Form of Underwriting Agreement

Exhibit 1.1

[         ] Shares

Entasis Therapeutics Holdings Inc.

COMMON STOCK, PAR VALUE $0.001 PER SHARE

UNDERWRITING AGREEMENT

[                    ], 2018

CREDIT SUISSE SECURITIES (USA) LLC

BMO CAPITAL MARKETS CORP.,

As Representatives of the Several Underwriters,

c/o Credit Suisse Securities (USA) LLC,

Eleven Madison Avenue,

New York, N.Y. 10010-3629

c/o BMO Capital Markets Corp.,

3 Times Square,

New York, NY 10036

Dear Sirs:

1.  Introductory.  Entasis Therapeutics Holdings Inc., a Delaware corporation (the “Company”), agrees with the several Underwriters named in Schedule A hereto (the “Underwriters”), for whom Credit Suisse Securities (USA) LLC and BMO Capital Markets Corp. are acting as representatives (the “Representatives”), to issue and sell to the several Underwriters [                   ] shares (the “Firm Securities”) of its common stock, par value $0.001 per share (the “Securities”). The Company also agrees to issue and sell to the Underwriters, at the option of the Underwriters, an aggregate of not more than [                   ] additional shares of its Securities (the “Optional Securities”). The Firm Securities and the Optional Securities are herein collectively called the “Offered Securities”.

2.  Representations and Warranties of the Company.  (a) The Company represents and warrants to, and agrees with, the several Underwriters that:

(i)  Filing and Effectiveness of Registration Statement; Certain Defined Terms.  The Company has filed with the Commission a registration statement on Form S-1 (No. 333-[                   ]) covering the registration of the Offered Securities under the Act, including a related preliminary prospectus or prospectuses.  At any particular time, this initial registration statement, in the form then on file with the Commission, including all information contained in the registration statement (if any) pursuant to Rule 462(b) of the Act and then deemed to be a part of the initial registration statement, and all 430A Information and 430C Information, that in any case has not then been superseded or modified, shall be referred to as the “Initial Registration Statement”.  The Company may also have filed, or may file with the Commission, a Rule 462(b) registration statement covering the registration of Offered Securities.   At any particular time, this Rule 462(b) registration statement, in the form then on file with the Commission, including the contents of the Initial Registration Statement incorporated by reference therein and including all 430A Information and all 430C Information, that in any case has not then been superseded or modified, shall be referred to as the “Additional Registration Statement”.  The Company has also filed, in accordance with Section 12 of the Exchange Act, a registration statement (the “Exchange Act Registration Statement”), on Form 8-A (No. 001-[                   ]) under the Exchange Act to register, under Section 12(b) of the Exchange Act, the Securities.

As of the time of execution and delivery of this Agreement, the Initial Registration Statement has been declared effective under the Act and is not proposed to be amended, and the Exchange Act Registration Statement has become effective, as provided in Section 12 of the Exchange Act.  Any Additional Registration Statement has or will become effective upon filing with the Commission pursuant to Rule 462(b) and is not proposed to be amended.  The Offered Securities all have been or will be duly registered under the Act pursuant to the Initial Registration Statement and, if applicable, the Additional Registration Statement.

For purposes of this Agreement:

“430A Information”, with respect to any registration statement, means information included in a prospectus and retroactively deemed to be a part of such registration statement pursuant to Rule 430A(b).

“430C Information”, with respect to any registration statement, means information included in a prospectus then deemed to be a part of such registration statement pursuant to Rule 430C.

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

“Applicable Time” means [   :  ] [a/p]m (Eastern time) on the date of this Agreement.

“Closing Date” has the meaning defined in Section 3 hereof.

“Commission” means the Securities and Exchange Commission.

“Effective Time” with respect to the Initial Registration Statement or, if filed prior to the execution and delivery of this Agreement, the Additional Registration Statement means the date and time as of which such Registration Statement was declared effective by the Commission or has become effective upon filing pursuant to Rule 462(c). If an Additional Registration Statement has not been filed prior to the execution and delivery of this Agreement but the Company has advised the Representatives that it proposes to file one, “Effective Time” with respect to such Additional Registration Statement means the date and time as of which such Registration Statement is filed and becomes effective pursuant to Rule 462(b).

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

“Final Prospectus” means the Statutory Prospectus that discloses the public offering price, other 430A Information and other final terms of the Offered Securities and otherwise satisfies Section 10(a) of the Act.

“General Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being so specified in Schedule B to this Agreement.

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433, relating to the Offered Securities in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g).

“Limited Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is not a General Use Issuer Free Writing Prospectus.

The Initial Registration Statement and the Additional Registration Statement, if any, are referred to collectively as the “Registration Statements” and each is individually referred to as a “Registration Statement”.  A “Registration Statement” with reference to a particular time means the Initial Registration Statement and any Additional Registration Statement as of such time.  A “Registration Statement” without reference to a time means such Registration Statement as of its Effective Time.  For purposes of the foregoing definitions, 430A Information with respect to a Registration Statement shall be considered to be included in such Registration Statement as of the time specified in Rule 430A.

“Rules and Regulations” means the rules and regulations of the Commission.

“Securities Laws” means, collectively, the Sarbanes-Oxley Act of 2002 (“Sarbanes-Oxley”), the Act, the Exchange Act, the Rules and Regulations, the auditing principles, rules, standards and practices applicable to auditors of “issuers” (as defined in Sarbanes-Oxley) promulgated or approved by the Public

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Company Accounting Oversight Board and the rules of The Nasdaq Stock Market LLC (“Exchange Rules”).

“Statutory Prospectus” with reference to a particular time means the prospectus included in a Registration Statement immediately prior to that time, including any 430A Information or 430C Information with respect to such Registration Statement.  For purposes of the foregoing definition, 430A Information shall be considered to be included in the Statutory Prospectus as of the actual time that form of prospectus is filed with the Commission pursuant to Rule 424(b) or Rule 462(c) and not retroactively.

“Testing-the-Waters Communication” means any oral or written communication with potential investors undertaken in reliance on Section 5(d) of the Act.

“Written Testing-the-Waters Communication” means any Testing-the-Waters Communication that is a written communication within the meaning of Rule 405 under the Act.

Unless otherwise specified, a reference to a “rule” is to the indicated rule under the Act.

(ii)  Compliance with Requirements of the Act and the Exchange Act.  (i) (A) At their respective Effective Times, (B) on the date of this Agreement and (C) on each Closing Date, each of the Initial Registration Statement and the Additional Registration Statement (if any) conformed and will conform in all material respects to the requirements of the Act and the Rules and Regulations, and did not and will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading, and (ii) on its date, at the time of filing of the Final Prospectus pursuant to Rule 424(b) or (if no such filing is required) at the Effective Time of the Additional Registration Statement in which the Final Prospectus is included, and on each Closing Date, the Final Prospectus will conform in all material respects to the requirements of the Act and the Rules and Regulations and will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading.  The preceding sentence does not apply to statements in or omissions from any such document based upon written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information is that described as such in Section 8(b) hereof.  The Exchange Act Registration Statement when it became effective conformed, and any further amendments thereto will conform, in all material respects to the requirements of the Exchange Act and the Rules and Regulations.

(iii)  Ineligible Issuer Status.  (i) At the time of the initial filing of the Initial Registration Statement and (ii) at the date of this Agreement, the Company was not and is not an “ineligible issuer,” as defined in Rule 405, including (x) the Company or any subsidiary of the Company in the preceding three years not having been convicted of a felony or misdemeanor or having been made the subject of a judicial or administrative decree or order as described in Rule 405 and (y) the Company in the preceding three years not having been the subject of a bankruptcy petition or insolvency or similar proceeding, not having had a registration statement be the subject of a proceeding under Section 8 of the Act and not being the subject of a proceeding under Section 8A of the Act in connection with the offering of the Offered Securities, all as described in Rule 405.

(iv) Emerging Growth Company Status. From the time of the initial confidential submission of the Initial 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 Act (an “Emerging Growth Company”).

(v)  General Disclosure Package.  As of the Applicable Time, none of (i) the General Use Issuer Free Writing Prospectus(es) issued at or prior to the Applicable Time, the preliminary prospectus, dated [       ], 2018 (which is the most recent Statutory Prospectus distributed to investors generally) and the other information, if any, stated in Schedule B to this Agreement to be included in the General Disclosure Package, all considered together (collectively, the “General Disclosure Package”), (ii) any individual Limited Use Issuer Free Writing Prospectus, when considered together with the General Disclosure Package, or (iii) any individual Written Testing-the-Waters Communication, when considered together with

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the General Disclosure Package, included any untrue statement of a material fact or omitted 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.  The preceding sentence does not apply to statements in or omissions from any Statutory Prospectus, any Issuer Free Writing Prospectus, or any Written Testing-the-Waters Communication made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(vi)  Issuer Free Writing Prospectuses.  Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Offered Securities or until any earlier date that the Company notified or notifies the Representatives as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will conflict with the information then contained in the Registration Statement.  If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information then contained in the Registration Statement or as a result of which such Issuer Free Writing Prospectus, if republished immediately following such event or development, 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 under which they were made, not misleading, (i) the Company has promptly notified or will promptly notify the Representatives and (ii) the Company has promptly amended or will promptly amend or supplement such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.  The preceding sentence does not apply to statements in or omissions from any Issuer Free Writing Prospectus made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(vii) Testing-the-Waters Communication. The Company (a) has not alone engaged in any Testing-the-Waters Communication 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 the Company’s behalf in undertaking Testing-the-Waters Communication. The Company has not distributed any Written Testing-the-Waters Communication.

(viii) Good Standing of the Company.  The Company has been duly incorporated and is validly existing and 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 General Disclosure Package and the Final Prospectus and to enter into and perform its obligations under this Agreement; and the Company is duly qualified to do business as a foreign corporation and is in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except where the failure to be so qualified or in such good standing would not, individually or in the aggregate, result in a material adverse effect on the condition (financial or otherwise), results of operations, business, properties or prospects of the Company and its subsidiaries taken as a whole (a “Material Adverse Effect”).

(ix) Subsidiaries.  Each subsidiary of the Company has been duly incorporated and is validly existing and (where relevant) in good standing under the laws of the jurisdiction of its incorporation, with power and authority (corporate and other) to own, lease and operate its properties and conduct its business as described in the General Disclosure Package and the Final Prospectus; and each subsidiary of the Company is duly qualified to do business as a foreign corporation and is in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except where the failure to be so qualified or in such good standing would not reasonably be expected to have a Material Adverse Effect; all of the issued and outstanding capital stock or other equity or ownership interests of each subsidiary of the Company has been duly authorized and validly issued and is fully paid and nonassessable; and the capital stock or other equity or ownership interests of each subsidiary owned by the Company, directly or through subsidiaries, is owned free from liens, encumbrances and defects.

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(x) Offered Securities.  The Offered Securities and all other outstanding shares of capital stock of the Company have been duly authorized; the authorized equity capitalization of the Company is as set forth in the General Disclosure Package and the Final Prospectus; all outstanding shares of capital stock of the Company are, and, when the Offered Securities have been issued, delivered and paid for in accordance with this Agreement, on each Closing Date, such Offered Securities will have been, validly issued, fully paid and nonassessable, will conform in all material respects to the information in the General Disclosure Package and to the description of such Offered Securities contained in the Final Prospectus; the stockholders of the Company have no preemptive rights with respect to the Offered Securities; and none of the outstanding shares of capital stock of the Company have been issued in violation of any preemptive or similar rights of any security holder.

(xi) No Finder’s Fee.  Except as disclosed in the General Disclosure Package and the Final Prospectus, there are no contracts, agreements or understandings between the Company and any person that would give rise to a valid claim against the Company or any Underwriter for a brokerage commission, finder’s fee or other like payment in connection with this offering.

(xii) Registration Rights.  Except as disclosed in the General Disclosure Package, there are no contracts, agreements or understandings between the Company and any person granting such person the right to require the Company to file a registration statement under the Act with respect to any securities of the Company owned or to be owned by such person or to require the Company to include such securities in the securities registered pursuant to a Registration Statement or in any securities being registered pursuant to any other registration statement filed by the Company under the Act (collectively, “registration rights”), and any person to whom the Company has granted registration rights has agreed not to exercise such rights until after the expiration of the Lock-Up Period referred to in Section 5(l) hereof.

(xiii) Listing.  The Offered Securities have been approved for listing on The Nasdaq Stock Market, subject to notice of issuance.

(xiv) Absence of Further Requirements.  No consent, approval, authorization, or order of, or filing or registration with, any person (including any governmental agency or body or any court) is required to be obtained or made by the Company for the consummation of the transactions contemplated by this Agreement in connection with the sale of the Offered Securities, except such as have been obtained, or made and such as may be required under state securities laws.

(xv) Title to Property.  Except as disclosed in the General Disclosure Package and the Final Prospectus, the Company and its subsidiaries have good and marketable title to all real properties and all other tangible personal properties and assets owned by them, in each case free from liens, charges, encumbrances and defects that would materially affect the value thereof or materially interfere with the use made or to be made thereof by them and, except as disclosed in the General Disclosure Package and the Final Prospectus, the Company and its subsidiaries hold any leased real or personal property under valid and enforceable leases with no terms or provisions that would materially interfere with the use made or to be made thereof by them.

(xvi) Absence of Defaults and Conflicts Resulting from Transaction.  The execution, delivery and performance of this Agreement, and the issuance and sale of the Offered Securities and the listing of the Offered Securities on the Nasdaq Stock Market, will not result in a breach or violation of any of the terms and provisions of, or constitute a default or a Debt Repayment Triggering Event (as defined below) under, or result in the imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, (i) the charter or by-laws of the Company or any of its subsidiaries, (ii) any statute, rule, regulation or order of any governmental agency or body or any court, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their properties, or (iii) any agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the properties of the Company or any of its subsidiaries is subject, except with respect to clauses (ii) and (iii) above where such breach, violation or default would not have a Material Adverse Effect or would not have a Material Adverse Effect on the consummation of the transactions contemplated by this Agreement; a “Debt Repayment Triggering Event” means any event or condition

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that gives, or with the giving of notice or lapse of time would give, the holder of any note, debenture, or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its subsidiaries.

(xvii) Absence of Existing Defaults and Conflicts.  Neither the Company nor any of its subsidiaries (i) is in violation of its respective charter or by-laws or (ii) in default (or with the giving of notice or lapse of time would be in default) under any existing obligation, agreement, covenant or condition contained in any indenture, loan agreement, mortgage, lease or other agreement or instrument to which any of them is a party or by which any of them is bound or to which any of the properties of any of them is subject, except with respect to clause (ii) only, such defaults that would not reasonably be expect to have a Material Adverse Effect.

(xviii) Authorization of Agreement.  This Agreement has been duly authorized, executed and delivered by the Company.

(xix) Possession of Licenses and Permits.  The Company and its subsidiaries possess, and are in compliance in all material respects with the terms of, all applicable certificates, authorizations, franchises, licenses and permits (collectively, the “Licenses”) necessary or material to the conduct of the business now conducted or proposed in the General Disclosure Package and the Final Prospectus to be conducted by them and have not received any notice of proceedings relating to the revocation or modification of any Licenses that, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate have a Material Adverse Effect.

(xx) Absence of Labor Dispute.  No labor dispute with the employees of the Company or any of its subsidiaries exists or, to the knowledge of the Company, is imminent that could have a Material Adverse Effect.

(xxi) Possession of Intellectual Property.  The Company and its subsidiaries own, possess or can acquire on reasonable terms sufficient trademarks, trade names, patent rights, copyrights, domain names, licenses, approvals, trade secrets, inventions, technology, know-how and other intellectual property and similar rights, including registrations and applications for registration thereof (collectively, “Intellectual Property Rights”) necessary or material to the conduct of the business now conducted or proposed in the General Disclosure Package and Final Prospectus to be conducted by them, and the expected expiration of any such Intellectual Property Rights would not, individually or in the aggregate, have a Material Adverse Effect.  Except as disclosed in the General Disclosure Package and the Final Prospectus (i) there are no rights of third parties to any of the Intellectual Property Rights owned by the Company or its subsidiaries; (ii) there is no material infringement, misappropriation breach, default or other violation, or the occurrence of any event that with notice or the passage of time would constitute any of the foregoing, by the Company, its subsidiaries or third parties of any of the Intellectual Property Rights of the Company or its subsidiaries; (iii) there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others challenging the Company’s or any subsidiary’s rights in or to, or the violation of any of the terms of, any of their Intellectual Property Rights, and the Company is unaware of any facts which would form a reasonable basis for any such claim; (iv) there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others challenging the validity, enforceability or scope of any such Intellectual Property Rights, and the Company is unaware of any facts which would form a reasonable basis for any such claim; (v) there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others that the Company or any subsidiary infringes, misappropriates or otherwise violates or conflicts with any Intellectual Property Rights or other proprietary rights of others and the Company is unaware of any other fact which would form a reasonable basis for any such claim; and (vi) none of the Intellectual Property Rights used by the Company or its subsidiaries in their businesses has been obtained or is being used by the Company or its subsidiaries in violation of any contractual obligation binding on the Company, any of its subsidiaries in violation of the rights of any persons, except in each case covered by clauses (i) — (vi) such as would not, if determined adversely to the Company or any of its subsidiaries, individually or in the aggregate, have a Material Adverse Effect.

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(xxii) Environmental Laws.  Except as disclosed in the General Disclosure Package and the Final Prospectus, (a) neither the Company nor any of its subsidiaries (i) is or has been in violation of any foreign, federal, state or local statute, law, rule, regulation, judgment, order, decree, decision, ordinance, code or other legally binding requirement (including common law) relating to the pollution,  protection or restoration of the environment, wildlife or natural resources; human health or safety; or the generation, use, handling, transportation, treatment, storage, discharge, disposal or release of, or exposure to, any Hazardous Substance (as defined below) (collectively, “Environmental Laws”), (ii) is conducting or funding, in whole or in part, any investigation, remediation, monitoring or other corrective action pursuant to any Environmental Law, including to address any actual or suspected Hazardous Substance, (iii) has received notice of, or is subject to any action, suit, claim or proceeding alleging, any actual or potential liability under, or violation of, any Environmental Law, including with respect to any Hazardous Substance, (iv) is party to any order, decree or agreement that imposes any obligation or liability under any Environmental Law, or (v) is or has been in violation of, or has failed to obtain and maintain, any permit, license, authorization, identification number or other approval required under applicable Environmental Laws; (b) to the knowledge of the Company, there are no facts or circumstances that would reasonably be expected to result in any violation of or liability under any Environmental Law, including with respect to any Hazardous Substance, except in the case of clause (a) and (b) above, for such matters as would not individually or in the aggregate have, or reasonably be expected to have, a Material Adverse Effect; and (c) neither the Company nor any of its subsidiaries (i) is subject to any pending proceeding pursuant to any Environmental Law in which any foreign, federal, state or local governmental entity is also a party, other than such proceedings regarding which it is reasonably believed no monetary sanctions of $100,000 or more will be imposed, nor does the Company or any of its subsidiaries know any such proceeding is contemplated, (ii) is aware of any material effect on the capital expenditures, earnings or competitive position of the Company and its subsidiaries resulting from compliance with Environmental Laws, or (iii) anticipates any material capital expenditures relating to any Environmental Laws.  For purposes of this subsection, “Hazardous Substance” means (A) any pollutant, contaminant, petroleum and petroleum products, by-products or breakdown products, radioactive materials, asbestos, asbestos-containing materials, polychlorinated biphenyls or toxic mold, and (B) any other toxic, radioactive, ignitable, corrosive, reactive or otherwise hazardous chemical, material, waste or substance.

(xxiii)  Accurate Disclosure.  The statements in the General Disclosure Package and the Final Prospectus under the headings [“Material U.S. Federal Income Tax Considerations for Non-U.S. Holders”], [“Description of Capital Stock”], [“Business — Intellectual Property”], [“Business — Government Regulation”], “[Risk Factors — Risks Related to our Intellectual Property]” and “[Risk Factors — Risks Related to Regulatory Approval of Our Candidates and Other Legal Compliance Matters]”, insofar as such statements summarize legal matters, agreements, documents or proceedings discussed therein, are accurate and fair summaries of such legal matters, agreements, documents or proceedings and present the information required to be shown.

(xxiv) Absence of Manipulation.  The Company has not taken, directly or indirectly, any action that is designed to or that has constituted or that would reasonably be expected to cause or result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Offered Securities.

(xxv)  Statistical and Market-Related Data.  Any third-party statistical and market-related data included in a Registration Statement, a Statutory Prospectus, the General Disclosure Package or any Written Testing-the-Waters Communication is based on or derived from sources that the Company believes to be reliable and accurate.

(xxvi)  Internal Controls and Compliance with the Sarbanes-Oxley Act.  Except as set forth in the General Disclosure Package and the Final Prospectus, the Company, its subsidiaries and the Company’s Board of Directors (the “Board”) are in compliance with Sarbanes-Oxley (to the extent applicable) and all applicable Exchange Rules.  The Company maintains a system of internal controls, including, but not limited to, disclosure controls and procedures, internal controls over accounting matters and financial reporting, an internal audit function and legal and regulatory compliance controls (collectively, “Internal Controls”) that comply with the U.S. federal securities laws and are sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management’s general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with

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U.S. Generally Accepted Accounting Principles (“GAAP”) and to maintain accountability for assets, (iii) access to assets is permitted only in accordance with management’s general or specific authorization, and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences.  The Internal Controls are, or upon consummation of the offering of the Offered Securities will be, overseen by the Audit Committee (the “Audit Committee”) of the Board in accordance with Exchange Rules.  The Company has not publicly disclosed or reported to the Audit Committee or the Board, and within the next 135 days the Company does not reasonably expect to publicly disclose or report to the Audit Committee or the Board, a “significant deficiency” or “material weakness” (each, as defined in Rule 12b-2 of the Exchange Act), a change in Internal Controls or fraud involving management or other employees who have a significant role in Internal Controls (each, an “Internal Control Event”), any violation of, or failure to comply with, the U.S. federal securities laws and the Exchange Rules, or any matter which, if determined adversely, would have a Material Adverse Effect.

(xxvii) Litigation.  Except as disclosed in the General Disclosure Package and the Final Prospectus, there are no pending actions, suits or proceedings (including any inquiries or investigations by any court or governmental agency or body, domestic or foreign) against or affecting the Company, any of its subsidiaries or any of their respective properties that, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate have a Material Adverse Effect, or would materially and adversely affect the ability of the Company to perform its obligations under this Agreement, or which are otherwise material in the context of the sale of the Offered Securities; and no such actions, suits or proceedings (including any inquiries or investigations by any court or governmental agency or body, domestic or foreign) are threatened or, to the Company’s knowledge, contemplated.

(xxviii) Financial Statements.  The financial statements included in each Registration Statement and the General Disclosure Package and the Final Prospectus present fairly in all material respects the financial position of the Company and its consolidated subsidiaries as of the dates shown and their results of operations and cash flows for the periods shown, and such financial statements have been prepared in conformity with GAAP applied on a consistent basis; the schedules to the financial statements included in each Registration Statement present fairly in all material respects the information required to be stated therein; and the assumptions used in preparing the pro forma financial statements included in each Registration Statement, the General Disclosure Package and the Final Prospectus provide a reasonable basis for presenting the significant effects directly attributable to the transactions or events described therein, the related pro forma adjustments give appropriate effect to those assumptions, and the pro forma columns therein reflect the proper application of those adjustments to the corresponding historical financial statement amounts.

(xxix) No Material Adverse Change in Business.  Except as disclosed in the General Disclosure Package and the Final Prospectus, since the end of the period covered by the latest audited financial statements included in the General Disclosure Package and the Final Prospectus (i) there has been no change, nor any development or event involving a prospective change, in the condition (financial or otherwise), results of operations, business, properties or prospects of the Company and its subsidiaries, taken as a whole, that is material and adverse, (ii) except as disclosed in or contemplated by the General Disclosure Package and the Final Prospectus, there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock, and (iii) except as disclosed in or contemplated by the General Disclosure Package and the Final Prospectus, there has been no material adverse change in the capital stock, short-term indebtedness, long-term indebtedness, net current assets or net assets of the Company and its subsidiaries.

(xxx)  Investment Company Act.  The Company is not and, after giving effect to the offering and sale of the Offered Securities and the application of the proceeds thereof as described in the General Disclosure Package and the Final Prospectus, will not be an “investment company” as defined in the Investment Company Act of 1940, as amended (the “Investment Company Act”).

(xxxi)  Ratings.  No “nationally recognized statistical rating organization” as such term is defined in Section (3)(a)(62) of the Exchange Act (i) has imposed (or has informed the Company that it is considering imposing) any condition (financial or otherwise) on the Company’s retaining any rating assigned to the

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Company or any securities of the Company or (ii) has indicated to the Company that it is considering any of the actions described in Section 7(c)(ii) hereof.

(xxxii)  Taxes.  The Company and each of its subsidiaries has filed all federal, state, local and foreign tax returns required to be filed through the date of this Agreement or have properly requested extensions thereof in accordance with all applicable laws and have paid all taxes required to be paid thereon (except as currently being contested in good faith and for which reserves required by GAAP have been created in the financial statements of the Company), except in each case, where the failure to file or pay would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect, and the Company has not received any notice from any taxing authority that any material tax deficiency has been asserted against the Company or any of its subsidiaries and no material tax deficiency could reasonably be expected to be asserted against the Company or any of its subsidiaries.

(xxxiii)  Insurance. The Company and its subsidiaries are insured by insurers with appropriately rated claims paying abilities against such losses and risks and in such amounts as are generally deemed prudent and customary for the businesses in which they are engaged; all policies of insurance and fidelity or surety bonds insuring the Company or any of its subsidiaries or their respective businesses, assets, employees, officers and directors are in full force and effect; the Company and its subsidiaries are in compliance with the terms of such policies and instruments in all material respects; and there are no claims by the Company or any of its subsidiaries under any such policy or instrument as to which any insurance company is denying liability or defending under a reservation of rights clause; neither the Company nor any such subsidiary has been refused any insurance coverage sought or applied for; neither the Company nor any such subsidiary has any 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, except as set forth in or contemplated in the General Disclosure Package and the Final Prospectus; and the Company will obtain directors’ and officers’ insurance in such amounts as is customary for an initial public offering.

(xxxiv)  Anti-Corruption. Neither the Company nor any of its subsidiaries or affiliates, nor any director, officer or employee, nor, to the Company’s knowledge, any agent or representative of the Company or of any of its subsidiaries or affiliates, has taken or will take any action in furtherance of an offer, payment, promise to pay, or authorization or approval of the payment or giving of money, property, gifts or anything else of value, directly or indirectly, to any “government official” (including any officer or employee of a government or government-owned or controlled entity or of a public international organization, or any person acting in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political office) to influence official action or secure an improper advantage; and the Company and its subsidiaries and affiliates have conducted their businesses in compliance with applicable anti-corruption laws and have instituted and maintain and will continue to maintain policies and procedures designed to promote and achieve compliance with such laws and with the representation and warranty contained herein.

(xxxv) Anti-Money Laundering. The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with all applicable financial recordkeeping and reporting requirements, including those of the Bank Secrecy Act, as amended by Title III of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA PATRIOT Act), and the applicable anti-money laundering statutes of jurisdictions where the Company and its subsidiaries conduct business, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Anti-Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Anti-Money Laundering Laws is pending or, to the best knowledge of the Company, threatened.

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(xxxvi)  Economic Sanctions.

(i)             Neither the Company nor any of its subsidiaries, nor any director, officer, employee thereof, nor, to the Company’s knowledge, any agent, affiliate or representative of the Company or any of its subsidiaries, is an individual or entity (“Person”) that is, or is owned or controlled by a Person that is:

(A)             the subject of any sanctions administered or enforced by the U.S. Department of Treasury’s Office of Foreign Assets Control (OFAC), the United Nations Security Council (UN), the European Union (EU), Her Majesty’s Treasury (UK HMT), the Swiss Secretariat of Economic Affairs (SECO), the Hong Kong Monetary Authority (HKMA), the Monetary Authority of Singapore (MAS), or other relevant sanctions authority (collectively, “Sanctions”), nor

(B)             located, organized or resident in a country or territory that is the subject of Sanctions (including, without limitation, Crimea, Cuba, Iran, North Korea, Sudan and Syria).

(ii)          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:

(A)             to fund or facilitate any activities or business of or with any Person or in any country or territory that, at the time of such funding or facilitation, is the subject of Sanctions; or

(B)             in any other manner that will result in a violation of Sanctions by any Person (including any Person participating in the offering, whether as underwriter, advisor, investor or otherwise).

(iii)       For the past five years, the Company and its subsidiaries have not knowingly engaged in, are not now knowingly engaged in, and will not engage in, any dealings or transactions with any Person, or in any country or territory, that at the time of the dealing or transaction is or was the subject of Sanctions.

(xxxvii) Regulatory Compliance.  Except as described in the Registration Statement, the General Disclosure Package and the Final Prospectus, the Company: (A) is and at all times has been in material compliance with all statutes, rules or regulations of the U.S. Food and Drug Administration (the “FDA”) and other comparable governmental entities applicable to the ownership, testing, development, manufacture, packaging, processing, use, distribution, marketing, labeling, promotion, sale, offer for sale, storage, import, export or disposal of any product under development, manufactured or distributed by the Company, including the federal Food, Drug and Cosmetic Act (“FFDCA”) (21 U.S.C. § 301 et seq.), the federal Anti-kickback Statute (42 U.S.C. § 1320a-7b(b)), the civil False Claims Act (31 U.S.C. §§ 3729 et seq.), the federal False Statements Law (42 U.S.C. § 1320a-7b(a)), the Civil Monetary Penalties Law (42 U.S.C. §1320a-7a), all criminal laws relating to health care fraud and abuse, including, but not limited, to 18 U.S.C. §§286 and 287, the exclusions law (42 U.S.C. §1320a-7), the Physician Payments Sunshine Act (42 U.S.C. §1320a-7h), the statutes, regulations and directives of Medicare (Title XVIII of the Social Security Act), Medicaid (Title XIX of the Social Security Act) and all other government funded or sponsored healthcare programs, the Health Insurance Portability and Accountability Act of 1996 (Public Law 104-191), as amended by the Health Information Technology for Economic and Clinical Health Act of 2009 (42 U.S.C. §17901), and the Patient Protection and Affordable Care Act of 2010 (Public Law 111-148), as amended by the Health Care and Education Reconciliation Act of 2010 (Public Law 111-152), and the regulations promulgated pursuant to such laws (collectively, “Applicable Laws”), except for such non-compliance as would not, individually or in the aggregate, have a Material Adverse Effect; (B) has not received any FDA Form 483, notice of adverse finding, warning letter, untitled letter or other correspondence or notice from the FDA or any governmental entity alleging or asserting material noncompliance with any Applicable Laws or any licenses, certificates, approvals, clearances, exemptions, authorizations, permits and supplements or amendments thereto required by any such Applicable Laws

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(“Authorizations”), except for such noncompliance as would not, individually or in the aggregate, have a Material Adverse Effect; (C) possesses all material Authorizations and such Authorizations are valid and in full force and effect and the Company is not in material violation of any term of any such Authorizations, except for such violations as would not, individually or in the aggregate, have a Material Adverse Effect; (D) has not received notice of any claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from the FDA or any governmental entity or third party alleging that any product operation or activity is in material violation of any Applicable Laws or Authorizations and has no knowledge that the FDA or any governmental entity or third party is considering any such claim, litigation, arbitration, action, suit, investigation or proceeding; (E) has not received notice that the FDA or any governmental entity has taken, is taking or intends to take action to limit, suspend, modify or revoke any material Authorizations and has no knowledge that the FDA or any governmental entity is considering such action; and (F) has filed, obtained, maintained or submitted all material reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments as required by any Applicable Laws or Authorizations and that all such reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments were materially complete and correct on the date filed (or were corrected or supplemented by a subsequent submission).

(xxxviii) Tests and Preclinical and Clinical Trials.  The studies, tests and preclinical and clinical trials conducted by or, to the Company’s knowledge, on behalf of the Company were and, if still ongoing, are being conducted in all material respects in accordance with experimental protocols, procedures and controls pursuant to accepted professional scientific standards and all Authorizations and Applicable Laws, including, without limitation, the FFDCA; the Company and its subsidiaries have made all such filings and obtained all such approvals as may be required by the European Medicines Agency, the FDA or any committee thereof or from any other United States or foreign government or drug regulatory agency, or health care facility Institutional Review Board; the descriptions of the results of such studies, tests and trials contained in the Registration Statement, the General Disclosure Package and the Final Prospectus are, to the Company’s knowledge, accurate and complete in all material respects and fairly present the data derived from such studies, tests and trials; except to the extent disclosed in the Registration Statement, the General Disclosure Package and the Final Prospectus, the Company is not aware of any studies, tests or trials, the results of which the Company believes reasonably call into question the study, test, or trial results described or referred to in the Registration Statement, the General Disclosure Package and the Final Prospectus when viewed in the context in which such results are described and the clinical state of development; and, except to the extent disclosed in the Registration Statement, the General Disclosure Package or the Final Prospectus, the Company has not received any notices or correspondence from the FDA, the European Medicines Agency or any governmental entity requiring the termination or suspension of any studies, tests or preclinical or clinical trials conducted by or on behalf of the Company, other than ordinary course communications with respect to modifications in connection with the design and implementation of such trials, copies of which communications have been made available to the Representatives.

3.  Purchase, Sale and Delivery of Offered Securities.  On the basis of the representations, warranties and agreements and subject to the terms and conditions set forth herein, the Company agrees to sell to each Underwriter, and each Underwriter agrees, severally and not jointly, to purchase from the Company at a purchase price of $[          ] per share, the number of Firm Securities set forth opposite the name of such Underwriter in Schedule A hereto.

The Company will deliver the Firm Securities to or as instructed by the Representatives for the accounts of the several Underwriters in a form reasonably acceptable to the Representatives, against payment of the purchase price by the Underwriters in Federal (same day) funds by wire transfer to an account at a bank acceptable to the Representatives drawn to the order of the Company at [9:30] A.M., New York time, on [                 ], 2018, 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 “First Closing Date”. For purposes of Rule 15c6-1 under the Exchange Act, the First 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 Offered Securities sold pursuant to the offering. The Firm Securities so to be delivered or evidence of their issuance will be made available for checking at the office of Wilmer Cutler Pickering Hale and Dorr LLP, 7 World Trade Center, 250 Greenwich Street, New York, New York, 10007 at least 24 hours prior to the First Closing Date.

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In addition, upon written notice from the Representatives given to the Company from time to time not more than 30 days subsequent to the date of the Final Prospectus, the Underwriters may purchase all or less than all of the Optional Securities at the purchase price per Security to be paid for the Firm Securities. The Company agrees to sell to the Underwriters the number of shares of Optional Securities specified in such notice and the Underwriters agree, severally and not jointly, to purchase such Optional Securities. Such Optional Securities shall be purchased for the account of each Underwriter in the same proportion as the number of Firm Securities set forth opposite such Underwriter’s name bears to the total number of Firm Securities (subject to adjustment by the Representatives to eliminate fractions) and may be purchased by the Underwriters only for the purpose of covering over-allotments made in connection with the sale of the Firm Securities. No Optional Securities shall be sold or delivered unless the Firm Securities previously have been, or simultaneously are, sold and delivered. The right to purchase the Optional Securities or any portion thereof may be exercised from time to time and to the extent not previously exercised may be surrendered and terminated at any time upon notice by the Representatives to the Company.

Each time for the delivery of and payment for the Optional Securities, being herein referred to as an “Optional Closing Date”, which may be the First Closing Date (the First Closing Date and each Optional Closing Date, if any, being sometimes referred to as a “Closing Date”), shall be determined by the Representatives but shall be not later than five full business days after written notice of election to purchase Optional Securities is given. The Company will deliver the Optional Securities being purchased on each Optional Closing Date to or as instructed by the Representatives for the accounts of the several Underwriters, in a form reasonably acceptable to the Representatives against payment of the purchase price therefore in Federal (same day) funds by wire transfer to an account at a bank acceptable to the Representatives drawn to the order of the Company. The certificates for the Optional Securities being purchased on each Optional Closing Date or evidence of their issuance will be made available for checking at the above office of Wilmer Cutler Pickering Hale and Dorr LLP at a reasonable time in advance of such Optional Closing Date.

4.  Offering by Underwriters.  It is understood that the several Underwriters propose to offer the Offered Securities for sale to the public as set forth in the Final Prospectus.

5.  Certain Agreements of the Company. The Company agrees with the several Underwriters that:

(a)  Additional Filings.  Unless filed pursuant to Rule 462(c) as part of the Additional Registration Statement in accordance with the next sentence, the Company will file the Final Prospectus, in a form approved by the Representatives, with the Commission pursuant to and in accordance with subparagraph (1) (or, if applicable and if consented to by the Representatives, which consent shall not be unreasonably withheld or delayed, subparagraph (4)) of Rule 424(b) not later than the earlier of (A) the second business day following the execution and delivery of this Agreement or (B) the fifteenth business day after the Effective Time of the Initial Registration Statement.  The Company will advise the Representatives promptly of any such filing pursuant to Rule 424(b) and provide satisfactory evidence to the Representatives of such timely filing.  If an Additional Registration Statement is necessary to register a portion of the Offered Securities under the Act but the Effective Time thereof has not occurred as of the execution and delivery of this Agreement, the Company will file the additional registration statement or, if filed, will file a post-effective amendment thereto with the Commission pursuant to and in accordance with Rule 462(b) on or prior to 10:00 P.M., New York time, on the date of this Agreement or, if earlier, on or prior to the time the Final Prospectus is finalized and distributed to any Underwriter, or will make such filing at such later date as shall have been consented to by the Representatives.

(b)  Filing of Amendments: Response to Commission Requests.  The Company will promptly advise the Representatives of any proposal to amend or supplement at any time the Initial Registration Statement, any Additional Registration Statement or any Statutory Prospectus and will not effect such amendment or supplementation without the Representatives’ consent, which consent shall not be unreasonably withheld; and the Company will also advise the Representatives promptly of (i) the effectiveness of any Additional Registration Statement (if its Effective Time is subsequent to the execution and delivery of this Agreement), (ii) any amendment or supplementation of a Registration Statement or any Statutory Prospectus, (iii) any request by the Commission or its staff for any amendment to any Registration Statement, for any supplement to any Statutory Prospectus or for any additional information, (iv) the institution by the Commission of any stop order proceedings in respect of a Registration Statement or the threatening of any proceeding for that

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purpose, and (v) the receipt by the Company of any notification with respect to the suspension of the qualification of the Offered Securities in any jurisdiction or the institution or threatening of any proceedings for such purpose.  The Company will use its best efforts to prevent the issuance of any such stop order or the suspension of any such qualification and, if issued, to obtain as soon as possible the withdrawal thereof.

(c)  Continued Compliance with Securities Laws.  If, at any time when a prospectus relating to the Offered Securities is (or but for the exemption in Rule 172 would be) required to be delivered under the Act by any Underwriter or dealer, any event occurs as a result of which the Final Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, or if it is necessary at any time to amend the Registration Statement or supplement the Final Prospectus to comply with the Act, the Company will promptly notify the Representatives of such event and will promptly prepare and file with the Commission and furnish, at its own expense, to the Underwriters and the dealers and any other dealers upon request of the Representatives, an amendment or supplement which will correct such statement or omission or an amendment which will effect such compliance.  Neither the Representatives’ consent to, nor the Underwriters’ delivery of, any such amendment or supplement shall constitute a waiver of any of the conditions set forth in Section 7 hereof.

(d) Testing-the-Waters Communication. 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 Communication 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 the Representatives and will promptly amend or supplement, at its own expense, such Written Testing-the-Waters Communication to eliminate or correct such statement or omission.

(e)  Rule 158.  As soon as practicable, but not later than the Availability Date (as defined below), the Company will make generally available to its security holders an earnings statement covering a period of at least 12 months beginning after the Effective Time of the Initial Registration Statement (or, if later, the Effective Time of the Additional Registration Statement), which will satisfy the provisions of Section 11(a) of the Act and Rule 158 under the Act. For the purpose of the preceding sentence, “Availability Date” means the day after the end of the fourth fiscal quarter following the fiscal quarter that includes such Effective Time on which the Company is required to file its Form 10-Q for such fiscal quarter except that, if such fourth fiscal quarter is the last quarter of the Company’s fiscal year, “Availability Date” means the day after the end of such fourth fiscal quarter on which the Company is required to file its Form 10-K.

(f)  Furnishing of Prospectuses.  The Company will furnish to the Representatives copies of each Registration Statement (of which will be signed and will include all exhibits), each related Statutory Prospectus and, so long as a prospectus relating to the Offered Securities is (or but for the exemption in Rule 172 would be) required to be delivered under the Act, the Final Prospectus and all amendments and supplements to such documents, in each case in such quantities as the Representatives reasonably request. The Final Prospectus shall be so furnished on or prior to 3:00 P.M., New York time, on the second business day following the execution and delivery of this Agreement.  All other such documents shall be so furnished as soon as available. The Company will pay the expenses of printing and distributing to the Underwriters all such documents.

(g)  Blue Sky Qualifications.  The Company will arrange for the qualification of the Offered Securities for sale under the laws of such jurisdictions as the Representatives designate and will continue such qualifications in effect so long as required for the distribution.

(h)  Reporting Requirements.  During the period of five years hereafter, the Company will furnish to the Representatives and, upon request, to each of the other Underwriters, as soon as practicable after the end of each fiscal year, a copy of its annual report to stockholders for such year; and the Company will furnish to the Representatives (i) as soon as available, a copy of each report and any definitive proxy statement of the Company filed with the Commission under the Exchange Act or mailed to stockholders, and (ii) from time to time, such other information concerning the Company as the Representatives may reasonably request.

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However, so long as the Company is subject to the reporting requirements of either Section 13 or Section 15(d) of the Exchange Act and is timely filing reports with the Commission on its Electronic Data Gathering, Analysis and Retrieval system (or any successor system) (“EDGAR”), it is not required to furnish any such reports or statements to the Underwriters under this subsection (h).

(i)  Payment of Expenses.  The Company agrees with the several Underwriters that the Company will pay all expenses incident to the performance of the obligations of the Company under this Agreement, including but not limited to any filing fees and other documented expenses (including reasonable fees and disbursements of counsel to the Underwriters) incurred in connection with qualification of the Offered Securities for sale under the laws of such jurisdictions as the Representatives designate and the preparation and printing of memoranda relating thereto (in an amount not to exceed $10,000 in the aggregate), documented costs and expenses related to the review by the Financial Industry Regulatory Authority, Inc. (“FINRA”) of the Offered Securities (including filing fees and the fees and expenses of counsel for the Underwriters relating to such review in an amount not to exceed $25,000 in the aggregate), costs and expenses relating to investor presentations or any “road show” in connection with the offering and sale of the Offered Securities including, without limitation, any travel expenses of the Company’s officers and employees and any other expenses of the Company, including the cost of transportation in connection with the road show; provided, that 50% of the cost of any aircraft chartered in connection with the road show shall be paid 50% by the Company and 50% by the Underwriters), fees and expenses incident to listing the Offered Securities on The Nasdaq Stock Market LLC and other national and foreign exchanges, fees and expenses in connection with the registration of the Offered Securities under the Exchange Act, any transfer taxes payable in connection with the delivery of the Offered Securities to the Underwriters and expenses incurred in distributing preliminary prospectuses and the Final Prospectus (including any amendments and supplements thereto) to the Underwriters and for expenses incurred for preparing, printing and distributing any Issuer Free Writing Prospectuses to investors or prospective investors.  Except as provided in this Section 5(i) and in Section 10, the Underwriters shall pay their own costs and expenses, including the costs and expenses of their counsel.

(j) Use of Proceeds.  The Company will use the net proceeds received by it in connection with this offering in the manner described in the “Use of Proceeds” section of the General Disclosure Package and, except as disclosed in the General Disclosure Package, the Company does not intend to use any of the proceeds from the sale of the Offered Securities hereunder to repay any outstanding debt owed to any Underwriter or affiliate of any Underwriter.

(k) Absence of Manipulation.  The Company will not take, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in, stabilization or manipulation of the price of any securities of the Company to facilitate the sale or resale of the Offered Securities.

(l) (A) Restriction on Sale of Securities by Company.  For the period specified below (the “Lock-Up Period”), the Company will not, directly or indirectly, take any of the following actions with respect to its Securities or any securities convertible into or exchangeable or exercisable for any of its Securities (“Lock-Up Securities”): (i) offer, sell, issue, contract to sell, pledge or otherwise dispose of Lock-Up Securities, (ii) offer, sell, issue, contract to sell, contract to purchase or grant any option, right or warrant to purchase Lock-Up Securities, (iii) enter into any swap, hedge or any other agreement that transfers, in whole or in part, the economic consequences of ownership of Lock-Up Securities, (iv) establish or increase a put equivalent position or liquidate or decrease a call equivalent position in Lock-Up Securities within the meaning of Section 16 of the Exchange Act or (v) file with the Commission a registration statement under the Act relating to Lock-Up Securities, or publicly disclose the intention to take any such action, without the prior written consent of the Representatives, except the Company may (a) effect the transactions contemplated pursuant to this Agreement, (b) grant stock options, restricted shares of common stock or other equity grants to employees or eligible consultants, in each case pursuant to the terms of the Company’s equity incentive plans in effect as of the date hereof and disclosed in the General Disclosure Package, (c) issue Lock-Up Securities pursuant to the exercise of options or equity grants, or the conversion of other convertible securities, outstanding on the date hereof and described in the General Disclosure Package, (d) file one or more registration statements on Form S-8, and (e) issue Lock-Up Securities or any securities convertible into, or exercisable, or exchangeable for, Lock-Up Securities in

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connection with any acquisition or strategic investment (including any joint venture, strategic alliance or partnership); provided, that in the case of clause (e) such issuances, sales or deliveries shall not be greater than 5% of the total outstanding shares of common stock of the Company immediately following the completion of this offering of Offered Securities and, in the cases of clauses (c) and (e), the recipients of such Lock-Up Securities agree to be bound by a lockup letter in the form executed by the officers of the Company pursuant to Section 7(h) hereof. The Lock-Up Period will commence on the date hereof and continue for 180 days after the date hereof or such earlier date that the Representatives consent to in writing.

(B)  Agreement to Announce Lock-Up Waiver.  If the Representatives, in their sole discretion, agree to release or waive the restrictions set forth in a lock-up letter described in Section 7(h) hereof for an officer or director of the Company and provide 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 E hereto through a major news service at least two business days before the effective date of the release or waiver.

(m) Emerging Growth Company Status. 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 Offered Securities within the meaning of the Act and (ii) completion of the Lock-Up Period.

6.  Free Writing Prospectuses. The Company represents and agrees that, unless it obtains the prior consent of the Representatives, and each Underwriter represents and agrees that, unless it obtains the prior consent of the Company and the Representatives, it has not made and will not make any offer relating to the Offered Securities that would constitute an Issuer Free Writing Prospectus, or that would otherwise constitute a “free writing prospectus,” as defined in Rule 405, required to be filed with the Commission.  Any such free writing prospectus consented to by the Company and the Representatives is hereinafter referred to as a “Permitted Free Writing Prospectus.”  The Company represents that it has treated and agrees that it will treat each Permitted Free Writing Prospectus as an “issuer free writing prospectus,” as defined in Rule 433, and has complied and will comply with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including timely Commission filing where required, legending and record keeping.  The Company represents that is has satisfied and agrees that it will satisfy the conditions in Rule 433 to avoid a requirement to file with the Commission any electronic road show.

7.  Conditions of the Obligations of the Underwriters. The obligations of the several Underwriters to purchase and pay for the Firm Securities on the First Closing Date and the Optional Securities to be purchased on each Optional Closing Date will be subject to the accuracy of the representations and warranties of the Company herein (as though made on such Closing Date), to the accuracy of the statements of Company officers made pursuant to the provisions hereof, to the performance by the Company of its obligations hereunder and to the following additional conditions precedent:

(a)  Accountants’ Comfort Letter.  The Representatives shall have received letters, dated, respectively, the date hereof and each Closing Date, of KPMG LLP confirming that they are a registered public accounting firm and independent public accountants within the meaning of the Securities Laws and in the form and substance satisfactory to the Representatives (except that, in any letter dated a Closing Date, the specified date referred to in the comfort letters shall be a date no more than three days prior to such Closing Date).

(b)  Effectiveness of Registration Statement.  If the Effective Time of the Additional Registration Statement (if any) is not prior to the execution and delivery of this Agreement, such Effective Time shall have occurred not later than 10:00 P.M., New York time, on the date of this Agreement or, if earlier, the time the Final Prospectus is finalized and distributed to any Underwriter, or shall have occurred at such later time as shall have been consented to by the Representatives.  The Final Prospectus shall have been filed with the Commission in accordance with the Rules and Regulations and Section 5(a) hereof. Prior to such Closing Date, no stop order suspending the effectiveness of a Registration Statement shall have been issued and no proceedings for that purpose shall have been instituted or, to the knowledge of the Company or the Representatives, shall be threatened by the Commission.

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(c)  No Material Adverse Change.  Subsequent to the execution and delivery of this Agreement, there shall not have occurred (i) any change, or any development or event involving a prospective change, in the condition (financial or otherwise), results of operations, business, properties or prospects of the Company and its subsidiaries taken as a whole which, in the judgment of the Representatives, is material and adverse and makes it impractical or inadvisable to market the Offered Securities; (ii) any downgrading in the rating of any debt securities of the Company by any “nationally recognized statistical rating organization” (as defined in Section 3(a)(62) of the Exchange Act), or any public announcement that any such organization has under surveillance or review its rating of any debt securities of the Company (other than an announcement with positive implications of a possible upgrading, and no implication of a possible downgrading, of such rating); (iii) any change in U.S. or international financial, political or economic conditions or currency exchange rates or exchange controls the effect of which is such as to make it, in the judgment of the Representatives, impractical to market or to enforce contracts for the sale of the Offered Securities, whether in the primary market or in respect of dealings in the secondary market; (iv) any suspension or material limitation of trading in securities generally on the New York Stock Exchange or the Nasdaq Stock Market, or any setting of minimum or maximum prices for trading on such exchange; (v) any suspension of trading of any securities of the Company on any exchange or in the over-the-counter market; (vi) any banking moratorium declared by any U.S. federal or New York authorities; (vii) any major disruption of settlements of securities, payment or clearance services in the United States or any other country where such securities are listed or (viii) any attack on, outbreak or escalation of hostilities or act of terrorism involving the United States or any declaration of war by Congress or any other national or international calamity or emergency if, in the judgment of the Representatives, the effect of any such attack, outbreak, escalation, act, declaration, calamity or emergency is such as to make it impractical or inadvisable to market the Offered Securities or to enforce contracts for the sale of the Offered Securities.

(d)  Opinion and 10b-5 Statement of Counsel for the Company.  The Representatives shall have received an opinion and 10b-5 statement, dated such Closing Date, of Cooley LLP, counsel for the Company, in the form attached hereto as Exhibit A.

(e) Opinion of Intellectual Property Counsel for the Company.  The Representatives shall have received an opinion with respect to intellectual property matters, dated such Closing Date, of McCarter & English, LLP, as intellectual property counsel for the Company, in the form attached hereto as Exhibit B.

(f) Opinion and 10b-5 Statement of Counsel for Underwriters.  The Representatives shall have received from Wilmer Cutler Pickering Hale and Dorr LLP, counsel for the Underwriters, such opinion or opinions and 10b-5 statement, dated such Closing Date, with respect to such matters as the Representatives may require, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters.

(g)  Officers’ Certificate.  The Representatives shall have received a certificate, dated such Closing Date, of an executive officer of the Company and a principal financial or accounting officer of the Company in which such officers shall state that: the representations and warranties of the Company in this Agreement are true and correct; the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date; no stop order suspending the effectiveness of any Registration Statement has been issued and no proceedings for that purpose have been instituted or, to the best of their knowledge and after reasonable investigation, are threatened by the Commission; the Additional Registration Statement (if any) satisfying the requirements of subparagraphs (1) and (3) of Rule 462(b) was timely filed pursuant to Rule 462(b), including payment of the applicable filing fee in accordance with Rule 111(a) or (b) of Regulation S-T of the Commission; and, subsequent to the date of the most recent financial statements in the General Disclosure Package and the Final Prospectus, there has been no material adverse change, nor any development or event involving a prospective material adverse change, in the condition (financial or otherwise), results of operations, business, properties or prospects of the Company and its subsidiaries taken as a whole except as set forth in the General Disclosure Package and the Final Prospectus or as described in such certificate.

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(h)  Lock-Up Agreements.  On or prior to the date hereof, the Representatives shall have received lockup agreements in the form set forth on Exhibit C hereto from each executive officer, director, stockholder and other equity holder of the Company.

The Company will furnish the Representatives with such conformed copies of such opinions, certificates, letters and documents as the Representatives reasonably request.  The Representatives may in their sole discretion waive on behalf of the Underwriters compliance with any conditions to the obligations of the Underwriters hereunder, whether in respect of an Optional Closing Date or otherwise.

8.  Indemnification and Contribution.  (a)  Indemnification of Underwriters by Company.  The Company will indemnify and hold harmless each Underwriter, its partners, members, directors, officers, employees, agents, affiliates and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each an “Indemnified Party”), against any and all losses, claims, damages or liabilities, joint or several, to which such Indemnified Party may become subject, under the Act, the Exchange Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of any material fact contained in any part of any Registration Statement at any time or any Statutory Prospectus as of any time, or arise out of or are based upon the omission or alleged omission of 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 any material fact contained in any part of the General Disclosure Package, the Final Prospectus, any Issuer Free Writing Prospectus or any Written Testing-the-Waters Communication, or arise out of or are based upon the omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances in which they were made, not misleading, and will reimburse each Indemnified Party for any legal or other expenses reasonably incurred by such Indemnified Party in connection with investigating or defending against any loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Indemnified Party is a party thereto), whether threatened or commenced, and in connection with the enforcement of this provision with respect to any of the above as such expenses are incurred; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement in or omission or alleged omission from any of such documents in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in subsection (b) below.

(b)  Indemnification of Company.  Each Underwriter will severally and not jointly indemnify and hold harmless the Company, each of its directors and each of its officers who signs a Registration Statement and each person, if any, who controls the Company within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each, an “Underwriter Indemnified Party”), against any losses, claims, damages or liabilities to which such Underwriter Indemnified Party may become subject, under the Act, the Exchange Act, or other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of any material fact contained in any part of any Registration Statement at any time or any Statutory Prospectus as of any time, or arise out of or are based upon the omission or the alleged omission of 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 any material fact contained in any part of the Final Prospectus, any Written Testing-the-Waters Communication or any Issuer Free Writing Prospectus or arise out of or are based upon the omission or the alleged omission of a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances in which they were made, not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in reliance upon and in conformity with written information furnished to the Company by such Underwriter through the Representatives specifically for use therein, and will reimburse any legal or other expenses reasonably incurred by such Underwriter Indemnified Party in connection with investigating or defending against any such loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Underwriter Indemnified Party is a party thereto), whether threatened or commenced, based upon any such untrue statement or omission, or any such alleged untrue statement or omission as such expenses are incurred, it being understood and agreed that the only such information furnished by any Underwriter consists of the following information in the Final Prospectus furnished on behalf of each Underwriter: the concession figure appearing in the sixth paragraph under the caption “Underwriting”.

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(c)  Actions against Parties; Notification.  Promptly after receipt by an indemnified party under this Section of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under subsection (a) or (b) above, notify the indemnifying party of the commencement thereof; but the failure to notify the indemnifying party shall not relieve it from any liability that it may have under subsection (a) or (b) above except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure; and provided further that the failure to notify the indemnifying party shall not relieve it from any liability that it may have to an indemnified party otherwise than under subsection (a) or (b) above.  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, to the extent that it may wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party will not be liable to such indemnified party under this Section for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof other than reasonable costs of investigation. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened action in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party unless such settlement (i) includes an unconditional release of such indemnified party from all liability on any claims that are the subject matter of such action 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 an indemnified party.

(d)  Contribution.  If the indemnification provided for in this Section is unavailable or insufficient to hold harmless an indemnified party under subsection (a) or (b) above, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of the losses, claims, damages or liabilities referred to in subsection (a) or (b) above (i) 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 Offered Securities or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above 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, claims, damages or liabilities 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 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. 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 or the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The amount paid by an indemnified party as a result of the losses, claims, damages or liabilities referred to in the first sentence of this subsection (d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any action or claim which is the subject of this subsection (d). Notwithstanding the provisions of this subsection (d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Securities 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 Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this subsection (d) to contribute are several in proportion to their respective underwriting obligations and not joint.  The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 8(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 in this Section 8(d).

9.  Default of Underwriters.  If any Underwriter or Underwriters default in their obligations to purchase Offered Securities hereunder on either the First Closing Date or any Optional Closing Date and the aggregate number of Offered Securities that such defaulting Underwriter or Underwriters agreed but failed to purchase does not exceed 10% of the total number of Offered Securities that the Underwriters are obligated to purchase on such Closing Date, the Representatives may make arrangements satisfactory to the Company for the purchase of such Offered Securities by

18

other persons, including any of the Underwriters, but if no such arrangements are made by such Closing Date, the non-defaulting Underwriters shall be obligated severally, in proportion to their respective commitments hereunder, to purchase the Offered Securities that such defaulting Underwriters agreed but failed to purchase on such Closing Date. If any Underwriter or Underwriters so default and the aggregate number of Offered Securities with respect to which such default or defaults occur exceeds 10% of the total number of shares of Offered Securities that the Underwriters are obligated to purchase on such Closing Date and arrangements satisfactory to the Representatives, and the Company for the purchase of such Offered Securities by other persons are not made within 36 hours after such default, this Agreement will terminate without liability on the part of any non-defaulting Underwriter or the Company, except as provided in Section 10 (provided that if such default occurs with respect to Optional Securities after the First Closing Date, this Agreement will not terminate as to the Firm Securities or any Optional Securities purchased prior to such termination). As used in this Agreement, the term “Underwriter” includes any person substituted for an Underwriter under this Section. Nothing herein will relieve a defaulting Underwriter from liability for its default.

10.  Survival of Certain Representations and Obligations.  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 Offered Securities. If the purchase of the Offered Securities by the Underwriters is not consummated for any reason other than any of the events specified in clauses (iii), (iv), (vi), (vii) or (viii) of Section 7(c), or because of the termination of this Agreement pursuant to Section 9 hereof, the Company will reimburse the Underwriters for all out-of-pocket expenses (including fees and disbursements of counsel) reasonably incurred by them in connection with the offering of the Offered Securities, and the respective obligations of the Company and the Underwriters pursuant to Section 8 hereof shall remain in effect.  In addition, if any Offered Securities have been purchased hereunder, the representations and warranties in Section 2 and all obligations under Section 5 shall also remain in effect.

11.  Notices. All communications hereunder will be in writing and, if sent to the Underwriters, will be mailed, delivered or telegraphed and confirmed to the Representatives, c/o Credit Suisse Securities (USA) LLC, Eleven Madison Avenue, New York, N.Y. 10010-3629, Attention:  IBCM-Legal and c/o BMO Capital Markets Corp., 3 Times Square, New York, NY 10036, Attention: ECM Syndicate Desk, with a copy to Legal Department, or, if sent to the Company, will be mailed, delivered or telegraphed and confirmed to it at 35 Gatehouse Drive, Waltham, Massachusetts 02451, Attention: Michael Gutch; provided, however, that any notice to an Underwriter pursuant to Section 8 will be mailed, delivered or telegraphed and confirmed to such Underwriter.

12.  Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and controlling persons referred to in Section 7, and no other person will have any right or obligation hereunder.

13.  Representation of Underwriters.  The Representatives will act for the several Underwriters in connection with the transactions contemplated by this Agreement, and any action under this Agreement taken by the Representatives jointly will be binding upon all the Underwriters.

14.  Counterparts.  This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same Agreement.

15.  Absence of Fiduciary Relationship.  The Company acknowledges and agrees that:

(a)  No Other Relationship.  The Representatives have been retained solely to act as underwriters in connection with the sale of the Offered Securities and that no fiduciary, advisory or agency relationship between the Company, on the one hand, and the Representatives, on the other, has been created in respect of any of the transactions contemplated by this Agreement or the Final Prospectus, irrespective of whether the Representatives have advised or are advising the Company on other matters;

(b) Arms’ Length Negotiations.  The price of the Offered Securities set forth in this Agreement was established by Company following discussions and arms-length negotiations with the Representatives and the

19

Company is capable of evaluating and understanding and understand and accept the terms, risks and conditions of the transactions contemplated by this Agreement;

(c) Absence of Obligation to Disclose.  The Company has been advised that the Representatives and their affiliates are engaged in a broad range of transactions which may involve interests that differ from those of the Company and that the Representatives have no obligation to disclose such interests and transactions to the Company by virtue of any fiduciary, advisory or agency relationship; and

(d)  Waiver.  The Company waives, to the fullest extent permitted by law, any claims it may have against the Representatives for breach of fiduciary duty or alleged breach of fiduciary duty and agrees that the Representatives shall have no liability (whether direct or indirect) to the Company in respect of such a fiduciary duty claim or to any person asserting a fiduciary duty claim on behalf of or in right of the Company, including stockholders, employees or creditors of the Company.

16.  Applicable Law. This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York.

The Company hereby submits to the non-exclusive jurisdiction of the Federal and state courts in the Borough of Manhattan in The City of New York in any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.  The Company irrevocably and unconditionally waives any objection to the laying of venue of any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby in Federal and state courts in the Borough of Manhattan in the City of New York and irrevocably and unconditionally waives and agrees not to plead or claim in any such court that any such suit or proceeding in any such court has been brought in an inconvenient forum.

17. Waiver of Jury Trial. The Company 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.

(Signature page follows)

20

If the foregoing is in accordance with the Representatives’ understanding of our agreement, kindly sign and return to the Company one of the counterparts hereof, whereupon it will become a binding agreement among the Company and the several Underwriters in accordance with its terms.

Very truly yours,

21

SCHEDULE A

22

SCHEDULE B

1.              General Use Free Writing Prospectuses (included in the General Disclosure Package)

“General Use Issuer Free Writing Prospectus” includes each of the following documents:

[None]

2.              Other Information Included in the General Disclosure Package

The following information is also included in the General Disclosure Package:

1.  The initial price to the public of the Offered Securities: $[  ] per share

2.  Firm Securities: [·] shares of common stock.

3.  Optional Securities: [·] shares of common stock.

Exhibit A

Form of Opinion of Counsel to the Company

A-1

Exhibit B

Form of Opinion of Intellectual Property Counsel for the Company

B-1

Exhibit C

Form of Lock-Up Agreement

                        , 2018

Entasis Therapeutics Holdings Inc.

35 Gatehouse Drive

Waltham, MA, 02451

Credit Suisse Securities (USA) LLC

BMO Capital Markets Corp.

As Representatives of the Several Underwriters,

c/o  Credit Suisse Securities (USA) LLC

Eleven Madison Avenue

New York, NY 10010-3629

c/o  BMO Capital Markets Corp.

3 Times Square

New York, NY 10036

Ladies and Gentlemen:

As an inducement to the underwriters to execute the Underwriting Agreement (the “Underwriting Agreement”), pursuant to which an offering (the “Offering”) will be made that is intended to result in the establishment of a public market for the common stock, par value $0.001 per share, (the “Securities”) of Entasis Therapeutics Holdings Inc., and any successor (by merger or otherwise) thereto (the “Company”), the undersigned hereby agrees that during the period specified below (the “Lock-Up Period”), the undersigned will not offer, sell, contract to sell, pledge or otherwise dispose of, directly or indirectly, any Securities or securities convertible into or exchangeable or exercisable for any Securities, 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 Securities, whether any such aforementioned transaction is to be settled by delivery of the Securities 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, without, in each case, the prior written consent of Credit Suisse Securities (USA) LLC and BMO Capital Markets Corp. (the “Representatives”).  In addition, the undersigned agrees that, without the prior written consent of the Representatives, it will not, during the Lock-Up Period, make any demand for or exercise any right with respect to, the registration of any Securities or any security convertible into or exercisable or exchangeable for the Securities.

The Lock-Up Period will commence on the date of this Lock-Up Agreement and continue and include the date that is 180 days after the public offering date set forth on the final prospectus used to sell the Securities (the “Public Offering Date”) pursuant to the Underwriting Agreement.

Notwithstanding the foregoing, and subject to the conditions below, the undersigned may transfer Securities during the Lock-Up Period without the prior written consent of the Representatives, provided that (1) in the case of clauses (i) through (vii) below, each donee, transferee or distributee executes and delivers to the Representatives an agreement in form and substance reasonably satisfactory to the Representatives stating that such donee, transferee or distributee is receiving and holding such Securities subject to the provisions of this Agreement and agrees not to sell or offer to sell such Securities, engage in any swap or engage in any other activities restricted under this Agreement except in accordance with this Agreement (as if such donee, transferee or distributee had been an original signatory hereto), (2) in the case of clauses (i) through (vii) below, any such transfer shall not involve a disposition for value, (3) in the case of clauses (i) through (v) below, such transfers are not required to be reported during the Lock-Up Period with the Securities and Exchange Commission (the “SEC”) under Section 16(a) of the Exchange Act, and (4) in each case, the undersigned does not otherwise voluntarily effect any public filing or report with the SEC regarding such transfers (other than a filing on a Form 5 made after the expiration of the Lock-Up Period):

(i)  the transfer of Securities as a bona fide gift;

(ii) the transfer of Securities to a trust whose beneficiaries consist exclusively of one or more of the undersigned and/or a Family Member;

(iii) the transfer or dispositions of Securities to any corporation, partnership, limited liability company or other legal entity, all of the beneficial ownership interests of which are held by the undersigned or any Family Member or that controls or is controlled by, or is under common control with, the undersigned or any Family Member;

(iv) if the undersigned is a corporation, partnership, limited liability company or other legal entity, any transfers or distributions of Securities to any stockholder, partner or member of, or owner of a similar equity interest in, the undersigned, as the case may be;

(v) in the case of an investment fund, that is managed by, or is under common management with, the undersigned (including, for the avoidance of doubt, a fund managed by the same manager or managing member or general partner or management company or by an entity controlling, controlled by, or under common control with such manager or managing member or general partner or management company as the undersigned or who shares a common investment advisor with the undersigned), distributions of Securities to partners, members, stockholders or other equityholders of the undersigned;

(vi) the transfer of Securities by operation of law, including pursuant to a domestic order or negotiated divorce settlement;

(vii)                 the transfer of Securities by will or intestate succession to the legal representative, heir or beneficiary of the undersigned; or

3

(viii)              the disposition of Securities to the Company, or the withholding of Securities by the Company, in a transaction exempt from Section 16(b) of the Exchange Act solely to the extent required for the payment of taxes due with respect to the vesting of options granted under a stock incentive plan as described in the Prospectus, insofar as such options are outstanding as of the date hereof or as of the date of the Prospectus; provided that any underlying equity securities of the Company shall continue to be subject to the restrictions on transfer set forth in this Agreement.

For purposes of this Lock-Up Agreement, a “Family Member” shall mean any relationship by blood, marriage, domestic partnership or adoption, not more remote than first cousin.

Notwithstanding anything herein to the contrary, nothing herein shall prevent the undersigned from (i) exercising an option or other equity award to purchase Securities, as applicable, granted under any of the Company’s current or future equity incentive plans or equity purchase plans described or referred to in the Prospectus (as defined in the Underwriting Agreement); provided that, the underlying Securities, as applicable, shall continue to be subject to the restrictions on transfer set forth in this Agreement; (ii) establishing a 10b5-1 trading plan that complies with Rule 10b5-1 under the Exchange Act (“10b5-1 Trading Plan”) or from amending an existing 10b5-1 Trading Plan so long as such 10b5-1 Trading Plan does not authorize, and there are no, sales of Securities and no public disclosure of any such action with respect to a 10b5-1 Trading Plan shall be required or shall be voluntarily made by any person during the Lock-Up Period; (iii) transferring or disposing of Securities acquired in the Offering or acquired on the open market following the Offering, provided that the undersigned is not required to make a filing under the Exchange Act reporting a reduction in beneficial ownership of Securities, other than [a filing on Form 13F]1 or pursuant to the annual amendment requirement contained in Rule 13d-2(b) and the requirements contained in Rule 13d-2(d) under the Exchange Act; or (iv) transferring Securities in connection with a bona fide third-party tender offer, merger, consolidation or other similar transaction made to all holders of the Company’s Securities involving a change of control of the Company (including, without limitation, the entering into any lock-up, voting or similar agreement pursuant to which the undersigned may agree to transfer, sell, tender or otherwise dispose of Securities in connection with such transaction, or vote any Securities in favor of any such transaction), provided that in the event that such tender offer, merger, consolidation or other such transaction is not completed, such securities held by the undersigned shall remain subject to the provisions of this Agreement.

In furtherance of the foregoing, the Company and its transfer agent and registrar are hereby authorized to decline to make any transfer of Securities if such transfer would constitute a violation or breach of this Lock-Up Agreement.

If the undersigned is an officer or director of the Company, the undersigned further agrees that the foregoing restrictions in this Lock-Up Agreement shall be equally applicable to any issuer-directed Securities the undersigned may purchase in the above-referenced offering.

If the undersigned is an officer or director of the Company, (i) 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 Securities, the Representatives will notify the Company of the impending release or waiver, and (ii) the Company has agreed in the Underwriting Agreement to announce the impending release or waiver by press release through a major news

1         Bracketed language applies only to institutional holders that beneficially own 5.0% or more of the outstanding Securities of the Company.

4

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 Lock-Up Agreement to the extent and for the duration that such terms remain in effect at the time of the transfer.

[In the event that during the Lock-Up Period, the Representatives release or waive any prohibition on the transfer of Securities held by any director or executive officer of the Company or any person or entity that beneficially owns 3.0% or more of the outstanding Securities, the same percentage of Ordinary Shares held by the undersigned (i.e., the total number of Ordinary Shares owned by the undersigned on the date of the early release, multiplied by a fraction, the numerator of which shall be the number of Ordinary Shares of the Company initially being granted an early release and the denominator of which shall be the total number of Ordinary Shares of the Company owned by the record or beneficial owner initially being granted an early release on the date thereof) (the “Pro-rata Release”) shall be immediately and fully released, without any further action, on the same terms from any remaining lockup restrictions set forth herein; provided, however, that such Pro-rata Release shall not be applied in the event the Representatives release employees of the Company from such lock-up restrictions in an amount less than or equal to $5,000,000 in aggregate value of Ordinary Shares (the value of such Ordinary Shares to be determined based on the closing price on the date that the Ordinary Shares are approved for release). The Representatives shall use reasonable efforts to promptly notify the Company of each such release (provided that the failure to provide such notice shall not give rise to any claim or liability against the Representatives or the Underwriters).  The undersigned further acknowledges that the Representatives are under no obligation to inquire into whether, or to ensure that, the Company notifies the undersigned of the delivery by the Representatives on behalf of the Underwriters of any such notice, which is a matter between the undersigned and the Company.]2

This Lock-Up Agreement (and for the avoidance of doubt, the Lock-Up Period described herein) and related restrictions shall automatically terminate and become null and void upon the earliest to occur, if any, of (i) the Representatives, on behalf of the Underwriters, on the one hand, or the Company, on the other hand, advising the other in writing that they have or it has determined not to proceed with the Offering, (ii) the registration statement with respect to the Offering is withdrawn, (iii) the termination of the Underwriting Agreement (other than the provisions thereof which survive termination) prior to the initial closing date of the sale of the Securities to be sold thereunder or (iv) February 20, 2019, in the event the initial closing of the Securities to be sold under the Underwriting Agreement has not occurred prior to such date. This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York.

[Signature page follows]

2         Bracketed language applies only to institutional holders that beneficially own 5.0% or more of the outstanding Securities of the Company.

5

Very truly yours,

C-1

Exhibit D

Form of Press Release

Entasis Therapeutics Holdings Inc.

[Date]

Entasis Therapeutics Holdings Inc. (the “Company”) announced today that Credit Suisse and BMO Capital Markets, the lead book-running managers in the Company’s recent public sale 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 for sale of the securities in the United States or in any other jurisdiction where such offer 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.

D-1