Hyperion Therapeutics S1/A IPO registration (amended) | HPTX 18 Jun 12

Exhibit 1.1

HYPERION THERAPEUTICS, INC.

(a Delaware corporation)

[ ] Shares of Common Stock

UNDERWRITING AGREEMENT

Dated: , 2012

Hyperion Therapeutics, Inc.

(a Delaware corporation)

[ ] Shares of Common Stock

($0.0001 Par Value Per Share)

UNDERWRITING AGREEMENT

, 2012

Leerink Swann LLC

Cowen and Company, LLC

As Representatives of

the Several Underwriters

c/o	Leerink Swann LLC

One Federal Street, 37^th Floor

Boston, Massachusetts 02110

c/o	Cowen and Company, LLC

599 Lexington Avenue, 27^th Floor

New York, New York 10022

Ladies and Gentlemen:

Hyperion Therapeutics, Inc., a Delaware corporation (the “Company”), confirms its agreement with Leerink Swann LLC (“Leerink Swann”) and Cowen and Company, LLC (“Cowen”) and each of the other Underwriters named inSchedule A hereto (collectively, the “Underwriters,” which term shall also include any underwriter substituted as hereinafter provided in Section 10 hereof), for whom Leerink Swann and Cowen are acting as representatives (in such capacity, the “Representatives”), with respect to (i) the issue and sale by the Company and the purchase by the Underwriters, acting severally and not jointly, of the respective numbers of shares of Common Stock, $0.0001 par value per share, of the Company (“Common Stock”) set forth inSchedule A, and (ii) the grant by the Company to the Underwriters, severally and not jointly, of the option described in Section 2(b) hereof to purchase all or any part of [ ] additional shares of Common Stock to cover overallotments, if any. The aforesaid [ ] shares of Common Stock (the “Initial Securities”) to be purchased by the Underwriters and all or any part of the [ ] shares of Common Stock subject to the option described in Section 2(b) hereof (the “Option Securities”) are hereinafter called, collectively, the “Securities.”

The Company understands that the Underwriters propose to make a public offering of the Securities as soon as the Representatives deem advisable after this Agreement has been executed and delivered.

The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-1 (No. 333-180694), including the related preliminary prospectus or prospectuses, covering the registration of the Securities under the Securities Act of 1933, as amended (the “1933 Act”). Promptly after execution and delivery of this Agreement, the Company will prepare and file a prospectus in accordance with the provisions of Rule 430A (“Rule 430A”) of the rules and regulations of the Commission under the 1933 Act (the “1933 Act Regulations”) and paragraph (b) of Rule 424 (“Rule 424(b)”) of the 1933 Act Regulations. The information included in such prospectus that was omitted from such registration statement at the time it became effective but that is deemed to be part

of and included in such registration statement at the time it became effective pursuant to Rule 430A is referred to as “Rule 430A Information.” Each prospectus used before such registration statement became effective, and any prospectus that omitted the Rule 430A Information that was used after such effectiveness and prior to the execution and delivery of this Agreement, is herein called a “preliminary prospectus.” Such registration statement, including the amendments thereto, the exhibits and any schedules thereto, at the time it became effective, and including the Rule 430A Information, is herein called the “Registration Statement.” Any registration statement filed pursuant to Rule 462(b) of the 1933 Act Regulations is herein referred to as the “Rule 462(b) Registration Statement,” and after such filing, if applicable, the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The final prospectus in the form first furnished to the Underwriters for use in connection with the offering of the Securities is herein called the “Prospectus.” For purposes of this Agreement, all references to the Registration Statement, any preliminary prospectus, the Prospectus or any amendment or supplement to any of the foregoing shall be deemed to include the copy filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval system (“EDGAR”).

All references in this Agreement to financial statements and schedules and other information which is “contained,” “included” or “stated” in the Registration Statement, any preliminary prospectus or the Prospectus (or other references of like import) shall be deemed to mean and include all such financial statements and schedules and other information which is incorporated by reference in or otherwise deemed by 1933 Act Regulations to be a part of or included in the Registration Statement, any preliminary prospectus or the Prospectus, as the case may be.

SECTION 1.Representations and Warranties.

(a)Representations and Warranties by the Company. The Company represents and warrants to each Underwriter as of the date hereof, as of the Applicable Time referred to in Section 1(a)(i) hereof, as of the Closing Time referred to in Section 2(c) hereof, and as of each Date of Delivery (if any) referred to in Section 2(b) hereof, and agrees with each Underwriter, as follows:

(i)Compliance with Registration Requirements. Each of the Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendment thereto has become effective under the 1933 Act and no stop order suspending the effectiveness of the Registration Statement, any Rule 462(b) Registration Statement or any post-effective amendment thereto has been issued under the 1933 Act and no proceedings for that purpose have been instituted or are pending or, to the knowledge of the Company, are contemplated by the Commission, and any request on the part of the Commission for additional information has been complied with.

At the respective times the Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendments thereto became effective and at the Closing Time (and, if any Option Securities are purchased, at the Date of Delivery (as defined below)), the Registration Statement, the Rule 462(b) Registration Statement and any amendments and supplements thereto complied and will comply in all material respects with the requirements of the 1933 Act and the 1933 Act Regulations and did not and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading, and the Prospectus, any preliminary prospectus and any supplement thereto or prospectus wrapper prepared in connection therewith, at their respective times of issuance and at the Closing Time, complied and will comply in all material respects with the requirements of the 1933 Act and the 1933 Act Regulations. Neither the Prospectus nor any amendments or supplements thereto (including any prospectus wrapper), at the time the Prospectus or any such amendment or supplement was issued and at the Closing Time (and, if

any Option Securities are purchased, at the Date of Delivery), included or, as amended or supplemented, as applicable, will include an untrue statement of a material fact or omitted or, as amended or supplemented, as applicable, will omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

As of the Applicable Time (as defined below), neither (x) the Issuer General Use Free Writing Prospectus(es) (as defined below) issued at or prior to the Applicable Time, the Statutory Prospectus (as defined below) and the information included onSchedule B hereto, all considered together (collectively, the “General Disclosure Package”), nor (y) any individual Issuer Limited Use Free Writing Prospectus, when considered together with the General Disclosure Package, nor (z) any Section 5(d) Writing (as defined below), when considered together with 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.

As used in this subsection and elsewhere in this Agreement:

“Applicable Time” means [ ] p.m. (Eastern time) on , 2012 or such other time as agreed upon in writing by the Company and the Representatives.

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433 of the 1933 Act Regulations (“Rule 433”), relating to the Securities that (i) is required to be filed with the Commission by the Company, (ii) is a “road show for an offering that is a written communication” within the meaning of Rule 433(d)(8)(i) whether or not required to be filed with the Commission or (iii) is exempt from filing pursuant to Rule 433(d)(5)(i) because it contains a description of the Securities or of the offering that does not reflect the final terms, in each case in the form filed or required to be filed with the Commission or, if not required to be filed, in the form required to be retained in the Company’s records pursuant to Rule 433(g).

“Issuer General Use Free Writing Prospectus” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors (other than a “bona fideelectronic road show,” as defined in Rule 433), as evidenced by its being specified inSchedule D hereto.

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

“Statutory Prospectus” as of any time means the prospectus relating to the Securities that is included in the Registration Statement immediately prior to that time, including any document incorporated by reference therein and any preliminary or other prospectus deemed to be a part thereof.

The Company has made available a “bona fide electronic road show” in compliance with Rule 433(d)(8)(ii) such that no filing of any “road show” (as defined in Rule 433(h)) is required in connection with the offering of the Securities.

Any oral or written communication with potential investors undertaken in reliance on Section 5(d) of the 1933 Act is hereinafter called a “Section 5(d) Communication”; and any Section 5(d) Communication that is a written communication within the meaning of Rule 405 under the 1933 Act is hereinafter called a “Section 5(d) Writing”.

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 Securities or until any earlier date that the issuer notified or notifies the Representatives as described in Section 3(e), did not, does not and will not include any information that conflicted, conflicts or will conflict with the information contained in the Registration Statement or the Prospectus and any preliminary or other prospectus deemed to be a part thereof that has not been superseded or modified.

The representations and warranties in this subsection shall not apply to statements in or omissions from the Registration Statement, the Prospectus or any Issuer Free Writing Prospectus, or any amendment or supplement to any of the foregoing, made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives expressly for use therein.

Each preliminary prospectus (including the prospectus filed as part of the Registration Statement as originally filed or as part of any amendment thereto) complied when so filed in all material respects with the 1933 Act Regulations and each preliminary prospectus and the Prospectus delivered to the Underwriters for use in connection with this offering was identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

At the time of filing the Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendments thereto and at the date hereof, the Company was not and is not an “ineligible issuer,” as defined in Rule 405 of the 1933 Act Regulations.

(ii)Independent Accountants. The accountants who certified the financial statements and supporting schedules included in the Registration Statement are independent public accountants as required by the 1933 Act and the 1933 Act Regulations and Rule 3600T of the Public Company Accounting Oversight Board.

(iii)Financial Statements. The financial statements included in the Registration Statement, the General Disclosure Package and the Prospectus, together with the related schedules and notes, present fairly the financial condition of the Company and its consolidated subsidiaries as of the respective dates thereof and the results of operations and cash flows of the Company and its consolidated subsidiaries for the respective periods covered thereby, all in conformity with generally accepted accounting principles (“GAAP”) applied on a consistent basis throughout the periods involved. The selected consolidated financial data included in the Registration Statement, the General Disclosure Package and the Prospectus present fairly the information shown therein and have been derived on a basis consistent with the audited financial statements presented therein.

(iv)No Material Adverse Change in Business. Subsequent to the respective dates as of which information is given in the Registration Statement, the General Disclosure Package or the Prospectus, except as set forth in or contemplated thereby (exclusive of any amendments or supplements thereto subsequent to the date of this Agreement), (A) there has not occurred any material adverse change, or any development involving a prospective material adverse change, in the condition, financial or otherwise, or in the earnings, business, prospects or operations of the Company and its subsidiaries, taken as a whole (a “Material Adverse Effect”), (B) there has not been any change in the capitalization of the Company, other than a change in the number of outstanding shares of Common Stock due to the issuance of shares upon the exercise of outstanding options or warrants of which the Underwriters have been advised in writing and that are described in the Registration Statement or the General Disclosure Package, as applicable, (C)

the Company has not incurred any material liabilities or obligations, direct or contingent, nor entered into any material transaction, and (D) the Company has not and will not have paid or declared any dividends or other distributions of any kind on any class of its capital stock.

(v)Good Standing of the Company. The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware, with corporate power and authority to own its properties and conduct its business as described in the General Disclosure Package and the Prospectus, and is duly qualified to do business as a foreign corporation in good standing in all other jurisdictions in which such qualification is required, whether by reason of its ownership or lease of property or the conduct of its business, except to the extent that the failure to be so qualified or be in good standing would not reasonably be expected to result in a Material Adverse Effect.

(vi)Good Standing of Subsidiaries. Each “significant subsidiary” of the Company (as such term is defined in Rule 1-02 of Regulation S-X) (each, a “Subsidiary” and, collectively, the “Subsidiaries”) has been duly incorporated or organized and is validly existing as a corporation or other valid legal entity in good standing under the laws of the jurisdiction of its incorporation or organization, with corporate power and authority to own its properties and conduct its business as described in the General Disclosure Package, and is duly qualified to do business as a foreign corporation in good standing in all other jurisdictions in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except to the extent that the failure to be so qualified or be in good standing would not reasonably be expected to have a Material Adverse Effect; except as otherwise disclosed in the Registration Statement, all of the issued and outstanding capital stock of each such Subsidiary has been duly authorized and validly issued, is fully paid and non-assessable and is owned by the Company, directly or through subsidiaries, free and clear of any security interest, mortgage, pledge, lien, encumbrance, claim or equity; and none of the outstanding shares of capital stock of any Subsidiary was issued in violation of the preemptive or similar rights of any security holder of such Subsidiary. The only subsidiaries of the Company are the subsidiaries listed on Exhibit 21 to the Registration Statement.

(vii)Capitalization. The authorized, issued and outstanding capital stock of the Company is as set forth in the Prospectus (except for subsequent issuances, if any, pursuant to this Agreement, pursuant to reservations, agreements or employee benefit or equity incentive plans described in the Prospectus or pursuant to the exercise or conversion of convertible securities or options referred to in the Prospectus). The shares of issued and outstanding capital stock of the Company have been duly authorized and validly issued and are fully paid and non-assessable; and none of the outstanding shares of capital stock of the Company have been issued in violation of preemptive or similar rights of any security holder of the Company.

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

(ix)Authorization and Description of Securities. The Securities to be purchased by the Underwriters from the Company have been duly authorized for issuance and sale to the Underwriters pursuant to this Agreement and, when issued and delivered by the Company pursuant to this Agreement against payment of the consideration set forth herein, will be validly issued and fully paid and non-assessable; the Common Stock conforms as to legal matters in all material respects to the description thereof contained in the General Disclosure Package and the Prospectus and such description conforms to the rights set forth in the instruments defining the same; no holder of the Securities will be subject to personal liability by reason of being such a

holder; and the issuance of the Securities is not subject to any preemptive or other similar rights of any security holder of the Company that have not been validly waived.

(x)Absence of Defaults and Conflicts. Neither the Company nor any of its subsidiaries is (A) in violation of its charter or by-laws or (B) in default in the performance or observance of any obligation, agreement, covenant or condition contained in any contract, indenture, mortgage, deed of trust, loan or credit agreement, note, lease or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which it or any of them may be bound, or to which any of the property or assets of the Company or any subsidiary is subject (collectively, “Agreements and Instruments”), except for such defaults that would not have a Material Adverse Effect; and the execution, delivery and performance of this Agreement and the consummation of the transactions contemplated herein (including the issuance and sale of the Securities and the use of the proceeds from the sale of the Securities as described in the Prospectus under the caption “Use of Proceeds”) and compliance by the Company with its obligations hereunder have been duly authorized by all necessary corporate action and do not and will not, whether with or without the giving of notice or passage of time or both, conflict with or constitute a breach of, or default or Repayment Event (as defined below) under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, the Agreements and Instruments (except for such conflicts, breaches, defaults or Repayment Events or liens, charges or encumbrances that would not have a Material Adverse Effect), nor will such action result in any violation of the provisions of the charter or by-laws of the Company or any of its subsidiaries, any applicable law, statute, rule, regulation, judgment, order, writ or decree of any government, government instrumentality or court, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their assets, properties or operations. As used herein, a “Repayment Event” means any event or condition which gives 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.

(xi)Absence of Labor Dispute. No labor problem or dispute with the employees of the Company or any of its subsidiaries exist or, to the Company’s knowledge, is threatened or imminent, and the Company is not aware of any existing, threatened or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers or contractors that could have a Material Adverse Effect. The Company is not aware that any key employee or significant group of employees of the Company plans to terminate employment with the Company.

(xii)Absence of Proceedings. There are no legal or governmental proceedings pending or, to the Company’s knowledge, threatened, to which the Company or any of its subsidiaries is a party or to which any of the properties of the Company or any of its subsidiaries is subject (A) other than proceedings accurately described in all material respects in the General Disclosure Package and proceedings that would not have a Material Adverse Effect or, if determined adversely to the Company, would not materially and adversely affect the power or ability of the Company to perform its obligations under this Agreement or to consummate the transactions contemplated by the General Disclosure Package or (ii) that are required to be described in the Registration Statement or the General Disclosure Package and are not so described; and there are no statutes, regulations, contracts or other documents that are required to be described in the Registration Statement or the General Disclosure Package or to be filed as exhibits to the Registration Statement that are not described or filed as required. The General

Disclosure Package contains in all material respects the same description of the foregoing matters contained in the Prospectus.

(xiii)Possession of Intellectual Property. The Company owns, possesses or has valid, binding and enforceable rights to use the Company Intellectual Property (as defined below). Except as described in the General Disclosure Package and the Prospectus, (A) neither the Company nor any of its subsidiaries has received any written notice, nor to the Company’s knowledge, any other notice, of any infringement by the Company or any of its subsidiaries with respect to any Intellectual Property (as defined below) of any third party, (B) the Company Intellectual Property and the discoveries, inventions, products or processes of the Company or any of its subsidiaries described in the General Disclosure Package or the Prospectus do not, to the Company’s knowledge, infringe or interfere with any right or valid patent claim of any third party, (C) the Company is not obligated to pay a royalty, grant a license or provide other consideration to any third party in connection with the Company Intellectual Property, (D) no third party has any ownership rights in or to any Company Intellectual Property. Except as described in the General Disclosure Package and the Prospectus or as would not reasonably be expected to have a Material Adverse Effect, (1) the Company is not aware of any facts or circumstances that constitute an infringement by the Company of any valid claim of a third-party patent, (2) the Company is not aware of any facts or circumstances that constitute an infringement by the Company of, or conflict with, any non-patented Intellectual Property right of any third party, and (3) the Company is not aware of any facts or circumstances that would render any Company Intellectual Property invalid or unenforceable. All Company Intellectual Property consisting of patents and patent applications (the “Company Patents”) has been duly and properly filed; the Company is not aware of any material information required to be disclosed to the United States Patent and Trademark Office (the “PTO”) that were not disclosed to the PTO and which would preclude the grant of a patent for the Company Patents; and the Company is not aware of any facts which would preclude it from having clear title to the Company Patents that have been identified by the Company as being owned by the Company. For purposes of this Agreement, “Intellectual Property” means patents, patent rights, trademarks, servicemarks, trade dress rights, copyrights, trade names and domain names, and all registrations and applications for each of the foregoing, trade secrets, know-how (including other unpatented and/or unpatentable proprietary or confidential information, systems or procedures), inventions and technology, and “Company Intellectual Property” means Intellectual Property that is reasonably necessary or used in any material respect to conduct the business now operated and as planned to be operated by the Company and its subsidiaries, taken as a whole, as described in the General Disclosure Package and the Prospectus.

(xiv)Absence of Further Requirements. No consent, approval, authorization or order of, or any filing or declaration with, any court or governmental agency or body is required for the consummation by the Company of the transactions contemplated herein, including the offering and sale of the Securities, except such as have been obtained or as may be required under the 1933 Act, the 1933 Act Regulations, state securities laws or the rules and regulations of the Financial Industry Regulatory Authority, Inc. (“FINRA”) or The NASDAQ Stock Market.

(xv)Absence of Manipulation. Neither the Company nor any of its subsidiaries has taken, nor will the Company or any of its subsidiaries take, directly or indirectly, any action which is designed to or which has constituted or which would reasonably be expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

(xvi)Possession of Licenses and Permits. The Company possesses all certificates, authorizations, registrations, permits, licenses, approvals and consents (collectively, “Governmental Licenses”) issued by the appropriate federal, state, local or foreign regulatory agencies or bodies necessary to conduct the business of the Company and its subsidiaries, taken as a whole, as described in the General Disclosure Package and the Prospectus, including without limitation, all such certificates, authorizations, registrations, permits, licenses, approvals and consents required by the United States Food and Drug Administration (the “FDA”) or any other federal, state, local or foreign agencies or bodies engaged in the regulation of clinical trials and pharmaceuticals, except where the failure so to possess such Governmental Licenses would not, singly or in the aggregate, have a Material Adverse Effect; the Company is in compliance with the terms and conditions of all such Governmental Licenses, except where the failure so to comply would not, singly or in the aggregate, have a Material Adverse Effect; all of the Governmental Licenses are valid and in full force and effect, except when the invalidity of such Governmental Licenses or the failure of such Governmental Licenses to be in full force and effect would not, singly or in the aggregate, have a Material Adverse Effect; and the Company has not received any written notice of proceedings relating to the revocation or modification of any such Governmental Licenses which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would have a Material Adverse Effect. To the extent required by applicable laws and regulations of the FDA, the Company has submitted to the FDA an Investigational New Drug Application or amendment or supplement thereto for each clinical trial it has conducted or sponsored or is conducting or sponsoring; all such submissions were in material compliance with applicable laws and rules and regulations when submitted and no material deficiencies have been asserted by the FDA with respect to any such submissions.

(xvii)Preclinical Studies and Tests and Clinical Trials. The Company has operated and currently is in compliance with the United States Federal Food, Drug, and Cosmetic Act, all applicable rules and regulations of the FDA and other federal, state, local and foreign governmental bodies exercising comparable authority, except where the failure to so operate or be in compliance would not have a Material Adverse Effect. The preclinical studies and tests and clinical trials conducted by or on behalf of the Company that are described in the General Disclosure Package or the Prospectus were, and, if still pending, are being, conducted in all material respects in accordance with experimental protocols, procedures and controls pursuant to, where applicable, accepted professional and scientific standards for products or product candidates comparable to those being developed by the Company; the descriptions of such studies, tests and trials, and the results thereof, conducted by or on behalf of the Company contained in the General Disclosure Package or the Prospectus are accurate and complete in all material respects; the Company is not aware of any tests, studies or trials not described in the General Disclosure Package and the Prospectus, the results of which reasonably call into question the results of the tests, studies and trials described in the General Disclosure Package and the Prospectus; and the Company has not received any written notice or correspondence from the FDA or any foreign, state or local governmental body exercising comparable authority or any Institutional Review Board or comparable authority requiring the termination, suspension, clinical hold or material modification of any tests, studies or trials, which termination, suspension, clinical hold or material modification would have a Material Adverse Effect.

(xviii)Title to Property. Neither the Company nor any of its subsidiaries own any real property. Each of the Company and its subsidiaries has good title to all other properties owned by them that are material to the business of the Company and its subsidiaries, taken as a whole, in each case, free and clear of all mortgages, pledges, liens, security interests, claims, restrictions or encumbrances of any kind except such as (A) are described in the General Disclosure Package and the Prospectus or (B) do not singly or in the aggregate, materially affect the value of such

property and do not materially interfere with the use made and proposed to be made as described in the General Disclosure Package and the Prospectus of such property by the Company; and all of the leases and subleases material to the business of the Company and its subsidiaries, taken as a whole, and under which the Company or any of its subsidiaries holds properties described in the General Disclosure Package or the Prospectus, are in full force and effect, and, except as described in the General Disclosure Package and the Prospectus, neither the Company nor any of its subsidiaries has any notice of any material claim of any sort that has been asserted by anyone adverse to the rights of the Company or any of its subsidiaries under any of the leases or subleases mentioned above, or affecting or questioning the rights of the Company or any of its subsidiaries to the continued possession of the leased or subleased premises under any such lease or sublease.

(xix)Investment Company Act. The Company is not required, and upon the issuance and sale of the Securities as herein contemplated and the application of the net proceeds therefrom as described in the Prospectus will not be required, to register as an “investment company” under the Investment Company Act of 1940, as amended (the “1940 Act”).

(xx)Environmental Laws. The Company and each of its subsidiaries (A) are in compliance with any and all applicable federal, state, local and foreign laws, rules, regulations, decisions and orders relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”); (B) have received and are in compliance with all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their business; and (C) have not received notice of any actual or potential liability for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants, except in each case as would not, individually or in the aggregate, have a Material Adverse Effect.

(xxi)Registration Rights. No person has any right to have any securities registered pursuant to the Registration Statement, which rights have not been waived or complied with, nor, except as set forth in the General Disclosure Package and the Prospectus, are there any persons with rights to have any securities otherwise registered by the Company under the 1933 Act.

(xxii)Accounting Controls. The Company and each of its subsidiaries maintain a system of internal accounting controls sufficient to provide reasonable assurance that (A) transactions are executed in accordance with management’s general or specific authorizations; (B) transactions are recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain accountability for assets; (C) access to assets is permitted only in accordance with management’s general or specific authorization; and (D) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. Except as described in the General Disclosure Package and the Prospectus, since the end of the Company’s most recent audited fiscal year, there has been (1) no material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (2) no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

(xxiii)Compliance with the Sarbanes-Oxley Act. The Company has taken all necessary actions to ensure that, upon effectiveness of the Registration Statement, it will be in compliance with all provisions of the Sarbanes-Oxley Act of 2002 and all rules and regulations promulgated thereunder or implementing the provisions thereof (the “Sarbanes-Oxley Act”) that are then in effect and which the Company is required to comply with as of the effectiveness of the

Registration Statement, and is actively taking such steps as are necessary to ensure that it will be in compliance with other provisions of the Sarbanes-Oxley Act not currently in effect, upon the effectiveness of such provisions, or which will become applicable to the Company at all times after the effectiveness of the Registration Statement.

(xxiv)FINRA Matters. Except as disclosed in writing to the Representatives, neither the Company nor, to the Company’s knowledge, the Company’s officers, directors or affiliates (within the meaning of FINRA Conduct Rule 2720(f)), directly or indirectly controls, is controlled by, or is under common control with, or is an associated person (within the meaning of Article I, paragraph (ff) of the By-laws of FINRA) of any member firm of FINRA.

(xxv)Payment of Taxes. The Company and its subsidiaries have filed all United States federal income tax returns that have been required to be filed and have paid all taxes shown thereon or otherwise assessed, which are due and payable, except assessments against which appeals have been or will be promptly taken and as to which adequate reserves have been provided. The United States federal income tax returns of the Company through the fiscal year ended December 31, 2007 have been settled and no assessment in connection therewith has been made against the Company. The Company and its subsidiaries have filed all other tax returns that are required to have been filed by them pursuant to applicable state, local or foreign law, except insofar as the failure to file such returns would not have a Material Adverse Effect, and have paid all taxes shown thereon or otherwise assessed, which are due and payable, except assessments against which appeals have been or will be promptly taken and as to which adequate reserves have been provided. Neither the Company nor any of its subsidiaries has any tax deficiency that has been or, to the best knowledge of the Company, might be asserted or threatened against them that would have a Material Adverse Effect.

(xxvi)Insurance. The Company and its subsidiaries carry or are entitled to the benefits of insurance, with financially sound and reputable insurers, in such amounts and covering such risks as is generally maintained by companies of established repute engaged in the same or similar business and at the same or a similar stage of development, and all such insurance is in full force and effect. The Company has no reason to believe that it or any of its subsidiaries will not be able to (A) renew its existing insurance coverage as and when such policies expire or (B) obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that would not have a Material Adverse Effect. Neither the Company nor any of its subsidiaries has been denied any insurance coverage which it has sought or for which it has applied.

(xxvii)Statistical and Market-Related Data. Any statistical and market-related data included in the Registration Statement, the General Disclosure Package or the Prospectus are based on or derived from sources that the Company believes to be reliable and accurate in all material respects, and, to the extent required by such sources, the Company has obtained the written consent to the use of such data from such sources

(xxviii)Foreign Corrupt Practices Act. Neither the Company nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or other person acting on behalf of the Company is aware of or has taken any action, directly or indirectly, that would result in a violation by such persons of the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder (the “FCPA”), including, without limitation, making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any “foreign official” (as

such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA; and the Company, and, to the knowledge of the Company, its affiliates have conducted their businesses in compliance with the FCPA, and have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith.

(xxix)Money Laundering Laws. The operations of the Company are and have been conducted at all times in material compliance with applicable financial recordkeeping, 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 reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all applicable jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “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 Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

(xxx)OFAC. Neither the Company nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or person acting on behalf of the Company is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”); and the Company will not directly or indirectly use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

(xxxi)No Broker Fees. Except as disclosed in the General Disclosure Package, 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 the offering of the Shares contemplated hereby.

(xxxii)No Integration. Except as described in the General Disclosure Package and the Registration Statement, the Company has not sold, issued or distributed any shares of Common Stock during the six-month period preceding the date hereof, including any sales pursuant to Rule 144A under, or Regulation D or S of, the 1933 Act, other than shares issued pursuant to employee benefit plans, qualified stock option plans or other employee compensation plans or pursuant to outstanding options, rights or warrants.

(xxxiii)JOBS Act. From the time of initial filing of the Registration Statement with 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 communication in reliance on Section 5(d) of the 1933 Act) through the date hereof, the Company has been and is an “emerging growth company,” as defined in Section 2(a) of the 1933 Act (an “Emerging Growth Company”).

(xxxiv)Testing the Waters. The Company represents and agrees that (i) it has not engaged in, or authorized any other person to engage in, any Section 5(d) Communications, other than Section 5(d) Communications with the prior consent of the Representatives with entities that are qualified institutional buyers as defined in Rule 144A under the 1933 Act or institutions that are accredited investors as defined in Rule 501(a) under the 1933 Act; and (ii) it has not distributed, or authorized any other person to distribute, any Section 5(d) Writings, other than

those distributed with the prior consent of the Representatives that are listed on Schedule E hereto; and the Company reconfirms that the Underwriters have been authorized to act on its behalf in engaging in Section 5(d) Communications.

(b)Officer’s Certificates. Any certificate signed by any officer of the Company or any of its subsidiaries delivered to the Representatives or to counsel for the Underwriters shall be deemed a representation and warranty by the Company to each Underwriter as to the matters covered thereby.

SECTION 2.Sale and Delivery to Underwriters; Closing.

(a)Initial Securities. On the basis of the representations and warranties herein contained and subject to the terms and conditions herein set forth, the Company agrees to sell to each Underwriter, severally and not jointly, and each Underwriter, severally and not jointly, agrees to purchase from the Company, at the price per share set forth inSchedule B, the number of Initial Securities set forth inSchedule A opposite the name of such Underwriter, plus any additional number of Initial Securities which such Underwriter may become obligated to purchase pursuant to the provisions of Section 10 hereof.

(b)Option Securities. In addition, on the basis of the representations and warranties herein contained and subject to the terms and conditions herein set forth, the Company hereby grants an option to the Underwriters, severally and not jointly, to purchase up to an additional [ ] shares of Common Stock, at the price per share set forth inSchedule B, less an amount per share equal to any dividends or distributions declared by the Company and payable on the Initial Securities but not payable on the Option Securities. The option hereby granted will expire 30 days after the date hereof and may be exercised in whole or in part from time to time only for the purpose of covering overallotments which may be made in connection with the offering and distribution of the Initial Securities upon notice by the Representatives to the Company setting forth the number of Option Securities as to which the several Underwriters are then exercising the option and the time and date of payment and delivery for such Option Securities. Any such time and date of delivery (a “Date of Delivery”) shall be determined by the Representatives, but shall not be later than seven full business days after the exercise of said option, nor in any event prior to the Closing Time, as hereinafter defined. If the option is exercised as to all or any portion of the Option Securities, each of the Underwriters, acting severally and not jointly, will purchase that proportion of the total number of Option Securities then being purchased which the number of Initial Securities set forth inSchedule A opposite the name of such Underwriter bears to the total number of Initial Securities, subject in each case to such adjustments as the Representatives in their discretion shall make to eliminate any sales or purchases of fractional shares.

(c)Payment. Payment of the purchase price for, and delivery of certificates for, the Initial Securities shall be made at the offices of Hogan Lovells US LLP, 525 University Avenue, 3^rd Floor, Palo Alto, CA 94301 or at such other place as shall be agreed upon by the Representatives and the Company, at 9:00 A.M. (Eastern time) on the fourth (third, if the pricing occurs before 4:30 P.M. (Eastern time) on any given day) business day after the date hereof (unless postponed in accordance with the provisions of Section 10), or such other time not later than ten business days after such date as shall be agreed upon by the Representatives and the Company (such time and date of payment and delivery being herein called “Closing Time”).

In addition, in the event that any or all of the Option Securities are purchased by the Underwriters, payment of the purchase price for, and delivery of certificates for, such Option Securities shall be made at the above-mentioned offices, or at such other place as shall be agreed upon by the Representatives and the Company, on each Date of Delivery as specified in the notice from the Representatives to the Company.

Payment shall be made to the Company by wire transfer of immediately available funds to a bank account designated by the Company against delivery to the Representatives for the respective accounts of the Underwriters of certificates for the Securities to be purchased by them. It is understood that each Underwriter has authorized the Representatives, for its account, to accept delivery of, receipt for, and make payment of the purchase price for, the Initial Securities and the Option Securities, if any, which it has agreed to purchase. Subject to Section 10, Leerink Swann or Cowen, individually and not as representative of the Underwriters, may (but shall not be obligated to) make payment of the purchase price for the Initial Securities or the Option Securities, if any, to be purchased by any Underwriter whose funds have not been received by the Closing Time or the relevant Date of Delivery, as the case may be, but such payment shall not relieve such Underwriter from its obligations hereunder.

(d)Denominations; Registration. The Initial Securities and the Option Securities, if any, shall be in such denominations and registered in such names as the Representatives may request in writing at least one full business day before the Closing Time or the relevant Date of Delivery, as the case may be. If the Representatives so elect, delivery of the Initial Securities and the Option Securities may be made by credit through full fast transfer to the accounts at The Depository Trust Company designated by the Representatives. Certificates representing the Initial Securities and the Option Securities, if any, will be made available for examination and packaging by the Representatives in The City of New York not later than 10:00 A.M. (Eastern time) on the business day prior to the Closing Time or the relevant Date of Delivery, as the case may be.

SECTION 3.Covenants of the Company. The Company covenants with each Underwriter as follows:

(a)Compliance with Securities Regulations and Commission Requests. The Company, subject to Section 3(b), will comply with the requirements of Rule 430A, and will notify the Representatives immediately, and confirm the notice in writing, (i) when any post-effective amendment to the Registration Statement shall become effective, or any supplement to the Prospectus or any amended Prospectus shall have been filed, (ii) of the receipt of any comments from the Commission, (iii) of any request by the Commission for any amendment to the Registration Statement or any amendment or supplement to the Prospectus or for additional information, (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any order preventing or suspending the use of any preliminary prospectus, or of the suspension of the qualification of the Securities for offering or sale in any jurisdiction, or of the initiation or threatening of any proceedings for any of such purposes or of any examination pursuant to Section 8(e) of the 1933 Act concerning the Registration Statement and (v) if the Company becomes the subject of a proceeding under Section 8A of the 1933 Act in connection with the offering of the Securities. The Company will effect the filings required under Rule 424(b), in the manner and within the time period required by Rule 424(b) (without reliance on Rule 424(b)(8)), and will take such steps as it deems necessary to ascertain promptly whether the form of prospectus transmitted for filing under Rule 424(b) was received for filing by the Commission and, in the event that it was not, it will promptly file such prospectus. The Company will make every reasonable effort to prevent the issuance of any stop order and, if any stop order is issued, to obtain the lifting thereof at the earliest possible moment.

(b)Filing of Amendments and Exchange Act Documents. The Company will give the Representatives notice of its intention to file or prepare any amendment to the Registration Statement (including any filing under Rule 462(b)) or any amendment, supplement or revision to either any preliminary prospectus (including any prospectus included in the Registration Statement at the time it became effective) or to the Prospectus, and will furnish the Representatives with copies of any such documents a reasonable amount of time prior to such proposed filing or use, as the case may be, and will not file or use any such document to which the Representatives or counsel for the Underwriters shall

object. The Company has given the Representatives notice of any filings made pursuant to the Securities Exchange Act of 1934, as amended (the “1934 Act”), or the rules and regulations of the Commission under the 1934 Act (the “1934 Act Regulations”) within 48 hours prior to the Applicable Time; the Company will give the Representatives notice of its intention to make any such filing from the Applicable Time to the Closing Time and will furnish the Representatives with copies of any such documents a reasonable amount of time prior to such proposed filing, as the case may be, and will not file or use any such document to which the Representatives or counsel for the Underwriters shall object.

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

(d)Delivery of Prospectuses. The Company has delivered to each Underwriter, without charge, as many copies of each preliminary prospectus as such Underwriter reasonably requested, and the Company hereby consents to the use of such copies for purposes permitted by the 1933 Act. The Company will furnish to each Underwriter, without charge, during the period when the Prospectus is required to be delivered under the 1933 Act, such number of copies of the Prospectus (as amended or supplemented) as such Underwriter may reasonably request. The Prospectus and any amendments or supplements thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

(e)Continued Compliance with Securities Laws. The Company will comply with the 1933 Act and the 1933 Act Regulations so as to permit the completion of the distribution of the Securities as contemplated in this Agreement and in the Prospectus. If at any time when a prospectus is required by the 1933 Act to be delivered in connection with sales of the Securities, any event shall occur or condition shall exist as a result of which it is necessary, in the opinion of counsel for the Underwriters or for the Company, to amend the Registration Statement or amend or supplement the Prospectus in order that the Prospectus will not include any untrue statements of a material fact or omit to state a material fact necessary in order to make the statements therein not misleading in the light of the circumstances existing at the time it is delivered to a purchaser, or if it shall be necessary, in the opinion of such counsel, at any such time to amend the Registration Statement or amend or supplement the Prospectus in order to comply with the requirements of the 1933 Act or the 1933 Act Regulations, the Company will promptly prepare and file with the Commission, subject to Section 3(b), such amendment or supplement as may be necessary to correct such statement or omission or to make the Registration Statement or the Prospectus comply with such requirements, and the Company will furnish to the Underwriters such number of copies of such amendment or supplement as the Underwriters may reasonably request. 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 contained in the Registration Statement relating to the Securities or 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, prevailing at that subsequent time, not misleading, the Company will promptly notify the Representatives and will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

(f)Blue Sky Qualifications. The Company will use its commercially reasonable efforts, in cooperation with the Underwriters, to qualify the Securities for offering and sale under the applicable securities laws of such states and other jurisdictions (domestic or foreign) as the Representatives may designate and to maintain such qualifications in effect so as to permit the completion of the distribution of the Securities as contemplated in this Agreement and in the Prospectus;provided,however, that the Company shall not be obligated to file any general consent to service of process or to qualify as a foreign corporation or as a dealer in securities in any jurisdiction in which it is not so qualified or to subject itself to taxation in respect of doing business in any jurisdiction in which it is not otherwise so subject.

(g)Rule 158. The Company will timely file such reports pursuant to the 1934 Act as are necessary in order to make generally available to its security holders as soon as practicable an earnings statement for the purposes of, and to provide to the Underwriters the benefits contemplated by, the last paragraph of Section 11(a) of the 1933 Act.

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

(i)Listing. The Company will use its reasonable best efforts to effect and maintain the listing of the Securities on the NASDAQ Global Market.

(j)Restriction on Sale of Securities. For the period specified below (the “Lock-Up Period”), the Company will not, directly or indirectly, without the written consent of Leerink Swann and Cowen: (i) offer, sell, contract to sell, pledge, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of any shares of Common Stock or any securities convertible into or exercisable or exchangeable for or that represent the right to receive shares of Common Stock, (ii) enter into any swap or any other agreement that transfers to another, in whole or in part, any of the economic consequences of ownership of Common Stock, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise, or (iii) file with the Commission a registration statement under the 1933 Act relating to the offering of any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock, or publicly disclose the intention to take any such action. The foregoing sentence shall not apply to (a) the Securities to be sold hereunder, (b) the issuance by the Company of shares of Common Stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof of which the Underwriters have been advised in writing or that is described in the General Disclosure Package and the Prospectus, (c) the grant by the Company of stock options or other stock-based awards (or the issuance of shares of Common Stock upon exercise thereof) to eligible participants pursuant to employee benefit or equity incentive plans of the Company described in the General Disclosure Package and the Prospectus;provided that, prior to the grant of any such stock options or other stock-based awards that vest within the Lock-Up Period, each recipient of such grant shall sign and deliver a lock-up agreement substantially in the form ofExhibit A hereto, or (d) the filing of a registration statement on Form S-8 or any successor form thereto with respect to the registration of securities to be offered under any employee benefit or equity incentive plans of the Company described in the General Disclosure Package and the Prospectus to the Company’s “employees” (as that term is used in Form S-8). The initial Lock-Up Period will commence on the date hereof and continue for 180 days after the date of the Prospectus or such earlier date that Leerink and Cowen consent to in writing. Notwithstanding the foregoing, if (A) during the last 17 days of the initial 180-day Lock-Up Period the Company releases earnings results or announces material news or a material event relating to the Company occurs; or (B) prior to the expiration of the initial 180-day Lock-Up Period, the Company announces that it will release earnings results during the 15-day period beginning on the last day of the 180-day period, the Lock-Up Period shall be automatically extended and continue until the expiration of the 18-day period beginning on the date of the issuance of the earnings release or the occurrence

of the material news or material event. The Company shall promptly notify Leerink Swann and Cowen of any earnings release, news or event that may give rise to an extension of the initial 180-day Lock-Up Period.

(k)Waiver or Release. If Leerink and Cowen, in their sole discretion, consent in writing to the release or waiver of the restrictions set forth in the lock-up agreements for an officer or director of the Company, and provide the Company with notice of the impending release or waiver, the Company agrees to announce the impending release or waiver by a press release substantially in the form ofExhibit C hereto through a major news service at least two business days before the effective date of the release or waiver.

(l)Reporting Requirements. The Company, during the period when the Prospectus is required to be delivered under the 1933 Act, will file all documents required to be filed with the Commission pursuant to the 1934 Act within the time periods required by the 1934 Act and the rules and regulations of the Commission thereunder.

(m)Issuer 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 Securities that would constitute an “issuer free writing prospectus,” as defined in Rule 433, 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 Representatives or by the Company and the Representatives, as the case may be, 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 Rule 433 applicable to any Permitted Free Writing Prospectus, including timely filing with the Commission where required, legending and record keeping.

(n)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 (a) completion of the distribution of the Securities within the meaning of the 1933 Act and (b) completion of the Lock-Up Period referred to in Section 3(j) hereof.

SECTION 4.Payment of Expenses.

(a)Expenses. The Company will pay or cause to be paid all expenses incident to the performance of its obligations under this Agreement, including (i) the preparation, printing and filing of the Registration Statement (including financial statements and exhibits) as originally filed and of each amendment thereto, (ii) the preparation, printing and delivery to the Underwriters of this Agreement, any Agreement among Underwriters and such other documents as may be required in connection with the offering, purchase, sale, issuance or delivery of the Securities, (iii) the preparation, issuance and delivery of the certificates for the Securities to the Underwriters, including any stock or other transfer taxes and any stamp or other duties payable upon the sale, issuance or delivery of the Securities to the Underwriters, (iv) the fees and disbursements of the Company’s counsel, accountants and other advisors, (v) the qualification of the Securities under securities laws in accordance with the provisions of Section 3(f) hereof, including filing fees and the reasonable fees and disbursements of counsel for the Underwriters in connection therewith and in connection with the preparation of the Blue Sky Survey and any supplement thereto, (vi) the printing and delivery to the Underwriters of copies of each preliminary prospectus, any Permitted Free Writing Prospectus and of the Prospectus and any amendments or supplements thereto and any costs associated with electronic delivery of any of the foregoing by the Underwriters to investors, (vii) the preparation, printing and delivery to the Underwriters of copies of the Blue Sky Survey and any supplement thereto, (viii) the fees and expenses of any transfer agent or registrar for the Securities,

(ix) the costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing of the Securities, including without limitation, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations, travel and lodging expenses of the representatives and officers of the Company and any such consultants, and the cost of aircraft and other transportation chartered in connection with the road show, (x) the filing fees incident to, and the reasonable fees and disbursements of counsel to the Underwriters in connection with, the review by FINRA of the terms of the sale of the Securities, (xi) the fees and expenses incurred in connection with the listing of the Securities on the NASDAQ Stock Market, and (xii) the costs and expenses (including without limitation any damages or other amounts payable in connection with legal or contractual liability) associated with the reforming of any contracts for sale of the Securities made by the Underwriter caused by a breach of the representation contained in the third paragraph of Section 1(a)(i). It is understood that, subject to this Section and Section 4(b) hereof, the Underwriters will pay all of their costs and expenses, including fees and disbursements of their counsel.

(b)Termination of Agreement. If this Agreement is terminated by the Representatives in accordance with the provisions of Section 5 or Section 9(a)(i) hereof, the Company shall reimburse the Underwriters for all of their out-of-pocket expenses, including the reasonable fees and disbursements of counsel for the Underwriters.

SECTION 5.Conditions of Underwriters’ Obligations. The obligations of the several Underwriters hereunder are subject to the accuracy of the representations and warranties of the Company contained in Section 1 hereof or in certificates of any officer of the Company or any subsidiary of the Company delivered pursuant to the provisions hereof, to the performance by the Company of its covenants and other obligations hereunder, and to the following further conditions:

(a)Effectiveness of Registration Statement. The Registration Statement, including any Rule 462(b) Registration Statement, has become effective and at Closing Time no stop order suspending the effectiveness of the Registration Statement shall have been issued under the 1933 Act or proceedings therefor initiated or threatened by the Commission, and any request on the part of the Commission for additional information shall have been complied with to the reasonable satisfaction of counsel to the Underwriters. A prospectus containing the Rule 430A Information shall have been filed with the Commission in the manner and within the time frame required by Rule 424(b) without reliance on Rule 424(b)(8) or a post-effective amendment providing such information shall have been filed and declared effective in accordance with the requirements of Rule 430A.

(b)Opinion of Counsels for the Company. At Closing Time, the Representatives shall have received an opinion, dated as of Closing Time, of (i) Hogan Lovells US LLP, counsel for the Company, substantially in the form ofExhibit B-1 hereto, together with a negative assurance letter, dated as of the Closing Time, substantially in the form ofExhibit B-2, (ii) Perkins Coie LLP, intellectual property counsel for the Company, substantially in the form ofExhibit B-3 hereto and (iii) Covington & Burling LLP, FDA regulatory counsel for the Company, substantially in the form ofExhibit B-4 hereto and, in each case, to such further effect as counsel to the Underwriters may reasonably request, together with signed or reproduced copies of such opinion letter for each of the other Underwriters.

(c)Opinion of Counsel for Underwriters. At Closing Time, the Representatives shall have received the favorable opinion, dated as of Closing Time, of Cooley LLP, counsel for the Underwriters, together with signed or reproduced copies of such opinion letter for each of the other Underwriters with respect to such matters as the Representatives may reasonably request.

(d)Officers’ Certificate. At Closing Time, there shall not have been, since the date hereof or since the respective dates as of which information is given in the Prospectus or the General Disclosure Package, any Material Adverse Effect, and the Representatives shall have received a certificate of the Chief Executive Officer of the Company and of the chief financial or chief accounting officer of the Company, dated as of Closing Time, to the effect that (i) there has been no such Material Adverse Effect, (ii) the representations and warranties in Section 1(a) hereof are true and correct with the same force and effect as though expressly made at and as of Closing Time, (iii) the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied at or prior to Closing Time, and (iv) no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or are pending or, to their knowledge, contemplated by the Commission.

(e)Accountant’s Comfort Letter. At the time of the execution of this Agreement, the Representatives shall have received from PricewaterhouseCoopers LLP a letter, dated such date, in form and substance satisfactory to the Representatives, together with signed or reproduced copies of such letter for each of the other Underwriters, containing statements and information of the type ordinarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement and the Prospectus.

(f)Bring-down Comfort Letter. At Closing Time, the Representatives shall have received from PricewaterhouseCoopers LLP a letter, dated as of Closing Time, to the effect that they reaffirm the statements made in the letter furnished pursuant to subsection (e) of this Section, except that the specified date referred to shall be a date not more than three business days prior to Closing Time.

(g)Approval of Listing. At Closing Time, the Securities shall have been approved for inclusion on the NASDAQ Global Market, subject only to official notice of issuance.

(h)Lock-up Agreements. At the date of this Agreement, the Representatives shall have received a lock-up agreement substantially in the form ofExhibit A hereto signed by the persons listed onSchedule C hereto.

(i)No Objection. FINRA shall not have raised any objection with respect to the fairness and reasonableness of the underwriting terms and arrangements.

(j)Conditions to Purchase of Option Securities. In the event that the Underwriters exercise their option provided in Section 2(b) hereof to purchase all or any portion of the Option Securities, the representations and warranties of the Company contained herein and the statements in any certificates furnished by the Company or any subsidiary of the Company shall be true and correct as of each Date of Delivery and, at the relevant Date of Delivery, the Representatives shall have received:

(i)Officers’ Certificate. A certificate, dated such Date of Delivery, of the Chief Executive Officer of the Company and of the chief financial or chief accounting officer of the Company confirming that the certificate delivered at the Closing Time pursuant to Section 5(d) hereof remains true and correct as of such Date of Delivery.

(ii)Opinion of Counsels for Company. The written opinions of (A) Hogan Lovells US LLP, counsel for the Company, together with a negative assurance letter, (B) Perkins Coie LLP, intellectual property counsel for the Company, and (C) Covington & Burling LLP, FDA regulatory counsel for the Company, in each case, dated such Date of Delivery, relating to the Option Securities to be purchased on such Date of Delivery and otherwise to the same effect as the opinions required by Section 5(b).

(iii)Opinion of Counsel for Underwriters. The written opinion of Cooley LLP, counsel for the Underwriters, dated such Date of Delivery, relating to the Option Securities to be purchased on such Date of Delivery and otherwise to the same effect as the opinion required by Section 5(c) hereof.

(iv)Bring-down Comfort Letter. A letter from PricewaterhouseCoopers LLP in form and substance satisfactory to the Representatives and dated such Date of Delivery, substantially in the same form and substance as the letter furnished to the Representatives pursuant to Section 5(f) hereof, except that the “specified date” in the letter furnished pursuant to this paragraph shall be a date not more than five days prior to such Date of Delivery.

(k)Additional Documents. At Closing Time and at each Date of Delivery counsel for the Underwriters shall have been furnished with such documents and opinions as they may require for the purpose of enabling them to pass upon the issuance and sale of the Securities as herein contemplated, or in order to evidence the accuracy of any of the representations or warranties, or the fulfillment of any of the conditions, herein contained; and all proceedings taken by the Company in connection with the issuance and sale of the Securities as herein contemplated shall be satisfactory in form and substance to the Representatives and counsel for the Underwriters.

(l)Termination of Agreement. If any condition specified in this Section shall not have been fulfilled when and as required to be fulfilled, this Agreement, or, in the case of any condition to the purchase of Option Securities on a Date of Delivery which is after the Closing Time, the obligations of the several Underwriters to purchase the relevant Option Securities, may be terminated by the Representatives by notice to the Company at any time at or prior to Closing Time or such Date of Delivery, as the case may be, and such termination shall be without liability of any party to any other party except as provided in Section 4 and except that Sections 1, 6, 7 and 8 shall survive any such termination and remain in full force and effect.

SECTION 6.Indemnification.

(a)Indemnification of Underwriters. The Company agrees to indemnify and hold harmless each Underwriter, its affiliates, as such term is defined in Rule 501(b) under the 1933 Act (each, an “Affiliate”), its selling agents and each person, if any, who controls any Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act as follows:

(i) against any and all loss, liability, claim, damage and expense whatsoever, as incurred, arising out of any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement (or any amendment thereto), including the Rule 430A Information or the omission or alleged omission therefrom of a material fact required to be stated therein or necessary to make the statements therein not misleading or arising out of any untrue statement or alleged untrue statement of a material fact included in any preliminary prospectus, any Issuer Free Writing Prospectus, Section 5(d) Writing or the Prospectus (or any amendment or supplement thereto), or the omission or alleged omission therefrom of a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading;

(ii) against any and all loss, liability, claim, damage and expense whatsoever, as incurred, to the extent of the aggregate amount paid in settlement of any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or of any claim whatsoever based upon any such untrue statement or omission, or any such alleged

untrue statement or omission;provided that (subject to Section 6(d) below) any such settlement is effected with the written consent of the Company; and

(iii) against any and all expense whatsoever, as incurred (including the fees and disbursements of counsel chosen by the Representatives), reasonably incurred in investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue statement or omission, or any such alleged untrue statement or omission, to the extent that any such expense is not paid under (i) or (ii) above;

provided,however, that this indemnity agreement shall not apply to any loss, liability, claim, damage or expense to the extent arising out of any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives expressly for use in the Registration Statement (or any amendment thereto), including the Rule 430A Information, or any preliminary prospectus, any Issuer Free Writing Prospectus, Section 5(d) Writing or the Prospectus (or any amendment or supplement thereto).

(b)Indemnification of Company, Directors and Officers. Each Underwriter severally agrees to indemnify and hold harmless the Company, its directors, each of its officers who signed the Registration Statement, and each person, if any, who controls the Company within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act against any and all loss, liability, claim, damage and expense described in the indemnity contained in Section 6(a) above, as incurred, but only with respect to untrue statements or omissions, or alleged untrue statements or omissions, made in the Registration Statement (or any amendment thereto), including the Rule 430A Information or any preliminary prospectus, any Issuer Free Writing Prospectus, Section 5(d) Writing or the Prospectus (or any amendment or supplement thereto) in reliance upon and in conformity with written information furnished to the Company by such Underwriter through the Representatives expressly for use therein.

(c)Actions against Parties; Notification. Each indemnified party shall give notice as promptly as reasonably practicable to each indemnifying party of any action commenced against it in respect of which indemnity may be sought hereunder, but failure to so notify an indemnifying party shall not relieve such indemnifying party from any liability hereunder to the extent it is not materially prejudiced as a result thereof and in any event shall not relieve it from any liability which it may have otherwise than on account of this indemnity agreement. In the case of parties indemnified pursuant to Section 6(a) above, counsel to the indemnified parties shall be selected by the Representatives and, in the case of parties indemnified pursuant to Section 6(b) above, counsel to the indemnified parties shall be selected by the Company. An indemnifying party may participate at its own expense in the defense of any such action and, to the extent it shall elect, jointly with any other indemnifying party, assume the defense thereof, with counsel reasonably satisfactory to such indemnified parties;provided,however, that counsel to the indemnifying party shall not (except with the consent of the indemnified party) also be counsel to the indemnified party. In no event shall the indemnifying parties be liable for fees and expenses of more than one counsel (in addition to any local counsel) separate from their own counsel for all indemnified parties in connection with any one action or separate but similar or related actions in the same jurisdiction arising out of the same general allegations or circumstances;providedfurther,however, that after notice from the indemnifying party to an indemnified party that the indemnifying party has elected to assume the defense of any action, the indemnifying party shall not be liable to such indemnified party for any legal fees or expenses of any other counsel or any other expenses, in each case subsequently incurred by such indemnified party, in connection with the defense thereof other than reasonable costs of investigation. The indemnified party will have the right to employ its own counsel in any such action, but the fees, expenses and other charges of such counsel will be at the expense of such indemnified party unless (i) the employment of counsel by the indemnified party has been authorized in writing by the indemnifying

party, (ii) the named parties to any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them (in which case the indemnifying party will not have the right to direct the defense of such action on behalf of the indemnified party), or (iii) the indemnifying party has not in fact employed counsel reasonably satisfactory to the indemnified party to assume the defense of such action within a reasonable time after receiving notice of the commencement of the action, in each of which cases the reasonable fees, disbursements and other charges of counsel will be at the expense of the indemnifying party or parties. No indemnifying party shall, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever in respect of which indemnification or contribution could be sought under this Section 6 or Section 7 hereof (whether or not the indemnified parties are actual or potential parties thereto), unless such settlement, compromise or consent (x) includes an unconditional release of each indemnified party from all liability arising out of such litigation, investigation, proceeding or claim and (y) does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

(d)Settlement without Consent if Failure to Reimburse. If at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel to which it is entitled hereunder, such indemnifying party agrees that it shall be liable for any settlement of the nature contemplated by Section 6(a)(ii) effected without its written consent if (i) such settlement is entered into more than 45 days after receipt by such indemnifying party of the aforesaid request, (ii) such indemnifying party shall have received notice of the terms of such settlement at least 30 days prior to such settlement being entered into and (iii) such indemnifying party shall not have reimbursed such indemnified party in accordance with such request prior to the date of such settlement.

SECTION 7.Contribution. If the indemnification provided for in Section 6 hereof is for any reason unavailable to or insufficient to hold harmless an indemnified party in respect of any losses, liabilities, claims, damages or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount of such losses, liabilities, claims, damages and expenses incurred by such indemnified party, as incurred, (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 hand from the offering of the Securities pursuant to this Agreement or (ii) if the allocation provided by clause (i) 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 of the Underwriters on the other hand in connection with the statements or omissions which resulted in such losses, liabilities, claims, damages or expenses, 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 hand in connection with the offering of the Securities pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Securities pursuant to this Agreement (before deducting expenses) received by the Company and the total underwriting discount received by the Underwriters, in each case as set forth on the cover of the Prospectus bear to the aggregate initial public offering price of the Securities as set forth on the cover of the Prospectus.

The relative fault of the Company on the one hand and the Underwriters on the other hand shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this Section 7. The aggregate amount of losses, liabilities, claims, damages and expenses incurred by an indemnified party and referred to above in this Section 7 shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue or alleged untrue statement or omission or alleged omission.

Notwithstanding the provisions of this Section 7, 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 any 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 1933 Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation.

For purposes of this Section 7, each person, if any, who controls an Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act and each Underwriter’s Affiliates and selling agents shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement, and each person, if any, who controls the Company within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act shall have the same rights to contribution as the Company. The Underwriters’ respective obligations to contribute pursuant to this Section 7 are several in proportion to the number of Initial Securities set forth opposite their respective names inSchedule A hereto and not joint.

SECTION 8.Representations, Warranties and Agreements to Survive. All representations, warranties and agreements contained in this Agreement or in certificates of officers of the Company or any of its subsidiaries submitted pursuant hereto, shall remain operative and in full force and effect regardless of (i) any investigation made by or on behalf of any Underwriter or its Affiliates or selling agents, any person controlling any Underwriter, its officers or directors, or any person controlling the Company and (ii) delivery of and payment for the Securities.

SECTION 9.Termination of Agreement.

(a)Termination; General. The Representatives may terminate this Agreement, by notice to the Company, at any time at or prior to Closing Time (i) if there has been, since the time of execution of this Agreement or since the respective dates as of which information is given in the Prospectus or General Disclosure Package, any Material Adverse Effect, which, in the reasonable judgment of the Representatives is material and adverse and makes it impractical or inadvisable to market the Securities, (ii) if there has occurred any material adverse change in the financial markets in the United States or the international financial markets, any outbreak of hostilities or escalation thereof or other calamity or crisis or any change or development involving a prospective change in national or international political, financial or economic conditions, in each case the effect of which is such as to make it, in the judgment of the Representatives, impracticable or inadvisable to market the Securities or to enforce contracts for the sale of the Securities, (iii) if trading in any securities of the Company has been suspended or materially limited by the Commission or the NASDAQ Global Market, or if trading generally on the American Stock Exchange or the New York Stock Exchange or in the NASDAQ Global Market has been suspended

or materially limited, or minimum or maximum prices for trading have been fixed, or maximum ranges for prices have been required, by any of said exchanges or by such system or by order of the Commission, FINRA or any other governmental authority, (iv) if a material disruption has occurred in commercial banking or securities settlement or clearance services in the United States, or (v) if a banking moratorium has been declared by either Federal or New York authorities.

(b)Liabilities. If this Agreement is terminated pursuant to this Section, such termination shall be without liability of any party to any other party except as provided in Section 4 hereof, and provided further that Sections 1, 6, 7 and 8 shall survive such termination and remain in full force and effect.

SECTION 10.Default by One or More of the Underwriters. If one or more of the Underwriters shall fail at Closing Time or a Date of Delivery to purchase the Securities which it or they are obligated to purchase under this Agreement (the “Defaulted Securities”), the Representatives shall have the right, within 24 hours thereafter, to make arrangements for one or more of the non-defaulting Underwriters, or any other underwriters, to purchase all, but not less than all, of the Defaulted Securities in such amounts as may be agreed upon and upon the terms herein set forth; if, however, the Representatives shall not have completed such arrangements within such 24-hour period, then:

(a) if the number of Defaulted Securities does not exceed 10% of the number of Securities to be purchased on such date, each of the non-defaulting Underwriters shall be obligated, severally and not jointly, to purchase the full amount thereof in the proportions that their respective underwriting obligations hereunder bear to the underwriting obligations of all non-defaulting Underwriters, or

(b) if the number of Defaulted Securities exceeds 10% of the number of Securities to be purchased on such date, this Agreement or, with respect to any Date of Delivery which occurs after the Closing Time, the obligation of the Underwriters to purchase and of the Company to sell the Option Securities to be purchased and sold on such Date of Delivery shall terminate without liability on the part of any non-defaulting Underwriter.

No action taken pursuant to this Section shall relieve any defaulting Underwriter from liability in respect of its default.

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

SECTION 11.Tax Disclosure. Notwithstanding any other provision of this Agreement, immediately upon commencement of discussions with respect to the transactions contemplated hereby, the Company (and each employee, representative or other agent of the Company) may disclose to any and all persons, without limitation of any kind, the tax treatment and tax structure of the transactions contemplated by this Agreement and all materials of any kind (including opinions or other tax analyses) that are provided to the Company relating to such tax treatment and tax structure. For purposes of the foregoing, the term “tax treatment” is the purported or claimed federal income tax treatment of the transactions contemplated hereby, and the term “tax structure” includes any fact that may be relevant to

understanding the purported or claimed federal income tax treatment of the transactions contemplated hereby.

SECTION 12.Notices. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given if mailed or transmitted by any standard form of telecommunication. Notices to the Underwriters shall be directed to the Representatives, c/o Leerink Swann LLC, One Federal Street, 37th Floor, Boston, MA 02110 and c/o Cowen and Company, LLC, 599 Lexington Avenue, 27^th Floor, New York, NY 10022, with copies to (i) Timothy A.G. Gerhold, Leerink Swann LLC, One Federal Street, 37th Floor, Boston, MA 02110, (ii) Bradley Friedman, Cowen and Company, LLC, 599 Lexington Avenue, 27^th Floor, New York, NY 10022, and (iii) Cooley LLP, 3175 Hanover Street, Palo Alto, California 94304, Attention: Mark Weeks, Esq.; notices to the Company shall be directed to it at 601 Gateway Boulevard Suite 200, South San Francisco, CA 94080, Attention: Jeffrey S. Farrow, with a copy to Hogan Lovells US LLP, 525 University Avenue, 3^rd Floor, Palo Alto, CA 94301, Attention: Laura Berezin, Esq.

SECTION 13.No Advisory or Fiduciary Relationship. The Company acknowledges and agrees that (a) the purchase and sale of the Securities pursuant to this Agreement, including the determination of the public offering price of the Securities and any related discounts and commissions, is an arm’s-length commercial transaction between the Company, on the one hand, and the several Underwriters, on the other hand, (b) in connection with the offering contemplated hereby and the process leading to such transaction each Underwriter is and has been acting solely as a principal and is not the agent or fiduciary of the Company or its respective stockholders, creditors, employees or any other party, (c) no Underwriter has assumed or will assume an advisory or fiduciary responsibility in favor of the Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Company on other matters) and no Underwriter has any obligation to the Company with respect to the offering contemplated hereby except the obligations expressly set forth in this Agreement, (d) the Underwriters and their respective affiliates may be engaged in a broad range of transactions that involve interests that differ from those of the Company, and (e) the Underwriters have not provided any legal, accounting, regulatory or tax advice with respect to the offering contemplated hereby and the Company has consulted its own respective legal, accounting, regulatory and tax advisors to the extent it deemed appropriate.

SECTION 14.Parties. This Agreement shall inure to the benefit of and be binding upon the Underwriters, the Company and their respective successors. Nothing expressed or mentioned in this Agreement is intended or shall be construed to give any person, firm or corporation, other than the Underwriters, the Company and their respective successors and the controlling persons and officers and directors referred to in Sections 6 and 7 and their heirs and legal representatives, any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision herein contained. This Agreement and all conditions and provisions hereof are intended to be for the sole and exclusive benefit of the Underwriters, the Company and their respective successors, and said controlling persons and officers and directors and their heirs and legal representatives, and for the benefit of no other person, firm or corporation. No purchaser of Securities from any Underwriter shall be deemed to be a successor by reason merely of such purchase.

SECTION 15.GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

SECTION 16.TIME. TIME SHALL BE OF THE ESSENCE OF THIS AGREEMENT. EXCEPT AS OTHERWISE SET FORTH HEREIN, SPECIFIED TIMES OF DAY REFER TO NEW YORK CITY TIME.

SECTION 17.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.

SECTION 18.Effect of Headings. The Section headings herein are for convenience only and shall not affect the construction hereof.

SECTION 19.General. This Agreement may be amended or modified, and the observance of any term of this Agreement may be waived, only by a writing signed by the Company and the Representatives.

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


Very truly yours,

HYPERION THERAPEUTICS, INC.

By:
Name: Donald J. Santel
Title: Chief Executive Officer and President

CONFIRMED AND ACCEPTED,

as of the date first above written:


LEERINK SWANN LLC

By:
Authorized Signatory

COWEN AND COMPANY, LLC

By:
Authorized Signatory

For themselves and as Representatives of the

other Underwriters named inSchedule A hereto.

SCHEDULE A


Name of Underwriter		Number of Initial Securities
Leerink Swann LLC
Cowen and Company, LLC


Total

SCHEDULE B

Hyperion Therapeutics, Inc.

(a Delaware corporation)

[ ] Shares of Common Stock

($0.0001 Par Value Per Share)

1. The initial public offering price per share for the Securities shall be $[ ].

2. The purchase price per share for the Securities to be paid by the several Underwriters shall be $[ ], being an amount equal to the initial public offering price set forth above less $[ ] per share.

SCHEDULE C

List of Persons and Entities Subject to Lock-up

All officer and directors and holders of all of the Company’s outstanding securities.

SCHEDULE D

Issuer General Use Free Writing Prospectus

[None.]

SCHEDULE E

Section 5(d) Writings

[None.]

EXHIBIT A

Form of Lock-up Agreement

April , 2012

Leerink Swann LLC

Cowen and Company, LLC

As Representatives of the Several Underwriters

c/o Leerink Swann LLC

201 Spear Street, 16F

San Francisco, CA 94150

Re:Hyperion Therapeutics, Inc. - Lock-Up Agreement

Ladies and Gentlemen:

The undersigned understands that you, as representatives (the “Representatives”), propose to enter into an Underwriting Agreement on behalf of the several Underwriters named in Schedule I to such agreement (collectively, the “Underwriters”), with Hyperion Therapeutics, Inc., a Delaware corporation (the “Company”), providing for a public offering of the Common Stock of the Company (the “Shares”) pursuant to a Registration Statement on Form S-1 to be filed with the Securities and Exchange Commission (the “SEC”).

In consideration of the agreement by the Underwriters to offer and sell the Shares and to continue their efforts in connection with the public offering, and of other good and valuable consideration the receipt and sufficiency of which is hereby acknowledged, the undersigned agrees that, during the period specified in the following paragraph (the “Lock-Up Period”), the undersigned will not offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of any shares of Common Stock of the Company (including any shares issued in the public offering or other issuer-directed shares), or any options or warrants to purchase any shares of Common Stock of the Company, or any securities convertible into, exchangeable for or that represent the right to receive shares of Common Stock of the Company, whether now owned or hereinafter acquired, owned directly by the undersigned (including holding as a custodian) or with respect to which the undersigned has beneficial ownership within the rules and regulations of the SEC (collectively the “Undersigned’s Shares”). The foregoing restriction is expressly agreed to preclude the undersigned from engaging in any hedging or other transaction which is designed to or which reasonably could be expected to lead to or result in a sale or disposition of the Undersigned’s Shares even if such Shares would be disposed of by someone other than the undersigned. Such prohibited hedging or other transactions would include without limitation any short sale or any purchase, sale or grant of any right (including without limitation any put or call option) with respect to any of the Undersigned’s Shares or with respect to any security that includes, relates to, or derives any significant part of its value from such Shares.

The initial Lock-Up Period will commence on the date of this Lock-Up Agreement and continue for 180 days after the public offering date set forth on the final prospectus used to sell the Shares (the “Public Offering Date”) pursuant to the Underwriting Agreement;provided,however, that if (1) during the last 17 days of the initial Lock-Up Period, the Company releases earnings results or announces material news or a material event or (2) prior to the expiration of the initial Lock-Up Period, the Company

announces that it will release earnings results during the 15-day period following the last day of the initial Lock-Up Period, then in each case the Lock-Up Period will be automatically extended until the expiration of the 18-day period beginning on the date of release of the earnings results or the announcement of the material news or material event, as applicable, unless Leerink Swann LLC and Cowen and Company, LLC each waive, in writing, such extension.

The undersigned hereby acknowledges that the Company has agreed in the Underwriting Agreement to provide written notice of any event that would result in an extension of the Lock-Up Period pursuant to the previous paragraph to the undersigned (in accordance with the Underwriting Agreement) and agrees that any such notice properly delivered will be deemed to have been given to, and received by, the undersigned. The undersigned and the Representatives agree that proper written notice may be delivered by the Company by filing a Form 8-K disclosing an extension of the Initial Lock-Up Period. The undersigned hereby further agrees that, prior to engaging in any transaction or taking any other action that is subject to the terms of this Lock-Up Agreement during the period from the date of this Lock-Up Agreement to and including the 34th day following the expiration of the initial Lock-Up Period, it will give notice thereof to the Company and will not consummate such transaction or take any such action unless it has received written confirmation from the Company that the Lock-Up Period (as such may have been extended pursuant to the previous paragraph) has expired. Compliance with the foregoing sentence shall not be required if the Company has filed a Form 8-K disclosing the expiration date of the Lock-Up Period.

Notwithstanding the foregoing, the undersigned may (a) transfer the Undersigned’s Shares (i) as abona fide gift or gifts,provided that the donee or donees thereof agree to be bound in writing by the restrictions set forth herein, (ii) upon death by will or intestacy,provided that the recipient agrees to be bound in writing by the restrictions set forth herein, (iii) to the undersigned’s immediate family or to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned,provided that the recipient or the trustee of the trust, as the case may be, agrees to be bound in writing by the restrictions set forth herein, (iv) to any affiliate (as such term is defined in Rule 405 of the Securities Act of 1933, as amended (the “Securities Act”)), limited partners, general partners, limited liability company members or stockholders of the undersigned, or if the undersigned is a corporation to any wholly-owned subsidiary of such corporation,provided that in each case the recipient agrees to be bound in writing by the restrictions set forth herein, (v) by operation of law, including a merger or a qualified domestic order,provided that the recipient agrees to be bound in writing by the restrictions set forth herein, andprovidedfurther with respect to (i), (ii), (iii), (iv) and (v) hereof that any such transfer shall not involve a disposition for value and no public reports, including but not limited to reports pursuant to Rule 144 of the Securities Act, or pursuant to Section 16 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), are required to be filed by the undersigned during the Lock-Up Period (as such may have been extended pursuant to the terms of this Lock-Up Agreement) and no such reports are voluntarily filed by the undersigned during the Lock-Up Period (as such may have been extended pursuant to the terms of this Lock-Up Agreement), or (vi) with the prior written consent of each of Leerink Swann LLC and Cowen and Company, LLC on behalf of the Underwriters (any such consent or waiver shall be in accordance with the notice and publication requirements of FINRA Rule 5131, as applicable), and (b) enter into a written plan meeting the requirements of Rule 10b5-1 under the Exchange Act after the date of this Lock-Up Agreement relating to the sale of securities of the Company, if then permitted by the Company, provided that the securities subject to such plan may not be sold until after the expiration of the Lock-Up Period (as such may have been modified pursuant to this Lock-Up Agreement) and no public announcement or filing under the Exchange Act regarding the establishment of such plan shall be required of or voluntarily made by or on behalf of the undersigned or the Company. For purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer

agent and registrar against the transfer of the Undersigned’s Shares except in compliance with the foregoing restrictions.

Notwithstanding anything to the contrary contained herein, the undersigned may sell shares of Common Stock of the Company purchased by the undersigned on the open market following the public offering of the Shares if and only if no public reports, including but not limited to reports pursuant to Rule 144 of the Securities Act, or pursuant to Section 16 of the Exchange Act, are required to be filed by the undersigned during the Lock-Up Period (as such may have been extended pursuant to the terms of this Lock-Up Agreement) and no such reports are voluntarily filed by the undersigned during the Lock-Up Period (as such may have been extended pursuant to the terms of this Lock-Up Agreement). Furthermore, nothing contained herein shall limit or restrict the ability of the undersigned to exercise any stock options,provided that any Shares received upon any such exercise will also be subject to this Lock-up Agreement, andprovidedfurther that no public reports including but not limited to filings under Section 16 of the Exchange Act shall be required to be filed by the undersigned within 90 days of the Public Offering Date and no such reports are voluntarily filed by the undersigned, and after such 90^th day any public report or filing under Section 16 of the Exchange Act shall clearly indicate in the footnotes thereto that the filing relates to the exercise of a stock option, that no shares were sold by the reporting person and that the shares received upon exercise of the stock option are subject to a lock-up agreement with the underwriters of the Company’s initial public offering. In addition, nothing contained herein shall limit or restrict the conversion of those certain convertible promissory notes or the exercise of the related warrants, issued pursuant to the Convertible Note and Warrant Purchase Agreement dated as of April 1, 2011 or the Convertible Note and Warrant Purchase Agreement dated as of October 26, 2011, in connection with the public offering,provided that any Shares received upon any such conversion or exercise will also be subject to this Lock-up Agreement, andprovidedfurther that any public report or filing under Section 16 of the Exchange Act shall clearly indicate in the footnotes thereto that the filing relates to the conversion of a convertible promissory note or exercise of a warrant, that no shares were sold by the reporting person and that the shares received upon conversion of a convertible promissory note or exercise of a warrant are subject to a lock-up agreement with the underwriters of the Company’s initial public offering.

In the event that all or any percentage of Common Stock held by any other person or entity subject to an agreement that is substantively identical to this Lock-Up Agreement is released by the Underwriters from any restrictions set forth in such agreement, the same percentage of Common Stock held by the undersigned, on a fully diluted basis, shall be immediately and fully released from any remaining restrictions under this Lock-Up Agreement concurrently therewith, and Leerink Swann LLC or Cowen and Company, LLC shall notify the undersigned of such release concurrently with notification to such other released party;provided,however, that the Underwriters may release employees of the Company for up to $100,000 worth of Common Stock from restrictions set forth in the lock-up agreement with such holders without being obligated to release any shares of Common Stock held by the undersigned pursuant to this paragraph.

If the undersigned is an officer or director of the Company, (1) the undersigned further agrees that the foregoing restrictions shall be equally applicable to any issuer-directed Shares the undersigned may purchase in the offering, (2) 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 Undersigned’s Shares, the Representatives will notify the Company of the impending release or waiver, and (3) the Company has agreed in the Underwriting Agreement to announce the impending release or waiver by press release through a major news service at least two business days before the effective date of the release or waiver. Any release or waiver granted by the Representatives hereunder to any such officer or director shall only be effective two business days after the publication date of such press release. The provisions of this paragraph will not apply if (a) the release or waiver is effected solely to permit a transfer not for

consideration and (b) the transferee has agreed in writing to be bound by the same terms described in this letter to the extent and for the duration that such terms remain in effect at the time of the transfer.

With respect to the offering of the Shares only, the undersigned waives any registration rights relating to registration under the Securities Act of any of the Undersigned’s Shares owned either of record or beneficially by the undersigned, including any rights to receive notice of the offering.

The undersigned understands that the Company and the Underwriters are relying upon this Lock-Up Agreement in proceeding toward consummation of the offering. The undersigned further understands that this Lock-Up Agreement is irrevocable and shall be binding upon the undersigned’s heirs, legal representatives, successors, and assigns. This Lock-Up Agreement shall automatically terminate upon the earlier to occur, if any, of (a) the date that the Company, on the one hand, or Leerink Swann LLC and Cowen and Company, LLC on the other hand, advises, in writing, prior to the execution of the Underwriting Agreement, that it has determined not to proceed with the offering, (b) the Company withdraws the registration statement registering the Shares or deregisters all the Shares covered by the registration statement or (c) termination of the Underwriting Agreement before the closing of the offering. Notwithstanding the foregoing, in the event that the offering is not consummated on or before October 31, 2012, this Lock-Up Agreement shall terminate and its provisions shall be of no further force and effect.

Very truly yours,

Exact Name of Stockholder

Authorized Signature

Title

EXHIBIT B-1

Form of Opinion for Company Counsel

EXHIBIT B-2

Form of Negative Assurance Letter for Company Counsel

EXHIBIT B-3

Form of Opinion for Company Intellectual Property Counsel

EXHIBIT B-4

Form of Opinion for Company FDA Counsel

EXHIBIT C

Form of Press Release

Hyperion Therapeutics, Inc.

[Date]

Hyperion Therapeutics, Inc. (the “Company”) announced today that Leerink Swann LLC and Cowen and Company, LLC, the joint-bookrunners in the recent public sale of [—] shares of the Company’s common stock, are [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 [—], 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.

Hyperion Therapeutics (HPTX) Inactive S-1/AIPO registration (amended)