You consummate Your IPO. 

  

	•	 	 If You dissolve or liquidate. 

 8

 All notices in this Section must set forth details of the event, how the event adjusts either Our number of shares or Our
Exercise Price and the method used for such adjustment. 
 Timely Notice. Your failure to timely provide such notice required above shall entitle Us
to retain the benefit of the applicable notice period notwithstanding anything to the contrary contained in any insufficient notice received by Us. 
 9.
DOCUMENTS YOU WILL PROVIDE US. 
  

	•	 	 Certified Resolutions of Your Board of Directors authorizing this issuance of this Warrant Agreement 

  

	•	 	 Your Amended and Restated Certificate of Incorporation, as amended through the date hereof 

  

	•	 	 Investors’ Rights Agreement 

  

	•	 	 Bylaws 

 10. OTHER LEGAL PROVISIONS THE PARTIES
WILL ABIDE BY. 
 Effective Date. This Warrant Agreement shall be construed and shall be given effect in all respects as if it had been executed
and delivered by the Parties on the date hereof. This Warrant Agreement shall be binding upon any of the successors or assigns of the Parties. 
 Attorney’s Fees. In any litigation, arbitration or court proceeding between the Parties relating to this Warrant Agreement, the prevailing party shall be entitled to attorneys’ fees and expenses and all costs of proceedings
incurred in enforcing this Warrant Agreement. 
 Governing Law. This Warrant Agreement shall be governed by and construed for all purposes under and
in accordance with the laws of the State of California without giving effect to that body of law pertaining to conflicts of laws. 
 Consent to
Jurisdiction and Venue. All judicial proceedings arising in or under or related to this Warrant Agreement may be brought in any state or federal court of competent jurisdiction located in the State of California. By execution and delivery of
this agreement, each party hereto generally and unconditionally: (a) consents to personal jurisdiction in San Mateo County, State of California; (b) waives any objection as to jurisdiction or venue in San Mateo County, State of California;
(c) agrees not to assert any defense based on lack of jurisdiction or venue in the aforesaid courts; and (d) irrevocably agrees to be bound by any judgment rendered thereby in connection with this Plain English Warrant Agreement. Service
of process on any party hereto in any action arising out of or relating to this agreement shall be effective if given in accordance with the requirements for notice set forth in this Section, and shall be deemed effective and received as set forth
therein. Nothing herein shall affect the right to serve process in any other manner permitted by law or shall limit the right of either party to bring proceedings in the courts of any other jurisdiction. 
 Mutual Waiver of Jury Trial. Because disputes arising in connection with complex financial transactions are most quickly and economically resolved by an
experienced and expert person and The Parties wish applicable state and federal laws to apply (rather than arbitration rules), The Parties desire that their disputes be resolved by a judge applying such applicable laws. EACH OF THE PARTIES
SPECIFICALLY WAIVES ANY RIGHT THEY MAY HAVE TO TRIAL BY JURY OF ANY CAUSE OF ACTION, CLAIM, CROSS-CLAIM, COUNTERCLAIM, THIRD PARTY CLAIM OR ANY OTHER CLAIM (COLLECTIVELY, “CLAIMS”) ASSERTED BY YOU AGAINST US OR OUR ASSIGNEE OR BY US OR OUR
ASSIGNEE AGAINST YOU. This waiver extends to all such Claims, including Claims that involve Persons other than You and Us; Claims that arise out of or are in any way connected to the relationship between You and Us; and any Claims for damages,
breach of contract, specific performance, or any equitable or legal relief of any kind, arising out of this Warrant Agreement. 
 9

 Counterparts. This Warrant Agreement may be executed in two or more counterparts, each of which shall be deemed an
original, but all of which together shall constitute one and the same instrument. 
 Notices. Any notice required or permitted under this Warrant
Agreement shall be given in writing and shall be deemed effectively given upon the earlier of (1) actual receipt or three (3) days after mailing if mailed postage prepaid by regular or airmail to Us or You or (2) one (1) day
after it is sent by overnight mail via nationally recognized courier or (3) on the same day as sent via confirmed facsimile transmission, provided that the original is sent by personal delivery or mail by the sending party. 
 If to TriplePoint Capital LLC, to Our “Contact Person” designated on the cover page at a specified “Address for Notices,” with a copy to: 

If to Bayhill Therapeutics, Inc., to Your “Contact Person” designated on the cover page at a specified “Address for Notices,” with a copy to:

 Latham & Watkins LLP 
 140 Scott Drive 
 Menlo Park, CA 94025 
 Tel: 650-328-4600 
 Fax: 650-463-2600 
 Attention: Alan C. Mendelson 
 Remedies. In the event of any default hereunder, the non-defaulting party may proceed to protect and enforce its rights either by suit in equity and/or by action
at law, including but not limited to an action for damages as a result of any such default, and/or an action for specific performance for any default where such party will not have an adequate remedy at law and where damages will not be readily
ascertainable. Each party expressly acknowledges and agrees that there is no adequate remedy at law for any breach of this Warrant Agreement and that in the event of any breach of this Agreement, the injured party shall be entitled to specific
performance of any or all provisions hereof or an injunction prohibiting the other party from continuing to commit any such breach of this Agreement. 
 No Impairment of Rights. You will not, by amendment of your Amended and Restated Certificate of Incorporation, as amended from time to time, or through any other means, avoid or seek to avoid the observance or performance of any of
the terms of this Warrant Agreement, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate in order to protect Our rights against impairment.

 Survival. The representations, warranties, covenants, and conditions of the Parties contained herein or made pursuant to this Warrant Agreement
shall survive the execution and delivery of this Warrant Agreement. 
 Severability. In the event any one or more of the provisions of this Warrant
Agreement shall for any reason be held invalid, illegal or unenforceable, the remaining provisions of this Warrant Agreement shall be unimpaired, and the invalid, illegal or unenforceable provision shall be replaced by a mutually acceptable valid,
legal and enforceable provision, which comes closest to the intention of the parties underlying the invalid, illegal or unenforceable provision. 
 Entire
Agreement. This Warrant Agreement constitutes the entire agreement between the Parties pertaining to the subject matter contained in it and supersedes all prior and contemporaneous agreements, representations and undertakings of the Parties,
whether oral or written, with respect to such subject matter. 
 Amendments. Any provision of this Warrant Agreement may only be amended by a written
instrument signed by the Parties. 
 Lost Warrants or Stock Certificates. You covenant to Us that, upon receipt of evidence reasonably satisfactory to
Us of the loss, theft, destruction or mutilation of this Warrant Agreement or any stock certificate and, in the case of any such loss, theft or destruction, upon receipt of an indemnity reasonably satisfactory to You, or in the case of any such
mutilation upon surrender and cancellation of such Warrant Agreement or stock certificate, You will make and deliver a new Warrant Agreement or stock certificate, of like tenor, in lieu of the lost, stolen, destroyed or mutilated Warrant Agreement
or stock certificate. 
 10 

 Rights as Stockholders. We shall not, as a party to this Warrant Agreement, be entitled to vote or receive
dividends or be deemed the holder of Series B Preferred Stock or any of Your other securities which may at any time be issuable upon the exercise hereof for any purpose, nor shall anything contained herein be construed to confer upon Us any of the
rights of one of Your stockholders or any right to vote for the election of directors or upon any matter submitted to stockholders at any meeting thereof, or to receive dividends or subscription rights or otherwise until this Warrant Agreement is
exercised and the shares purchasable upon the exercise hereof shall have become deliverable, as provided herein. 
 Facsimile Signatures. This Warrant
Agreement may be executed and delivered by facsimile and upon such delivery the facsimile signature will be deemed to have the same effect as if the original signature had been delivered to the other party. 
 (Signature Page to Follow) 
 11

 IN WITNESS WHEREOF, each of the Parties have caused this Warrant Agreement to be executed by its officers who are
duly authorized as of the Effective Date. 
  

					
	 YOU:
	 	BAYHILL THERAPEUTICS, INC.
			
		 	By:	 	 /s/ Mark Schwartz

		 	Title:	 	CEO & President
		
	 US:
	 	TRIPLEPOINT CAPITAL LLC
			
		 	By:	 	 /s/ Sajal Srivastava, COO

		 	Title:	 	COO

 EXHIBIT I 
 NOTICE OF EXERCISE 
  

	To:	[                                      
  ] 

  

	1.	We hereby elect to purchase [            ] shares of Your Series B Preferred Stock. Pursuant to the terms of the
Plain English Warrant Agreement dated the [            ] day of [            ], [2006] (the “Plain English
Warrant Agreement”) between You and Us, We hereby tender here payment of the purchase price for such shares in full, together with all applicable transfer taxes, if any. 

  

	2.	Method of Exercise (Please initial the applicable blank) 

  

	 	a.	             The undersigned elects to exercise the Plain English Warrant Agreement by means of a cash payment,
and gives You full payment for the purchase price of the shares being purchased, together with all applicable transfer taxes, if any. 

  

	 	b.	             The undersigned elects to exercise the Plain English Warrant Agreement by means of the Net Issuance
Exercise method of Section 3 of the Plain English Warrant Agreement. 

  

	3.	In exercising Our rights to purchase Your Series B Preferred Stock, We hereby confirm and acknowledge the investment representations, warranties and covenants made in Section 7
of the Plain English Warrant Agreement. 

 Please issue a certificate or certificates representing these purchased shares of Series B Preferred
Stock in Our name or in such other name as is specified below. 
  

					
		 	  

		 	(Name)
		
		 	  

		 	(Address)
			
		 	US:	 	TRIPLEPOINT CAPITAL LLC
			
		 	By:	 	  

			
		 	Title:	 	  

			
		 	Date:	 	  

 13 

 EXHIBIT II 
 ACKNOWLEDGMENT OF EXERCISE 
 [                                      
                      ], hereby acknowledges receipt of the “Notice of Exercise” from TRIPLEPOINT CAPITAL LLC, to purchase
[            ] shares of the Series B Preferred Stock of Bayhill Therapeutics, Inc., pursuant to the terms of the Plain English Warrant Agreement, and further acknowledges that
[            ] shares remain subject to purchase under the terms of the Plain English Warrant Agreement. 
  

					
	 YOU:
	 	  

			
		 	By:	 	  

			
		 	Title:	 	  

			
		 	Date:	 	  

 14 

 EXHIBIT III 
 TRANSFER NOTICE 
 FOR VALUE RECEIVED, the foregoing Plain English Warrant Agreement and all rights
evidenced thereby are hereby transferred and assigned to 
 _______________________________________________________________________ 
 (Please Print) 
 Whose address is                                 
                                        
                                        
                                        
                                        
                              
                                       
                                        
                                        
                                        
                                        
                                        
                    
  

			
	Dated:	  	__________________________________
		
	Holder’s Signature:	  	__________________________________
		
	Holder’s Address:	  	__________________________________
		
	Transferee’s Signature:	  	__________________________________
		
	Transferee’s Address:	  	__________________________________
		
	Signature Guaranteed:	  	__________________________________

 NOTE: The signature to this Transfer Notice must correspond with the name as it appears on the face of the
Plain English Warrant Agreement, without alteration or enlargement or any change whatever. Officers of corporations and those acting in a fiduciary or other representative capacity must provide Bayhill Therapeutics, Inc. proper evidence of authority
to assign the foregoing Plain English Warrant Agreement. 
 15Bayhill Therapeutics, Inc. 2002 Equity Incentive Plan

 Exhibit 10.1 
 AMENDED AND RESTATED 
 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 1.
Purposes of the Plan. The purposes of the Bayhill Therapeutics, Inc. 2002 Equity Incentive Plan are to attract and retain the best available personnel for positions of substantial responsibility, to provide additional incentive to Employees,
Directors and Consultants and to promote the success of the Company’s business. Options granted under the Plan may be Incentive Stock Options or Non-Qualified Stock Options, as determined by the Administrator at the time of grant. Stock
Purchase Rights may also be granted under the Plan. 
 2. Definitions. As used herein, the following definitions shall apply:

 (a) “Acquisition” means (1) a dissolution, liquidation or sale of all or substantially all of the assets of the
Company; (2) a merger or consolidation in which the Company is not the surviving corporation; or (3) a reverse merger in which the Company is the surviving corporation but the shares of the Company’s common stock outstanding
immediately preceding the merger are converted by virtue of the merger into other property, whether in the form of securities, cash or otherwise. 
 (b) “Administrator” means the Board or the Committee responsible for conducting the general administration of the Plan, as applicable, in accordance with Section 4 hereof. 
 (c) “Applicable Laws” means the requirements relating to the administration of stock option plans under U.S. state corporate laws, U.S.
federal and state securities laws, the Code, any stock exchange or quotation system on which the Common Stock is listed or quoted and the applicable laws of any foreign country or jurisdiction where Options or Stock Purchase Rights are granted under
the Plan. 
 (d) “Board” means the Board of Directors of the Company. 
 (e) “Code” means the Internal Revenue Code of 1986, as amended, or any successor statute or statutes thereto. Reference to any
particular Code section shall include any successor section. 
 (f) “Committee” means a committee appointed by the Board in
accordance with Section 4 hereof. 
 (g) “Common Stock” means the Common Stock of the Company, par value $0.001 per
share. 
 (h) “Company” means Bayhill Therapeutics, Inc., a Delaware corporation. 
 (i) “Consultant” means any consultant or adviser if: (i) the consultant or adviser renders bona fide services to the Company
or any Parent or Subsidiary of the Company; (ii) the services rendered by the consultant or adviser are not in connection with the offer or sale of securities in a capital-raising transaction and do not directly or indirectly promote or
maintain 

 
a market for the Company’s securities; and (iii) the consultant or adviser is a natural person who has contracted directly with the Company or any
Parent or Subsidiary of the Company to render such services. 
 (j) “Director” means a member of the Board. 
 (k) “Employee” means any person, including an Officer or Director, who is an employee (as defined in accordance with
Section 3401(c) of the Code) of the Company or any Parent or Subsidiary of the Company. A Service Provider shall not cease to be an Employee in the case of (i) any leave of absence approved by the Company or (ii) transfers between
locations of the Company or between the Company, its Parent, any Subsidiary, or any successor. For purposes of Incentive Stock Options, no such leave may exceed ninety (90) days, unless reemployment upon expiration of such leave is guaranteed
by statute or contract. Neither service as a Director nor payment of a director’s fee by the Company shall be sufficient, by itself, to constitute “employment” by the Company. 
 (l) “Exchange Act” means the Securities Exchange Act of 1934, as amended, or any successor statute or statutes thereto. Reference to any
particular Exchange Act section shall include any successor section. 
 (m) “Fair Market Value” means, as of any date, the
value of a share of Common Stock determined as follows: 
 (i) If the Common Stock is listed on any established stock exchange or a national
market system, including, without limitation, The Nasdaq National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, its Fair Market Value shall be the closing sales price for a share of such stock (or the closing bid, if no sales were
reported) as quoted on such exchange or system for the last market trading day prior to the time of determination, as reported in The Wall Street Journal or such other source as the Administrator deems reliable; 
 (ii) If the Common Stock is regularly quoted by a recognized securities dealer but selling prices are not reported, its Fair Market Value shall be the
mean between the high bid and low asked prices for a share of the Common Stock on the last market trading day prior to the day of determination; or 
 (iii) In the absence of an established market for the Common Stock, the Fair Market Value thereof shall be determined in good faith by the Administrator. 
 (n) “Holder” means a person who has been granted or awarded an Option or Stock Purchase Right or who holds Shares acquired pursuant to
the exercise of an Option or Stock Purchase Right. 
 (o) “Incentive Stock Option” means an Option intended to qualify as an
incentive stock option within the meaning of Section 422 of the Code and which is designated as an Incentive Stock Option by the Administrator. 
  

 2 

 (p) “Independent Director” means a Director who is not an Employee of the Company.

 (q) “Non-Qualified Stock Option” means an Option (or portion thereof) that is not designated as an Incentive Stock Option
by the Administrator, or which is designated as an Incentive Stock Option by the Administrator but fails to qualify as an incentive stock option within the meaning of Section 422 of the Code. 
 (r) “Officer” means a person who is an officer of the Company within the meaning of Section 16 of the Exchange Act and the rules
and regulations promulgated thereunder. 
 (s) “Option” means a stock option granted pursuant to the Plan. 
 (t) “Option Agreement” means a written agreement between the Company and a Holder evidencing the terms and conditions of an individual
Option grant. The Option Agreement is subject to the terms and conditions of the Plan. 
 (u) “Parent” means any
corporation, whether now or hereafter existing (other than the Company), in an unbroken chain of corporations ending with the Company if each of the corporations other than the last corporation in the unbroken chain owns stock possessing more than
fifty percent of the total combined voting power of all classes of stock in one of the other corporations in such chain. 
 (v)
“Plan” means the Bayhill Therapeutics, Inc. 2002 Equity Incentive Plan. 
 (w) “Public Trading Date” means
the first date upon which Common Stock of the Company is listed (or approved for listing) upon notice of issuance on any securities exchange or designated (or approved for designation) upon notice of issuance as a national market security on an
interdealer quotation system. 
 (x) “Restricted Stock” means Shares acquired pursuant to the exercise of an unvested Option
in accordance with Section 10(h) below or pursuant to a Stock Purchase Right granted under Section 12 below. 
 (y) “Rule
16b-3” means that certain Rule 16b-3 under the Exchange Act, as such Rule may be amended from time to time. 
 (z) “Section
16(b)” means Section 16(b) of the Exchange Act, as such Section may be amended from time to time. 
 (aa) “Securities
Act” means the Securities Act of 1933, as amended, or any successor statute or statutes thereto. Reference to any particular Securities Act section shall include any successor section. 
 (bb) “Service Provider” means an Employee, Director or Consultant. 
  

 3 

 (cc) “Share” means a share of Common Stock, as adjusted in accordance with
Section 13 below. 
 (dd) “Stock Purchase Right” means a right to purchase Common Stock pursuant to Section 12
below. 
 (ee) “Subsidiary” means any corporation, whether now or hereafter existing (other than the Company), in an
unbroken chain of corporations beginning with the Company if each of the corporations other than the last corporation in the unbroken chain owns stock possessing more than fifty percent of the total combined voting power of all classes of stock in
one of the other corporations in such chain. 
 3. Stock Subject to the Plan. Subject to the provisions of Section 13 of the
Plan, the shares of stock subject to Options or Stock Purchase Rights shall be Common Stock, initially shares of the Company’s Common Stock. Subject to the provisions of Section 13 of the Plan, the maximum aggregate number of Shares which
may be issued upon exercise of such Options or Stock Purchase Rights is 8,500,000 shares. Shares issued upon exercise of Options or Stock Purchase Rights may be authorized but unissued, or reacquired Common Stock. If an Option or Stock Purchase
Right expires or becomes unexercisable without having been exercised in full, the unpurchased Shares which were subject thereto shall become available for future grant or sale under the Plan (unless the Plan has terminated). Shares which are
delivered by the Holder or withheld by the Company upon the exercise of an Option or Stock Purchase Right under the Plan, in payment of the exercise price thereof or tax withholding thereon, may again be optioned, granted or awarded hereunder,
subject to the limitations of this Section 3. If Shares of Restricted Stock are repurchased by the Company at their original purchase price, such Shares shall become available for future grant under the Plan. Notwithstanding the provisions of
this Section 3, no Shares may again be optioned, granted or awarded if such action would cause an Incentive Stock Option to fail to qualify as an Incentive Stock Option under Code Section 422. 
 4. Administration of the Plan. 
 (a)
Administrator. Unless and until the Board delegates administration to a Committee as set forth below, the Plan shall be administered by the Board. The Board may delegate administration of the Plan to a Committee or Committees of one or more
members of the Board, and the term “Committee” shall apply to any person or persons to whom such authority has been delegated. If administration is delegated to a Committee, the Committee shall have, in connection with the administration
of the Plan, the powers theretofore possessed by the Board, including the power to delegate to a subcommittee any of the administrative powers the Committee is authorized to exercise (and references in this Plan to the Board shall thereafter be to
the Committee or subcommittee), subject, however, to such resolutions, not inconsistent with the provisions of the Plan, as may be adopted from time to time by the Board. Notwithstanding the foregoing, however, from and after the Public Trading
Date, a Committee of the Board shall administer the Plan and the Committee shall consist solely of two or more Independent Directors each of whom is both an “outside director,” within the meaning of Section 162(m) of the Code, and a
“non-employee director” within the meaning of Rule 16b-3. Within the scope of such authority, the Board or the Committee may (i) delegate to a committee of one or more members of the Board who are not Independent Directors the
authority to grant awards under the Plan to 

  

 4 

 
eligible persons who are either (1) not then “covered employees,” within the meaning of Section 162(m) of the Code and are not expected
to be “covered employees” at the time of recognition of income resulting from such award or (2) not persons with respect to whom the Company wishes to comply with Section 162(m) of the Code and/or (ii) delegate to a
committee of one or more members of the Board who are not “non-employee directors,” within the meaning of Rule 16b-3, the authority to grant awards under the Plan to eligible persons who are not then subject to Section 16 of the
Exchange Act. The Board may abolish the Committee at any time and revest in the Board the administration of the Plan. Appointment of Committee members shall be effective upon acceptance of appointment. Committee members may resign at any time by
delivering written notice to the Board. Vacancies in the Committee may only be filled by the Board. 
 (b) Powers of the
Administrator. Subject to the provisions of the Plan and the specific duties delegated by the Board to such Committee, and subject to the approval of any relevant authorities, the Administrator shall have the authority in its sole discretion:

 (i) to determine the Fair Market Value; 
 (ii) to select the Service Providers to whom Options and Stock Purchase Rights may from time to time be granted hereunder; 
 (iii) to determine the number of Shares to be covered by each such award granted hereunder; 
 (iv) to
approve forms of agreement for use under the Plan; 
 (v) to determine the terms and conditions of any Option or Stock Purchase Right
granted hereunder (such terms and conditions include, but are not limited to, the exercise price, the time or times when Options or Stock Purchase Rights may vest or be exercised (which may be based on performance criteria), any vesting acceleration
or waiver of forfeiture restrictions, and any restriction or limitation regarding any Option or Stock Purchase Right or the Common Stock relating thereto, based in each case on such factors as the Administrator, in its sole discretion, shall
determine); 
 (vi) to determine whether to offer to buyout a previously granted Option as provided in subsection 10(i) and to determine the
terms and conditions of such offer and buyout (including whether payment is to be made in cash or Shares); 
 (vii) to prescribe, amend and
rescind rules and regulations relating to the Plan, including rules and regulations relating to sub-plans established for the purpose of qualifying for preferred tax treatment under foreign tax laws; 
 (viii) to allow Holders to satisfy withholding tax obligations by electing to have the Company withhold from the Shares to be issued upon exercise of an
Option or Stock Purchase Right that number of Shares having a Fair Market Value equal to the minimum amount required to be withheld based on the statutory withholding rates for federal and state tax purposes that apply to supplemental taxable
income. The Fair Market Value of the Shares to be withheld shall be determined on the date that the amount of tax to be withheld is to be determined. All elections by Holders to have Shares withheld for this purpose shall be made in such form and
under such conditions as the Administrator may deem necessary or advisable; 
  

 5 

 (ix) to amend the Plan or any Option or Stock Purchase Right granted under the Plan as provided in
Section 15; and 
 (x) to construe and interpret the terms of the Plan and awards granted pursuant to the Plan and to exercise such
powers and perform such acts as the Administrator deems necessary or desirable to promote the best interests of the Company which are not in conflict with the provisions of the Plan. 
 (c) Effect of Administrator’s Decision. All decisions, determinations and interpretations of the Administrator shall be final and binding on
all Holders. 
 5. Eligibility. Non-Qualified Stock Options and Stock Purchase Rights may be granted to Service Providers. Incentive
Stock Options may be granted only to Employees. If otherwise eligible, a Service Provider who has been granted an Option or Stock Purchase Right may be granted additional Options or Stock Purchase Rights. 
 6. Limitations. 
 (a) Each Option
shall be designated by the Administrator in the Option Agreement as either an Incentive Stock Option or a Non-Qualified Stock Option. However, notwithstanding such designations, to the extent that the aggregate Fair Market Value of Shares subject to
a Holder’s Incentive Stock Options and other incentive stock options granted by the Company, any Parent or Subsidiary, which become exercisable for the first time during any calendar year (under all plans of the Company or any Parent or
Subsidiary) exceeds $100,000, such excess Options or other options shall be treated as Non-Qualified Stock Options. 
 For purposes of this
Section 6(a), Incentive Stock Options shall be taken into account in the order in which they were granted, and the Fair Market Value of the Shares shall be determined as of the time of grant. 
 (b) Neither the Plan, any Option nor any Stock Purchase Right shall confer upon a Holder any right with respect to continuing the Holder’s
employment or consulting relationship with the Company, nor shall they interfere in any way with the Holder’s right or the Company’s right to terminate such employment or consulting relationship at any time, with or without cause.

 (c) No Service Provider shall be granted, in any calendar year, Options or Stock Purchase Rights to purchase more than 8,500,000 Shares;
provided, however, that the foregoing limitation shall not apply prior to the Public Trading Date and, following the Public Trading Date, the foregoing limitation shall not apply until the earliest of: (i) the first material modification
of the Plan (including any increase in the number of shares reserved for issuance under the Plan in accordance with Section 3); (ii) the issuance of all of the shares of Common Stock reserved for issuance under the Plan; (iii) the
expiration of the Plan; (iv) the first meeting of stockholders at which Directors of the Company are to be elected that occurs after the close of the third calendar year following the calendar year in which occurred the first registration of an

  

 6 

 
equity security of the Company under Section 12 of the Exchange Act; or (v) such other date required by Section 162(m) of the Code and the
rules and regulations promulgated thereunder. The foregoing limitation shall be adjusted proportionately in connection with any change in the Company’s capitalization as described in Section 13. For purposes of this Section 6(c), if
an Option is canceled in the same calendar year it was granted (other than in connection with a transaction described in Section 13), the canceled Option will be counted against the limit set forth in this Section 6(c). For this purpose,
if the exercise price of an Option is reduced, the transaction shall be treated as a cancellation of the Option and the grant of a new Option. 
 7. Term of Plan. The Plan shall become effective upon its initial adoption by the Board and shall continue in effect until it is terminated under Section 15 of the Plan. No Options or Stock Purchase Rights may be issued under
the Plan after the tenth (10th) anniversary of the earlier of (i) the date upon which the Plan is adopted by the Board or (ii) the date the Plan is approved by the stockholders. 
 8. Term of Option. The term of each Option shall be stated in the Option Agreement; provided, however, that the term shall be no more than
ten (10) years from the date of grant thereof. In the case of an Incentive Stock Option granted to a Holder who, at the time the Option is granted, owns (or is treated as owning under Code Section 424) stock representing more than ten
percent (10%) of the voting power of all classes of stock of the Company or any Parent or Subsidiary, the term of the Option shall be five (5) years from the date of grant or such shorter term as may be provided in the Option Agreement.

 9. Option Exercise Price and Consideration. 
 (a) Except as provided in Section 13, the per share exercise price for the Shares to be issued upon exercise of an Option shall be such price as is determined by the Administrator, but shall be subject to the
following: 
 (i) In the case of an Incentive Stock Option 
 (A) granted to an Employee who, at the time of grant of such Option, owns (or is treated as owning under Code Section 424) stock representing more than ten percent (10%) of the voting power of all classes of
stock of the Company or any Parent or Subsidiary, the per Share exercise price shall be no less than one hundred ten percent (110%) of the Fair Market Value per Share on the date of grant. 
 (B) granted to any other Employee, the per Share exercise price shall be no less than one hundred percent (100%) of the Fair Market Value per Share
on the date of grant. 
 (ii) In the case of a Non-Qualified Stock Option 
 (A) granted to a Service Provider who, at the time of grant of such Option, owns stock representing more than ten percent (10%) of the voting power
of all classes of stock of the Company or any Parent or Subsidiary, the exercise price shall be no less than one hundred ten percent (110%) of the Fair Market Value per Share on the date of the grant. 
  

 7 

 (B) granted to any other Service Provider, the per Share exercise price shall be no less than
eighty-five percent (85%) of the Fair Market Value per Share on the date of grant. 
 (iii) Notwithstanding the foregoing, Options may
be granted with a per Share exercise price other than as required above pursuant to a merger or other corporate transaction. 
 (b) The
consideration to be paid for the Shares to be issued upon exercise of an Option, including the method of payment, shall be determined by the Administrator (and, in the case of an Incentive Stock Option, shall be determined at the time of grant).
Such consideration may consist of (1) cash, (2) check, (3) with the consent of the Administrator, a full recourse promissory note bearing interest (at no less than such rate as is a market rate of interest and which then precludes the
imputation of interest under the Code) and payable upon such terms as may be prescribed by the Administrator, (4) with the consent of the Administrator, other Shares which (x) in the case of Shares acquired from the Company, have been
owned by the Holder for more than six (6) months on the date of surrender, and (y) have a Fair Market Value on the date of surrender equal to the aggregate exercise price of the Shares as to which such Option shall be exercised,
(5) with the consent of the Administrator, surrendered Shares then issuable upon exercise of the Option having a Fair Market Value on the date of exercise equal to the aggregate exercise price of the Option or exercised portion thereof,
(6) with the consent of the Administrator, property of any kind which constitutes good and valuable consideration, (7) with the consent of the Administrator, delivery of a notice that the Holder has placed a market sell order with a broker
with respect to Shares then issuable upon exercise of the Options and that the broker has been directed to pay a sufficient portion of the net proceeds of the sale to the Company in satisfaction of the Option exercise price, provided, that
payment of such proceeds is then made to the Company upon settlement of such sale, or (8) with the consent of the Administrator, any combination of the foregoing methods of payment. 
 10. Exercise of Option. 
 (a)
Vesting; Fractional Exercises. Except as provided in Section 13, Options granted hereunder shall be vested and exercisable according to the terms hereof at such times and under such conditions as determined by the Administrator and set
forth in the Option Agreement; provided, however, that, except with regard to Options granted to Officers, Directors or Consultants, in no event shall an Option granted hereunder become vested and exercisable at a rate of less than twenty
percent (20%) per year over five (5) years from the date the Option is granted, subject to reasonable conditions, such as continuing to be a Service Provider. An Option may not be exercised for a fraction of a Share. 
 (b) Deliveries upon Exercise. All or a portion of an exercisable Option shall be deemed exercised upon delivery of all of the following to the
Secretary of the Company or his or her office: 
 (i) A written or electronic notice complying with the applicable rules established by the
Administrator stating that the Option, or a portion thereof, is exercised. The notice shall be signed by the Holder or other person then entitled to exercise the Option or such portion of the Option; 
  

 8 

 (ii) Such representations and documents as the Administrator, in its sole discretion, deems necessary or
advisable to effect compliance with Applicable Laws. The Administrator may, in its sole discretion, also take whatever additional actions it deems appropriate to effect such compliance, including, without limitation, placing legends on share
certificates and issuing stop transfer notices to agents and registrars; 
 (iii) Upon the exercise of all or a portion of an unvested
Option pursuant to Section 10(h), a Restricted Stock purchase agreement in a form determined by the Administrator and signed by the Holder or other person then entitled to exercise the Option or such portion of the Option; and 
 (iv) In the event that the Option shall be exercised pursuant to Section 10(f) by any person or persons other than the Holder, appropriate proof of
the right of such person or persons to exercise the Option. 
 (c) Conditions to Delivery of Share Certificates. The Company shall not
be required to issue or deliver any certificate or certificates for Shares purchased upon the exercise of any Option or portion thereof prior to fulfillment of all of the following conditions: 
 (i) The admission of such Shares to listing on all stock exchanges on which such class of stock is then listed; 
 (ii) The completion of any registration or other qualification of such Shares under any state or federal law, or under the rulings or regulations of the
Securities and Exchange Commission or any other governmental regulatory body which the Administrator shall, in its sole discretion, deem necessary or advisable; 
 (iii) The obtaining of any approval or other clearance from any state or federal governmental agency which the Administrator shall, in its sole discretion, determine to be necessary or advisable; 
 (iv) The lapse of such reasonable period of time following the exercise of the Option as the Administrator may establish from time to time for reasons
of administrative convenience; and 
 (v) The receipt by the Company of full payment for such Shares, including payment of any applicable
withholding tax, which in the sole discretion of the Administrator may be in the form of consideration used by the Holder to pay for such Shares under Section 9(b). 
 (d) Termination of Relationship as a Service Provider. If a Holder ceases to be a Service Provider other than by reason of the Holder’s disability or death, such Holder may exercise his or her Option
within such period of time as is specified in the Option Agreement to the extent that the Option is vested on the date of termination; provided, however, that prior to the Public Trading Date, such period of time shall not be less than
thirty (30) days (but in no 

  

 9 

 
event later than the expiration of the term of the Option as set forth in the Option Agreement). In the absence of a specified time in the Option Agreement,
the Option shall remain exercisable for three (3) months following the Holder’s termination. If, on the date of termination, the Holder is not vested as to his or her entire Option, the Shares covered by the unvested portion of the Option
immediately cease to be issuable under the Option and shall again become available for issuance under the Plan. If, after termination, the Holder does not exercise his or her Option within the time period specified herein, the Option shall
terminate, and the Shares covered by such Option shall again become available for issuance under the Plan. 
 (e) Disability of
Holder. If a Holder ceases to be a Service Provider as a result of the Holder’s disability, the Holder may exercise his or her Option within such period of time as is specified in the Option Agreement to the extent the Option is vested on
the date of termination; provided, however, that prior to the Public Trading Date, such period of time shall not be less than six (6) months (but in no event later than the expiration of the term of such Option as set forth in the
Option Agreement). In the absence of a specified time in the Option Agreement, the Option shall remain exercisable for twelve (12) months following the Holder’s termination. If such disability is not a “disability” as such term
is defined in Section 22(e)(3) of the Code, in the case of an Incentive Stock Option such Incentive Stock Option shall automatically cease to be treated as an Incentive Stock Option and shall be treated for tax purposes as a Non-Qualified Stock
Option from and after the day which is three (3) months and one (1) day following such termination. If, on the date of termination, the Holder is not vested as to his or her entire Option, the Shares covered by the unvested portion of the
Option shall immediately cease to be issuable under the Option and shall again become available for issuance under the Plan. If, after termination, the Holder does not exercise his or her Option within the time specified herein, the Option shall
terminate, and the Shares covered by such Option shall again become available for issuance under the Plan. 
 (f) Death of Holder. If
a Holder dies while a Service Provider, the Option may be exercised within such period of time as is specified in the Option Agreement provided, however, that prior to the Public Trading Date, such period of time shall not be less than
six (6) months (but in no event later than the expiration of the term of such Option as set forth in the Notice of Grant), by the Holder’s estate or by a person who acquires the right to exercise the Option by bequest or inheritance, but
only to the extent that the Option is vested on the date of death. In the absence of a specified time in the Option Agreement, the Option shall remain exercisable for twelve (12) months following the Holder’s termination. If, at the time
of death, the Holder is not vested as to his or her entire Option, the Shares covered by the unvested portion of the Option shall immediately cease to be issuable under the Option and shall again become available for issuance under the Plan. The
Option may be exercised by the executor or administrator of the Holder’s estate or, if none, by the person(s) entitled to exercise the Option under the Holder’s will or the laws of descent or distribution. If the Option is not so exercised
within the time specified herein, the Option shall terminate, and the Shares covered by such Option shall again become available for issuance under the Plan. 
 (g) Regulatory Extension. A Holder’s Option Agreement may provide that if the exercise of the Option following the termination of the Holder’s status as a Service Provider (other than upon the
Holder’s death or Disability) would be prohibited at any time solely because the issuance of shares would violate the registration requirements under the Securities Act, then 

  

 10 

 
the Option shall terminate on the earlier of (i) the expiration of the term of the Option set forth in Section 8 or (ii) the expiration of a
period of three (3) months after the termination of the Holder’s status as a Service Provider during which the exercise of the Option would not be in violation of such registration requirements. 
 (h) Early Exercisability. The Administrator may provide in the terms of a Holder’s Option Agreement that the Holder may, at any time before
the Holder’s status as a Service Provider terminates, exercise the Option in whole or in part prior to the full vesting of the Option; provided, however, that subject to Section 20, Shares acquired upon exercise of an Option which
has not fully vested may be subject to any forfeiture, transfer or other restrictions as the Administrator may determine in its sole discretion. 
 (i) Buyout Provisions. The Administrator may at any time offer to buyout for a payment in cash or Shares, an Option previously granted, based on such terms and conditions as the Administrator shall establish and communicate to the
Holder at the time that such offer is made. 
 11. Non-Transferability of Options and Stock Purchase Rights. Options and Stock
Purchase Rights may not be sold, pledged, assigned, hypothecated, transferred, or disposed of in any manner other than by will or by the laws of descent or distribution and may be exercised, during the lifetime of the Holder, only by the Holder.

 12. Stock Purchase Rights. 
 (a) Rights to Purchase. Stock Purchase Rights may be issued either alone, in addition to, or in tandem with Options granted under the Plan and/or cash awards made outside of the Plan. After the Administrator determines that it will
offer Stock Purchase Rights under the Plan, it shall advise the offeree in writing of the terms, conditions and restrictions related to the offer, including the number of Shares that such person shall be entitled to purchase, the price to be paid,
and the time within which such person must accept such offer; provided, however, that to the extent required to comply with applicable securities laws, the purchase price of such Shares shall not be less than the purchase price requirements
set forth in Section 260.140.42 of Title 10 of the California Code of Regulations. The offer shall be accepted by execution of a Restricted Stock purchase agreement in the form determined by the Administrator. 
 (b) Repurchase Right. Unless the Administrator determines otherwise, the Restricted Stock purchase agreement shall grant the Company the right to
repurchase Shares acquired upon exercise of a Stock Purchase Right upon the termination of the purchaser’s status as a Service Provider for any reason. Subject to Section 20, the purchase price for Shares repurchased by the Company
pursuant to such repurchase right and the rate at which such repurchase right shall lapse shall be determined by the Administrator in its sole discretion, and shall be set forth in the Restricted Stock purchase agreement. 
 (c) Other Provisions. The Restricted Stock purchase agreement shall contain such other terms, provisions and conditions not inconsistent with the
Plan as may be determined by the Administrator in its sole discretion. 
  

 11 

 (d) Rights as a Shareholder. Once the Stock Purchase Right is exercised, the purchaser shall have
rights equivalent to those of a shareholder and shall be a shareholder when his or her purchase is entered upon the records of the duly authorized transfer agent of the Company. No adjustment shall be made for a dividend or other right for which the
record date is prior to the date the Stock Purchase Right is exercised, except as provided in Section 13 of the Plan. 
 13.
Adjustments upon Changes in Capitalization, Merger or Asset Sale. 
 (a) In the event that the Administrator determines that any
dividend or other distribution (whether in the form of cash, Common Stock, other securities, or other property), recapitalization, reclassification, stock split, reverse stock split, reorganization, merger, consolidation, split-up, spin-off,
combination, repurchase, liquidation, dissolution, or sale, transfer, exchange or other disposition of all or substantially all of the assets of the Company, or exchange of Common Stock or other securities of the Company, issuance of warrants or
other rights to purchase Common Stock or other securities of the Company, or other similar corporate transaction or event, in the Administrator’s sole discretion, affects the Common Stock such that an adjustment is determined by the
Administrator to be appropriate in order to prevent dilution or enlargement of the benefits or potential benefits intended by the Company to be made available under the Plan or with respect to any Option, Stock Purchase Right or Restricted Stock,
then the Administrator shall, in such manner as it may deem equitable, adjust any or all of: 
 (i) the number and kind of shares of Common
Stock (or other securities or property) with respect to which Options or Stock Purchase Rights may be granted or awarded (including, but not limited to, adjustments of the limitations in Section 3 on the maximum number and kind of shares which
may be issued and adjustments of the maximum number of Shares that may be purchased by any Holder in any calendar year pursuant to Section 6(c)); 
 (ii) the number and kind of shares of Common Stock (or other securities or property) subject to outstanding Options, Stock Purchase Rights or Restricted Stock; and 
 (iii) the grant or exercise price with respect to any Option or Stock Purchase Right. 
 (b) In the event of any transaction or event described in Section 13(a), the Administrator, in its sole discretion, and on such terms and conditions
as it deems appropriate, either by the terms of the Option, Stock Purchase Right or Restricted Stock or by action taken prior to the occurrence of such transaction or event and either automatically or upon the Holder’s request, is hereby
authorized to take any one or more of the following actions whenever the Administrator determines that such action is appropriate in order to prevent dilution or enlargement of the benefits or potential benefits intended by the Company to be made
available under the Plan or with respect to any Option, Stock Purchase Right or Restricted Stock granted or issued under the Plan or to facilitate such transaction or event: 
  

 12 

 (i) To provide for either the purchase of any such Option, Stock Purchase Right or Restricted Stock for
an amount of cash equal to the amount that could have been obtained upon the exercise of such Option or Stock Purchase Right or realization of the Holder’s rights had such Option, Stock Purchase Right or Restricted Stock been currently
exercisable or payable or fully vested or the replacement of such Option, Stock Purchase Right or Restricted Stock with other rights or property selected by the Administrator in its sole discretion; 
 (ii) To provide that such Option or Stock Purchase Right shall be exercisable as to all shares covered thereby, notwithstanding anything to the contrary
in the Plan or the provisions of such Option or Stock Purchase Right; 
 (iii) To provide that such Option, Stock Purchase Right or
Restricted Stock be assumed by the successor or survivor corporation, or a parent or subsidiary thereof, or shall be substituted for by similar options, rights or awards covering the stock of the successor or survivor corporation, or a parent or
subsidiary thereof, with appropriate adjustments as to the number and kind of shares and prices; 
 (iv) To make adjustments in the number
and type of shares of Common Stock (or other securities or property) subject to outstanding Options and Stock Purchase Rights, and/or in the terms and conditions of (including the grant or exercise price), and the criteria included in, outstanding
Options, Stock Purchase Rights or Restricted Stock or Options, Stock Purchase Rights or Restricted Stock which may be granted in the future; and 
 (v) To provide that immediately upon the consummation of such event, such Option or Stock Purchase Right shall not be exercisable and shall terminate; provided, that for a specified period of time prior to such event, such Option or
Stock Purchase Right shall be exercisable as to all Shares covered thereby, and the restrictions imposed under an Option Agreement or Restricted Stock purchase agreement upon some or all Shares may be terminated and, in the case of Restricted Stock,
some or all shares of such Restricted Stock may cease to be subject to repurchase, notwithstanding anything to the contrary in the Plan or the provisions of such Option, Stock Purchase Right or Restricted Stock purchase agreement. 
 (c) Subject to Section 3, the Administrator may, in its sole discretion, include such further provisions and limitations in any Option, Stock
Purchase Right, Restricted Stock agreement or certificate, as it may deem equitable and in the best interests of the Company. 
 (d) If the
Company undergoes an Acquisition, then any surviving corporation or entity or acquiring corporation or entity, or affiliate of such corporation or entity, may assume any Options, Stock Purchase Rights or Restricted Stock outstanding under the Plan
or may substitute similar stock awards (including an award to acquire the same consideration paid to the stockholders in the transaction described in this subsection 13(d)) for those outstanding under the Plan. In the event any surviving corporation
or entity or acquiring corporation or entity in an Acquisition, or affiliate of such corporation or entity, does not assume such Options, Stock Purchase Rights or Restricted Stock or does not substitute similar stock awards for those outstanding
under the Plan, then with respect to (i) Options, Stock Purchase Rights or Restricted Stock held by participants in the Plan whose status as a Service Provider has not terminated prior 

  

 13 

 
to such event, the vesting of such Options, Stock Purchase Rights or Restricted Stock (and, if applicable, the time during which such awards may be
exercised) shall be accelerated and made fully exercisable and all restrictions thereon shall lapse at least ten (10) days prior to the closing of the Acquisition (and the Options or Stock Purchase Rights terminated if not exercised prior to
the closing of such Acquisition), and (ii) any other Options or Stock Purchase Rights outstanding under the Plan, such Options or Stock Purchase rights shall be terminated if not exercised prior to the closing of the Acquisition. 
 (e) The existence of the Plan, any Option Agreement or Restricted Stock purchase agreement and the Options or Stock Purchase Rights granted hereunder
shall not affect or restrict in any way the right or power of the Company or the stockholders of the Company to make or authorize any adjustment, recapitalization, reorganization or other change in the Company’s capital structure or its
business, any merger or consolidation of the Company, any issue of stock or of options, warrants or rights to purchase stock or of bonds, debentures, preferred or prior preference stocks whose rights are superior to or affect the Common Stock or the
rights thereof or which are convertible into or exchangeable for Common Stock, or the dissolution or liquidation of the Company, or any sale or transfer of all or any part of its assets or business, or any other corporate act or proceeding, whether
of a similar character or otherwise. 
 14. Time of Granting Options and Stock Purchase Rights. The date of grant of an Option or
Stock Purchase Right shall, for all purposes, be the date on which the Administrator makes the determination granting such Option or Stock Purchase Right, or such other date as is determined by the Administrator. Notice of the determination shall be
given to each Employee or Consultant to whom an Option or Stock Purchase Right is so granted within a reasonable time after the date of such grant. 
 15. Amendment and Termination of the Plan. 
 (a) Amendment and Termination. The Board may at any time wholly or
partially amend, alter, suspend or terminate the Plan. However, without approval of the Company’s stockholders given within twelve (12) months before or after the action by the Board, no action of the Board may, except as provided in
Section 13, increase the limits imposed in Section 3 on the maximum number of Shares which may be issued under the Plan or extend the term of the Plan under Section 7. 
 (b) Stockholder Approval. The Board shall obtain stockholder approval of any Plan amendment to the extent necessary and desirable to comply with
Applicable Laws. 
 (c) Effect of Amendment or Termination. No amendment, alteration, suspension or termination of the Plan shall
impair the rights of any Holder, unless mutually agreed otherwise between the Holder and the Administrator, which agreement must be in writing and signed by the Holder and the Company. Termination of the Plan shall not affect the
Administrator’s ability to exercise the powers granted to it hereunder with respect to Options, Stock Purchase Rights or Restricted Stock granted or awarded under the Plan prior to the date of such termination. 
  

 14 

 16. Stockholder Approval. The Plan will be submitted for the approval of the Company’s
stockholders within twelve (12) months after the date of the Board’s initial adoption of the Plan. Options, Stock Purchase Rights or Restricted Stock may be granted or awarded prior to such stockholder approval, provided that such Options,
Stock Purchase Rights and Restricted Stock shall not be exercisable, shall not vest and the restrictions thereon shall not lapse prior to the time when the Plan is approved by the stockholders, and provided further that if such approval has not been
obtained at the end of said twelve-month period, all Options, Stock Purchase Rights and Restricted Stock previously granted or awarded under the Plan shall thereupon be canceled and become null and void. 
 17. Inability to Obtain Authority. The inability of the Company to obtain authority from any regulatory body having jurisdiction, which authority
is deemed by the Company’s 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. 
 18. Reservation of Shares. The Company, during the term of this Plan, shall at all times reserve and
keep available such number of Shares as shall be sufficient to satisfy the requirements of the Plan. 
 19. Information to Holders and
Purchasers. Prior to the Public Trading Date and to the extent required by Section 260.140.46 of Title 10 of the California Code of Regulations, the Company shall provide to each Holder and to each individual who acquires Shares pursuant to
the Plan, not less frequently than annually during the period such Holder or purchaser has one or more Options or Stock Purchase Rights outstanding, and, in the case of an individual who acquires Shares pursuant to the Plan, during the period such
individual owns such Shares, copies of annual financial statements. Notwithstanding the preceding sentence, the Company shall not be required to provide such statements to key employees whose duties in connection with the Company assure their access
to equivalent information. 
 20. Repurchase Provisions. The Administrator in its sole discretion may provide that the Company may
repurchase Shares acquired upon exercise of an Option or Stock Purchase Right upon the occurrence of certain specified events, including, without limitation, a Holder’s termination as a Service Provider, divorce, bankruptcy or insolvency;
provided, however, that any such repurchase right shall be set forth in the applicable Option Agreement or Restricted Stock purchase agreement or in another agreement referred to in such agreement and, provided further, that to the extent
required by Section 260.140.41 and Section 260.140.42 of Title 10 of the California Code of Regulations, any such repurchase right set forth in an Option or Stock Purchase Right granted prior to the Public Trading Date to a person who is
not an Officer, Director or Consultant shall be upon the following terms: (i) if the repurchase option gives the Company the right to repurchase the shares upon termination as a Service Provider at not less than the Fair Market Value of the
shares to be purchased on the date of termination of status as a Service Provider, then (A) the right to repurchase shall be exercised for cash or cancellation of purchase money indebtedness for the shares within ninety (90) days of
termination of status as a Service Provider (or in the case of shares issued upon exercise of Options or Stock Purchase Rights after such date of termination, within ninety (90) days after the date of the exercise) or such longer period as may
be agreed to by the Administrator and the Plan participant and (B) the 
  

 15 

 
right terminates when the shares become publicly traded; and (ii) if the repurchase option gives the Company the right to repurchase the Shares upon
termination as a Service Provider at the original purchase price for such Shares, then (A) the right to repurchase at the original purchase price shall lapse at the rate of at least twenty percent (20%) of the shares per year over five
(5) years from the date the Option or Stock Purchase Right is granted (without respect to the date the Option or Stock Purchase Right was exercised or became exercisable) and (B) the right to repurchase shall be exercised for cash or
cancellation of purchase money indebtedness for the shares within ninety (90) days of termination of status as a Service Provider (or, in the case of shares issued upon exercise of Options or Stock Purchase Rights, after such date of
termination, within ninety (90) days after the date of the exercise) or such longer period as may be agreed to by the Company and the Plan participant. 
 21. Investment Intent. The Company may require a Plan participant, as a condition of exercising or acquiring stock under any Option or Stock Purchase Right, (i) to give written assurances satisfactory to
the Company as to the participant’s knowledge and experience in financial and business matters and/or to employ a purchaser representative reasonably satisfactory to the Company who is knowledgeable and experienced in financial and business
matters and that he or she is capable of evaluating, alone or together with the purchaser representative, the merits and risks of exercising the Option or Stock Purchase Right; and (ii) to give written assurances satisfactory to the Company
stating that the participant is acquiring the stock subject to the Option or Stock Purchase Right for the participant’s own account and not with any present intention of selling or otherwise distributing the stock. The foregoing requirements,
and any assurances given pursuant to such requirements, shall be inoperative if (A) the issuance of the shares upon the exercise or acquisition of stock under the applicable Option or Stock Purchase Right has been registered under a then
currently effective registration statement under the Securities Act or (B) as to any particular requirement, a determination is made by counsel for the Company that such requirement need not be met in the circumstances under the then applicable
securities laws. The Company may, upon advice of counsel to the Company, place legends on stock certificates issued under the Plan as such counsel deems necessary or appropriate in order to comply with applicable securities laws, including, but not
limited to, legends restricting the transfer of the stock. 
 22. Governing Law. The validity and enforceability of this Plan shall be
governed by and construed in accordance with the laws of the State of Delaware without regard to otherwise governing principles of conflicts of law. 
 ************ 
  

 16 

 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 STOCK OPTION AGREEMENT 
 Bayhill Therapeutics, Inc. (the “Company”), pursuant to its 2002 Equity Incentive Plan (the “Plan”), hereby grants to Optionee listed
below (“Optionee”), an option to purchase the number of shares of the Company’s Common Stock set forth below, subject to the terms and conditions of the Plan and this Stock Option Agreement. Unless otherwise defined herein, the terms
defined in the Plan shall have the same defined meanings in this Stock Option Agreement. 
 NOTICE OF STOCK OPTION GRANT 
  

	
	 Optionee:

	
	 Date of Stock Option Agreement:

	
	 Date of Grant:

	
	 Vesting Commencement Date:

	
	 Exercise Price per Share:

	
	 Total Number of Shares Granted:

	
	 Total Exercise Price:

	
	 Term/Expiration Date:

  

			
	Type of Option:	  	x  Incentive Stock Option             ̈  Non-Qualified Stock Option
		
	Vesting Schedule:	  	The Shares subject to this Option shall vest according to the following schedule:
		  	Twenty five percent (25%) of the Shares subject to the Option (rounded down to the next whole number of shares) shall vest one year after the Vesting Commencement Date, and 1/48th of the Shares subject to the Option (rounded down to the next whole number of shares) shall vest on the first day of each full month thereafter, so that all
of the Shares shall be vested on the first day of the forty eighth (48th) full month after the Vesting Commencement Date.
		
	Termination Period:	  	This Option may be exercised, to the extent vested, for three (3) months after Optionee ceases to be a Service Provider, or such longer period as may be applicable upon the death or
disability of Optionee as provided herein (or, if not provided herein, then as provided in the Plan), but in no event later than the Term/Expiration Date as provided above.

  

 17 

 AGREEMENT 
 Grant of Option. The Company hereby grants to Optionee an Option to purchase the number of shares of Common Stock (the “Shares”) set forth in the Notice of Grant, at the exercise price per share set forth in the Notice of
Grant (the “Exercise Price”). Notwithstanding anything to the contrary anywhere else in this Option Agreement, this grant of an Option is subject to the terms, definitions and provisions of the Plan adopted by the Company, which is
incorporated herein by reference. 
 If designated in the Notice of Grant as an Incentive Stock Option, this Option is intended to qualify as
an Incentive Stock Option as defined in Section 422 of the Code; provided, however, that to the extent that the aggregate Fair Market Value of stock with respect to which Incentive Stock Options (within the meaning of Code Section 422, but
without regard to Code Section 422(d)), including the Option, are exercisable for the first time by Optionee during any calendar year (under the Plan and all other incentive stock option plans of the Company or any Subsidiary) exceeds $100,000,
such options shall be treated as not qualifying under Code Section 422, but rather shall be treated as Non-Qualified Stock Options to the extent required by Code Section 422. The rule set forth in the preceding sentence shall be applied by
taking options into account in the order in which they were granted. For purposes of these rules, the Fair Market Value of stock shall be determined as of the time the option with respect to such stock is granted. 
 Exercise of Option. This Option is exercisable as follows: 
 Right to Exercise. 
 This Option shall be exercisable cumulatively according to the vesting schedule
set out in the Notice of Grant. For purposes of this Stock Option Agreement, Shares subject to this Option shall vest based on Optionee’s continued status as a Service Provider. 
 This Option may not be exercised for a fraction of a Share. 
 In the event of Optionee’s death, disability or other termination of Optionee’s status as a Service Provider, the exercisability of the Option is governed by Sections 7, 8 and 9 below. 
 In no event may this Option be exercised after the date of expiration of the term of this Option as set forth in the Notice of Grant. 
 Method of Exercise. This Option shall be exercisable by written Notice (in the form attached as Exhibit A). The Notice must state the
number of Shares for which the Option is being exercised, and such other representations and agreements with respect to such shares of Common Stock as may be required by the Company pursuant to the provisions of the Plan. The Notice must be signed
by Optionee and shall be delivered in person or by certified mail to the Secretary of the Company. The Notice must be accompanied by payment of the Exercise Price plus payment of any applicable withholding tax. This Option shall be deemed to
be exercised upon receipt by the Company of such written Notice accompanied by the Exercise Price and payment of any applicable withholding tax. 
  

 18 

 No Shares shall be issued pursuant to the exercise of an Option unless such issuance and such exercise
comply with all relevant provisions of law and the requirements of any stock exchange upon which the Shares may then be listed. Assuming such compliance, for income tax purposes the Shares shall be considered transferred to Optionee on the date on
which the Option is exercised with respect to such Shares. 
 Optionee’s Representations. If the Shares purchasable pursuant to
the exercise of this Option have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), at the time this Option is exercised, Optionee shall, if required by the Company, concurrently with the exercise of
all or any portion of this Option, deliver to the Company his or her Investment Representation Statement in the form attached hereto as Exhibit B. 
 Lock-Up Period. Optionee hereby agrees that if so requested by the Company or any representative of the underwriters (the “Managing Underwriter”) in connection with any registration of the offering of
any securities of the Company under the Securities Act, Optionee shall not sell or otherwise transfer any Shares or other securities of the Company during the 180-day period (or such longer period as may be requested in writing by the Managing
Underwriter and agreed to in writing by the Company) (the “Market Standoff Period”) following the effective date of a registration statement of the Company filed under the Securities Act; provided, however, that such restriction shall
apply only to the first registration statement of the Company to become effective under the Securities Act that includes securities to be sold on behalf of the Company to the public in an underwritten public offering under the Securities Act. The
Company may impose stop-transfer instructions with respect to securities subject to the foregoing restrictions until the end of such Market Standoff Period and these restrictions shall be binding on any transferee of such Shares. 
 Method of Payment. Payment of the Exercise Price shall be by any of the following, or a combination thereof, at the election of Optionee:

 cash; 
 check; 
 with the consent of the Administrator, a full recourse promissory note bearing interest (at no less than such rate as is a market rate of interest and
which then precludes the imputation of interest under the Code) and payable upon such terms as may be prescribed by the Administrator; 
 with the consent of the Administrator, surrender of other shares of Common Stock of the Company which (A) in the case of Shares acquired from the Company, have been owned by Optionee for more than six (6) months on the date of
surrender, and (B) have a Fair Market Value on the date of surrender equal to the Exercise Price of the Shares as to which the Option is being exercised; 
 with the consent of the Administrator, surrendered Shares issuable upon the exercise of the Option having a Fair Market Value on the date of exercise equal to the aggregate Exercise Price of the Option or exercised
portion thereof; 
  

 19 

 with the consent of the Administrator, property of any kind which constitutes good and valuable
consideration; 
 with the consent of the Administrator, delivery of a notice that Optionee has placed a market sell order with a broker with
respect to Shares then issuable upon exercise of the Option and that the broker has been directed to pay a sufficient portion of the net proceeds of the sale to the Company in satisfaction of the aggregate Exercise Price; provided, that payment of
such proceeds is then made to the Company upon settlement of such sale; or 
 with the consent of the Administrator, any combination of the
foregoing methods of payment. 
 Restrictions on Exercise. This Option may not be exercised until the Plan has been approved by the
stockholders of the Company. If the issuance of Shares upon such exercise or if the method of payment for such shares would constitute a violation of any applicable federal or state securities or other law or regulation, then the Option may also not
be exercised. The Company may require Optionee to make any representation and warranty to the Company as may be required by any applicable law or regulation before allowing the Option to be exercised. 
 Termination of Relationship. If Optionee ceases to be a Service Provider (other than by reason of Optionee’s death or the total and permanent
disability of Optionee as defined in Code Section 22(e)(3)), Optionee may exercise this Option during the Termination Period set out in the Notice of Grant, to the extent the Option was vested at the date on which Optionee ceases to be a
Service Provider. To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise this Option within the time specified herein, the Option shall terminate. 
 Disability of Optionee. If Optionee ceases to be a Service Provider as a result of his or her total and permanent disability as defined in Code
Section 22(e)(3), Optionee may exercise the Option to the extent the Option was vested at the date on which Optionee ceases to be a Service Provider, but only within twelve (12) months from such date (and in no event later than the
expiration date of the term of this Option as set forth in the Notice of Grant). To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise such Option within the time
specified herein, the Option shall terminate. 
 Death of Optionee. If Optionee ceases to be a Service Provider as a result of the
death of Optionee, the vested portion of the Option may be exercised at any time within twelve (12) months following the date of death (and in no event later than the expiration date of the term of this Option as set forth in the Notice of
Grant) by Optionee’s estate or by a person who acquires the right to exercise the Option by bequest or inheritance. To the extent that the Option is not vested at the date of death, or if the Option is not exercised within the time specified
herein, the Option shall terminate. 
  

 20 

 Non-Transferability of Option. This Option may not be transferred in any manner except by will or
by the laws of descent or distribution . It may be exercised during the lifetime of Optionee only by Optionee. The terms of this Option shall be binding upon the executors, administrators, heirs, successors and assigns of Optionee. 
 Term of Option. This Option may be exercised only within the term set out in the Notice of Grant. 
 [Signature page follows] 
  

 21 

 This Agreement may be executed in two or more counterparts, each of which shall be deemed an original and
all of which shall constitute one document. 
  

			
	BAYHILL THERAPEUTICS, INC.
		
	By:	 	  

	Name:	 	Mark W. Schwartz
	Title:	 	Chief Executive Officer

 OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO THE OPTION HEREOF IS
EARNED ONLY BY CONTINUING CONSULTANCY OR EMPLOYMENT AT THE WILL OF THE COMPANY (NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR ACQUIRING SHARES HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT NOTHING IN THIS AGREEMENT,
NOR IN THE COMPANY’S 2002 EQUITY INCENTIVE PLAN WHICH IS INCORPORATED HEREIN BY REFERENCE, SHALL CONFER UPON OPTIONEE ANY RIGHT WITH RESPECT TO CONTINUATION OF EMPLOYMENT OR CONSULTANCY BY THE COMPANY, NOR SHALL IT INTERFERE IN ANY WAY WITH
OPTIONEE’S RIGHT OR THE COMPANY’S RIGHT TO TERMINATE OPTIONEE’S EMPLOYMENT OR CONSULTANCY AT ANY TIME, WITH OR WITHOUT CAUSE AND WITH OR WITHOUT PRIOR NOTICE. 
 Optionee acknowledges receipt of a copy of the Plan and represents that he or she is familiar with the terms and provisions thereof. Optionee hereby
accepts this Option subject to all of the terms and provisions hereof. Optionee has reviewed the Plan and this Option in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Option and fully understands all
provisions of the Option. Optionee hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan or this Option. Optionee further agrees to notify the Company
upon any change in the residence address indicated below. 
  

			
	Dated:                     	  	  

		  	 Name

		
		  	Residence Address:
		
		  	  

		
		  	  

  

 22 

 EXHIBIT A 
 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 EXERCISE NOTICE 
 Bayhill Therapeutics, Inc.

 Attention: Stock Administration 
 Exercise
of Option. Effective as of today,                     ,             ,
the undersigned (“Optionee”) hereby elects to exercise Optionee’s option to purchase                      shares of the Common
Stock (the “Shares”) of Bayhill Therapeutics, Inc. (the “Company”) under and pursuant to the Bayhill Therapeutics, Inc. 2002 Equity Incentive Plan (the “Plan”) and the  ̈ Incentive  ̈ Non-Qualified Stock Option Agreement dated
                    ,             , (the “Option Agreement”).
Capitalized terms used herein without definition shall have the meanings given in the Option Agreement. 
  

					
	Date of Grant:	 		    	  

			
	 Number of Shares as to which Option is
 Exercised:
	 		    	  

			
	Exercise Price per Share:	 		    	$                    
			
	Total Exercise Price:	 		    	$                    
			
	Certificate to be issued in Name of:	 		    	  

			
	Cash Payment delivered herewith:	 	 ̈	    	$                    
			
	Promissory note delivered herewith:	 	 ̈	    	$                    

  

			
	Type of Option:	  	 ̈  Incentive Stock Option             ̈  Non-Qualified Stock Option

 Representations of Optionee. Optionee acknowledges that Optionee has received, read and
understood the Plan and the Option Agreement. Optionee agrees to abide by and be bound by their terms and conditions. 
 Rights as
Stockholder. Until the stock certificate evidencing such Shares is issued (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), no right to vote or receive dividends or any
other rights as a stockholder shall exist with respect to Shares subject to the Option, notwithstanding the exercise of the Option. The Company shall issue (or cause to be issued) such stock certificate promptly after the Option is exercised. No
adjustment will be made for a dividend or other right for which the record date is prior to the date the stock certificate is issued, except as provided in Section 13 of the Plan. 

 Optionee shall enjoy rights as a stockholder until such time as Optionee disposes of the Shares or the
Company and/or its assignee(s) exercises the Right of First Refusal hereunder. Upon such exercise, Optionee shall have no further rights as a holder of the Shares so purchased except the right to receive payment for the Shares so purchased in
accordance with the provisions of this Agreement, and Optionee shall forthwith cause the certificate(s) evidencing the Shares so purchased to be surrendered to the Company for transfer or cancellation. 
 Optionee’s Rights to Transfer Shares. 
 Company’s Right of First Refusal. Before any Shares held by Optionee or any permitted transferee (each, a “Holder”) may be sold, pledged, assigned, hypothecated, transferred, or otherwise disposed of (each, a
“Transfer”), the Company or its assignee(s) shall have a right of first refusal to purchase the Shares proposed to be Transferred on the terms and conditions set forth in this Section (the “Right of First Refusal”). 

Notice of Proposed Transfer. In the event any Holder desires to Transfer any Shares, the Holder shall deliver to the Company a written notice
(the “Notice”) stating: (w) the Holder’s bona fide intention to sell or otherwise Transfer such Shares; (x) the Name of each proposed purchaser or other transferee (“Proposed Transferee”); (y) the number of
Shares to be Transferred to each Proposed Transferee; and (z) the bona fide cash price or other consideration for which the Holder proposes to Transfer the Shares (the “Offered Price”), and the Holder shall offer such Shares at the
Offered Price to the Company or its assignee(s). 
 Exercise of Right of First Refusal. Within thirty (30) days after receipt of
the Notice, the Company and/or its assignee(s) may elect in writing to purchase all, but not less than all, of the Shares proposed to be Transferred to any one or more of the Proposed Transferees. The purchase price will be determined in accordance
with subsection (iii) below. 
 Purchase Price. The purchase price (“Purchase Price”) for the Shares repurchased under
this Section shall be the Offered Price. If the Offered Price includes consideration other than cash, the cash equivalent value of the non-cash consideration shall be determined by the Board of Directors of the Company in good faith. 
 Payment. Payment of the Purchase Price shall be made, at the option of the Company or its assignee(s), in cash (by check), by cancellation of all
or a portion of any outstanding indebtedness of the Holder to the Company (or, in the case of repurchase by an assignee, to the assignee), or by any combination thereof within thirty (30) days after receipt of the Notice or in the manner and at
the times mutually agreed to by the Company and the Holder. 
 Holder’s Right to Transfer. If all of the Shares proposed in the
Notice to be Transferred are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise Transfer such Shares to that Proposed Transferee at the Offered Price or at a higher price, provided
that such sale or other Transfer is consummated within one hundred twenty (120) days after the date of the Notice and provided further that any such sale or other Transfer is effected in accordance with any applicable securities laws and the
Proposed Transferee agrees in writing that the provisions of this Section shall continue to apply to the Shares in the hands of such Proposed Transferee. If the Shares 

  

 2 

 
described in the Notice are not Transferred to the Proposed Transferee within such 120-day period, a new Notice shall be given to the Company, and the
Company and/or its assignees shall again be offered the Right of First Refusal as provided herein before any Shares held by the Holder may be sold or otherwise Transferred. 
 Exception for Certain Family Transfers. Anything to the contrary contained in this Section notwithstanding, the Transfer of any or all of the
Shares during Optionee’s lifetime or upon Optionee’s death by will or intestacy to Optionee’s Immediate Family or a trust for the benefit of Optionee’s Immediate Family shall be exempt from the Right of First Refusal. As used
herein, “Immediate Family” shall mean spouse, lineal descendant or antecedent, father, mother, brother or sister or stepchild (whether or not adopted). In such case, the transferee or other recipient shall receive and hold the Shares so
Transferred subject to the provisions of this Section (including the Right of First Refusal) and there shall be no further Transfer of such Shares except in accordance with the terms of this Section. 
 Termination of Right of First Refusal. The Right of First Refusal shall terminate as to all Shares upon a sale of Common Stock of the Company to
the general public pursuant to a registration statement filed with and declared effective by the Securities and Exchange Commission under the Securities Act of 1933, as amended (a “Public Offering”). 
 Transfer Restrictions. Any transfer or sale of the Share is subject to restrictions on transfer imposed by any applicable state and federal
securities laws. Any Transfer or attempted Transfer of any of the Shares not in accordance with the terms of this Agreement shall be void and the Company may enforce the terms of this Agreement by stop transfer instructions or similar actions by the
Company and its agents or designees. 
 Tax Consultation. Optionee understands that Optionee may suffer adverse tax consequences as a
result of Optionee’s purchase or disposition of the Shares. Optionee represents that Optionee has consulted with any tax consultants Optionee deems advisable in connection with the purchase or disposition of the Shares and that Optionee is not
relying on the Company for any tax advice. 
 Restrictive Legends and Stop-Transfer Orders. 
 Legends. Optionee understands and agrees that the Company shall cause the legends set forth below or legends substantially equivalent thereto, to
be placed upon any certificate(s) evidencing ownership of the Shares together with any other legends that may be required by state or federal securities laws: 
 THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE “ACT”) AND MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
REGISTERED UNDER THE ACT OR, IN THE OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE THEREWITH. 
  

 3 

 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND RIGHT OF
FIRST REFUSAL OPTIONS HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER
RESTRICTIONS AND RIGHT OF FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES. 
 Stop-Transfer Notices. Optionee agrees that, in
order to ensure compliance with the restrictions referred to herein, the Company may issue appropriate “stop transfer” instructions to its transfer agent, if any, and that, if the Company transfers its own securities, it may make
appropriate notations to the same effect in its own records. 
 Refusal to Transfer. The Company shall not be required (i) to
transfer on its books any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Shares or to accord the right to vote or pay dividends to any purchaser or
other transferee to whom such Shares shall have been so transferred. 
 Successors and Assigns. The Company may assign any of its
rights under this Agreement to single or multiple assignees, and this Agreement shall inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement shall be binding upon
Optionee and his or her heirs, executors, administrators, successors and assigns. 
 Interpretation. Any dispute regarding the
interpretation of this Agreement shall be submitted by Optionee or by the Company forthwith to the Company’s Board of Directors or committee thereof that is responsible for the administration of the Plan (the “Administrator”), which
shall review such dispute at its next regular meeting. The resolution of such a dispute by the Administrator shall be final and binding on the Company and on Optionee. 
 Governing Law; Severability. This Agreement shall be governed by and construed in accordance with the laws of the State of California excluding that body of law pertaining to conflicts of law. Should any
provision of this Agreement be determined by a court of law to be illegal or unenforceable, the other provisions shall nevertheless remain effective and shall remain enforceable. 
 Notices. Any notice required or permitted hereunder shall be given in writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States mail by certified mail, with postage and fees prepaid, addressed to the other party at its address as shown below beneath its signature, or to such other address as such party may designate in writing from time to time
to the other party. 
  

 4 

 Further Instruments. The parties agree to execute such further instruments and to take such
further action as may be reasonably necessary to carry out the purposes and intent of this Agreement. 
 Delivery of Payment. Optionee
herewith delivers to the Company the full Exercise Price for the Shares, as well as any applicable withholding tax. 
 Entire
Agreement. The Plan and Option Agreement are incorporated herein by reference. This Agreement, the Plan, the Option Agreement and the Investment Representation Statement constitute the entire agreement of the parties and supersede in their
entirety all prior undertakings and agreements of the Company and Optionee with respect to the subject matter hereof. 
  

							
	Accepted by:	  		  	Submitted by:
			
	BAYHILL THERAPEUTICS, INC.	  		  	NAME
				
	 By:
	 	  
	  		  	  

	 Name:
	 	  
	  		  	Name
	 Its:
	 	  
	  		  	
				
		 		  		  	Address:
				
		 		  		  	  

		 		  		  	  

		 		  		  	  

  

 5 

 EXHIBIT B 
 INVESTMENT REPRESENTATION STATEMENT 
  

			
	OPTIONEE:	  	
		
	COMPANY:	  	Bayhill Therapeutics, Inc.
		
	SECURITY:	  	Common Stock
		
	AMOUNT:	  	
		
	DATE:	  	

 In connection with the purchase of the above-listed shares of Common Stock (the
“Securities”) of Bayhill Therapeutics, Inc. (the “Company”), the undersigned (the “Optionee”) represents to the Company the following: 
 Optionee is aware of the Company’s business affairs and financial condition and has acquired sufficient information about the Company to reach an informed and knowledgeable decision to acquire the Securities.
Optionee is acquiring these Securities for investment for Optionee’s own account only and not with a view to, or for resale in connection with, any “distribution” thereof within the meaning of the Securities Act of 1933, as amended
(the “Securities Act”). 
 Optionee acknowledges and understands that the Securities constitute “restricted securities”
under the Securities Act and have not been registered under the Securities Act in reliance upon a specific exemption therefrom, which exemption depends upon, among other things, the bona fide nature of Optionee’s investment intent as expressed
herein. In this connection, Optionee understands that, in the view of the Securities and Exchange Commission, the statutory basis for such exemption may be unavailable if Optionee’s representation was predicated solely upon a present intention
to hold these Securities for the minimum capital gains period specified under tax statutes, for a deferred sale, for or until an increase or decrease in the market price of the Securities, or for a period of one year or any other fixed period in the
future. Optionee further understands that the Securities must be held indefinitely unless they are subsequently registered under the Securities Act or an exemption from such registration is available. Optionee further acknowledges and understands
that the Company is under no obligation to register the Securities. Optionee understands that the certificate evidencing the Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such
registration is not required in the opinion of counsel satisfactory to the Company and any other legend required under applicable state securities laws. 
 Optionee is familiar with the provisions of Rule 701 and Rule 144, each promulgated under the Securities Act, which, in substance, permit limited public resale of “restricted securities” acquired, directly
or indirectly from the issuer thereof, in a non-public offering subject to the satisfaction of certain conditions. Rule 701 provides that if the issuer 

 
qualifies under Rule 701 at the time of the grant of the Option to Optionee, the exercise will be exempt from registration under the Securities Act. In the
event the Company becomes subject to the reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, ninety (90) days thereafter (or such longer period as any market stand-off agreement may require) the Securities
exempt under Rule 701 may be resold, subject to the satisfaction of certain of the conditions specified by Rule 144, including: (1) the resale being made through a broker in an unsolicited “broker’s transaction” or in
transactions directly with a market maker (as said term is defined under the Securities Exchange Act of 1934); and, in the case of an affiliate, (2) the availability of certain public information about the Company, (3) the amount of
Securities being sold during any three (3) month period not exceeding the limitations specified in Rule 144(e), and (4) the timely filing of a Form 144, if applicable. 
 In the event that the Company does not qualify under Rule 701 at the time of grant of the Option, then the Securities may be resold in certain limited
circumstances subject to the provisions of Rule 144, which requires the resale to occur not less than one year after the later of the date the Securities were sold by the Company or the date the Securities were sold by an affiliate of the Company,
within the meaning of Rule 144; and, in the case of acquisition of the Securities by an affiliate, or by a non-affiliate who subsequently holds the Securities less than two (2) years, the satisfaction of the conditions set forth in sections
(1), (2), (3) and (4) of the paragraph immediately above. 
 Optionee further understands that in the event all of the applicable
requirements of Rule 701 or 144 are not satisfied, registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required; and that, notwithstanding the fact that Rules 144 and 701 are not
exclusive, the Staff of the Securities and Exchange Commission has expressed its opinion that persons proposing to sell private placement securities other than in a registered offering and otherwise than pursuant to Rules 144 or 701 will have a
substantial burden of proof in establishing that an exemption from registration is available for such offers or sales, and that such persons and their respective brokers who participate in such transactions do so at their own risk. Optionee
understands that no assurances can be given that any such other registration exemption will be available in such event. 
  

	
	Signature of Optionee:
	
	  

	Name

 Date:
                            ,
             
  

 7 

 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 STOCK OPTION AGREEMENT 
 Bayhill Therapeutics, Inc. (the “Company”), pursuant to its 2002 Equity Incentive Plan (the “Plan”), hereby grants to Optionee listed
below (“Optionee”), an option to purchase the number of shares of the Company’s Common Stock set forth below, subject to the terms and conditions of the Plan and this Stock Option Agreement. Unless otherwise defined herein, the terms
defined in the Plan shall have the same defined meanings in this Stock Option Agreement. 
 NOTICE OF STOCK OPTION GRANT 
  

			
	Optionee:	 	
		
	Date of Stock Option Agreement:	 	
		
	Date of Grant:	 	
		
	Vesting Commencement Date:	 	
		
	Exercise Price per Share:	 	
		
	Total Number of Shares Granted:	 	
		
	Total Exercise Price:	 	
		
	Term/Expiration Date:	 	

  

			
	Type of Option:	  	x  Incentive Stock Option             ̈  Non-Qualified Stock Option
		
	Vesting Schedule:	  	The Shares subject to this Option shall vest according to the following schedule:
		
		  	1/48th of the Shares subject to the Option (rounded down to the next whole number of shares)
shall vest on the first day of each full month after the Vesting Commencement Date, so that all of the Shares shall be vested on the first day of the forty eighth (48th) full month after the Vesting Commencement Date.
		
	Termination Period:	  	This Option may be exercised, to the extent vested, for three (3) months after Optionee ceases to be a Service Provider, or such longer period as may be applicable upon the death or
disability of Optionee as provided herein (or, if not provided herein, then as provided in the Plan), but in no event later than the Term/Expiration Date as provided above.

 AGREEMENT 
 Grant of Option. The Company hereby grants to Optionee an Option to purchase the number of shares of Common Stock (the “Shares”) set forth in the Notice of Grant, at the 

  

 8 

 
exercise price per share set forth in the Notice of Grant (the “Exercise Price”). Notwithstanding anything to the contrary anywhere else in this
Option Agreement, this grant of an Option is subject to the terms, definitions and provisions of the Plan adopted by the Company, which is incorporated herein by reference. 
 If designated in the Notice of Grant as an Incentive Stock Option, this Option is intended to qualify as an Incentive Stock Option as defined in
Section 422 of the Code; provided, however, that to the extent that the aggregate Fair Market Value of stock with respect to which Incentive Stock Options (within the meaning of Code Section 422, but without regard to Code
Section 422(d)), including the Option, are exercisable for the first time by Optionee during any calendar year (under the Plan and all other incentive stock option plans of the Company or any Subsidiary) exceeds $100,000, such options shall be
treated as not qualifying under Code Section 422, but rather shall be treated as Non-Qualified Stock Options to the extent required by Code Section 422. The rule set forth in the preceding sentence shall be applied by taking options into
account in the order in which they were granted. For purposes of these rules, the Fair Market Value of stock shall be determined as of the time the option with respect to such stock is granted. 
 Exercise of Option. This Option is exercisable as follows: 
 Right to Exercise. 
 This Option shall be exercisable cumulatively according to the vesting schedule
set out in the Notice of Grant. For purposes of this Stock Option Agreement, Shares subject to this Option shall vest based on Optionee’s continued status as a Service Provider. 
 This Option may not be exercised for a fraction of a Share. 
 In the event of Optionee’s death, disability or other termination of Optionee’s status as a Service Provider, the exercisability of the Option is governed by Sections 7, 8 and 9 below. 
 In no event may this Option be exercised after the date of expiration of the term of this Option as set forth in the Notice of Grant. 
 Method of Exercise. This Option shall be exercisable by written Notice (in the form attached as Exhibit A). The Notice must state the
number of Shares for which the Option is being exercised, and such other representations and agreements with respect to such shares of Common Stock as may be required by the Company pursuant to the provisions of the Plan. The Notice must be signed
by Optionee and shall be delivered in person or by certified mail to the Secretary of the Company. The Notice must be accompanied by payment of the Exercise Price plus payment of any applicable withholding tax. This Option shall be deemed to
be exercised upon receipt by the Company of such written Notice accompanied by the Exercise Price and payment of any applicable withholding tax. 
  

 9 

 No Shares shall be issued pursuant to the exercise of an Option unless such issuance and such exercise
comply with all relevant provisions of law and the requirements of any stock exchange upon which the Shares may then be listed. Assuming such compliance, for income tax purposes the Shares shall be considered transferred to Optionee on the date on
which the Option is exercised with respect to such Shares. 
 Optionee’s Representations. If the Shares purchasable pursuant to
the exercise of this Option have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), at the time this Option is exercised, Optionee shall, if required by the Company, concurrently with the exercise of
all or any portion of this Option, deliver to the Company his or her Investment Representation Statement in the form attached hereto as Exhibit B. 
 Lock-Up Period. Optionee hereby agrees that if so requested by the Company or any representative of the underwriters (the “Managing Underwriter”) in connection with any registration of the offering of
any securities of the Company under the Securities Act, Optionee shall not sell or otherwise transfer any Shares or other securities of the Company during the 180-day period (or such longer period as may be requested in writing by the Managing
Underwriter and agreed to in writing by the Company) (the “Market Standoff Period”) following the effective date of a registration statement of the Company filed under the Securities Act; provided, however, that such restriction shall
apply only to the first registration statement of the Company to become effective under the Securities Act that includes securities to be sold on behalf of the Company to the public in an underwritten public offering under the Securities Act. The
Company may impose stop-transfer instructions with respect to securities subject to the foregoing restrictions until the end of such Market Standoff Period and these restrictions shall be binding on any transferee of such Shares. 
 Method of Payment. Payment of the Exercise Price shall be by any of the following, or a combination thereof, at the election of Optionee:

 cash; 
 check; 
 with the consent of the Administrator, a full recourse promissory note bearing interest (at no less than such rate as is a market rate of interest and
which then precludes the imputation of interest under the Code) and payable upon such terms as may be prescribed by the Administrator; 
 with the consent of the Administrator, surrender of other shares of Common Stock of the Company which (A) in the case of Shares acquired from the Company, have been owned by Optionee for more than six (6) months on the date of
surrender, and (B) have a Fair Market Value on the date of surrender equal to the Exercise Price of the Shares as to which the Option is being exercised; 
 with the consent of the Administrator, surrendered Shares issuable upon the exercise of the Option having a Fair Market Value on the date of exercise equal to the aggregate Exercise Price of the Option or exercised
portion thereof; 
  

 10 

 with the consent of the Administrator, property of any kind which constitutes good and valuable
consideration; 
 with the consent of the Administrator, delivery of a notice that Optionee has placed a market sell order with a broker with
respect to Shares then issuable upon exercise of the Option and that the broker has been directed to pay a sufficient portion of the net proceeds of the sale to the Company in satisfaction of the aggregate Exercise Price; provided, that payment of
such proceeds is then made to the Company upon settlement of such sale; or 
 with the consent of the Administrator, any combination of the
foregoing methods of payment. 
 Restrictions on Exercise. This Option may not be exercised until the Plan has been approved by the
stockholders of the Company. If the issuance of Shares upon such exercise or if the method of payment for such shares would constitute a violation of any applicable federal or state securities or other law or regulation, then the Option may also not
be exercised. The Company may require Optionee to make any representation and warranty to the Company as may be required by any applicable law or regulation before allowing the Option to be exercised. 
 Termination of Relationship. If Optionee ceases to be a Service Provider (other than by reason of Optionee’s death or the total and permanent
disability of Optionee as defined in Code Section 22(e)(3)), Optionee may exercise this Option during the Termination Period set out in the Notice of Grant, to the extent the Option was vested at the date on which Optionee ceases to be a
Service Provider. To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise this Option within the time specified herein, the Option shall terminate. 
 Disability of Optionee. If Optionee ceases to be a Service Provider as a result of his or her total and permanent disability as defined in Code
Section 22(e)(3), Optionee may exercise the Option to the extent the Option was vested at the date on which Optionee ceases to be a Service Provider, but only within twelve (12) months from such date (and in no event later than the
expiration date of the term of this Option as set forth in the Notice of Grant). To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise such Option within the time
specified herein, the Option shall terminate. 
 Death of Optionee. If Optionee ceases to be a Service Provider as a result of the
death of Optionee, the vested portion of the Option may be exercised at any time within twelve (12) months following the date of death (and in no event later than the expiration date of the term of this Option as set forth in the Notice of
Grant) by Optionee’s estate or by a person who acquires the right to exercise the Option by bequest or inheritance. To the extent that the Option is not vested at the date of death, or if the Option is not exercised within the time specified
herein, the Option shall terminate. 
  

 11 

 Non-Transferability of Option. This Option may not be transferred in any manner except by will or
by the laws of descent or distribution . It may be exercised during the lifetime of Optionee only by Optionee. The terms of this Option shall be binding upon the executors, administrators, heirs, successors and assigns of Optionee. 
 Term of Option. This Option may be exercised only within the term set out in the Notice of Grant. 
 [Signature page follows] 
  

 12 

 This Agreement may be executed in two or more counterparts, each of which shall be deemed an original and
all of which shall constitute one document. 
  

			
	BAYHILL THERAPEUTICS, INC.
		
	By:	 	  

	Name:	 	Mark W. Schwartz
	Title:	 	Chief Executive Officer

 OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO THE OPTION HEREOF IS
EARNED ONLY BY CONTINUING CONSULTANCY OR EMPLOYMENT AT THE WILL OF THE COMPANY (NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR ACQUIRING SHARES HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT NOTHING IN THIS AGREEMENT,
NOR IN THE COMPANY’S 2002 EQUITY INCENTIVE PLAN WHICH IS INCORPORATED HEREIN BY REFERENCE, SHALL CONFER UPON OPTIONEE ANY RIGHT WITH RESPECT TO CONTINUATION OF EMPLOYMENT OR CONSULTANCY BY THE COMPANY, NOR SHALL IT INTERFERE IN ANY WAY WITH
OPTIONEE’S RIGHT OR THE COMPANY’S RIGHT TO TERMINATE OPTIONEE’S EMPLOYMENT OR CONSULTANCY AT ANY TIME, WITH OR WITHOUT CAUSE AND WITH OR WITHOUT PRIOR NOTICE. 
 Optionee acknowledges receipt of a copy of the Plan and represents that he or she is familiar with the terms and provisions thereof. Optionee hereby
accepts this Option subject to all of the terms and provisions hereof. Optionee has reviewed the Plan and this Option in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Option and fully understands all
provisions of the Option. Optionee hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan or this Option. Optionee further agrees to notify the Company
upon any change in the residence address indicated below. 
  

					
	 Dated:
	 	                     
	 	  

		 		 	 Name

			
		 		 	Residence Address:
			
		 		 	  

			
		 		 	  

  

 13 

 EXHIBIT A 
 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 EXERCISE NOTICE 
 Bayhill Therapeutics, Inc.

 Attention: Stock Administration 
 Exercise
of Option. Effective as of today,                     ,             ,
the undersigned (“Optionee”) hereby elects to exercise Optionee’s option to purchase                      shares of the Common
Stock (the “Shares”) of Bayhill Therapeutics, Inc. (the “Company”) under and pursuant to the Bayhill Therapeutics, Inc. 2002 Equity Incentive Plan (the “Plan”) and the  ̈ Incentive  ̈ Non-Qualified Stock Option Agreement dated
                    ,             , (the “Option Agreement”).
Capitalized terms used herein without definition shall have the meanings given in the Option Agreement. 
  

					
	Date of Grant:	 		    	  

			
	 Number of Shares as to which Option is
 Exercised:
	 		    	  

			
	Exercise Price per Share:	 		    	$                    
			
	Total Exercise Price:	 		    	$                    
			
	Certificate to be issued in Name of:	 		    	  

			
	Cash Payment delivered herewith:	 	 ̈	    	$                    
			
	Promissory note delivered herewith:	 	 ̈	    	$                    

  

			
	Type of Option:	  	 ̈  Incentive Stock
Option             ̈  Non-Qualified Stock Option

 Representations of Optionee. Optionee acknowledges that Optionee has received, read and
understood the Plan and the Option Agreement. Optionee agrees to abide by and be bound by their terms and conditions. 
 Rights as
Stockholder. Until the stock certificate evidencing such Shares is issued (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), no right to vote or receive dividends or any
other rights as a stockholder shall exist with respect to Shares subject to the Option, notwithstanding the exercise of the Option. The Company shall issue (or cause to be issued) such stock certificate promptly after the Option is exercised. No
adjustment will be made for a dividend or other right for which the record date is prior to the date the stock certificate is issued, except as provided in Section 13 of the Plan. 

 Optionee shall enjoy rights as a stockholder until such time as Optionee disposes of the Shares or the
Company and/or its assignee(s) exercises the Right of First Refusal hereunder. Upon such exercise, Optionee shall have no further rights as a holder of the Shares so purchased except the right to receive payment for the Shares so purchased in
accordance with the provisions of this Agreement, and Optionee shall forthwith cause the certificate(s) evidencing the Shares so purchased to be surrendered to the Company for transfer or cancellation. 
 Optionee’s Rights to Transfer Shares. 
 Company’s Right of First Refusal. Before any Shares held by Optionee or any permitted transferee (each, a “Holder”) may be sold, pledged, assigned, hypothecated, transferred, or otherwise disposed of (each, a
“Transfer”), the Company or its assignee(s) shall have a right of first refusal to purchase the Shares proposed to be Transferred on the terms and conditions set forth in this Section (the “Right of First Refusal”). 

Notice of Proposed Transfer. In the event any Holder desires to Transfer any Shares, the Holder shall deliver to the Company a written notice
(the “Notice”) stating: (w) the Holder’s bona fide intention to sell or otherwise Transfer such Shares; (x) the Name of each proposed purchaser or other transferee (“Proposed Transferee”); (y) the number of
Shares to be Transferred to each Proposed Transferee; and (z) the bona fide cash price or other consideration for which the Holder proposes to Transfer the Shares (the “Offered Price”), and the Holder shall offer such Shares at the
Offered Price to the Company or its assignee(s). 
 Exercise of Right of First Refusal. Within thirty (30) days after receipt of
the Notice, the Company and/or its assignee(s) may elect in writing to purchase all, but not less than all, of the Shares proposed to be Transferred to any one or more of the Proposed Transferees. The purchase price will be determined in accordance
with subsection (iii) below. 
 Purchase Price. The purchase price (“Purchase Price”) for the Shares repurchased under
this Section shall be the Offered Price. If the Offered Price includes consideration other than cash, the cash equivalent value of the non-cash consideration shall be determined by the Board of Directors of the Company in good faith. 
 Payment. Payment of the Purchase Price shall be made, at the option of the Company or its assignee(s), in cash (by check), by cancellation of all
or a portion of any outstanding indebtedness of the Holder to the Company (or, in the case of repurchase by an assignee, to the assignee), or by any combination thereof within thirty (30) days after receipt of the Notice or in the manner and at
the times mutually agreed to by the Company and the Holder. 
 Holder’s Right to Transfer. If all of the Shares proposed in the
Notice to be Transferred are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise Transfer such Shares to that Proposed Transferee at the Offered Price or at a higher price, provided
that such sale or other Transfer is consummated within one hundred twenty (120) days after the date of the Notice and provided further that any such sale or other Transfer is effected in accordance with any applicable securities laws and the
Proposed Transferee agrees in writing that the provisions of this Section shall continue to apply to the Shares in the hands of such Proposed Transferee. If the Shares 

  

 2 

 
described in the Notice are not Transferred to the Proposed Transferee within such 120-day period, a new Notice shall be given to the Company, and the
Company and/or its assignees shall again be offered the Right of First Refusal as provided herein before any Shares held by the Holder may be sold or otherwise Transferred. 
 Exception for Certain Family Transfers. Anything to the contrary contained in this Section notwithstanding, the Transfer of any or all of the
Shares during Optionee’s lifetime or upon Optionee’s death by will or intestacy to Optionee’s Immediate Family or a trust for the benefit of Optionee’s Immediate Family shall be exempt from the Right of First Refusal. As used
herein, “Immediate Family” shall mean spouse, lineal descendant or antecedent, father, mother, brother or sister or stepchild (whether or not adopted). In such case, the transferee or other recipient shall receive and hold the Shares so
Transferred subject to the provisions of this Section (including the Right of First Refusal) and there shall be no further Transfer of such Shares except in accordance with the terms of this Section. 
 Termination of Right of First Refusal. The Right of First Refusal shall terminate as to all Shares upon a sale of Common Stock of the Company to
the general public pursuant to a registration statement filed with and declared effective by the Securities and Exchange Commission under the Securities Act of 1933, as amended (a “Public Offering”). 
 Transfer Restrictions. Any transfer or sale of the Share is subject to restrictions on transfer imposed by any applicable state and federal
securities laws. Any Transfer or attempted Transfer of any of the Shares not in accordance with the terms of this Agreement shall be void and the Company may enforce the terms of this Agreement by stop transfer instructions or similar actions by the
Company and its agents or designees. 
 Tax Consultation. Optionee understands that Optionee may suffer adverse tax consequences as a
result of Optionee’s purchase or disposition of the Shares. Optionee represents that Optionee has consulted with any tax consultants Optionee deems advisable in connection with the purchase or disposition of the Shares and that Optionee is not
relying on the Company for any tax advice. 
 Restrictive Legends and Stop-Transfer Orders. 
 Legends. Optionee understands and agrees that the Company shall cause the legends set forth below or legends substantially equivalent thereto, to
be placed upon any certificate(s) evidencing ownership of the Shares together with any other legends that may be required by state or federal securities laws: 
 THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE “ACT”) AND MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
REGISTERED UNDER THE ACT OR, IN THE OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE THEREWITH. 
  

 3 

 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND RIGHT OF
FIRST REFUSAL OPTIONS HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER
RESTRICTIONS AND RIGHT OF FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES. 
 Stop-Transfer Notices. Optionee agrees that, in
order to ensure compliance with the restrictions referred to herein, the Company may issue appropriate “stop transfer” instructions to its transfer agent, if any, and that, if the Company transfers its own securities, it may make
appropriate notations to the same effect in its own records. 
 Refusal to Transfer. The Company shall not be required (i) to
transfer on its books any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Shares or to accord the right to vote or pay dividends to any purchaser or
other transferee to whom such Shares shall have been so transferred. 
 Successors and Assigns. The Company may assign any of its
rights under this Agreement to single or multiple assignees, and this Agreement shall inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement shall be binding upon
Optionee and his or her heirs, executors, administrators, successors and assigns. 
 Interpretation. Any dispute regarding the
interpretation of this Agreement shall be submitted by Optionee or by the Company forthwith to the Company’s Board of Directors or committee thereof that is responsible for the administration of the Plan (the “Administrator”), which
shall review such dispute at its next regular meeting. The resolution of such a dispute by the Administrator shall be final and binding on the Company and on Optionee. 
 Governing Law; Severability. This Agreement shall be governed by and construed in accordance with the laws of the State of California excluding that body of law pertaining to conflicts of law. Should any
provision of this Agreement be determined by a court of law to be illegal or unenforceable, the other provisions shall nevertheless remain effective and shall remain enforceable. 
 Notices. Any notice required or permitted hereunder shall be given in writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States mail by certified mail, with postage and fees prepaid, addressed to the other party at its address as shown below beneath its signature, or to such other address as such party may designate in writing from time to time
to the other party. 
  

 4 

 Further Instruments. The parties agree to execute such further instruments and to take such
further action as may be reasonably necessary to carry out the purposes and intent of this Agreement. 
 Delivery of Payment. Optionee
herewith delivers to the Company the full Exercise Price for the Shares, as well as any applicable withholding tax. 
 Entire
Agreement. The Plan and Option Agreement are incorporated herein by reference. This Agreement, the Plan, the Option Agreement and the Investment Representation Statement constitute the entire agreement of the parties and supersede in their
entirety all prior undertakings and agreements of the Company and Optionee with respect to the subject matter hereof. 
  

							
	Accepted by:	  		  	Submitted by:
			
	BAYHILL THERAPEUTICS, INC.	  		  	NAME
				
	 By:
	 	  
	  		  	  

	 Name:
	 	  
	  		  	Name
	 Its:
	 	  
	  		  	
				
		 		  		  	Address:
				
		 		  		  	  

		 		  		  	  

		 		  		  	  

  

 5 

 EXHIBIT B 
 INVESTMENT REPRESENTATION STATEMENT 
  

			
	OPTIONEE :	  	
		
	COMPANY :	  	Bayhill Therapeutics, Inc.
		
	SECURITY :	  	Common Stock
		
	AMOUNT :	  	
		
	DATE :	  	

 In connection with the purchase of the above-listed shares of Common Stock (the
“Securities”) of Bayhill Therapeutics, Inc. (the “Company”), the undersigned (the “Optionee”) represents to the Company the following: 
 Optionee is aware of the Company’s business affairs and financial condition and has acquired sufficient information about the Company to reach an informed and knowledgeable decision to acquire the Securities.
Optionee is acquiring these Securities for investment for Optionee’s own account only and not with a view to, or for resale in connection with, any “distribution” thereof within the meaning of the Securities Act of 1933, as amended
(the “Securities Act”). 
 Optionee acknowledges and understands that the Securities constitute “restricted securities”
under the Securities Act and have not been registered under the Securities Act in reliance upon a specific exemption therefrom, which exemption depends upon, among other things, the bona fide nature of Optionee’s investment intent as expressed
herein. In this connection, Optionee understands that, in the view of the Securities and Exchange Commission, the statutory basis for such exemption may be unavailable if Optionee’s representation was predicated solely upon a present intention
to hold these Securities for the minimum capital gains period specified under tax statutes, for a deferred sale, for or until an increase or decrease in the market price of the Securities, or for a period of one year or any other fixed period in the
future. Optionee further understands that the Securities must be held indefinitely unless they are subsequently registered under the Securities Act or an exemption from such registration is available. Optionee further acknowledges and understands
that the Company is under no obligation to register the Securities. Optionee understands that the certificate evidencing the Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such
registration is not required in the opinion of counsel satisfactory to the Company and any other legend required under applicable state securities laws. 
 Optionee is familiar with the provisions of Rule 701 and Rule 144, each promulgated under the Securities Act, which, in substance, permit limited public resale of “restricted securities” acquired, directly
or indirectly from the issuer thereof, in a non-public offering subject to the satisfaction of certain conditions. Rule 701 provides that if the issuer 

 
qualifies under Rule 701 at the time of the grant of the Option to Optionee, the exercise will be exempt from registration under the Securities Act. In the
event the Company becomes subject to the reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, ninety (90) days thereafter (or such longer period as any market stand-off agreement may require) the Securities
exempt under Rule 701 may be resold, subject to the satisfaction of certain of the conditions specified by Rule 144, including: (1) the resale being made through a broker in an unsolicited “broker’s transaction” or in
transactions directly with a market maker (as said term is defined under the Securities Exchange Act of 1934); and, in the case of an affiliate, (2) the availability of certain public information about the Company, (3) the amount of
Securities being sold during any three (3) month period not exceeding the limitations specified in Rule 144(e), and (4) the timely filing of a Form 144, if applicable. 
 In the event that the Company does not qualify under Rule 701 at the time of grant of the Option, then the Securities may be resold in certain limited
circumstances subject to the provisions of Rule 144, which requires the resale to occur not less than one year after the later of the date the Securities were sold by the Company or the date the Securities were sold by an affiliate of the Company,
within the meaning of Rule 144; and, in the case of acquisition of the Securities by an affiliate, or by a non-affiliate who subsequently holds the Securities less than two (2) years, the satisfaction of the conditions set forth in sections
(1), (2), (3) and (4) of the paragraph immediately above. 
 Optionee further understands that in the event all of the applicable
requirements of Rule 701 or 144 are not satisfied, registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required; and that, notwithstanding the fact that Rules 144 and 701 are not
exclusive, the Staff of the Securities and Exchange Commission has expressed its opinion that persons proposing to sell private placement securities other than in a registered offering and otherwise than pursuant to Rules 144 or 701 will have a
substantial burden of proof in establishing that an exemption from registration is available for such offers or sales, and that such persons and their respective brokers who participate in such transactions do so at their own risk. Optionee
understands that no assurances can be given that any such other registration exemption will be available in such event. 
  

	
	Signature of Optionee:
	
	  

	Name

 Date:
                                ,
             
  

 7 

 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 STOCK OPTION AGREEMENT 
 Bayhill Therapeutics, Inc. (the “Company”), pursuant to its 2002 Equity Incentive Plan (the “Plan”), hereby grants to Optionee listed
below (“Optionee”), an option to purchase the number of shares of the Company’s Common Stock set forth below, subject to the terms and conditions of the Plan and this Stock Option Agreement. Unless otherwise defined herein, the terms
defined in the Plan shall have the same defined meanings in this Stock Option Agreement. 
 NOTICE OF STOCK OPTION GRANT 
  

	
	Optionee:
	
	Date of Stock Option Agreement:
	
	Date of Grant:
	
	Vesting Commencement Date:
	
	Exercise Price per Share:
	
	Total Number of Shares Granted:
	
	Total Exercise Price:
	
	Term/Expiration Date:

  

					
	Type of Option:	  	 ̈  Incentive Stock
Option             x   Non-Qualified Stock Option
		
	Vesting Schedule:	  	The Shares subject to this Option shall vest according to the following schedule:
		
		  	Twenty five percent (25%) of the Shares subject to the Option (rounded down to the next whole number of shares) shall vest one year after the Vesting Commencement Date, and 1/48th
of the Shares subject to the Option (rounded down to the next whole number of shares) shall vest on the first day of each full month thereafter, so that all of the Shares shall be vested on the first day of the forty eighth (48th) full month after
the Vesting Commencement Date.
		
	Termination Period:	  	This Option may be exercised, to the extent vested, for three (3) months after Optionee ceases to be a Service Provider, or such longer period as may be applicable upon the death
or disability of Optionee as provided herein (or, if not provided herein, then as provided in the Plan), but in no event later than the Term/Expiration Date as provided above.

  

 8 

 AGREEMENT 
 Grant of Option. The Company hereby grants to Optionee an Option to purchase the number of shares of Common Stock (the “Shares”) set forth in the Notice of Grant, at the exercise price per share set forth in the Notice of
Grant (the “Exercise Price”). Notwithstanding anything to the contrary anywhere else in this Option Agreement, this grant of an Option is subject to the terms, definitions and provisions of the Plan adopted by the Company, which is
incorporated herein by reference. 
 If designated in the Notice of Grant as an Incentive Stock Option, this Option is intended to qualify as
an Incentive Stock Option as defined in Section 422 of the Code; provided, however, that to the extent that the aggregate Fair Market Value of stock with respect to which Incentive Stock Options (within the meaning of Code Section 422, but
without regard to Code Section 422(d)), including the Option, are exercisable for the first time by Optionee during any calendar year (under the Plan and all other incentive stock option plans of the Company or any Subsidiary) exceeds $100,000,
such options shall be treated as not qualifying under Code Section 422, but rather shall be treated as Non-Qualified Stock Options to the extent required by Code Section 422. The rule set forth in the preceding sentence shall be applied by
taking options into account in the order in which they were granted. For purposes of these rules, the Fair Market Value of stock shall be determined as of the time the option with respect to such stock is granted. 
 Exercise of Option. This Option is exercisable as follows: 
 Right to Exercise. 
 This Option shall be exercisable cumulatively according to the vesting schedule
set out in the Notice of Grant. For purposes of this Stock Option Agreement, Shares subject to this Option shall vest based on Optionee’s continued status as a Service Provider. 
 This Option may not be exercised for a fraction of a Share. 
 In the event of Optionee’s death, disability or other termination of Optionee’s status as a Service Provider, the exercisability of the Option is governed by Sections 7, 8 and 9 below. 
 In no event may this Option be exercised after the date of expiration of the term of this Option as set forth in the Notice of Grant. 
 Method of Exercise. This Option shall be exercisable by written Notice (in the form attached as Exhibit A). The Notice must state the
number of Shares for which the Option is being exercised, and such other representations and agreements with respect to such shares of Common Stock as may be required by the Company pursuant to the provisions of the Plan. The Notice must be signed
by Optionee and shall be delivered in person or by certified mail to the Secretary of the Company. The Notice must be accompanied by payment of the Exercise Price plus payment of any applicable withholding tax. This Option shall be deemed to
be exercised upon receipt by the Company of such written Notice accompanied by the Exercise Price and payment of any applicable withholding tax. 
  

 9 

 No Shares shall be issued pursuant to the exercise of an Option unless such issuance and such exercise
comply with all relevant provisions of law and the requirements of any stock exchange upon which the Shares may then be listed. Assuming such compliance, for income tax purposes the Shares shall be considered transferred to Optionee on the date on
which the Option is exercised with respect to such Shares. 
 Optionee’s Representations. If the Shares purchasable pursuant to
the exercise of this Option have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), at the time this Option is exercised, Optionee shall, if required by the Company, concurrently with the exercise of
all or any portion of this Option, deliver to the Company his or her Investment Representation Statement in the form attached hereto as Exhibit B. 
 Lock-Up Period. Optionee hereby agrees that if so requested by the Company or any representative of the underwriters (the “Managing Underwriter”) in connection with any registration of the offering of
any securities of the Company under the Securities Act, Optionee shall not sell or otherwise transfer any Shares or other securities of the Company during the 180-day period (or such longer period as may be requested in writing by the Managing
Underwriter and agreed to in writing by the Company) (the “Market Standoff Period”) following the effective date of a registration statement of the Company filed under the Securities Act; provided, however, that such restriction shall
apply only to the first registration statement of the Company to become effective under the Securities Act that includes securities to be sold on behalf of the Company to the public in an underwritten public offering under the Securities Act. The
Company may impose stop-transfer instructions with respect to securities subject to the foregoing restrictions until the end of such Market Standoff Period and these restrictions shall be binding on any transferee of such Shares. 
 Method of Payment. Payment of the Exercise Price shall be by any of the following, or a combination thereof, at the election of Optionee:

 cash; 
 check; 
 with the consent of the Administrator, a full recourse promissory note bearing interest (at no less than such rate as is a market rate of interest and
which then precludes the imputation of interest under the Code) and payable upon such terms as may be prescribed by the Administrator; 
 with the consent of the Administrator, surrender of other shares of Common Stock of the Company which (A) in the case of Shares acquired from the Company, have been owned by Optionee for more than six (6) months on the date of
surrender, and (B) have a Fair Market Value on the date of surrender equal to the Exercise Price of the Shares as to which the Option is being exercised; 
 with the consent of the Administrator, surrendered Shares issuable upon the exercise of the Option having a Fair Market Value on the date of exercise equal to the aggregate Exercise Price of the Option or exercised
portion thereof; 
  

 10 

 with the consent of the Administrator, property of any kind which constitutes good and valuable
consideration; 
 with the consent of the Administrator, delivery of a notice that Optionee has placed a market sell order with a broker with
respect to Shares then issuable upon exercise of the Option and that the broker has been directed to pay a sufficient portion of the net proceeds of the sale to the Company in satisfaction of the aggregate Exercise Price; provided, that payment of
such proceeds is then made to the Company upon settlement of such sale; or 
 with the consent of the Administrator, any combination of the
foregoing methods of payment. 
 Restrictions on Exercise. This Option may not be exercised until the Plan has been approved by the
stockholders of the Company. If the issuance of Shares upon such exercise or if the method of payment for such shares would constitute a violation of any applicable federal or state securities or other law or regulation, then the Option may also not
be exercised. The Company may require Optionee to make any representation and warranty to the Company as may be required by any applicable law or regulation before allowing the Option to be exercised. 
 Termination of Relationship. If Optionee ceases to be a Service Provider (other than by reason of Optionee’s death or the total and permanent
disability of Optionee as defined in Code Section 22(e)(3)), Optionee may exercise this Option during the Termination Period set out in the Notice of Grant, to the extent the Option was vested at the date on which Optionee ceases to be a
Service Provider. To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise this Option within the time specified herein, the Option shall terminate. 
 Disability of Optionee. If Optionee ceases to be a Service Provider as a result of his or her total and permanent disability as defined in Code
Section 22(e)(3), Optionee may exercise the Option to the extent the Option was vested at the date on which Optionee ceases to be a Service Provider, but only within twelve (12) months from such date (and in no event later than the
expiration date of the term of this Option as set forth in the Notice of Grant). To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise such Option within the time
specified herein, the Option shall terminate. 
 Death of Optionee. If Optionee ceases to be a Service Provider as a result of the
death of Optionee, the vested portion of the Option may be exercised at any time within twelve (12) months following the date of death (and in no event later than the expiration date of the term of this Option as set forth in the Notice of
Grant) by Optionee’s estate or by a person who acquires the right to exercise the Option by bequest or inheritance. To the extent that the Option is not vested at the date of death, or if the Option is not exercised within the time specified
herein, the Option shall terminate. 
  

 11 

 Non-Transferability of Option. This Option may not be transferred in any manner except by will or
by the laws of descent or distribution . It may be exercised during the lifetime of Optionee only by Optionee. The terms of this Option shall be binding upon the executors, administrators, heirs, successors and assigns of Optionee. 
 Term of Option. This Option may be exercised only within the term set out in the Notice of Grant. 
 [Signature page follows] 
  

 12 

 This Agreement may be executed in two or more counterparts, each of which shall be deemed an original and
all of which shall constitute one document. 
  

			
	BAYHILL THERAPEUTICS, INC.
		
	By:	 	  

	Name:	 	Mark W. Schwartz
	Title:	 	Chief Executive Officer

 OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO THE OPTION HEREOF IS
EARNED ONLY BY CONTINUING CONSULTANCY OR EMPLOYMENT AT THE WILL OF THE COMPANY (NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR ACQUIRING SHARES HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT NOTHING IN THIS AGREEMENT,
NOR IN THE COMPANY’S 2002 EQUITY INCENTIVE PLAN WHICH IS INCORPORATED HEREIN BY REFERENCE, SHALL CONFER UPON OPTIONEE ANY RIGHT WITH RESPECT TO CONTINUATION OF EMPLOYMENT OR CONSULTANCY BY THE COMPANY, NOR SHALL IT INTERFERE IN ANY WAY WITH
OPTIONEE’S RIGHT OR THE COMPANY’S RIGHT TO TERMINATE OPTIONEE’S EMPLOYMENT OR CONSULTANCY AT ANY TIME, WITH OR WITHOUT CAUSE AND WITH OR WITHOUT PRIOR NOTICE. 
 Optionee acknowledges receipt of a copy of the Plan and represents that he or she is familiar with the terms and provisions thereof. Optionee hereby
accepts this Option subject to all of the terms and provisions hereof. Optionee has reviewed the Plan and this Option in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Option and fully understands all
provisions of the Option. Optionee hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan or this Option. Optionee further agrees to notify the Company
upon any change in the residence address indicated below. 
  

							
	Dated:	 	  
	 		  	  

		 		 		  	 Name

				
		 		 		  	Residence Address:
				
		 		 		  	  

				
		 		 		  	  

  

 13 

 EXHIBIT A 
 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 EXERCISE NOTICE 
 Bayhill Therapeutics, Inc.

 Attention: Stock Administration 
 Exercise
of Option. Effective as of today,                     ,             ,
the undersigned (“Optionee”) hereby elects to exercise Optionee’s option to purchase                      shares of the Common
Stock (the “Shares”) of Bayhill Therapeutics, Inc. (the “Company”) under and pursuant to the Bayhill Therapeutics, Inc. 2002 Equity Incentive Plan (the “Plan”) and the  ̈ Incentive  ̈ Non-Qualified Stock Option Agreement dated
                    ,             , (the “Option Agreement”).
Capitalized terms used herein without definition shall have the meanings given in the Option Agreement. 
  

					
	Date of Grant:	 		    	  

			
	 Number of Shares as to which Option is
 Exercised:
	 		    	  

			
	Exercise Price per Share:	 		    	$                    
			
	Total Exercise Price:	 		    	$                    
			
	Certificate to be issued in name of:	 		    	  

			
	Cash Payment delivered herewith:	 	 ̈	    	$                    
			
	Promissory note delivered herewith:	 	 ̈	    	$                    

  

			
	Type of Option:	  	 ̈  Incentive Stock
Option             ̈  Non-Qualified Stock Option

 Representations of Optionee. Optionee acknowledges that Optionee has received, read and
understood the Plan and the Option Agreement. Optionee agrees to abide by and be bound by their terms and conditions. 
 Rights as
Stockholder. Until the stock certificate evidencing such Shares is issued (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), no right to vote or receive dividends or any
other rights as a stockholder shall exist with respect to Shares subject to the Option, notwithstanding the exercise of the Option. The Company shall issue (or cause to be issued) such stock certificate promptly after the Option is exercised. No
adjustment will be made for a dividend or other right for which the record date is prior to the date the stock certificate is issued, except as provided in Section 13 of the Plan. 

 Optionee shall enjoy rights as a stockholder until such time as Optionee disposes of the Shares or the
Company and/or its assignee(s) exercises the Right of First Refusal hereunder. Upon such exercise, Optionee shall have no further rights as a holder of the Shares so purchased except the right to receive payment for the Shares so purchased in
accordance with the provisions of this Agreement, and Optionee shall forthwith cause the certificate(s) evidencing the Shares so purchased to be surrendered to the Company for transfer or cancellation. 
 Optionee’s Rights to Transfer Shares. 
 Company’s Right of First Refusal. Before any Shares held by Optionee or any permitted transferee (each, a “Holder”) may be sold, pledged, assigned, hypothecated, transferred, or otherwise disposed of (each, a
“Transfer”), the Company or its assignee(s) shall have a right of first refusal to purchase the Shares proposed to be Transferred on the terms and conditions set forth in this Section (the “Right of First Refusal”). 

Notice of Proposed Transfer. In the event any Holder desires to Transfer any Shares, the Holder shall deliver to the Company a written notice
(the “Notice”) stating: (w) the Holder’s bona fide intention to sell or otherwise Transfer such Shares; (x) the name of each proposed purchaser or other transferee (“Proposed Transferee”); (y) the number of
Shares to be Transferred to each Proposed Transferee; and (z) the bona fide cash price or other consideration for which the Holder proposes to Transfer the Shares (the “Offered Price”), and the Holder shall offer such Shares at the
Offered Price to the Company or its assignee(s). 
 Exercise of Right of First Refusal. Within thirty (30) days after receipt of
the Notice, the Company and/or its assignee(s) may elect in writing to purchase all, but not less than all, of the Shares proposed to be Transferred to any one or more of the Proposed Transferees. The purchase price will be determined in accordance
with subsection (iii) below. 
 Purchase Price. The purchase price (“Purchase Price”) for the Shares repurchased under
this Section shall be the Offered Price. If the Offered Price includes consideration other than cash, the cash equivalent value of the non-cash consideration shall be determined by the Board of Directors of the Company in good faith. 
 Payment. Payment of the Purchase Price shall be made, at the option of the Company or its assignee(s), in cash (by check), by cancellation of all
or a portion of any outstanding indebtedness of the Holder to the Company (or, in the case of repurchase by an assignee, to the assignee), or by any combination thereof within thirty (30) days after receipt of the Notice or in the manner and at
the times mutually agreed to by the Company and the Holder. 
 Holder’s Right to Transfer. If all of the Shares proposed in the
Notice to be Transferred are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise Transfer such Shares to that Proposed Transferee at the Offered Price or at a higher price, provided
that such sale or other Transfer is consummated within one hundred twenty (120) days after the date of the Notice and provided further that any such sale or other Transfer is effected in accordance with any applicable securities laws and the
Proposed Transferee agrees in writing that the provisions of this Section shall continue to apply to the Shares in the hands of such Proposed Transferee. If the Shares 

  

 2 

 
described in the Notice are not Transferred to the Proposed Transferee within such 120-day period, a new Notice shall be given to the Company, and the
Company and/or its assignees shall again be offered the Right of First Refusal as provided herein before any Shares held by the Holder may be sold or otherwise Transferred. 
 Exception for Certain Family Transfers. Anything to the contrary contained in this Section notwithstanding, the Transfer of any or all of the
Shares during Optionee’s lifetime or upon Optionee’s death by will or intestacy to Optionee’s Immediate Family or a trust for the benefit of Optionee’s Immediate Family shall be exempt from the Right of First Refusal. As used
herein, “Immediate Family” shall mean spouse, lineal descendant or antecedent, father, mother, brother or sister or stepchild (whether or not adopted). In such case, the transferee or other recipient shall receive and hold the Shares so
Transferred subject to the provisions of this Section (including the Right of First Refusal) and there shall be no further Transfer of such Shares except in accordance with the terms of this Section. 
 Termination of Right of First Refusal. The Right of First Refusal shall terminate as to all Shares upon a sale of Common Stock of the Company to
the general public pursuant to a registration statement filed with and declared effective by the Securities and Exchange Commission under the Securities Act of 1933, as amended (a “Public Offering”). 
 Transfer Restrictions. Any transfer or sale of the Share is subject to restrictions on transfer imposed by any applicable state and federal
securities laws. Any Transfer or attempted Transfer of any of the Shares not in accordance with the terms of this Agreement shall be void and the Company may enforce the terms of this Agreement by stop transfer instructions or similar actions by the
Company and its agents or designees. 
 Tax Consultation. Optionee understands that Optionee may suffer adverse tax consequences as a
result of Optionee’s purchase or disposition of the Shares. Optionee represents that Optionee has consulted with any tax consultants Optionee deems advisable in connection with the purchase or disposition of the Shares and that Optionee is not
relying on the Company for any tax advice. 
 Restrictive Legends and Stop-Transfer Orders. 
 Legends. Optionee understands and agrees that the Company shall cause the legends set forth below or legends substantially equivalent thereto, to
be placed upon any certificate(s) evidencing ownership of the Shares together with any other legends that may be required by state or federal securities laws: 
 THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE “ACT”) AND MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
REGISTERED UNDER THE ACT OR, IN THE OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE THEREWITH. 
  

 3 

 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND RIGHT OF
FIRST REFUSAL OPTIONS HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER
RESTRICTIONS AND RIGHT OF FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES. 
 Stop-Transfer Notices. Optionee agrees that, in
order to ensure compliance with the restrictions referred to herein, the Company may issue appropriate “stop transfer” instructions to its transfer agent, if any, and that, if the Company transfers its own securities, it may make
appropriate notations to the same effect in its own records. 
 Refusal to Transfer. The Company shall not be required (i) to
transfer on its books any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Shares or to accord the right to vote or pay dividends to any purchaser or
other transferee to whom such Shares shall have been so transferred. 
 Successors and Assigns. The Company may assign any of its
rights under this Agreement to single or multiple assignees, and this Agreement shall inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement shall be binding upon
Optionee and his or her heirs, executors, administrators, successors and assigns. 
 Interpretation. Any dispute regarding the
interpretation of this Agreement shall be submitted by Optionee or by the Company forthwith to the Company’s Board of Directors or committee thereof that is responsible for the administration of the Plan (the “Administrator”), which
shall review such dispute at its next regular meeting. The resolution of such a dispute by the Administrator shall be final and binding on the Company and on Optionee. 
 Governing Law; Severability. This Agreement shall be governed by and construed in accordance with the laws of the State of California excluding that body of law pertaining to conflicts of law. Should any
provision of this Agreement be determined by a court of law to be illegal or unenforceable, the other provisions shall nevertheless remain effective and shall remain enforceable. 
 Notices. Any notice required or permitted hereunder shall be given in writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States mail by certified mail, with postage and fees prepaid, addressed to the other party at its address as shown below beneath its signature, or to such other address as such party may designate in writing from time to time
to the other party. 
  

 4 

 Further Instruments. The parties agree to execute such further instruments and to take such
further action as may be reasonably necessary to carry out the purposes and intent of this Agreement. 
 Delivery of Payment. Optionee
herewith delivers to the Company the full Exercise Price for the Shares, as well as any applicable withholding tax. 
 Entire
Agreement. The Plan and Option Agreement are incorporated herein by reference. This Agreement, the Plan, the Option Agreement and the Investment Representation Statement constitute the entire agreement of the parties and supersede in their
entirety all prior undertakings and agreements of the Company and Optionee with respect to the subject matter hereof. 
  

							
	Accepted by:	  		  	Submitted by:
			
	BAYHILL THERAPEUTICS, INC.	  		  	NAME
				
	 By:
	 	  
	  		  	  

	 Name:
	 	  
	  		  	Name
	 Its:
	 	  
	  		  	
				
		 		  		  	Address:
				
		 		  		  	  

		 		  		  	  

		 		  		  	  

  

 5 

 EXHIBIT B 
 INVESTMENT REPRESENTATION STATEMENT 
  

					
	OPTIONEE	 	:	  	
			
	COMPANY	 	:	  	Bayhill Therapeutics, Inc.
			
	SECURITY	 	:	  	Common Stock
			
	AMOUNT	 	:	  	
			
	DATE	 	:	  	

 In connection with the purchase of the above-listed shares of Common Stock (the
“Securities”) of Bayhill Therapeutics, Inc. (the “Company”), the undersigned (the “Optionee”) represents to the Company the following: 
 Optionee is aware of the Company’s business affairs and financial condition and has acquired sufficient information about the Company to reach an informed and knowledgeable decision to acquire the Securities.
Optionee is acquiring these Securities for investment for Optionee’s own account only and not with a view to, or for resale in connection with, any “distribution” thereof within the meaning of the Securities Act of 1933, as amended
(the “Securities Act”). 
 Optionee acknowledges and understands that the Securities constitute “restricted securities”
under the Securities Act and have not been registered under the Securities Act in reliance upon a specific exemption therefrom, which exemption depends upon, among other things, the bona fide nature of Optionee’s investment intent as expressed
herein. In this connection, Optionee understands that, in the view of the Securities and Exchange Commission, the statutory basis for such exemption may be unavailable if Optionee’s representation was predicated solely upon a present intention
to hold these Securities for the minimum capital gains period specified under tax statutes, for a deferred sale, for or until an increase or decrease in the market price of the Securities, or for a period of one year or any other fixed period in the
future. Optionee further understands that the Securities must be held indefinitely unless they are subsequently registered under the Securities Act or an exemption from such registration is available. Optionee further acknowledges and understands
that the Company is under no obligation to register the Securities. Optionee understands that the certificate evidencing the Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such
registration is not required in the opinion of counsel satisfactory to the Company and any other legend required under applicable state securities laws. 
 Optionee is familiar with the provisions of Rule 701 and Rule 144, each promulgated under the Securities Act, which, in substance, permit limited public resale of “restricted securities” acquired, directly
or indirectly from the issuer thereof, in a non-public offering subject to the satisfaction of certain conditions. Rule 701 provides that if the issuer 

 
qualifies under Rule 701 at the time of the grant of the Option to Optionee, the exercise will be exempt from registration under the Securities Act. In the
event the Company becomes subject to the reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, ninety (90) days thereafter (or such longer period as any market stand-off agreement may require) the Securities
exempt under Rule 701 may be resold, subject to the satisfaction of certain of the conditions specified by Rule 144, including: (1) the resale being made through a broker in an unsolicited “broker’s transaction” or in
transactions directly with a market maker (as said term is defined under the Securities Exchange Act of 1934); and, in the case of an affiliate, (2) the availability of certain public information about the Company, (3) the amount of
Securities being sold during any three (3) month period not exceeding the limitations specified in Rule 144(e), and (4) the timely filing of a Form 144, if applicable. 
 In the event that the Company does not qualify under Rule 701 at the time of grant of the Option, then the Securities may be resold in certain limited
circumstances subject to the provisions of Rule 144, which requires the resale to occur not less than one year after the later of the date the Securities were sold by the Company or the date the Securities were sold by an affiliate of the Company,
within the meaning of Rule 144; and, in the case of acquisition of the Securities by an affiliate, or by a non-affiliate who subsequently holds the Securities less than two (2) years, the satisfaction of the conditions set forth in sections
(1), (2), (3) and (4) of the paragraph immediately above. 
 Optionee further understands that in the event all of the applicable
requirements of Rule 701 or 144 are not satisfied, registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required; and that, notwithstanding the fact that Rules 144 and 701 are not
exclusive, the Staff of the Securities and Exchange Commission has expressed its opinion that persons proposing to sell private placement securities other than in a registered offering and otherwise than pursuant to Rules 144 or 701 will have a
substantial burden of proof in establishing that an exemption from registration is available for such offers or sales, and that such persons and their respective brokers who participate in such transactions do so at their own risk. Optionee
understands that no assurances can be given that any such other registration exemption will be available in such event. 
  

	
	Signature of Optionee:
	
	  

	Name

 Date:
                            ,
             
  

 7 

 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 STOCK OPTION AGREEMENT 
 Bayhill Therapeutics, Inc. (the “Company”), pursuant to its 2002 Equity Incentive Plan (the “Plan”), hereby grants to Optionee listed
below (“Optionee”), an option to purchase the number of shares of the Company’s Common Stock set forth below, subject to the terms and conditions of the Plan and this Stock Option Agreement. Unless otherwise defined herein, the terms
defined in the Plan shall have the same defined meanings in this Stock Option Agreement. 
 NOTICE OF STOCK OPTION GRANT 
  

			
	Optionee:	 	
		
	Date of Stock Option Agreement:	 	
		
	Date of Grant:	 	
		
	Vesting Commencement Date:	 	
		
	Exercise Price per Share:	 	
		
	Total Number of Shares Granted:	 	
		
	Total Exercise Price:	 	
		
	Term/Expiration Date:	 	

  

			
	Type of Option:	  	 ̈  Incentive Stock Option            x  Non-Qualified Stock Option
		
	Vesting Schedule:	  	The Shares subject to this Option shall vest according to the following schedule:
		
		  	Twenty five percent (25%) of the Shares subject to the Option (rounded down to the next whole number of shares) shall vest one year after the Vesting Commencement Date, and 1/48th of the
Shares subject to the Option (rounded down to the next whole number of shares) shall vest on the first day of each full month thereafter, so that all of the Shares shall be vested on the first day of the forty eighth (48th) full month after the
Vesting Commencement Date.
		
	Termination Period:	  	This Option may be exercised, to the extent vested, for three (3) months after Optionee ceases to be a Service Provider, or such longer period as may be applicable upon the death or
disability of Optionee as provided herein (or, if not provided herein, then as provided in the Plan), but in no event later than the Term/Expiration Date as provided above.

  

 8 

 AGREEMENT 
 Grant of Option. The Company hereby grants to Optionee an Option to purchase the number of shares of Common Stock (the “Shares”) set forth in the Notice of Grant, at the exercise price per share set forth in the Notice of
Grant (the “Exercise Price”). Notwithstanding anything to the contrary anywhere else in this Option Agreement, this grant of an Option is subject to the terms, definitions and provisions of the Plan adopted by the Company, which is
incorporated herein by reference. 
 If designated in the Notice of Grant as an Incentive Stock Option, this Option is intended to qualify as
an Incentive Stock Option as defined in Section 422 of the Code; provided, however, that to the extent that the aggregate Fair Market Value of stock with respect to which Incentive Stock Options (within the meaning of Code Section 422, but
without regard to Code Section 422(d)), including the Option, are exercisable for the first time by Optionee during any calendar year (under the Plan and all other incentive stock option plans of the Company or any Subsidiary) exceeds $100,000,
such options shall be treated as not qualifying under Code Section 422, but rather shall be treated as Non-Qualified Stock Options to the extent required by Code Section 422. The rule set forth in the preceding sentence shall be applied by
taking options into account in the order in which they were granted. For purposes of these rules, the Fair Market Value of stock shall be determined as of the time the option with respect to such stock is granted. 
 Exercise of Option. This Option is exercisable as follows: 
 Right to Exercise. 
 This Option shall be exercisable cumulatively according to the vesting schedule
set out in the Notice of Grant. For purposes of this Stock Option Agreement, Shares subject to this Option shall vest based on Optionee’s continued status as a Service Provider. 
 This Option may not be exercised for a fraction of a Share. 
 In the event of Optionee’s death, disability or other termination of Optionee’s status as a Service Provider, the exercisability of the Option is governed by Sections 7, 8 and 9 below. 
 In no event may this Option be exercised after the date of expiration of the term of this Option as set forth in the Notice of Grant. 
 Method of Exercise. This Option shall be exercisable by written Notice (in the form attached as Exhibit A). The Notice must state the
number of Shares for which the Option is being exercised, and such other representations and agreements with respect to such shares of Common Stock as may be required by the Company pursuant to the provisions of the Plan. The Notice must be signed
by Optionee and shall be delivered in person or by certified mail to the Secretary of the Company. The Notice must be accompanied by payment of the Exercise Price plus payment of any applicable withholding tax. This Option shall be deemed to
be exercised upon receipt by the Company of such written Notice accompanied by the Exercise Price and payment of any applicable withholding tax. 
  

 9 

 No Shares shall be issued pursuant to the exercise of an Option unless such issuance and such exercise
comply with all relevant provisions of law and the requirements of any stock exchange upon which the Shares may then be listed. Assuming such compliance, for income tax purposes the Shares shall be considered transferred to Optionee on the date on
which the Option is exercised with respect to such Shares. 
 Optionee’s Representations. If the Shares purchasable pursuant to
the exercise of this Option have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), at the time this Option is exercised, Optionee shall, if required by the Company, concurrently with the exercise of
all or any portion of this Option, deliver to the Company his or her Investment Representation Statement in the form attached hereto as Exhibit B. 
 Lock-Up Period. Optionee hereby agrees that if so requested by the Company or any representative of the underwriters (the “Managing Underwriter”) in connection with any registration of the offering of
any securities of the Company under the Securities Act, Optionee shall not sell or otherwise transfer any Shares or other securities of the Company during the 180-day period (or such longer period as may be requested in writing by the Managing
Underwriter and agreed to in writing by the Company) (the “Market Standoff Period”) following the effective date of a registration statement of the Company filed under the Securities Act; provided, however, that such restriction shall
apply only to the first registration statement of the Company to become effective under the Securities Act that includes securities to be sold on behalf of the Company to the public in an underwritten public offering under the Securities Act. The
Company may impose stop-transfer instructions with respect to securities subject to the foregoing restrictions until the end of such Market Standoff Period and these restrictions shall be binding on any transferee of such Shares. 
 Method of Payment. Payment of the Exercise Price shall be by any of the following, or a combination thereof, at the election of Optionee:

 cash; 
 check; 
 with the consent of the Administrator, a full recourse promissory note bearing interest (at no less than such rate as is a market rate of interest and
which then precludes the imputation of interest under the Code) and payable upon such terms as may be prescribed by the Administrator; 
 with the consent of the Administrator, surrender of other shares of Common Stock of the Company which (A) in the case of Shares acquired from the Company, have been owned by Optionee for more than six (6) months on the date of
surrender, and (B) have a Fair Market Value on the date of surrender equal to the Exercise Price of the Shares as to which the Option is being exercised; 
 with the consent of the Administrator, surrendered Shares issuable upon the exercise of the Option having a Fair Market Value on the date of exercise equal to the aggregate Exercise Price of the Option or exercised
portion thereof; 
  

 10 

 with the consent of the Administrator, property of any kind which constitutes good and valuable
consideration; 
 with the consent of the Administrator, delivery of a notice that Optionee has placed a market sell order with a broker with
respect to Shares then issuable upon exercise of the Option and that the broker has been directed to pay a sufficient portion of the net proceeds of the sale to the Company in satisfaction of the aggregate Exercise Price; provided, that payment of
such proceeds is then made to the Company upon settlement of such sale; or 
 with the consent of the Administrator, any combination of the
foregoing methods of payment. 
 Restrictions on Exercise. This Option may not be exercised until the Plan has been approved by the
stockholders of the Company. If the issuance of Shares upon such exercise or if the method of payment for such shares would constitute a violation of any applicable federal or state securities or other law or regulation, then the Option may also not
be exercised. The Company may require Optionee to make any representation and warranty to the Company as may be required by any applicable law or regulation before allowing the Option to be exercised. 
 Termination of Relationship. If Optionee ceases to be a Service Provider (other than by reason of Optionee’s death or the total and permanent
disability of Optionee as defined in Code Section 22(e)(3)), Optionee may exercise this Option during the Termination Period set out in the Notice of Grant, to the extent the Option was vested at the date on which Optionee ceases to be a
Service Provider. To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise this Option within the time specified herein, the Option shall terminate. 
 Disability of Optionee. If Optionee ceases to be a Service Provider as a result of his or her total and permanent disability as defined in Code
Section 22(e)(3), Optionee may exercise the Option to the extent the Option was vested at the date on which Optionee ceases to be a Service Provider, but only within twelve (12) months from such date (and in no event later than the
expiration date of the term of this Option as set forth in the Notice of Grant). To the extent that the Option is not vested at the date on which Optionee ceases to be a Service Provider, or if Optionee does not exercise such Option within the time
specified herein, the Option shall terminate. 
 Death of Optionee. If Optionee ceases to be a Service Provider as a result of the
death of Optionee, the vested portion of the Option may be exercised at any time within twelve (12) months following the date of death (and in no event later than the expiration date of the term of this Option as set forth in the Notice of
Grant) by Optionee’s estate or by a person who acquires the right to exercise the Option by bequest or inheritance. To the extent that the Option is not vested at the date of death, or if the Option is not exercised within the time specified
herein, the Option shall terminate. 
  

 11 

 Non-Transferability of Option. This Option may not be transferred in any manner except by will or
by the laws of descent or distribution . It may be exercised during the lifetime of Optionee only by Optionee. The terms of this Option shall be binding upon the executors, administrators, heirs, successors and assigns of Optionee. 
 Term of Option. This Option may be exercised only within the term set out in the Notice of Grant. 
 [Signature page follows] 
  

 12 

 This Agreement may be executed in two or more counterparts, each of which shall be deemed an original and
all of which shall constitute one document. 
  

			
	BAYHILL THERAPEUTICS, INC.
		
	By:	 	  

	Name:	 	Mark W. Schwartz
	Title:	 	Chief Executive Officer

 OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO THE OPTION HEREOF IS
EARNED ONLY BY CONTINUING CONSULTANCY OR EMPLOYMENT AT THE WILL OF THE COMPANY (NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR ACQUIRING SHARES HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT NOTHING IN THIS AGREEMENT,
NOR IN THE COMPANY’S 2002 EQUITY INCENTIVE PLAN WHICH IS INCORPORATED HEREIN BY REFERENCE, SHALL CONFER UPON OPTIONEE ANY RIGHT WITH RESPECT TO CONTINUATION OF EMPLOYMENT OR CONSULTANCY BY THE COMPANY, NOR SHALL IT INTERFERE IN ANY WAY WITH
OPTIONEE’S RIGHT OR THE COMPANY’S RIGHT TO TERMINATE OPTIONEE’S EMPLOYMENT OR CONSULTANCY AT ANY TIME, WITH OR WITHOUT CAUSE AND WITH OR WITHOUT PRIOR NOTICE. 
 Optionee acknowledges receipt of a copy of the Plan and represents that he or she is familiar with the terms and provisions thereof. Optionee hereby
accepts this Option subject to all of the terms and provisions hereof. Optionee has reviewed the Plan and this Option in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Option and fully understands all
provisions of the Option. Optionee hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan or this Option. Optionee further agrees to notify the Company
upon any change in the residence address indicated below. 
  

							
	Dated:	 		 		  	  

		 		 		  	 Name

				
		 		 		  	Residence Address:
				
		 		 		  	  

				
		 		 		  	  

  

 13 

 EXHIBIT A 
 BAYHILL THERAPEUTICS, INC. 
 2002 EQUITY INCENTIVE PLAN 
 EXERCISE NOTICE 
 Bayhill Therapeutics, Inc.

 Attention: Stock Administration 
 Exercise
of Option. Effective as of today,                     ,             ,
the undersigned (“Optionee”) hereby elects to exercise Optionee’s option to purchase                      shares of the Common
Stock (the “Shares”) of Bayhill Therapeutics, Inc. (the “Company”) under and pursuant to the Bayhill Therapeutics, Inc. 2002 Equity Incentive Plan (the “Plan”) and the  ̈ Incentive  ̈ Non-Qualified Stock Option Agreement dated
                    ,              (the “Option Agreement”).
Capitalized terms used herein without definition shall have the meanings given in the Option Agreement. 
  

					
	Date of Grant:	 		    	  

			
	 Number of Shares as to which Option is
 Exercised:
	 		    	  

			
	Exercise Price per Share:	 		    	$                    
			
	Total Exercise Price:	 		    	$                    
			
	Certificate to be issued in name of:	 		    	  

			
	Cash Payment delivered herewith:	 	 ̈	    	$                    
			
	Promissory note delivered herewith:	 	 ̈	    	$                    

  

			
	Type of Option:	  	 ̈  Incentive Stock
Option             ̈  Non-Qualified Stock Option

 Representations of Optionee. Optionee acknowledges that Optionee has received, read and
understood the Plan and the Option Agreement. Optionee agrees to abide by and be bound by their terms and conditions. 
 Rights as
Stockholder. Until the stock certificate evidencing such Shares is issued (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), no right to vote or receive dividends or any
other rights as a stockholder shall exist with respect to Shares subject to the Option, notwithstanding the exercise of the Option. The Company shall issue (or cause to be issued) such stock certificate promptly after the Option is exercised. No
adjustment will be made for a dividend or other right for which the record date is prior to the date the stock certificate is issued, except as provided in Section 13 of the Plan. 

 Optionee shall enjoy rights as a stockholder until such time as Optionee disposes of the Shares or the
Company and/or its assignee(s) exercises the Right of First Refusal hereunder. Upon such exercise, Optionee shall have no further rights as a holder of the Shares so purchased except the right to receive payment for the Shares so purchased in
accordance with the provisions of this Agreement, and Optionee shall forthwith cause the certificate(s) evidencing the Shares so purchased to be surrendered to the Company for transfer or cancellation. 
 Optionee’s Rights to Transfer Shares. 
 Company’s Right of First Refusal. Before any Shares held by Optionee or any permitted transferee (each, a “Holder”) may be sold, pledged, assigned, hypothecated, transferred, or otherwise disposed of (each, a
“Transfer”), the Company or its assignee(s) shall have a right of first refusal to purchase the Shares proposed to be Transferred on the terms and conditions set forth in this Section (the “Right of First Refusal”). 

Notice of Proposed Transfer. In the event any Holder desires to Transfer any Shares, the Holder shall deliver to the Company a written notice
(the “Notice”) stating: (w) the Holder’s bona fide intention to sell or otherwise Transfer such Shares; (x) the name of each proposed purchaser or other transferee (“Proposed Transferee”); (y) the number of
Shares to be Transferred to each Proposed Transferee; and (z) the bona fide cash price or other consideration for which the Holder proposes to Transfer the Shares (the “Offered Price”), and the Holder shall offer such Shares at the
Offered Price to the Company or its assignee(s). 
 Exercise of Right of First Refusal. Within thirty (30) days after receipt of
the Notice, the Company and/or its assignee(s) may elect in writing to purchase all, but not less than all, of the Shares proposed to be Transferred to any one or more of the Proposed Transferees. The purchase price will be determined in accordance
with subsection (iii) below. 
 Purchase Price. The purchase price (“Purchase Price”) for the Shares repurchased under
this Section shall be the Offered Price. If the Offered Price includes consideration other than cash, the cash equivalent value of the non-cash consideration shall be determined by the Board of Directors of the Company in good faith. 
 Payment. Payment of the Purchase Price shall be made, at the option of the Company or its assignee(s), in cash (by check), by cancellation of all
or a portion of any outstanding indebtedness of the Holder to the Company (or, in the case of repurchase by an assignee, to the assignee), or by any combination thereof within thirty (30) days after receipt of the Notice or in the manner and at
the times mutually agreed to by the Company and the Holder. 
 Holder’s Right to Transfer. If all of the Shares proposed in the
Notice to be Transferred are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise Transfer such Shares to that Proposed Transferee at the Offered Price or at a higher price, provided
that such sale or other Transfer is consummated within one hundred twenty (120) days after the date of the Notice and provided further that any such sale or other Transfer is effected in accordance with any applicable securities laws and the
Proposed Transferee agrees in writing that the provisions of this Section shall continue to apply to the Shares in the hands of such Proposed Transferee. If the Shares 

  

 2 

 
described in the Notice are not Transferred to the Proposed Transferee within such 120-day period, a new Notice shall be given to the Company, and the
Company and/or its assignees shall again be offered the Right of First Refusal as provided herein before any Shares held by the Holder may be sold or otherwise Transferred. 
 Exception for Certain Family Transfers. Anything to the contrary contained in this Section notwithstanding, the Transfer of any or all of the
Shares during Optionee’s lifetime or upon Optionee’s death by will or intestacy to Optionee’s Immediate Family or a trust for the benefit of Optionee’s Immediate Family shall be exempt from the Right of First Refusal. As used
herein, “Immediate Family” shall mean spouse, lineal descendant or antecedent, father, mother, brother or sister or stepchild (whether or not adopted). In such case, the transferee or other recipient shall receive and hold the Shares so
Transferred subject to the provisions of this Section (including the Right of First Refusal) and there shall be no further Transfer of such Shares except in accordance with the terms of this Section. 
 Termination of Right of First Refusal. The Right of First Refusal shall terminate as to all Shares upon a sale of Common Stock of the Company to
the general public pursuant to a registration statement filed with and declared effective by the Securities and Exchange Commission under the Securities Act of 1933, as amended (a “Public Offering”). 
 Transfer Restrictions. Any transfer or sale of the Share is subject to restrictions on transfer imposed by any applicable state and federal
securities laws. Any Transfer or attempted Transfer of any of the Shares not in accordance with the terms of this Agreement shall be void and the Company may enforce the terms of this Agreement by stop transfer instructions or similar actions by the
Company and its agents or designees. 
 Tax Consultation. Optionee understands that Optionee may suffer adverse tax consequences as a
result of Optionee’s purchase or disposition of the Shares. Optionee represents that Optionee has consulted with any tax consultants Optionee deems advisable in connection with the purchase or disposition of the Shares and that Optionee is not
relying on the Company for any tax advice. 
 Restrictive Legends and Stop-Transfer Orders. 
 Legends. Optionee understands and agrees that the Company shall cause the legends set forth below or legends substantially equivalent thereto, to
be placed upon any certificate(s) evidencing ownership of the Shares together with any other legends that may be required by state or federal securities laws: 
 THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE “ACT”) AND MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
REGISTERED UNDER THE ACT OR, IN THE OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE THEREWITH. 
  

 3 

 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND RIGHT OF
FIRST REFUSAL OPTIONS HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER
RESTRICTIONS AND RIGHT OF FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES. 
 Stop-Transfer Notices. Optionee agrees that, in
order to ensure compliance with the restrictions referred to herein, the Company may issue appropriate “stop transfer” instructions to its transfer agent, if any, and that, if the Company transfers its own securities, it may make
appropriate notations to the same effect in its own records. 
 Refusal to Transfer. The Company shall not be required (i) to
transfer on its books any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Shares or to accord the right to vote or pay dividends to any purchaser or
other transferee to whom such Shares shall have been so transferred. 
 Successors and Assigns. The Company may assign any of its
rights under this Agreement to single or multiple assignees, and this Agreement shall inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement shall be binding upon
Optionee and his or her heirs, executors, administrators, successors and assigns. 
 Interpretation. Any dispute regarding the
interpretation of this Agreement shall be submitted by Optionee or by the Company forthwith to the Company’s Board of Directors or committee thereof that is responsible for the administration of the Plan (the “Administrator”), which
shall review such dispute at its next regular meeting. The resolution of such a dispute by the Administrator shall be final and binding on the Company and on Optionee. 
 Governing Law; Severability. This Agreement shall be governed by and construed in accordance with the laws of the State of California excluding that body of law pertaining to conflicts of law. Should any
provision of this Agreement be determined by a court of law to be illegal or unenforceable, the other provisions shall nevertheless remain effective and shall remain enforceable. 
 Notices. Any notice required or permitted hereunder shall be given in writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States mail by certified mail, with postage and fees prepaid, addressed to the other party at its address as shown below beneath its signature, or to such other address as such party may designate in writing from time to time
to the other party. 
  

 4 

 Further Instruments. The parties agree to execute such further instruments and to take such
further action as may be reasonably necessary to carry out the purposes and intent of this Agreement. 
 Delivery of Payment. Optionee
herewith delivers to the Company the full Exercise Price for the Shares, as well as any applicable withholding tax. 
 Entire
Agreement. The Plan and Option Agreement are incorporated herein by reference. This Agreement, the Plan, the Option Agreement and the Investment Representation Statement constitute the entire agreement of the parties and supersede in their
entirety all prior undertakings and agreements of the Company and Optionee with respect to the subject matter hereof. 
  

							
	Accepted by:	 		 	Submitted by:
			
	BAYHILL THERAPEUTICS, INC.	 		 	NAME
				
	By:	 	  
	 		 	  

	Name:	 	  
	 		 	Name
	Its:	 	  
	 		 	
				
		 		 		 	Address:
				
		 		 		 	  

		 		 		 	  

		 		 		 	  

  

 5 

 EXHIBIT B 
 INVESTMENT REPRESENTATION STATEMENT 
  

			
	OPTIONEE :	  	
		
	COMPANY :	  	Bayhill Therapeutics, Inc.
		
	SECURITY :	  	Common Stock
		
	AMOUNT :	  	
		
	DATE :	  	

 In connection with the purchase of the above-listed shares of Common Stock (the
“Securities”) of Bayhill Therapeutics, Inc. (the “Company”), the undersigned (the “Optionee”) represents to the Company the following: 
 Optionee is aware of the Company’s business affairs and financial condition and has acquired sufficient information about the Company to reach an informed and knowledgeable decision to acquire the Securities.
Optionee is acquiring these Securities for investment for Optionee’s own account only and not with a view to, or for resale in connection with, any “distribution” thereof within the meaning of the Securities Act of 1933, as amended
(the “Securities Act”). 
 Optionee acknowledges and understands that the Securities constitute “restricted securities”
under the Securities Act and have not been registered under the Securities Act in reliance upon a specific exemption therefrom, which exemption depends upon, among other things, the bona fide nature of Optionee’s investment intent as expressed
herein. In this connection, Optionee understands that, in the view of the Securities and Exchange Commission, the statutory basis for such exemption may be unavailable if Optionee’s representation was predicated solely upon a present intention
to hold these Securities for the minimum capital gains period specified under tax statutes, for a deferred sale, for or until an increase or decrease in the market price of the Securities, or for a period of one year or any other fixed period in the
future. Optionee further understands that the Securities must be held indefinitely unless they are subsequently registered under the Securities Act or an exemption from such registration is available. Optionee further acknowledges and understands
that the Company is under no obligation to register the Securities. Optionee understands that the certificate evidencing the Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such
registration is not required in the opinion of counsel satisfactory to the Company and any other legend required under applicable state securities laws. 
 Optionee is familiar with the provisions of Rule 701 and Rule 144, each promulgated under the Securities Act, which, in substance, permit limited public resale of “restricted securities” acquired, directly
or indirectly from the issuer thereof, in a non-public offering subject to the satisfaction of certain conditions. Rule 701 provides that if the issuer 

 
qualifies under Rule 701 at the time of the grant of the Option to Optionee, the exercise will be exempt from registration under the Securities Act. In the
event the Company becomes subject to the reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, ninety (90) days thereafter (or such longer period as any market stand-off agreement may require) the Securities
exempt under Rule 701 may be resold, subject to the satisfaction of certain of the conditions specified by Rule 144, including: (1) the resale being made through a broker in an unsolicited “broker’s transaction” or in
transactions directly with a market maker (as said term is defined under the Securities Exchange Act of 1934); and, in the case of an affiliate, (2) the availability of certain public information about the Company, (3) the amount of
Securities being sold during any three (3) month period not exceeding the limitations specified in Rule 144(e), and (4) the timely filing of a Form 144, if applicable. 
 In the event that the Company does not qualify under Rule 701 at the time of grant of the Option, then the Securities may be resold in certain limited
circumstances subject to the provisions of Rule 144, which requires the resale to occur not less than one year after the later of the date the Securities were sold by the Company or the date the Securities were sold by an affiliate of the Company,
within the meaning of Rule 144; and, in the case of acquisition of the Securities by an affiliate, or by a non-affiliate who subsequently holds the Securities less than two (2) years, the satisfaction of the conditions set forth in sections
(1), (2), (3) and (4) of the paragraph immediately above. 
 Optionee further understands that in the event all of the applicable
requirements of Rule 701 or 144 are not satisfied, registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required; and that, notwithstanding the fact that Rules 144 and 701 are not
exclusive, the Staff of the Securities and Exchange Commission has expressed its opinion that persons proposing to sell private placement securities other than in a registered offering and otherwise than pursuant to Rules 144 or 701 will have a
substantial burden of proof in establishing that an exemption from registration is available for such offers or sales, and that such persons and their respective brokers who participate in such transactions do so at their own risk. Optionee
understands that no assurances can be given that any such other registration exemption will be available in such event. 
  

	
	Signature of Optionee:
	
	  

	Name

 Date:
                                 ,
             
  

 7

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