[ ] Shares AMBRX, INC. Common Stock UNDERWRITINGAGREEMENT

EX-1.1 2 d690417dex11.htm EX-1.1 EX-1.1

Exhibit 1.1

[ ] Shares

AMBRX, INC.

Common Stock

UNDERWRITING AGREEMENT

[ ], 2014

STIFEL, NICOLAUS & COMPANY, INCORPORATED

WELLS FARGO SECURITIES, LLC

As Representatives of the Several Underwriters

named in Schedule I hereto

c/o Stifel, Nicolaus & Company, Incorporated

787 7th Avenue

11th Floor

New York, New York 10019

Ladies and Gentlemen:

Ambrx, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule I hereto (the “Underwriters”) for whom you are acting as representatives (the “Representatives”) an aggregate of [ ] shares (the “Firm Shares”) of the common stock, par value $0.001 per share, of the Company (“Common Stock”). The Company also proposes to sell to the several Underwriters, at the option of the Underwriters, up to an additional [ ] shares of Common Stock (the “Option Shares”). The Firm Shares and the Option Shares are hereinafter referred to collectively as the “Shares”.

The Company confirms as follows its agreements with the Representatives and the several other Underwriters.

1. The Company represents and warrants to, and agrees with, each of the Underwriters that, as of the date hereof and as of the Closing Date and each Option Closing Date, if any:

(a) A registration statement on Form S-1 (File No. 333-195666) in respect of the Shares and one or more pre-effective amendments thereto (at the time it became effective, the “Initial Registration Statement”) have been filed with the Securities and Exchange Commission (the “Commission”); the Initial Registration Statement and any post-effective

amendment thereto, each in the form heretofore delivered to you, have been declared effective by the Commission in such form; other than a registration statement, if any, increasing the size of the offering (a “Rule 462(b) Registration Statement”), filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the “Securities Act”), which became effective upon filing, no other document with respect to the Initial Registration Statement has heretofore been filed with the Commission; no stop order suspending the effectiveness of the Initial Registration Statement, any post-effective amendment thereto or the Rule 462(b) Registration Statement, if any, has been issued, no proceeding for that purpose has been initiated or, to the Company’s knowledge, threatened by the Commission and any request on the part of the Commission for additional information from the Company has been satisfied in all material respects; any preliminary prospectus included in the Initial Registration Statement, as originally filed or as part of any amendment thereto, or filed with the Commission pursuant to Rule 424(a) of the rules and regulations of the Commission under the Securities Act is hereinafter called a “Preliminary Prospectus”; the various parts of the Initial Registration Statement and the Rule 462(b) Registration Statement, if any, including all schedules and exhibits thereto and including the information contained in the form of final prospectus filed with the Commission pursuant to Rule 424(b) under the Securities Act and deemed by virtue of Rule 430A under the Securities Act to be part of the Initial Registration Statement at the time it was declared effective or such part of the Rule 462(b) Registration Statement, if any, became or hereafter becomes effective, each as amended at the time such part of the Initial Registration Statement became effective, are hereinafter collectively called the “Registration Statement”; the Preliminary Prospectus relating to the Shares that was included in the Registration Statement immediately prior to the Applicable Time (as defined in Section 1(c) hereof) is hereinafter called the “Pricing Prospectus”; such final prospectus, in the form first filed pursuant to Rule 424(b) under the Securities Act, is hereinafter called the “Prospectus”; and any “issuer free writing prospectus” as defined in Rule 433 under the Securities Act relating to the Shares is hereinafter called an “Issuer Free Writing Prospectus”; and all references to the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus, the Prospectus, any Issuer Free Writing Prospectus or any amendment or supplement to any of the foregoing shall be deemed to include the copy filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval system (“EDGAR”). From the time of the initial confidential submission of the Registration Statement to the Commission (or, if earlier, the first date on which the Company engaged directly or through any person authorized to act on its behalf in any Testing-the-Waters Communication) through the date hereof, the Company has been and is an “emerging growth company,” as defined in Section 2(a) of the Securities Act (an “Emerging Growth Company”). “Testing-the-Waters Communication” means any oral or written communication with potential investors undertaken in reliance on Section 5(d) of the Securities Act;

(b) (1) at the respective times the Initial Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendments thereto became effective and at the Closing Date (as defined herein) (and, if any Option Shares are purchased, at each Option Closing Date) (as defined herein)), the Initial Registration Statement, any Rule 462(b) Registration Statement and any amendments and supplements thereto complied and will comply in all material respects with the requirements of the Securities Act and the rules and regulations of the Commission thereunder (the “Rules and Regulations”) and did not and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading, and (2) at the time the Prospectus or

any amendments or supplements thereto were issued and at the Closing Date (and, if any Option Shares are purchased, at each Option Closing Date), neither the Prospectus nor any amendment or supplement thereto included or will include an untrue statement of a material fact or omitted or will omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the representations and warranties in clauses (1) and (2) above shall not apply to statements in or omissions from the Registration Statement or the Prospectus made in reliance upon and in strict conformity with information furnished to the Company in writing by any Underwriter through the Representatives expressly for use in the Registration Statement or the Prospectus, it being understood and agreed that the only such information provided by any Underwriter is that described as such in Section 9(b) hereof. No order preventing or suspending the use of any Preliminary Prospectus, the Pricing Prospectus or any Issuer Free Writing Prospectus has been issued by the Commission. Each Preliminary Prospectus, Pricing Prospectus, Issuer Free Writing Prospectus and the Prospectus filed as part of the Initial Registration Statement as originally filed or as part of any amendment thereto, or filed pursuant to Rule 424 under the Securities Act, complied when so filed in all material respects with the requirements of the Securities Act and the Rules and Regulations and each Preliminary Prospectus, Pricing Prospectus, Issuer Free Writing Prospectus and the Prospectus delivered to the Underwriters for use in connection with this offering was identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T;

(c) For the purposes of this Agreement, the “Applicable Time” is [ : ] [a.m.][p.m.] (New York time) on the date of this Agreement; the Pricing Prospectus as supplemented by the Issuer Free Writing Prospectuses and other documents listed in Schedule II hereto, taken together (collectively, the “Pricing Disclosure Package”) as of the Applicable Time, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; and each Issuer Free Writing Prospectus listed in Schedule II hereto and/or written Testing-the-Waters Communication listed on Schedule III hereto does not conflict with the information contained in the Registration Statement, the Pricing Prospectus or the Prospectus and each such Issuer Free Writing Prospectus and/or written Testing-the-Waters Communication, as supplemented by and taken together with the Pricing Disclosure Package as of the Applicable Time, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to statements or omissions made in an Issuer Free Writing Prospectus or written Testing-the-Waters Communication in reliance upon and in strict conformity with information furnished in writing to the Company by an Underwriter through the Representatives expressly for use therein;

(d) The Company has filed a registration statement pursuant to the Securities Exchange Act of 1934, as amended (the “Exchange Act”), to register the Common Stock, and such registration statement has been declared effective. At the time of filing the Initial Registration Statement the Company was not and is not an “ineligible issuer,” as defined under Rule 405 under the Securities Act;

(e) The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware, with power and authority (corporate and other) to own, lease and operate its properties and conduct its business as described in the Pricing Prospectus and to enter into and perform its obligations under this Agreement, and has been duly qualified as a foreign corporation for the transaction of business and is in good standing under the laws of each other jurisdiction in which it owns or leases properties or conducts any business so as to require such qualification, except where the failure so to qualify or be in good standing would not have a material adverse effect on the business, prospects, management, financial position, stockholders’ equity or results of operations of the Company (a “Material Adverse Effect”);

(f) The Company does not have any subsidiaries and does not own or control, directly or indirectly, any corporation, association or other entity;

(g) The Company has an authorized capitalization as set forth in the Pricing Prospectus under the caption “Capitalization”, and all of the issued and outstanding shares of capital stock of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and conform to the descriptions thereof contained in the Pricing Prospectus; and none of the issued and outstanding shares of capital stock of the Company are subject to any preemptive or similar rights;

(h) The Shares have been duly and validly authorized and, when issued and delivered to and paid for by the Underwriters in accordance with the terms of this Agreement, will be duly and validly issued and fully paid and non-assessable and will conform to the descriptions thereof contained in the Prospectus; and the issuance of such Shares is not subject to any preemptive or similar rights that have not been duly waived;

(i) This Agreement has been duly authorized, executed and delivered by the Company;

(j) The issue and sale of the Shares, the execution of this Agreement by the Company and the consummation of the transactions herein contemplated will not (1) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company is a party or by which the Company is bound or to which any of the property or assets of the Company is subject, (2) result in any violation of the provisions of the certificate of incorporation or by-laws of the Company or (3) result in any violation of any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over the Company or any of its properties, except, in the case of clauses (1) and (3) for any such conflict, violation, breach or default that would not have a Material Adverse Effect; and no consent, approval, authorization, order, registration or qualification of or with any such court or governmental agency or body is required for the issue and sale of the Shares or the consummation by the Company of the transactions contemplated by this Agreement, except the registration under the Securities Act of the Shares and such consents, approvals, authorizations, registrations or qualifications as may be required by FINRA or under state securities or Blue Sky laws in connection with the purchase and distribution of the Shares by the Underwriters;

(k) Ernst & Young LLP, who have certified certain financial statements of the Company, are independent public accountants as required by the Securities Act, the Rules and Regulations and the Public Company Accounting Oversight Board (United States). The financial statements, together with related schedules and notes, included in the Registration Statement and the Pricing Prospectus comply in all material respects with the requirements of the Securities Act and present fairly in all material respects the financial position, results of operations, cash flows and changes in convertible preferred stock and stockholders’ equity of the Company on the basis stated in the Registration Statement at the respective dates or for the respective periods to which they apply; such financial statements and related schedules and notes have been prepared in accordance with generally accepted accounting principles consistently applied throughout the periods involved, except as disclosed therein; and the selected financial data and the summary financial data included in the Pricing Prospectus present fairly the information shown therein and have been compiled on a basis consistent with that of the financial statements included in the Registration Statement. Except as otherwise included therein, no historical or pro forma financial statements or supporting schedules are required to be included or incorporated by reference in the Registration Statement, the Pricing Prospectus or the Prospectus under the Securities Act or the Rules and Regulations;

(l) The Company has not sustained since the date of the latest audited financial statements included in the Pricing Disclosure Package any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Disclosure Package; and, since the respective dates as of which information is given in the Registration Statement and the Pricing Disclosure Package, (1) there has not been any change in the capital stock (other than the issuance of shares of Common Stock upon the exercise of stock options described as outstanding in, or the grant of options, restricted stock or other equity based awards under the Company’s existing equity incentive plans described in, the Pricing Disclosure Package) or long-term debt of the Company, (2) there has not been any material adverse change, or any development that would reasonably be expected to result in a prospective material adverse change, in or affecting the general affairs, business, prospects, management, financial position, stockholders’ equity or results of operations of the Company, (3) there have been no transactions entered into by, and no obligations or liabilities, contingent or otherwise, incurred by the Company, whether or not in the ordinary course of business, which are material to the Company or (4) there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock, in each case, otherwise than as set forth or contemplated in the Pricing Disclosure Package;

(m) The Company is not (1) in violation of its certificate of incorporation or bylaws or (2) in violation of any law, ordinance, administrative or governmental rule or regulation applicable to the Company, or (3) in violation of any decree of any court or governmental agency or body having jurisdiction over the Company, or (4) in default in the performance of any obligation, agreement or condition contained in any bond, debenture, note or any other evidence of indebtedness or in any agreement, indenture, lease or other instrument to which the Company is a party or by which it or any of its properties may be bound, except, in the case of clauses (2), (3) and (4), where any such violation or default, individually or in the aggregate, would not have a Material Adverse Effect;

(n) The Company has good and marketable title to all real and personal property owned by it, in each case free and clear of all liens, encumbrances and defects except such as are described in the Pricing Disclosure Package or such as do not materially affect the value of such property and do not interfere with the use made and proposed to be made of such property by the Company; and any real property and buildings held under lease by the Company are held under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere with the use made and proposed to be made of such property and buildings by the Company;

(o) Other than as set forth in the Pricing Disclosure Package, there are no legal or governmental proceedings pending to which the Company is a party or of which any property of the Company is the subject which, if determined adversely to the Company, individually or in the aggregate, would have or may reasonably be expected to have a Material Adverse Effect, or would prevent or impair the consummation of the transactions contemplated by this Agreement, or which are required to be described in the Registration Statement or the Pricing Disclosure Package; and, to the best of the Company’s knowledge, no such proceedings are threatened or contemplated by governmental authorities or others;

(p) The Company possesses all permits, licenses, approvals, consents and other authorizations (collectively, “Permits”) issued by the appropriate federal, state, local or foreign regulatory agencies or bodies necessary to conduct the businesses now operated by it, except where the failure to possess such permit, license, approval, consent or authorization would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect; the Company is in compliance with the terms and conditions of all such Permits and all of the Permits are valid and in full force and effect, except, in each case, where the failure so to comply or where the invalidity of such Permits or the failure of such Permits to be in full force and effect, individually or in the aggregate, would not have a Material Adverse Effect; and the Company has not received any written notice of proceedings relating to the revocation or material adverse modification of any such Permits;

(q) The Company owns or has obtained valid licenses for the patents, patent applications, patent rights, inventions, know-how (including trade secrets and other unpatented and/or unpatentable proprietary or confidential information, systems or procedures), trademarks, service marks and trade names, and other intellectual property (collectively “Intellectual Property”) described in the Pricing Disclosure Package and Registration Statement as being owned or licensed by it or which are necessary for the conduct of its business as currently conducted or as currently proposed to be conducted as described in the Pricing Disclosure Package and Registration Statement. To the knowledge of the Company: (i) there are no third parties who have rights to any Intellectual Property except as described in the Pricing Disclosure Package and the Registration Statement; and (ii) there is no infringement by third parties of any Intellectual Property. There is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others: (A) challenging the Company’s rights in or to any Intellectual Property, and the Company is unaware of any facts which would form a reasonable basis for any such action, suit, proceeding or claim; (B) challenging the validity, enforceability or scope of any Intellectual Property, and the Company is unaware of any facts which would form a reasonable basis for any such action, suit, proceeding or claim; or (C) asserting that the Company infringes or otherwise violates, or would, upon the commercialization of any product

or service described in the Registration Statement and the Pricing Disclosure Package as under development, infringe or violate, any copyright, patent, trademark, trade name, service mark, copyright, trade secret or other proprietary rights of others, and the Company is unaware of any facts which would form a reasonable basis for any such action, suit, proceeding or claim. The Company has taken all steps reasonably necessary to secure its interest in the Company’s Intellectual Property, including obtaining all necessary assignments from its employees, consultants and contractors pursuant to a written agreement requiring assignment to the Company of all Intellectual Property created by such employee, consultant or contractor pursuant to such employee, consultant or contractor’s relationship with the Company. The Company has taken commercially reasonable steps to protect and maintain all Company owned Intellectual Property, including without limitation to preserve the confidentiality of any trade secrets. To the Company’s knowledge, all material Intellectual Property owned by or licensed to the Company is valid and enforceable. To the Company’s knowledge, the Company is not in violation of any Company License Agreements (as defined below), other than such violations which, individually or in the aggregate, would not reasonably be expected to have a Material Adverse Effect. The license agreements by which the Company has been licensed Intellectual Property owned by third parties (“Company License Agreements”) are valid and are in full force and effect and constitute legal, valid and binding obligations of the Company, and to the Company’s knowledge, the other parties thereto;

(r) No material labor dispute with the employees of the Company exists, or, to the knowledge of the Company, is imminent. The Company is not aware of any existing or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers, customers or contractors, which, individually or in the aggregate, may reasonably be expected to result in a Material Adverse Effect;

(s) The Company is insured by insurers of recognized financial responsibility against such losses and risks (including without limitation risks related to clinical trials and product liability) and in such amounts as are prudent and customary in the businesses in which it is engaged; the Company has not been refused any insurance coverage sought or applied for; and the Company has no reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that would not have a Material Adverse Effect;

(t) The Company maintains a system of internal accounting controls sufficient to provide reasonable assurance that (1) transactions are executed in accordance with management’s general or specific authorizations; (2) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain accountability for assets; (3) access to assets is permitted only in accordance with management’s general or specific authorization; and (4) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences;

(u) Since the date of the latest audited financial statements included in the Pricing Disclosure Package, (i) the Company has not been advised of (1) any significant deficiencies in the design or operation of internal controls that could adversely affect the ability

of the Company to record, process, summarize and report financial data, or any material weaknesses in internal controls and (2) any fraud, whether or not material, that involves management or other employees who have a significant role in the internal controls of the Company, and (ii) since that date, there has been no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting;

(v) The Company maintains disclosure controls and procedures (as such term is defined in Rule 13a-15(e) of the Exchange Act) that comply with the requirements of the Exchange Act; and such disclosure controls and procedures are effective;

(w) All United States federal, state and foreign income and franchise tax returns and other material tax returns of the Company required by law to be filed have been filed and such tax returns are true, complete and correct in all material respects. All taxes required to be paid by the Company, and any related or similar assessments, fines or penalties levied, which are due and payable, have been paid, except assessments against which appeals have been or will be promptly taken and as to which adequate reserves in conformity with generally accepted accounting principles have been provided, and except for cases in which the failure to pay, individually or in the aggregate, would not reasonably be expected to have a Material Adverse Effect. The charges, accruals and reserves on the books of the Company in respect of any income and corporation tax liability for any years not finally determined are, in conformity with generally accepted accounting principles, adequate in all material respects to meet any assessments or re-assessments for additional income tax for any years not finally determined;

(x) There are no statutes, regulations, documents or contracts of a character required to be described in the Registration Statement or the Pricing Prospectus or to be filed as an exhibit to the Registration Statement which are not described or filed as required;

(y) The Company is not in violation of any statute or any rule, regulation, decision or order of any governmental agency or body or any court, domestic or foreign, relating to the use, production, disposal or release of hazardous or toxic substances or relating to the protection or restoration of the environment or human exposure to hazardous or toxic substances (collectively, “environmental laws”), does not own or operate any real property contaminated with any substance that is subject to any environmental laws, is not liable for any off-site disposal or contamination pursuant to any environmental laws, and is not subject to any claim relating to any environmental laws, which violation, contamination, liability or claim, individually or in the aggregate, would have a Material Adverse Effect; and the Company is not aware of any pending investigation which might reasonably be expected to lead to such a claim;

(z) Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), that is maintained, administered or contributed to by the Company for employees or former employees of the Company and its affiliates has been maintained in compliance with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Internal Revenue Code of 1986, as amended (the “Code”), except to the extent that failure to so comply, individually or in the aggregate, would not have a Material Adverse Effect. No prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975

of the Code has occurred with respect to any such plan excluding transactions effected pursuant to a statutory or administrative exemption;

(aa) Neither the Company nor, to the Company’s knowledge, any director, officer, agent, employee or other person acting on behalf of the Company, has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds, (iii) violated or is in violation of any provision of the Foreign Corrupt Practices Act of 1977 or (iv) made any bribe, unlawful rebate, payoff, influence payment, kickback or other unlawful payment. Neither the Company nor, to the Company’s knowledge, any director, officer, agent, employee or affiliate of the Company is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”); and the Company will not directly or indirectly use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC;

(bb) There are no persons with registration rights or other similar rights to have securities registered pursuant to the Registration Statement or otherwise registered by the Company under the Securities Act, which rights have not been duly waived in writing;

(cc) The Company is not and, after giving effect to the offering and sale of the Shares as contemplated herein and the application of the net proceeds therefrom as described in the Pricing Disclosure Package, will not be an “investment company”, as such term is defined in the Investment Company Act of 1940, as amended (the “Investment Company Act”);

(dd) The Company has not distributed and, prior to the later to occur of the Closing Date (as defined in Section 4 hereof) and completion of distribution of the Shares, will not distribute any offering materials in connection with the offering and sale of the Shares, other than the Pricing Prospectus, the Prospectus and, subject to compliance with Section 6 hereof, any Issuer Free Writing Prospectus; and the Company has not taken and will not take, directly or indirectly, any action designed to cause or result in, or which constitutes or might reasonably be expected to constitute, the stabilization or manipulation of the price of any security of the Company to facilitate the sale of the Shares. The Company (a) has not alone engaged in any Testing-the-Waters Communication other than Testing-the-Waters Communications with the consent of the Representatives with entities that are qualified institutional buyers within the meaning of Rule 144A under the Securities Act or institutions that are accredited investors within the meaning of Rule 501 under the Securities Act and (b) has not authorized anyone other than the Representatives to engage in Testing-the-Waters Communications. The Company reconfirms that the Representatives have been authorized to act on its behalf in undertaking Testing-the-Waters Communications. The Company has not distributed any written Testing-the-Waters Communications other than those listed on Schedule III hereto;

(ee) The statistical and market and industry-related data included in the Pricing Prospectus and the Prospectus are based on or derived from sources which the Company believes to be reliable and accurate or represent the Company’s good faith estimates that are made on the

basis of data derived from such sources, and the Company has obtained the written consent to the use of such data from sources to the extent required;

(ff) The audiovisual presentation made available to the public by the Company at http://www.netroadshow.com is a “bona fide electronic roadshow” for purposes of Rule 433(d)(8)(ii) of the Securities Act, and such presentation, together with the Pricing Prospectus, does not contain any untrue statement of material fact or omit to state a material fact necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, except that the representations and warranties set forth in this paragraph do not apply to statements in or omissions from such presentation or Pricing Prospectus made in reliance upon and in strict conformity with information furnished to the Company in writing by any Underwriter through the Representatives expressly for use therein;

(gg) Any certificate signed by any officer of the Company delivered to the Underwriters or to counsel for the Underwriters shall be deemed a representation and warranty by the Company to the Underwriters as to the matters covered thereby;

(hh) Solely to the extent that the Sarbanes-Oxley Act of 2002, as amended, and the rules and regulations promulgated by the Commission and the NASDAQ Global Market thereunder (the “Sarbanes-Oxley Act”) have been applicable to the Company, there is and has been no failure on the part of the Company or, to the Company’s knowledge, any of its directors or officers, in their capacities as such, to comply in all material respects with any provisions of the Sarbanes-Oxley Act. The Company has taken all necessary actions to ensure that it is in compliance with all provisions of the Sarbanes-Oxley Act that are in effect and with which the Company is required to comply, and it is actively taking steps to ensure that it will be in compliance with other provisions of the Sarbanes-Oxley Act not currently in effect or which the Company is not required to comply with, that are reasonably expected to be applicable to the Company after the effectiveness of the Registration Statement;

(ii) To the Company’s knowledge, there are no affiliations or associations between any member of FINRA and any of the Company’s officers, directors or 5% or greater securityholders, except as set forth in the Registration Statement;

(jj) The Shares have been approved for listing subject to notice of issuance on the NASDAQ Global Market;

(kk) There are no relationships or related-party transactions involving the Company or any other person required to be described in the Prospectus which have not been described as required;

(ll) Except as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, and except as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect: (i) the Company has not received any warning letter, untitled letter or other written correspondence or notice from the U.S. Food and Drug Administration, or any other court or arbitrator or federal, state, local or foreign governmental or regulatory authority, alleging or asserting noncompliance with the Federal Food, Drug and Cosmetic Act (21 U.S.C. § 301 et seq.) (the “FFDCA”), or similar law; (ii) the

Company is and since January 1, 2011 has been in compliance with applicable health care laws, including without limitation, the FFDCA, and the federal Anti-Kickback Statute (42 U.S.C. § 1320a-7b(b)), and the regulations promulgated pursuant to such laws, and comparable state laws, and all other local, state, federal, national, supranational and foreign health care laws relating to the regulation of the Company (collectively, “Health Care Laws”); (iii) the Company possesses all licenses, certificates, approvals, clearances, authorizations, permits and supplements or amendments thereto required by any such Health Care Laws and/or to carry on its businesses as currently conducted (“Authorizations”) and such Authorizations are valid and in full force and effect and the Company is not in violation of any term of any such Authorizations; (iv) the Company has not received written notice of any ongoing claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from any U.S. or non-U.S. federal, state, local or other governmental or regulatory authority, governmental or regulatory agency or body, court, arbitrator or self-regulatory organization (each, a “Governmental Authority”) alleging that any product operation or activity is in violation of any Health Care Laws or Authorizations and, to the Company’s knowledge, no Governmental Authority is considering any such claim, litigation, arbitration, action, suit, investigation or proceeding; (v) the Company has not received written notice that any Governmental Authority has taken, is taking or intends to take action to limit, suspend, make a material adverse modification or revoke any Authorizations and to the Company’s knowledge no Governmental Authority is considering such action; and (vi) the Company has filed, obtained, maintained or submitted all reports, documents, forms, notices, applications, records, submissions and supplements or amendments as required by any Health Care Laws or Authorizations and all such reports, documents, forms, notices, applications, records, submissions and supplements or amendments were complete, correct and not misleading on the date filed (or were corrected or supplemented by a subsequent submission);

(mm) To the knowledge of the Company, the research, studies and tests described in the Registration Statement, the Pricing Disclosure Package and the Prospectus and conducted by or on behalf of the Company have been and, if still pending, are being conducted in all material respects in accordance with all Health Care Laws and Authorizations; the descriptions of the results of such research, studies and tests contained in the Registration Statement, the Pricing Disclosure Package and the Prospectus are accurate and complete in all material respects and fairly present the data derived from such research, studies, and tests; except to the extent disclosed in the Registration Statement, the Pricing Disclosure Package and the Prospectus, the Company is not aware of any research, studies or tests, the results of which the Company believes reasonably call into question the research, study or test results described or referred to in the Registration Statement, the Pricing Disclosure Package and the Prospectus when viewed in the context in which such results are described; and the Company has not received any written notices or correspondence from any Governmental Authority requiring the termination, suspension or material adverse modification of any research, study or test conducted by or on behalf of the Company. ;

(nn) Except as disclosed in the Registration Statement, the Pricing Disclosure Package and the Prospectus, the Company (i) does not have any material lending or other relationship with any Underwriter or lending affiliate of any Underwriter and (ii) does not intend to use any of the proceeds from the sale of the Shares to repay any outstanding debt owed to any affiliate of any Underwriter; and

(oo) Except as disclosed in the Registration Statement, the Pricing Disclosure Package and the Prospectus, the Company has not sold, issued or distributed any shares of Common Stock during the six-month period preceding the date hereof, including any sales pursuant to Rule 144A, Regulation D or Regulation S under the Securities Act, other than shares issued pursuant to employee benefit plans, qualified stock option plans or other employee compensation plans or pursuant to outstanding options, rights or warrants.

2. Subject to the terms and conditions herein set forth, (a) the Company agrees to sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at a purchase price per share of $[ ] (the “Purchase Price”), the number of Firm Shares (to be adjusted by you so as to eliminate fractional shares) determined by multiplying the aggregate number of Firm Shares to be sold by the Company hereunder by a fraction, the numerator of which is the aggregate number of Firm Shares to be purchased by such Underwriter as set forth opposite the name of such Underwriter in Schedule I hereto and the denominator of which is the aggregate number of Firm Shares to be purchased by all of the Underwriters from the Company hereunder and (b) in the event and to the extent that the Underwriters shall exercise the election to purchase Option Shares as provided below, the Company agrees to sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at the Purchase Price, the number of Option Shares (to be adjusted by you so as to eliminate fractional shares) determined by multiplying the number of Option Shares as to which such election shall have been exercised by the fraction set forth in clause (a) above.

The Company hereby grants to the Underwriters the right to purchase at their election up to [ ] Option Shares, at the Purchase Price, for the sole purpose of covering over-allotments in connection with the sale of the Firm Shares. The Underwriters may exercise their option to acquire Option Shares in whole or in part from time to time only by written notice from the Representatives to the Company, given within a period of 30 calendar days after the date of this Agreement and setting forth the aggregate number of Option Shares to be purchased and the date on which such Option Shares are to be delivered, as determined by the Representatives but in no event earlier than the Closing Date or, unless the Representatives and the Company otherwise agree in writing, earlier than two or later than ten business days after the date of such notice.

3. It is understood that the several Underwriters propose to offer the Firm Shares for sale to the public upon the terms and conditions set forth in the Prospectus.

4. The Company will deliver the Firm Shares to the Representatives through the facilities of the Depository Trust Company (“DTC”) for the accounts of the Underwriters, against payment of the purchase price therefor in Federal (same day) funds by wire transfer to the account specified by the Company at the office of Latham & Watkins LLP, 12670 High Bluff Drive, San Diego, California 92130, at 10:00 a.m., New York time, on [ ], 2014, or at such other time not later than seven full business days thereafter as the Representatives and the Company determine, such time being herein referred to as the “Closing Date”. For purposes of Rule 15c6-1 under the Exchange Act, the Closing Date (if later than the otherwise applicable settlement date) shall be the settlement date for payment of funds and delivery of securities for all the Firm Shares.

Each time for the delivery of and payment for the Option Shares, being herein referred to as an “Option Closing Date”, which may be the Closing Date, shall be determined by the Representatives as provided above. The Company will deliver the Option Shares being purchased on each Option Closing Date to the Representatives through the facilities of the DTC for the accounts of the Underwriters, against payment of the purchase price therefor in Federal (same day) funds by wire transfer to the account specified by the Company at the above office of Latham & Watkins LLP, at 10:00 a.m., New York time on the applicable Option Closing Date.

Certificates for the Firm Shares and the Option Shares, if any, shall be in such denominations and registered in such names as the Representatives may request in writing at least one full business day before the Closing Date or the relevant Option Closing Date, as the case may be. The certificates for the Firm Shares and the Option Shares, if any, will be made available for examination and packaging by the Representatives in the City of New York not later than 10:00 a.m., New York time on the business day prior to the Closing Date or the relevant Option Closing Date, as the case may be.

5. The Company covenants and agrees with each of the Underwriters as follows:

(a) The Company, subject to Section 5(b), will comply with the requirements of Rule 430A under the Securities Act, and will notify the Representatives promptly (and in any event within 24 hours), and confirm the notice in writing (which may occur by email), (i) when any post-effective amendment to the Registration Statement shall become effective, or any supplement to the Prospectus or any amended prospectus shall have been filed, and furnish the Representatives with copies thereof, and file promptly all material required to be filed by the Company with the Commission pursuant to Rule 433(d) under the Securities Act, (ii) of the receipt of any comments from the Commission relating to the Registration Statement, (iii) of any request by the Commission for any amendment to the Registration Statement or any amendment or supplement to the Prospectus or for additional information, (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any order preventing or suspending the use of any Preliminary Prospectus, or of the suspension of the qualification of the Shares for offering or sale in any jurisdiction, or of the initiation or threatening of any proceedings for any of such purposes; and (v) if the Company ceases to be an Emerging Growth Company at any time prior to the later of (A) completion of the distribution of the Shares within the meaning of the Securities Act and (B) completion of the 180-day restricted period referred to in Section 5(j) hereof. The Company will promptly effect the filings necessary pursuant to Rule 424(b) under the Securities Act and will take such steps as it deems necessary to ascertain promptly whether the form of prospectus transmitted for filing under Rule 424(b) was received for filing by the Commission and, in the event that it was not, it will promptly file such prospectus. The Company will make every reasonable effort to prevent the issuance of any stop order and, if any stop order is issued, to obtain the lifting thereof at the earliest possible moment.

(b) The Company will give the Representatives notice of its intention to file or prepare any amendment to the Registration Statement (including any filing under Rule 462(b) under the Securities Act), or any amendment, supplement or revision to the Prospectus, or any Issuer Free Writing Prospectus, will furnish the Representatives with copies of any such documents a reasonable amount of time prior to such proposed filing or use, as the case may be,

and will not file or use any such document to which the Representatives or counsel for the Underwriters shall reasonably object.

(c) The Company will use its best efforts to qualify the Shares for offering and sale under the securities laws of such jurisdictions as you may reasonably request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long as may be necessary to complete the distribution of the Shares, provided that nothing in this Section 5(c) shall require the Company to (i) qualify as a foreign corporation in any jurisdiction in which it is not already so qualified, (ii) file a general consent to service of process in any jurisdiction or (iii) subject itself to taxation in any jurisdiction if it is not otherwise so subject.

(d) The Company has furnished or will deliver to the Representatives, without charge, three signed copies of the Registration Statement as originally filed, any Rule 462(b) Registration Statement and of each amendment to each (including exhibits filed therewith) and signed copies of all consents and certificates of experts, and will also, upon your request, deliver to the Representatives, without charge, a conformed copy of the Registration Statement as originally filed and of each amendment thereto (without exhibits) for each of the Underwriters. The copies of the Registration Statement and each amendment thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

(e) The Company has delivered to each Underwriter, without charge, as many written and electronic copies of the Pricing Prospectus as such Underwriter reasonably requested, and the Company hereby consents to the use of such copies for purposes permitted by the Securities Act. The Company will furnish to each Underwriter, without charge, prior to 5:00 p.m., New York time, on the second business day next succeeding the date of this Agreement and from time to time thereafter during the period when the Prospectus is required to be delivered in connection with sales of the Shares under the Securities Act or the Exchange Act or in lieu thereof, the notice referred to in Rule 173(a) under the Securities Act, such number of written and electronic copies of the Prospectus (as amended or supplemented) as such Underwriter may reasonably request. The Prospectus and any amendments or supplements thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

(f) The Company will comply with the Securities Act and the Rules and Regulations so as to permit the completion of the distribution of the Shares as contemplated in this Agreement and in the Prospectus. If at any time when, in the opinion of counsel for the Underwriters, a prospectus is required to be delivered in connection with sales of the Shares under the Securities Act or the Exchange Act (or in lieu thereof, the notice referred to in Rule 173(a) under the Securities Act), any event shall occur or condition shall exist as a result of which it is necessary, in the opinion of counsel for the Underwriters or for the Company, to amend the Registration Statement or amend or supplement the Prospectus in order that the Prospectus will not include any untrue statements of a material fact or omit to state a material fact necessary in order to make the statements therein not misleading in the light of the circumstances existing at the time it (or in lieu thereof, the notice referred to in Rule 173(a)

under the Securities Act) is delivered to a purchaser, or if it shall be necessary, in the opinion of either such counsel, at any such time to amend the Registration Statement or amend or supplement the Prospectus in order to comply with the requirements of the Securities Act or the Rules and Regulations, the Company will promptly prepare and file with the Commission, subject to Section 5(b), such amendment or supplement as may be necessary to correct such statement or omission or to make the Registration Statement or the Prospectus comply with such requirements, and the Company will furnish to the Underwriters such number of written and electronic copies of such amendment or supplement as the Underwriters may reasonably request. The Company will provide the Representatives with notice of the occurrence of any event during the period specified above that may give rise to the need to amend or supplement the Registration Statement or the Prospectus as provided in the preceding sentence promptly after the occurrence of such event. If at any time following the distribution of any written Testing-the-Waters Communication there occurred or occurs an event or development as a result of which such written Testing-the-Waters Communications included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances existing at that subsequent time, not misleading, the Company will promptly notify (and in any event within 24 hours) the Representatives and will promptly amend or supplement, at its own expense, such written Testing-the-Waters Communication to eliminate or correct such untrue statement or omission.

(g) The Company will make generally available (within the meaning of Section 11(a) of the Securities Act) to its security holders and to the Representatives as soon as practicable, but not later than 45 days after the end of its fiscal quarter in which the first anniversary date of the effective date of the Registration Statement occurs, an earnings statement (in form complying with the provisions of Rule 158 under the Securities Act) covering a period of at least twelve consecutive months beginning after the effective date of the Registration Statement.

(h) The Company will use the net proceeds received by it from the sale of the Shares in the manner specified in the Pricing Prospectus under the heading “Use of Proceeds”.

(i) The Company will use its best efforts to effect and maintain the listing of the Common Stock (including the Shares) on the NASDAQ Global Market.

(j) During a period of 180 days from the date of the Prospectus, the Company will not, without the prior written consent of each of the Representatives, (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend or otherwise transfer or dispose of, directly or indirectly, any Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or (ii) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of Common Stock, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise, other than (1) the Shares to be sold hereunder, (2) the issuance of equity based awards granted pursuant to the Company’s benefit plans existing on the date hereof that are described in the Prospectus, as such plans may be amended (the “Company Incentive Plans”), (3) the issuance of shares of Common Stock upon the exercise of any such equity based awards, (4) any shares of stock of the Company issued upon the conversion of

securities outstanding on the date of this Agreement and described in the Pricing Disclosure Package, (5) the filing of a registration statement on Form S-8 relating to the shares of Common Stock granted pursuant to the Company Incentive Plans, (6) shares of Common Stock, or any securities convertible into, or exercisable, or exchangeable for, shares of Common Stock, to be issued as payment of any accrued dividends described in the Pricing Disclosure Package and (7) shares of Common Stock, or any securities convertible into, or exercisable, or exchangeable for, shares of Common Stock issued in connection with future collaborations, strategic partnerships or joint ventures, as long as (x) the aggregate number of shares of Common Stock issued or issuable does not exceed 5% of the number of shares of Common Stock outstanding immediately after the issuance and sale of the Shares and (y) each recipient agrees to be bound by the terms of the “lock-up” agreements described in Section 8(m) hereof for the remainder of the 180-day restricted period set forth therein.

(k) If the Representatives, in their sole discretion, agree to release or waive the restrictions set forth in a “lock-up” agreement described in Section 8(m) hereof for an officer or director of the Company and provides the Company with notice of the impending release or waiver at least three business days before the effective date of the release or waiver, the Company agrees to announce the impending release or waiver by a press release substantially in the form of Exhibit D hereto through a major news service at least two business days before the effective date of the release or waiver. For avoidance of doubt, no release or waiver of the restrictions set forth in a “lock-up” agreement described in Section 8(m) shall be made other than pursuant to the express written consent of the Representatives.

(l) The Company, during the period when the Prospectus is required to be delivered in connection with sales of the Shares under the Securities Act or the Exchange Act (or in lieu thereof, the notice referred to in Rule 173(a) under the Securities Act), will file all documents and reports required to be filed with the Commission and the NASDAQ Global Market pursuant to the Exchange Act within the time periods required by the Exchange Act or the NASDAQ Global Market and the rules and regulations of the Commission thereunder.

(m) The Company shall report the use of proceeds from the issuance of the Shares as may be required pursuant to Rule 463 under the Securities Act.

(n) During a period of three years from the effective date of the Registration Statement, the Company will furnish to you copies of all reports or other communications (financial or other) furnished to stockholders generally, and deliver to you as soon as they are available, copies of any reports and financial statements furnished to or filed with the Commission or any national securities exchange on which any class of securities of the Company is listed; provided that the Company will be deemed to have furnished such reports and financial statements to the extent they are filed on EDGAR.

(o) If the Company elects to rely upon Rule 462(b) under the Securities Act, the Company will file a Rule 462(b) Registration Statement with the Commission in compliance with Rule 462(b) by 10:00 p.m., Washington, D.C. time, on the date of this Agreement, and at the time of filing either pay to the Commission the filing fee for the Rule 462(b) Registration Statement or to give irrevocable instructions for the payment of such fee pursuant to Rule 111(b) under the Securities Act.

(p) The Company will promptly notify the Representatives if the Company ceases to be an “emerging growth company” at any time prior to the later of (i) completion of the distribution of the Shares within the meaning of the Securities Act and (ii) completion of the 180-day restricted period referred to in Section 5(j).

(q) If so requested by the Representatives, the Company shall cause to be prepared and delivered, at its expense, within one business day from the effective date of this Agreement, to the Representatives an “electronic Prospectus” to be used by the Underwriters in connection with the offering and sale of the Shares. As used herein, the term “electronic Prospectus” means a form of the most recent Preliminary Prospectus, any Issuer Free Writing Prospectus or the Prospectus, and any amendment or supplement thereto, that meets each of the following conditions: (i) it shall be encoded in an electronic format, satisfactory to the Representatives, that may be transmitted electronically by the Representatives and the other Underwriters to offerees and purchasers of the Shares, (ii) it shall disclose the same information as such paper Preliminary Prospectus, Issuer Free Writing Prospectus or the Prospectus, as the case may be; and (iii) it shall be in or convertible into a paper format or an electronic format, satisfactory to the Representatives, that will allow investors to store and have continuously ready access to such Preliminary Prospectus, Issuer Free Writing Prospectus or the Prospectus at any future time, without charge to investors (other than any fee charged for subscription to the Internet generally). The Company hereby confirms that, if so requested by the Representatives, it has included or will include in the Prospectus filed with the Commission an undertaking that, upon receipt of a request by an investor or his or her representative, the Company shall transmit or cause to be transmitted promptly, without charge, a paper copy of such paper Preliminary Prospectus, Issuer Free Writing Prospectus or the Prospectus to such investor or representative.

(r) The Company shall engage and maintain, at its expense, a registrar and transfer agent for the Shares.

6. (a) The Company represents and agrees that, without the prior consent of the Representatives, it has not made and will not make any offer relating to the Shares that would constitute a “free writing prospectus” as defined in Rule 405 under the Securities Act; each Underwriter represents and agrees that, without the prior consent of the Company and the Representatives, it has not made and will not make any offer relating to the Shares that would constitute a free writing prospectus; any such free writing prospectus the use of which has been consented to by the Company and the Representatives is listed on Schedule II hereto.

(b) The Company has complied and will comply with the requirements of Rule 433 under the Securities Act applicable to any Issuer Free Writing Prospectus, including timely filing with the Commission or retention where required and legending; the Company represents that it has satisfied and agrees that it will satisfy the conditions under Rule 433 under the Securities Act to avoid a requirement to file with the Commission any electronic road show.

(c) The Company agrees that if at any time following issuance of an Issuer Free Writing Prospectus any event occurred or occurs as a result of which such Issuer Free Writing Prospectus would conflict with the information in the Registration Statement, the Pricing Prospectus or the Prospectus or, when considered together with the information in the Pricing Prospectus and other Issuer Free Writing Prospectuses, would include an untrue statement of a

material fact or omit to state any material fact necessary in order to make the statements therein, in light of the circumstances then prevailing, not misleading, the Company will give prompt notice thereof to the Representatives and, if requested by the Representatives, will prepare and furnish without charge to each Underwriter an Issuer Free Writing Prospectus or other document which will correct such conflict, statement or omission; provided, however, that this covenant shall not apply to any statements or omissions in an Issuer Free Writing Prospectus made in reliance upon and in strict conformity with information furnished in writing to the Company by an Underwriter through the Representatives expressly for use therein.

7. The Company covenants and agrees with the several Underwriters that, whether or not the transactions contemplated by this Agreement are consummated, the Company will pay or cause to be paid all expenses incident to the performance of its obligations under this Agreement, including (i) the fees, disbursements and expenses of the Company’s counsel, accountants and other advisors; (ii) filing fees and all other expenses in connection with the preparation, printing and filing of the Registration Statement, each Preliminary Prospectus, any Issuer Free Writing Prospectus and the Prospectus and amendments and supplements thereto and the mailing and delivering of copies thereof to the Underwriters and dealers; (iii) the cost of printing or producing this Agreement, closing documents (including any compilations thereof) and such other documents as may be required in connection with the offering, purchase, sale and delivery of the Shares; (iv) all expenses in connection with the qualification of the Shares for offering and sale under state securities laws as provided in Section 5(c), including filing fees and the reasonable fees and disbursements of counsel for the Underwriters (not to exceed $5,000) in connection with such qualification and in connection with the Blue Sky survey; (v) all fees and expenses in connection with listing the Common Stock (including the Shares) on the NASDAQ Global Market; (vi) the filing fees incident to, and the reasonable fees and disbursements of counsel for the Underwriters (not to exceed $20,000) in connection with, securing any required review by FINRA of the terms of the sale of the Shares; (vii) all fees and expenses in connection with the preparation, issuance and delivery of the certificates representing the Shares to the Underwriters, including any stock or other transfer taxes and any stamp or other duties payable upon the sale, issuance or delivery of the Shares to the Underwriters; (viii) the cost and charges of any transfer agent or registrar; (ix) the transportation and other expenses incurred by the Company in connection with presentations to prospective purchasers of Shares (provided, however, that the Underwriters and the Company shall each pay 50% of the cost of any aircraft chartered in connection with the road show by the Company and the Underwriters); and (x) all other costs and expenses incident to the performance of its obligations hereunder which are not otherwise specifically provided for in this Section 7. It is understood that, subject to this Section 7 and Section 12, the Underwriters will pay all of their costs and expenses associated with the transactions contemplated hereunder, including all fees and disbursements of their counsel.

8. The several obligations of the Underwriters hereunder to purchase the Shares on the Closing Date or each Option Closing Date, as the case may be, are subject to the performance by the Company of its obligations hereunder and to the following additional conditions:

(a) The Registration Statement shall have become effective. The Prospectus shall have been filed with the Commission pursuant to Rule 424(b) under the Securities Act within the applicable time period prescribed for such filing by the Rules and Regulations and in

accordance with Section 5(a); all material required to be filed by the Company pursuant to Rule 433(d) under the Securities Act shall have been filed with the Commission within the applicable time period prescribed for such filing by Rule 433 under the Securities Act; if the Company has elected to rely upon Rule 462(b) under the Securities Act, the Rule 462(b) Registration Statement shall have become effective by 10:00 p.m., Washington, D.C. time, on the date of this Agreement; no stop order suspending the effectiveness of the Registration Statement or any part thereof or the Prospectus or any part thereof or any Issuer Free Writing Prospectus shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission or any state securities commission; and all requests for additional information on the part of the Commission shall have been complied with to your reasonable satisfaction.

(b) The representations and warranties of the Company contained herein are true and correct on and as of the Closing Date or the Option Closing Date, as the case may be, as if made on and as of the Closing Date or the Option Closing Date, as the case may be, and the Company shall have complied with all agreements and all conditions on its part to be performed or satisfied hereunder at or prior to the Closing Date or the Option Closing Date, as the case may be.

(c) Subsequent to the execution and delivery of this Agreement and prior to the Closing Date or the Option Closing Date, as the case may be, there shall not have occurred any downgrading, nor shall any notice have been given of (i) any downgrading, (ii) any intended or potential downgrading or (iii) any review or possible change that does not indicate an improvement, in the rating accorded any securities of or guaranteed by the Company by any “nationally recognized statistical rating organization”, as such term is defined for purposes of Rule 436(g)(2) under the Securities Act.

(d) (i) The Company shall not have sustained since the date of the latest audited financial statements included in the Pricing Disclosure Package any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Disclosure Package, and (ii) since the respective dates as of which information is given in the Registration Statement and the Prospectus and except as described in the Registration Statement and the Prospectus, (1) there shall not have been any change in the capital stock (other than the issuance of shares of Common Stock upon the exercise or conversion of securities described as outstanding in, or the grant of options, restricted stock or other equity-based awards under the Company’s existing equity incentive plans described in, the Pricing Disclosure Package) or long-term debt of the Company and (2) there shall not have been any material adverse change, or any development that would reasonably be expected to result in a prospective material adverse change, in or affecting the general affairs, business, prospects, management, financial position, stockholders’ equity or results of operations of the Company, the effect of which, in any such case described in clause (i) or (ii), is in the judgment of the Representatives so material and adverse as to make it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Closing Date or Option Closing Date, as the case may be, on the terms and in the manner contemplated in the Pricing Prospectus.

(e) the Representatives shall have received on and as of the Closing Date or the Option Closing Date, as the case may be, a certificate of two executive officers of the Company, at least one of whom has specific knowledge about the Company’s financial matters, satisfactory to the Representatives, to the effect (1) set forth in Sections 8(b) (with respect to the respective representations, warranties, agreements and conditions of the Company) and 8(c), (2) that none of the situations set forth in clause (i) or (ii) of Section 8(c) shall have occurred and (3) that no stop order suspending the effectiveness of the Registration Statement has been issued and to the knowledge of the Company, no proceedings for that purpose have been instituted or are pending or contemplated by the Commission.

(f) On the Closing Date or Option Closing Date, as the case may be, Latham & Watkins LLP, counsel for the Company, shall have furnished to the Representatives their favorable written opinion and negative assurance letter, dated the Closing Date or the Option Closing Date, as the case may be, in form and substance reasonably satisfactory to counsel for the Underwriters and set forth on Exhibit A attached hereto.

(g) On the Closing Date or Option Closing Date, as the case may be, John Wallen, internal intellectual property counsel for the Company, shall have furnished to the Representatives their favorable written opinion (including negative assurance statements), each dated the Closing Date or the Option Closing Date, as the case may be, in form and substance satisfactory to counsel for the Underwriters and set forth on Exhibit B attached hereto.

(h) On the effective date of the Registration Statement and, if applicable, the effective date of the most recently filed post-effective amendment to the Registration Statement, Ernst & Young LLP shall have furnished to the Representatives a letter, dated the date of delivery thereof, in form and substance satisfactory to the Representatives, containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement and the Prospectus.

(i) On the Closing Date or Option Closing Date, as the case may be, the Representatives shall have received from Ernst & Young LLP a letter, dated the Closing Date or such Option Closing Date, as the case may be, to the effect that they reaffirm the statements made in the letter or letters furnished pursuant to Section 8(h), except that the specified date referred to shall be a date not more than three business days prior to the Closing Date or such Option Closing Date, as the case may be.

(j) On the Closing Date or Option Closing Date, as the case may be, Goodwin Procter LLP, counsel for the Underwriters, shall have furnished to the Representatives their favorable opinion dated the Closing Date or the Option Closing Date, as the case may be, with respect to the due authorization and valid issuance of the Shares, the Registration Statement, the Prospectus and other related matters as the Representatives may reasonably request, and such counsel shall have received such papers and information as they may reasonably request to enable them to pass upon such matters.

(k) The Shares to be delivered on the Closing Date or Option Closing Date, as the case may be, shall have been approved for listing on the NASDAQ Global Market, subject to official notice of issuance.

(l) FINRA shall have confirmed that it has not raised any objection with respect to the fairness and reasonableness of the underwriting terms and conditions.

(m) The Representatives shall have received “lock-up” agreements, each substantially in the form of Exhibit C hereto, from all officers and directors of the Company, and stockholders that, together with the officers and directors, hold substantially all of the Company’s Common Stock outstanding immediately prior to the offering of the Shares, and such agreements shall be in full force and effect on the Closing Date or Option Closing Date, as the case may be.

(n) On or prior to the Closing Date or Option Closing Date, as the case may be, the Company shall have furnished to the Representatives such further information, certificates and documents as the Representatives shall reasonably request.

(o) On or after the Applicable Time there shall not have occurred any of the following: (i) a suspension or material limitation in trading in securities generally on the NASDAQ Stock Market; (ii) a suspension or material limitation in trading in the Company’s securities on the NASDAQ Global Market; (iii) a general moratorium on commercial banking activities declared by any of Federal or New York State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States; (iv) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (v) the occurrence of any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (iv) or (v) in the judgment of the Representatives makes it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Closing Date or Option Closing Date, as the case may be, on the terms and in the manner contemplated in the Prospectus.

The certificates mentioned in this Agreement shall be deemed to be in compliance with the provisions hereof only if they are in all material respects reasonably satisfactory to the Representatives and to Goodwin Procter LLP, counsel for the Underwriters.

If any condition specified in this Section 8 shall not have been fulfilled when and as required to be fulfilled, this Agreement may be terminated, subject to the provisions of Section 12, by the Representatives by notice to the Company at any time at or prior to the Closing Date or Option Closing Date, as the case may be, and such termination shall be without liability of any party to any other party, except as provided in Section 12.

9. (a) The Company agrees to indemnify and hold harmless each Underwriter and each person, if any, who controls any Underwriter within the meaning of Section 15 of the Securities Act or Section 20(a) of the Exchange Act against any and all losses, liabilities, claims, damages and expenses whatsoever as incurred (including without limitation, reasonable attorneys’ fees and any and all reasonable expenses whatsoever incurred in investigating,

preparing or defending against any litigation, commenced or threatened, or any claim whatsoever, and any and all amounts paid in settlement of any claim or litigation), joint or several, to which they or any of them may become subject under the Securities Act, the Exchange Act or otherwise, insofar as such losses, liabilities, claims, damages or expenses (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, or any post-effective amendment thereof, or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, or (ii) any untrue statement or alleged untrue statement of a material fact contained in any Preliminary Prospectus, the Pricing Disclosure Package or the Prospectus, or in any supplement thereto or amendment thereof, any Issuer Free Writing Prospectus, any written Testing-the-Waters Communication, or any “issuer information” filed or required to be filed pursuant to Rule 433(d) under the Securities Act, or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading; provided, however, that the Company will not be liable in any such case to the extent that any such loss, liability, claim, damage or expense arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made in the Initial Registration Statement, as originally filed or any amendment thereof, the Registration Statement, or any post-effective amendment thereof, any Preliminary Prospectus, the Pricing Disclosure Package or the Prospectus, or in any supplement thereto or amendment thereof, any Issuer Free Writing Prospectus, or any written Testing-the-Waters Communication in reliance upon and in strict conformity with written information furnished to the Company by or on behalf of any Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information furnished by any Underwriter is the information described as such in Section 9(b) below.

(b) Each Underwriter severally, and not jointly, agrees to indemnify and hold harmless the Company, each of the directors of the Company, each of the officers of the Company who shall have signed the Registration Statement, and each other person, if any, who controls the Company within the meaning of Section 15 of the Securities Act or Section 20(a) of the Exchange Act, against any losses, liabilities, claims, damages and expenses whatsoever as incurred (including without limitation, reasonable attorneys’ fees and any and all reasonable expenses whatsoever incurred in investigating, preparing or defending against any litigation, commenced or threatened, or any claim whatsoever, and any and all amounts paid in settlement of any claim or litigation), joint or several, to which they or any of them may become subject under the Act, the Exchange Act or otherwise, insofar as such losses, liabilities, claims, damages or expenses (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, or any post-effective amendment thereof, or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, or (ii) any untrue statement or alleged untrue statement of a material fact contained in any Preliminary Prospectus, the Pricing Disclosure Package or the Prospectus, or in any supplement thereto or amendment thereof, any Issuer Free Writing Prospectus, any written Testing-the-Waters Communication, or any “issuer information” filed or required to be filed pursuant to Rule 433(d) under the Securities Act, or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, in light of the

circumstances under which they were made, not misleading, in each case to the extent, but only to the extent, that any such loss, liability, claim, damage or expense arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made therein in reliance upon and in strict conformity with written information furnished to the Company by or on behalf of such Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information concerning the terms of the offering on the cover page of the Prospectus and the information in the following paragraphs under the caption “Underwriting” in the Prospectus: (i) the first paragraph under the heading “Commissions and Expenses,” (ii) the paragraphs under the heading “Short Sales, Stabilizing Transaction and Penalty Bids” and (iii) the paragraph under the heading “Discretionary Sales.”

(c) Promptly after receipt by an indemnified party under Section 9(a) or 9(b) of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such Section, notify each party against whom indemnification is to be sought in writing of the commencement thereof (but the failure so to notify an indemnifying party shall not relieve it from any liability which it may have under this Section 9). In case any such action is brought against any indemnified party, and it notifies an indemnifying party of the commencement thereof, the indemnifying party will be entitled to participate therein, and jointly with any other indemnifying party similarly notified, to the extent it may elect by written notice delivered to the indemnified party promptly after receiving the aforesaid notice from such indemnified party, to assume the defense thereof with counsel reasonably satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnified party). Notwithstanding the foregoing, the indemnified party or parties shall have the right to employ its or their own counsel in any such case, but the fees and expenses of such counsel shall be at the expense of such indemnified party or parties unless (i) the employment of such counsel shall have been authorized in writing by one of the indemnifying parties in connection with the defense of such action, (ii) the indemnifying parties shall not have employed counsel to have charge of the defense of such action within a reasonable time after notice of commencement of the action, or (iii) such indemnified party or parties shall have reasonably concluded that there may be defenses available to it or them which are different from or additional to those available to one or all of the indemnifying parties (in which case the indemnifying parties shall not have the right to direct the defense of such action on behalf of the indemnified party or parties), in any of which events the reasonable fees and expenses of such counsel shall be borne by the indemnifying parties. In no event shall the indemnifying parties be liable for fees and expenses of more than one counsel (in addition to any local counsel) separate from their own counsel for all indemnified parties in connection with any one action or separate but similar or related actions in the same jurisdiction arising out of the same general allegations or circumstances, which counsel, in the event of indemnified parties under Section 9(a), shall be selected by the Representatives. No indemnifying party shall, without the written consent of the indemnified party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the indemnified party from all liability arising out of such action or claim and (ii) does

not include a statement as to or an admission of fault, culpability or a failure to act, by or on behalf of any indemnified party.

(d) If the indemnification provided for in this Section 9 is unavailable to or insufficient to hold harmless an indemnified party under Section 9(a) or 9(b) in respect of any losses, liabilities, claims, damages or expenses (or actions in respect thereof) referred to therein, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses, liabilities, claims, damages or expenses (or actions in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Shares. If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law, then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, liabilities, claims, damages or expenses (or actions in respect thereof), as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Shares shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover page of the Prospectus. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company on the one hand or the Underwriters on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The Company and the Underwriters agree that it would not be just and equitable if contributions pursuant to this Section 9(d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this Section 9(d). The amount paid or payable by an indemnified party as a result of the losses, liabilities, claims, damages or expenses (or actions in respect thereof) referred to above in this Section 9(d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this Section 9(d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission.

No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this Section 9(d) to contribute are several in proportion to their respective underwriting obligations and not joint.

(e) The obligations of the parties to this Agreements contained in this Section 9 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any indemnified party at law or in equity.

10. If any Underwriter or Underwriters default in its or their obligations to purchase Shares hereunder on the Closing Date or any Option Closing Date and the aggregate number of Shares that such defaulting Underwriter or Underwriters agreed but failed to purchase does not exceed 10% of the total number of Shares that the Underwriters are obligated to purchase on such Closing Date or Option Closing Date, as the case may be, the Representatives may make arrangements satisfactory to the Company for the purchase of such Shares by other persons, including any of the Underwriters, but if no such arrangements are made by such Closing Date or Option Closing Date, as the case may be, the non-defaulting Underwriters shall be obligated severally, in proportion to their respective commitments hereunder, to purchase the Shares that such defaulting Underwriters agreed but failed to purchase on such Closing Date or Option Closing Date, as the case may be. If any Underwriter or Underwriters so default and the aggregate number of Shares with respect to which such default or defaults occur exceeds 10% of the total number of Shares that the Underwriters are obligated to purchase on such Closing Date or Option Closing Date, as the case may be, and arrangements satisfactory to the Representatives and the Company for the purchase of such Shares by other persons are not made within 36 hours after such default, this Agreement will terminate, subject to the provisions of Section 12, without liability on the part of any non-defaulting Underwriter or the Company, except as provided in Section 12. Nothing herein will relieve a defaulting Underwriter from liability for its default.

In the event of any such default which does not result in a termination of this Agreement, either the Representatives or the Company shall have the right to postpone the Closing Date or the relevant Option Closing Date, as the case may be, for a period not exceeding seven days in order to effect any required changes in the Registration Statement or Prospectus or in any other documents or arrangements. As used in this Agreement, the term “Underwriter” includes any person substituted for an Underwriter under this Section 10.

11. Notwithstanding anything herein contained, this Agreement (or the obligations of the several Underwriters with respect to any Option Shares which have yet to be purchased) may be terminated, subject to the provisions of Section 12, in the absolute discretion of the Representatives, by notice given to the Company, if after the execution and delivery of this Agreement and prior to the Closing Date or the Option Closing Date, as the case may be, (a) trading generally on the NYSE MKT, the New York Stock Exchange or on the NASDAQ Global Select Market or the NASDAQ Global Market shall have been suspended or materially limited, or minimum or maximum prices for trading have been fixed, or maximum ranges for prices have been required, by any of said exchanges or by such system or by order of the Commission, FINRA or any other governmental or regulatory authority, (b) trading of any securities of or guaranteed by the Company shall have been suspended on any exchange or in any over-the-counter market, (c) a general moratorium on commercial banking activities in New York shall have been declared by Federal or New York State authorities or a new restriction materially adversely affecting the distribution of the Firm Shares or the Option Shares, as the case may be, shall have become effective, or (d) there has occurred any material adverse change in the financial markets in the United States or the international financial markets, any outbreak

of hostilities or escalation thereof or other calamity or crisis or any change or development involving a prospective change in national or international political, financial or economic conditions, in each case the effect of which is such as to make it, in the judgment of the Representatives, impracticable to market the Shares to be delivered on the Closing Date or Option Closing Date, as the case may be, or to enforce contracts for the sale of the Shares.

If this Agreement is terminated pursuant to this Section 11, such termination will be without liability of any party to any other party except as provided in Section 12 hereof.

12. The respective indemnities, agreements, representations, warranties and other statements of the Company or its officers and of the several Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation, or statement as to the results thereof, made by or on behalf of any Underwriter, the Company or any of their respective representatives, officers or directors or any controlling person, and will survive delivery of and payment for the Shares. If this Agreement is terminated pursuant to Section 8, 10 or 11 or if for any reason the purchase of any of the Shares by the Underwriters is not consummated, the Company shall remain responsible for the expenses to be paid or reimbursed by it pursuant to Section 7, the respective obligations of the Company and the Underwriters pursuant to Section 9 and the provisions of Sections 12, 13 and 16 shall remain in effect and, if any Shares have been purchased hereunder the representations and warranties in Section 1 and all obligations under Section 5 and Section 6 shall also remain in effect. If this Agreement shall be terminated by the Underwriters, or any of them, under Section 8 or otherwise because of any failure or refusal on the part of the Company to comply with the terms or to fulfill any of the conditions of this Agreement (other than solely by reason of the failure of any Underwriter to perform its obligations hereunder), or if for any reason the Company shall be unable to perform its obligations under this Agreement (other than solely by reason of the failure of any Underwriter to perform its obligations hereunder) or any condition of the Underwriters’ obligations cannot be fulfilled, the Company agrees to reimburse the Underwriters or such Underwriters as have so terminated this Agreement with respect to themselves, severally, for all out-of-pocket expenses (including the fees and expenses of its counsel) reasonably incurred by the Underwriter in connection with this Agreement or the offering contemplated hereunder.

13. This Agreement shall inure to the benefit of and be binding upon the Company and the Underwriters, the officers and directors of the Company referred to herein, any controlling persons referred to herein and their respective successors and assigns. Nothing expressed or mentioned in this Agreement is intended or shall be construed to give any other person, firm or corporation any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision herein contained. No purchaser of Shares from any Underwriter shall be deemed to be a successor or assign by reason merely of such purchase.

14. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given upon receipt thereof by the recipient if mailed or transmitted by any standard form of telecommunication. Notices to the Underwriters shall be given to the Representatives, c/o Stifel, Nicolaus & Company, Incorporated, 237 Park Avenue, 8^th Floor, New York, New York 10017 (fax no.: (212) ###-###-####), Attention: General Counsel; with a copy to Goodwin Procter LLP, The New York Times Building, 620 Eighth Avenue, New York,

New York 10018 (fax no.: (212) ###-###-####); Attention: Thomas S. Levato, Esq. Notices to the Company shall be given to it at Ambrx, Inc., 10975 North Torrey Pines Road, La Jolla, California 92037 (fax no.: (858) ###-###-####), Attention: Chief Executive Officer; with a copy to Latham & Watkins LLP, 12670 High Bluff Drive, San Diego, California 92130 (fax no.: (858) ###-###-####), Attention: Michael E. Sullivan, Esq.

15. This Agreement may be signed in counterparts, each of which shall be an original and all of which together shall constitute one and the same instrument.

16. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO SUCH STATE’S PRINCIPLES OF CONFLICTS OF LAWS.

17. The parties hereby submit to the jurisdiction of and venue in the federal courts located in the City of New York, New York in connection with any dispute related to this Agreement, any transaction contemplated hereby, or any other matter contemplated hereby.

18. The Company acknowledges and agrees that (i) the purchase and sale of the Shares pursuant to this Agreement, including the determination of the public offering price of the Shares and any related discounts and commissions, is an arm’s-length commercial transaction between the Company on the one hand, and the several Underwriters, on the other, (ii) in connection therewith and with the process leading to such transaction each Underwriter is acting solely as a principal and not the agent or fiduciary of the Company or its respective stockholders, creditors, employees or any other party, (iii) no Underwriter has assumed an advisory or fiduciary responsibility in favor of the Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Company on other matters) or any other obligation to the Company except the obligations expressly set forth in this Agreement, and (iv) the Company has consulted its own legal and financial advisors to the extent it deemed appropriate. The Company agrees that it will not claim that the Underwriters, or any of them, has rendered advisory services of any nature or respect, or owes a fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto.

19. The Company acknowledges that the Underwriters’ research analysts and research departments are required to be independent from their respective investment banking divisions and are subject to certain regulations and internal policies, and that such Underwriters’ research analysts may hold views and make statements or investment recommendations and/or publish research reports with respect to the Company and/or the offering that differ from the views of their respective investment banking divisions. The Company hereby waives and releases, to the fullest extent permitted by law, any claims that the Company may have against the Underwriters with respect to any conflict of interest that may arise from the fact that the views expressed by their independent research analysts and research departments may be different from or inconsistent with the views or advice communicated to the Company by such Underwriters’ investment banking divisions. The Company acknowledges that each of the Underwriters is a full service securities firm and as such from time to time, subject to applicable securities laws, may effect transaction for its own account or the account of its customers and

hold long or short positions in debt or equity securities of the companies that may be the subject of the transactions contemplated by this Agreement.

20. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Underwriters, or any of them, with respect to the subject matter hereof.

21. The Company and each of the Underwriters hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.

[Remainder of page left intentionally blank]

If the foregoing is in accordance with your understanding of our agreement, please sign and return to the Company a counterpart hereof, whereupon this instrument will become a binding agreement among the Company and the Underwriters.


Very truly yours,

AMBRX, INC.

By:
		Name:
		Title:

Accepted as of the date hereof:

STIFEL, NICOLAUS & COMPANY, INCORPORATED



By:
		Name:
		Title:

WELLS FARGO SECURITIES, LLC



By:
		Name:
		Title:

For themselves and as Representatives of the

other Underwriters named in Schedule I hereto

[Signature page to Underwriting Agreement]

SCHEDULE I

Underwriters


Underwriter		Number of Firm Shares to be Purchased
Stifel, Nicolaus & Company, Incorporated		[ ]
Wells Fargo Securities, LLC		[ ]
Canaccord Genuity Inc.		[ ]
Needham & Company, LLC		[ ]
Roth Capital Partners, LLC		[ ]

Total:		[ ]

SCHEDULE II

Free Writing Prospectuses

[None.]

SCHEDULE III

Written Testing-the-Waters Communications

[ ]

EXHIBIT A

OPINION & NEGATIVE ASSURANCE OF LATHAM & WATKINS LLP

[—], 2014

Stifel, Nicolaus & Company, Incorporated

Wells Fargo Securities, LLC

As representatives of the several Underwriters

named in Schedule I to the Underwriting Agreement

c/o Stifel, Nicolaus & Company, Incorporated

787 7th Avenue, 11th Floor

New York, NY 10019

and

c/o Wells Fargo Securities, LLC

600 California Street, 12th Floor

San Francisco, CA 94108

Re: Ambrx, Inc.

Ladies and Gentlemen:

We have acted as special counsel to Ambrx, Inc., a Delaware corporation (the “Company”), in connection with the sale to you and the several underwriters for whom you are acting as representatives (the “Underwriters”) by the Company of [—] shares (the “Shares”) of common stock of the Company, par value $0.001 per share (the “Common Stock”), pursuant to a registration statement on Form S-1 under the Securities Act of 1933, as amended (the “Act”), filed with the Securities and Exchange Commission (the “Commission”) on May [—], 2014 (Registration No. 333-[ ]) (as so filed and as amended, [together with the additional registration statement relating to the Shares filed with the Commission pursuant to Rule 462(b) under the Act,] the “Registration Statement”), a preliminary prospectus dated [—], 2014 (the “Preliminary Prospectus”), [each document that the Company has identified to us as an “issuer free writing prospectus” (as defined in Rules 433 and 405 under the Act) and that is described on Exhibit A hereto (each a “Specified IFWP”),] a prospectus dated [—], 2014 filed with the Commission pursuant to Rule 424(b) under the Act (the “Prospectus”) and an underwriting agreement dated [—], 2014 between you, as representatives of the several Underwriters named in the underwriting agreement, and the Company (the “Underwriting Agreement”). This letter is being delivered to you pursuant to Section [8(f)] of the Underwriting Agreement.

As such counsel, we have examined such matters of fact and questions of law as we have considered appropriate for purposes of this letter, except where a specific fact confirmation procedure is stated to have been performed (in which case we have with your consent performed the stated procedure), and except where a statement is qualified as to knowledge or awareness (in which case we have with your consent made no or limited inquiry as specified below). We have examined, among other things, the following:

(a) The Underwriting Agreement, the Registration Statement, the Preliminary Prospectus[, the Specified IFWP[s]] and the Prospectus; and

(b) The agreements identified to us by an officer of the Company as material to the Company and listed in Exhibit [B][A] hereto (the “Specified Agreements”); and

(c) The Amended and Restated Certificate of Incorporation, as amended, and the Amended and Restated Bylaws of the Company (the “Governing Documents”) and certain resolutions of the Board of Directors of the Company and the Pricing Committee of the Board of Directors of the Company.

Except as otherwise stated herein, as to factual matters, we have, with your consent, relied upon the foregoing and upon oral or written statements and representations of officers and other representatives of the Company and others, including the representations and warranties of the Company in the Underwriting Agreement. We have not independently verified such factual matters.

Whenever a statement herein is qualified as to knowledge, awareness, or a similar phrase, it is intended to indicate that those attorneys in the firm who have rendered legal services in connection with the transaction referenced in the first paragraph do not have current actual knowledge of the inaccuracy of such statement. However, except as otherwise expressly indicated, we have not undertaken any independent inquiry to determine the accuracy of any such statement.

Except as otherwise stated herein, we are opining as to the effect on the subject transaction only of the federal laws of the United States, the internal laws of the State of California and, in numbered paragraphs 1, 2, 3, 4, 5(i), 5(iii) and 5(iv) of this letter, the General Corporation Law of the State of Delaware (the “DGCL”), and we express no opinion with respect to the applicability thereto, or the effect thereon, of the laws of any other jurisdiction or, in the case of Delaware, any other laws, or as to any matters of municipal law or the laws of any local agencies within any state. Except as otherwise stated herein, our opinions are based upon our consideration of only those statutes, rules and regulations which, in our experience, are normally applicable to registered public offerings of common stock. Various matters concerning intellectual property are addressed in the opinion of even date herewith of John Wallen, Ph.D., J.D., which has been separately provided to you. We express no opinion with respect to those matters herein, and to the extent elements of that opinion are necessary to the conclusions expressed herein, we have, with your consent, assumed such matters.

Subject to the foregoing and the other matters set forth herein, as of the date hereof:

1. The Company is a corporation under the DGCL with corporate power and authority to own its properties and to conduct its business as described in the Registration Statement, the Preliminary Prospectus and the Prospectus and to perform its obligations under the Underwriting Agreement. With your consent, based solely on certificates from public officials, we confirm that the Company is validly existing and in good standing under the laws of the State of Delaware and is qualified to do business in California.

2. The authorized capital stock of the Company consists of 200,000,000 shares of Common Stock and 10,000,000 shares of Preferred Stock (the “Preferred Stock”), par value $0.001 per share. The Shares to be issued and sold by the Company pursuant to the Underwriting Agreement have been duly authorized by all necessary corporate action of the

Company and, when issued to and paid for by you and the other Underwriters in accordance with the terms of the Underwriting Agreement, will be validly issued, fully paid and nonassessable and free of preemptive rights arising from the Governing Documents or, with your consent based solely on a review of the Specified Agreements and a certificate of an officer of the Company as to factual matters, similar contractual rights against the Company with regard to the Common Stock.

3. With your consent, based solely on a review of the minute books and stock books and records of the Company made available to us, an officers’ certificate as to factual matters, including receipt of consideration, issuance of stock certificates, giving of notice required by the DGCL with respect to uncertificated shares, and acquisitions or cancellation of stock by the Company, (i) immediately after giving effect to the sale of the Shares in accordance with the Underwriting Agreement as of the date hereof, [—] shares of Common Stock and no shares of Preferred Stock will be issued and outstanding and (ii) the outstanding shares of Common Stock have been duly authorized and validly issued, and are fully paid and nonassessable. With your consent, we have assumed that Common Stock issued upon exercise of employee stock options, stock appreciation rights or other equity awards was issued pursuant to grants or awards that were duly authorized by all necessary corporate action and duly granted or awarded in accordance with the requirements of law and the applicable equity plans, agreements, and arrangements.

4. The execution, delivery and performance of the Underwriting Agreement have been duly authorized by all necessary corporate action of the Company, and the Underwriting Agreement has been duly executed and delivered by the Company.

5. The execution and delivery of the Underwriting Agreement and the issuance and sale of the Shares by the Company to the Underwriters pursuant to the Underwriting Agreement do not on the date hereof:

(i) violate the Company’s Governing Documents;

(ii) result in the breach of or a default under any of the Specified Agreements;

(iii) violate any federal or California statute, rule or regulation applicable to the Company or the DGCL; or

(iv) require any consents, approvals or authorizations to be obtained by the Company from, or any registrations, declarations or filings to be made by the Company with, any governmental authority under the DGCL or any federal or California statute, rule or regulation applicable to the Company on or prior to the date hereof that have not been obtained or made.

6. The Registration Statement has become effective under the Act. With your consent, based solely on our review of the list of stop orders contained on the Commission’s website at http://www.sec.gov/litigation/stoporders.shtml on [—], 2014, we confirm that no stop order suspending the effectiveness of the Registration Statement has been issued under the Act and no proceedings therefor have been initiated, or to our knowledge, threatened by the Commission. The Prospectus has been filed in accordance with Rules 424(b) and 430A under the Act.

7. The Registration Statement at [—], 2014, including the information deemed to be a part thereof pursuant to Rule 430A under the Act, and the Prospectus, as of its date, each appeared on their face to be appropriately responsive in all material respects to the applicable form requirements for registration statements on Form S-1 under the Act and the rules and regulations of the Commission thereunder; it being understood, however, that we express no view with respect to Regulation S-T or the financial statements, schedules, or other financial data, included in, or omitted from, the Registration Statement or the Prospectus. For purposes of this paragraph, we have assumed that the statements made in the Registration Statement and the Prospectus are correct and complete.

8. The statements in the Preliminary Prospectus and the Prospectus under the caption “Description of Capital Stock,” insofar as they purport to constitute a summary of the terms of the Common Stock, and under the caption “Shares Eligible for Future Sale,” and in the Registration Statement under Part II, Item 14, insofar as they purport to describe or summarize certain provisions of documents or U.S. federal laws or the DGCL, as applicable, referred to therein, are accurate descriptions or summaries in all material respects.

9. With your consent, based solely upon a certificate of an officer of the Company as to factual matters and a review of the Specified Agreements, we confirm that there are no contracts or documents of a character required to be described in the Registration Statement, the Preliminary Prospectus[, the Specified IFWP[s]] or the Prospectus or to be filed as exhibits to the Registration Statement that are not described or filed, it being understood, however, that we express no view with respect to the financial statements, schedules, or other financial data included in or omitted from the Registration Statement, the Preliminary Prospectus[, the Specified IFWP[s]] or the Prospectus.

10. The Company is not, and immediately after giving effect to the sale of the Shares in accordance with the Underwriting Agreement and the application of the proceeds as described in the Prospectus under the caption “Use of Proceeds,” will not be required to be, registered as an “investment company” within the meaning of the Investment Company Act of 1940, as amended.

11. With your consent based solely on a written advice from The NASDAQ Stock Market LLC, the Shares to be issued by the Company and sold pursuant to the Underwriting Agreement have been approved for listing, subject to official notice of issuance, on The NASDAQ Global Market.

Our opinions are subject to: (i) the effect of bankruptcy, insolvency, reorganization, preference, fraudulent transfer, moratorium or other similar laws relating to or affecting the rights and remedies of creditors; and (ii) the effect of general principles of equity, whether considered in a proceeding in equity or at law (including the possible unavailability of specific performance or injunctive relief), concepts of materiality, reasonableness, good faith and fair dealing, and the discretion of the court before which a proceeding is brought. We express no opinion or confirmation as to federal or state securities laws (except as set forth in paragraphs 6, 7, 8 and 10 as to federal securities laws), tax laws (except as set forth in our letter to you of even date herewith regarding certain tax matters), antitrust or trade regulation laws, insolvency or fraudulent transfer laws, antifraud laws, compliance with fiduciary duty requirements, pension or employee benefit laws, usury laws, environmental laws, margin regulations, FINRA rules, or stock exchange rules (without limiting other laws excluded by customary practice).

Insofar as our opinions require interpretation of the Specified Agreements, with your consent, (i) we have assumed that courts of competent jurisdiction would enforce such agreements in accordance with their plain meaning, (ii) to the extent that any questions of legality or legal construction have arisen in connection with our review, we have applied the laws of the State of California in resolving such questions (except with respect to the Underwriting Agreement which is governed by the laws of the State of New York and as to which we have applied the laws of the State of New York), although certain of the Specified Agreements may be governed by other laws which differ from California law, (iii) we express no opinion with respect to any breach or default under a Specified Agreement that would occur only upon the happening of a contingency, and (iv) we express no opinion with respect to any matters which would require us to perform a mathematical calculation or make a financial or accounting determination.

This letter is furnished only to you in your capacity as representatives of the several Underwriters in their capacity as underwriters under the Underwriting Agreement and is solely for the benefit of the Underwriters in connection with the transactions referenced in the first paragraph. This letter may not be relied upon by you or them for any other purpose, or furnished to, assigned to, quoted to, or relied upon by any other person, firm or other entity for any purpose (including any person, firm or other entity that acquires Shares or any interest therein from you or the other Underwriters) without our prior written consent, which may be granted or withheld in our sole discretion.

Very truly yours,

[—], 2014

Stifel, Nicolaus & Company, Incorporated

Wells Fargo Securities, LLC

As representatives of the several Underwriters

named in Schedule I to the Underwriting Agreement

c/o Stifel, Nicolaus & Company, Incorporated

787 7th Avenue, 11th Floor

New York, NY 10019

and

c/o Wells Fargo Securities, LLC

600 California Street, 12th Floor

San Francisco, CA 94108

Re: Ambrx, Inc.

Ladies and Gentlemen:

We have acted as special counsel to Ambrx, Inc., a Delaware corporation (the “Company”), in connection with the sale to you and the several underwriters for whom you are acting as representatives (the “Underwriters”) by the Company of [—] shares (the “Shares”) of common stock of the Company, par value $0.001 per share, pursuant to a registration statement on Form S-1 under the Securities Act of 1933, as amended (the “Act”), filed with the Securities and Exchange Commission (the “Commission”) on May [—], 2014 (Registration No. 333-[ ]) (as so filed and as amended, [together with the additional registration statement relating to the Shares filed with the Commission pursuant to Rule 462(b) under the Act,] the “Registration Statement”), a preliminary prospectus dated [—], 2014 (the “Preliminary Prospectus”), [each document that the Company has identified to us as an “issuer free writing prospectus” (as defined in Rules 433 and 405 under the Act) and that is described on Exhibit A hereto (each a “Specified IFWP”),] the Pricing Information Annex attached as Exhibit [B][A] hereto (the “Pricing Information Annex”), a prospectus dated [—], 2014 filed with the Commission pursuant to Rule 424(b) under the Act (the “Prospectus”) and an underwriting agreement dated [—], 2014 between you, as representatives of the several Underwriters named in the underwriting agreement, and the Company (the “Underwriting Agreement”). This letter is being delivered to you pursuant to Section [8(f)] of the Underwriting Agreement.

The primary purpose of our professional engagement was not to establish or confirm factual matters or financial or quantitative information. Therefore, we are not passing upon and do not assume any responsibility for the accuracy, completeness or fairness of the statements contained in, the Registration Statement, the Preliminary Prospectus, [any Specified IFWP,] the Pricing Information Annex or the Prospectus (except to the extent expressly set forth in the numbered paragraph [6] of our letter to you of even date), and in our letter to you of even date with respect to certain tax matters, and have not made an independent check or verification thereof (except as

aforesaid). However, in the course of acting as special counsel to the Company in connection with the preparation by the Company of the Registration Statement, the Preliminary Prospectus, [each Specified IFWP,] the Pricing Information Annex, and the Prospectus, we reviewed the Registration Statement, the Preliminary Prospectus, [each Specified IFWP,] the Pricing Information Annex, and the Prospectus, and participated in conferences and telephone conversations with officers and other representatives of the Company, the independent public accountants for the Company, your representatives, and your counsel, during which conferences and conversations the contents of the Registration Statement, the Preliminary Prospectus, [each Specified IFWP,] the Pricing Information Annex, and the Prospectus and related matters were discussed. We also reviewed and relied upon certain corporate records and documents, letters from counsel and accountants, and oral and written statements of officers and other representatives of the Company and others as to the existence and consequence of certain factual and other matters.

Based on our participation, review and reliance as described above, we advise you that no facts came to our attention that caused us to believe that:

•

the Registration Statement, at the time it became effective on [—], 2014, including the information deemed to be a part of the Registration Statement pursuant to Rule 430A under the Act, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading;

•

the Preliminary Prospectus, as of [—], 2014 [(together with the Specified IFWP[s])], when taken together with the Pricing Information Annex, contained an untrue statement of a material fact or omitted to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; or

•

the Prospectus, as of its date or as of the date hereof, contained or contains an untrue statement of a material fact or omitted or omits to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading;

it being understood that we express no belief with respect to the financial statements, schedules, or other financial data included in, or omitted from, the Registration Statement, the Preliminary Prospectus, [the Specified IFWP[s],] the Pricing Information Annex, or the Prospectus.

Very truly yours,

EXHIBIT B

OPINION (INCLUDING NEGATIVE ASSURANCE) OF JOHN WALLEN

(INTELLECTUAL PROPERTY COUNSEL TO THE COMPANY)

EXHIBIT C

FORM OF LOCK-UP AGREEMENT

AMBRX, INC.

10975 North Torrey Pines Road

La Jolla, CA 92037

STIFEL, NICOLAUS & COMPANY, INCORPORATED

WELLS FARGO SECURITIES, LLC

as Representatives of the Several Underwriters

c/o Stifel, Nicolaus & Company, Incorporated

787 Seventh Avenue

New York, New York 10019

Ladies and Gentlemen:

The undersigned refers to the proposed Underwriting Agreement (the “Underwriting Agreement”) among Ambrx, Inc., a Delaware corporation (the “Company”), and the several underwriters named therein (the “Underwriters”) for whom Stifel, Nicolaus & Company, Incorporated and Wells Fargo Securities, LLC (together, the “Representatives”) are acting as representatives. As an inducement to the Representatives to execute the Underwriting Agreement on behalf of the Underwriters in connection with the proposed initial public offering of shares of the Company’s common stock, par value $0.001 per share (“Common Stock”), pursuant to a Registration Statement on Form S-1, the undersigned hereby agrees that from the date hereof and until 180 days after the public offering date set forth on the final prospectus used to sell the Common Stock (the “Public Offering Date”) pursuant to the Underwriting Agreement (such period being referred to herein as the “Lock-Up Period”), the undersigned will not (and will cause any spouse, domestic partner or immediate family member of any spouse, domestic partner or the undersigned living in the undersigned’s household, any partnership, corporation, limited liability company or other entity within the undersigned’s control, and any trustee of any trust that holds Common Stock or other securities of the Company for the benefit of the undersigned or such spouse, domestic partner or immediate family member not to) offer, sell, contract to sell (including any short sale), pledge, hypothecate, establish an open “put equivalent position” within the meaning of Rule 16a-1(h) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), grant any option, right or warrant for the sale of, purchase any option or contract to sell, sell any option or contract to purchase, or otherwise encumber, dispose of or transfer, or grant any rights with respect to, directly or indirectly, any shares of Common Stock or securities convertible into or exchangeable or exercisable for any shares of Common Stock, enter into a transaction which would have the same effect, or enter into any swap, hedge or other arrangement that transfers, in whole or in part, any of the economic consequences of ownership of the Common Stock held immediately prior to the Public Offering Date, whether any such aforementioned transaction is to be settled by delivery of the Common Stock or such other securities, in cash or otherwise, or publicly disclose the intention to make any such offer, sale, pledge or disposition, or to enter into any such transaction, swap, hedge or other arrangement with respect to such securities, without, in each case, the prior written consent of the Representatives, which consent may be withheld in the Representatives’ sole discretion. For purposes of this

Agreement, “immediate family member” shall mean any relation by blood, marriage or adoption, not more remote than first cousin.

If the undersigned is an officer or director of the Company, (i) the undersigned agrees that the foregoing restrictions shall be equally applicable to any issuer-directed or “friends and family” shares of Common Stock that the undersigned may purchase in the proposed initial public offering; (ii) the Representatives agree that, at least three business days before the effective date of any release or waiver of the foregoing restrictions in connection with a transfer of shares of Common Stock, the Representatives will notify the Company of the impending release or waiver, and (iii) the Company has agreed in the Underwriting Agreement to announce the impending release or waiver by press release through a major news service at least two business days before the effective date of the release or waiver. Any release or waiver granted by the Representatives hereunder to any such officer or director shall only be effective two business days after the publication date of such press release. The provisions of this paragraph will not apply if (a) the release or waiver is effected solely to permit a transfer not for consideration and (b) the transferee has agreed in writing to be bound by the same terms described in this Agreement to the extent and for the duration that such terms remain in effect at the time of the transfer.

The foregoing restrictions shall not apply to (A)(i) transactions relating to securities acquired in open market transactions after the Public Offering Date and (ii) transfers or other dispositions of shares of Common Stock purchased by the undersigned in the offering contemplated by the Underwriting Agreement, provided that, in the case of any transactions pursuant to the preceding clauses (A)(i) and (ii), no filing by any party under the Exchange Act or other public announcement shall be required or shall be voluntarily made before the expiration of the Lock-Up Period showing a decrease in the number of shares of Common Stock held by the undersigned and its affiliates in such filing; or (B)(i) bona fide gifts by the undersigned, (ii) transfers of Common Stock or any security convertible into or exercisable for Common Stock to an immediate family member, an immediate family member of a spouse, a domestic partner or a trust for the benefit of the undersigned, a spouse, a domestic partner or an immediate family member or to any partnership, corporation, limited liability company or other entity all of the beneficial ownership interests of which are held exclusively by the undersigned, a spouse, a domestic partner and/or one or more family members of the undersigned or the undersigned’s spouse or domestic partner in a transaction not involving a disposition for value, (iii) transfers of Common Stock or any security convertible into or exercisable for Common Stock upon death by will or intestate succession, (iv) securities transferred to one or more affiliates of the undersigned and distributions of securities to current or former partners, members or equityholders of the undersigned in a transaction not in exchange for new consideration, (v) transfers of Common Stock or any security convertible into or exercisable for Common Stock to any business entity that is managed and governed by the same management company as the undersigned or any business entity that is controlled by, under common control with, managed or advised by the same management company or registered investment advisor (or an affiliate of such management company or registered investment advisor) as the undersigned in a transaction not in exchange for new consideration (except for such new consideration as may be necessary to rebalance the accounts of commonly controlled, managed or advised business entities as the result of such transaction) and (vi) transfers of Common Stock or any security convertible into or exercisable

for Common Stock solely by operation of law, such as pursuant to a qualified domestic order or in connection with a divorce settlement, provided that, in the case of any transactions pursuant to the preceding clauses (B)(i)-(vi), each resulting transferee of the Company’s securities agrees in writing prior to such transfer to be bound by the terms of this Agreement as if it were a party hereto, and no filing by any party under the Exchange Act or other public announcement shall be required or shall be voluntarily made before the expiration of the Lock-Up Period showing a decrease in the number of shares of Common Stock held by the undersigned and its affiliates in such filing.

In addition, the foregoing restrictions shall not apply to (A) the exercise of any option, warrant or other right to acquire shares of Common Stock, the settlement of any stock-settled stock appreciation rights, restricted stock or restricted stock units, or the conversion of any convertible security into securities of the Company, provided, however, that in any such case the securities issued upon exercise shall remain subject to the provisions of this Agreement, (B) the entry into any trading plan established pursuant to Rule 10b5-1 under the Exchange Act, provided that such plan does not provide for any sales or other dispositions of Common Stock during the Lock-Up Period and the entry into such plan is not publicly announced or disclosed, including in any filing under the Exchange Act, or (C) the surrender or forfeiture of shares of Common Stock to the Company in a transaction exempt from Section 16(b) of the Exchange Act to satisfy tax withholding obligations upon exercise or vesting of stock options or equity awards.

In addition, the undersigned agrees that, during the period commencing on the date hereof and ending 180 days after the Public Offering Date, without the prior written consent of the Representatives (which consent may be withheld in their sole discretion): (a) the undersigned will not request, make any demand for or exercise any right with respect to, the registration of any Common Stock or any security convertible into or exercisable or exchangeable for Common Stock and (b) the undersigned waives any and all notice requirements and rights with respect to the registration of any such security pursuant to any agreement, understanding or otherwise to which the undersigned is a party.

In furtherance of the foregoing, the Company and its transfer agent and registrar are hereby authorized to (a) decline to make any transfer of shares of Common Stock if such transfer would constitute a violation or breach of this Agreement and (b) place legends on any shares of Common Stock held immediately prior to the Public Offering Date and stop transfer instructions on any shares of Common Stock owned or beneficially owned by the undersigned.

This Agreement is irrevocable and shall be binding on the undersigned and the successors, heirs, personal representatives and assigns of the undersigned. This Agreement shall be governed by and construed in accordance with the laws of the State of New York, without regard to choice of law rules. This Agreement shall lapse and become null and void if the Public Offering Date shall not have occurred on or before the earliest of (i) such time as the Representatives, on the one hand, or the Company, on the other hand, advises the other in writing, prior to the execution of the Underwriting Agreement that it has determined not to proceed with the Public Offering, (ii) the termination of the Underwriting Agreement or (iii) October 31, 2014, in the event the Underwriting Agreement has not been executed by that date.


Very truly yours,


Printed Name:


Date:

EXHIBIT D

FORM OF PRESS RELEASE

Ambrx, Inc.

[Date]

Ambrx, Inc. (the “Company”) announced today that Stifel, Nicolaus & Company, Incorporated and Wells Fargo Securities, LLC, the lead book-running managing underwriters in the Company’s recent public offering of shares of common stock, is [waiving] [releasing] a lock-up restriction with respect to shares of the Company’s common stock held by [certain officers or directors] [an officer or director] of the Company. The [waiver] [release] will take effect on , 20 , and the shares may be sold on or after such date.

This press release is not an offer or sale of the securities in the United States or in any other jurisdiction where such offer or sale is prohibited, and such securities may not be offered or sold in the United States absent registration or an exemption from registration under the United States Securities Act of 1933, as amended.