11,000,000 Shares OREXIGEN THERAPEUTICS, INC. Common Stock, par value $0.001 per share UNDERWRITING AGREEMENT

EX-1.1 2 d430067dex11.htm UNDERWRITING AGREEMENT Underwriting Agreement

Exhibit 1.1

11,000,000 Shares

OREXIGEN THERAPEUTICS, INC.

Common Stock, par value $0.001 per share

UNDERWRITING AGREEMENT

October 25, 2012

CREDIT SUISSE SECURITIES (USA) LLC,

MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED

LEERINK SWANN LLC

As Representatives of the Several Underwriters,

c/o Credit Suisse Securities (USA) LLC

Eleven Madison Avenue

New York, N.Y. 10010-3629

Dear Sirs:

1. Introductory. Orexigen Therapeutics, Inc., a Delaware corporation (“Company”), agrees with the several Underwriters named in Schedule A hereto (“Underwriters”) to issue and sell to the several Underwriters 11,000,000 shares (“Firm Securities”) of its common stock, par value $0.001 per share (“Common Stock”) and also proposes to issue and sell to the Underwriters, at the option of the Underwriters, an aggregate of not more than 1,650,000 additional shares (“Optional Securities”) of its Common Stock as set forth below. The Firm Securities and the Optional Securities are herein collectively called the “Offered Securities”.

The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-3 (No. 333-183918), including the related preliminary prospectus or prospectuses, covering the registration of the Offered 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 430B (“Rule 430B”) 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 pursuant to Rule 430B is referred to as “Rule 430B Information.” Each prospectus used in connection with the offering of the Offered Securities that omitted the Rule 430B Information is herein called a “preliminary prospectus.” Such registration statement, at any given time, including all exhibits, financial schedules and the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the 1933 Act, as amended from time to time, and the documents otherwise deemed to be a part thereof or included therein by 1933 Act Regulations, 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

Offered Securities, including the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the 1933 Act at the time of the execution of this Agreement and any preliminary prospectuses that form a part thereof, 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; and all references in this Agreement to amendments or supplements to the Registration Statement, any preliminary prospectus or the Prospectus shall be deemed to mean and include the filing of any document under the Securities Exchange Act of 1934, as amended (the “1934 Act”) which is incorporated by reference in or otherwise deemed by 1933 Act Regulations to be a part of or included in the Registration Statement, such preliminary prospectus or the Prospectus, as the case may be.

2. Representations and Warranties of the Company. The Company represents and warrants to each Underwriter as of the date hereof, the Applicable Time referred to in Section 2 hereof and as of the First Closing Date referred to in Section 3 hereof, and as of each Optional Closing Date (if any) referred to in Section 3 hereof, and agrees with each Underwriter, as follows:

(a) Compliance with Registration Requirements. The Company meets the requirements for use of Form S-3 under the 1933 Act. 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 First Closing Date (and, if any Optional Securities are purchased, at the Optional Closing Date) 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. Neither the Prospectus nor any amendments or supplements thereto, at the time the Prospectus or any such amendment or supplement was issued and at the First Closing Date (and, if any Optional Securities are purchased, at the Optional Closing Date), included or will include an untrue statement of a material fact or omitted or will omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

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 on Schedule B hereto (collectively, the “General Disclosure Package”), nor (y) any individual Issuer Limited Use Free Writing Prospectus, 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 9:07 a.m. (Eastern time) on October 25, 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 Offered 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 Offered 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 Fide Electronic Road Show (as defined in Rule 433)), as evidenced by its being specified in Schedule B 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 Offered 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,” as defined in Rule 433, in compliance with Rule 433(d)(8)(ii) (the “Bona Fide Electronic Road Show”) such that no filing of any “road show” (as defined in Rule 433(h)) is required in connection with the offering of the Offered Securities.

Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Offered Securities or until any earlier date that the issuer notified or notifies the Representatives as described in Section 5(c), 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, including any document incorporated by reference therein, 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 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.

(b) Incorporated Documents. The documents incorporated or deemed to be incorporated by reference in the Registration Statement and the Prospectus, when they became effective or at the time they were or hereafter are filed with the Commission, complied and will comply in all material respect with the requirements of the 1934 Act, and the rules and regulations of the Commission under the 1934 Act (the

“1934 Regulations”), and, when read together with the other information in the Prospectus, did not and will not contain an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made or are made, not misleading.

(c) Independent Accountants. The accountants who certified the financial statements and supporting schedules included or incorporated by reference in the Registration Statement are independent public accountants as required by the 1933 Act and the 1933 Act Regulations.

(d) 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 position of the Company at the dates indicated and the statement of operations, stockholders’ equity and cash flows of the Company for the periods specified; said financial statements have been prepared in conformity with generally accepted accounting principles (“GAAP”) applied on a consistent basis throughout the periods involved. The supporting schedules to such financial statements included or incorporated by reference in the Registration Statement, if any, present fairly in accordance with GAAP the information required to be stated therein. The selected financial data and the summary financial information included in the Prospectus present fairly the information shown therein and have been compiled on a basis consistent with that of the audited financial statements included in the Registration Statement.

(e) No Material Adverse Change in Business. Since the respective dates as of which information is given in the Registration Statement, the General Disclosure Package or the Prospectus, except as otherwise stated therein, (i) there has been no material adverse change in the condition, financial or otherwise, or in the earnings, business affairs or business prospects of the Company, whether or not arising in the ordinary course of business (a “Material Adverse Effect”), (ii) there have been no transactions entered into by the Company other than those in the ordinary course of business, which are material with respect to the Company, and (iii) there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock.

(f) Good Standing of the Company. The Company has been duly organized and is validly existing as a corporation in good standing under the laws of the State of Delaware and has corporate power and authority to own, lease and operate its properties and to conduct its business as described in the Prospectus and to enter into and perform its obligations under this Agreement; and the Company is duly qualified as a foreign corporation to transact business and is in good standing in each other jurisdiction in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except where the failure so to qualify or to be in good standing would not result in a Material Adverse Effect.

(g) No Subsidiaries. The Company has no subsidiaries.

(h) Capitalization. The authorized, issued and outstanding capital stock of the Company is as set forth in the Registration Statement and the Prospectus (except for subsequent issuances, if any, pursuant to this Agreement, pursuant to reservations, agreements or employee benefit plans referred to in the Prospectus or pursuant to the exercise 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; none of the outstanding shares of capital stock was issued in violation of the preemptive or other similar rights of any securityholder of the Company.

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

(j) Authorization of the Offered Securities. The Offered 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;

no holder of the Offered Securities will be subject to personal liability by reason of being such a holder; and the issuance of the Offered Securities is not subject to the preemptive or other similar rights of any securityholder of the Company that have not been validly waived.

(k) Description of the Offered Securities. The Offered Securities conform in all material respects to all statements relating thereto contained or incorporated by reference in the Prospectus and such description conforms to the rights set forth in the instruments defining the same.

(l) Absence of Defaults and Conflicts. The Company is not (i) in violation of its charter or by-laws or (ii) 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 is a party or by which it may be bound, or to which any of the property or assets of the Company is subject (collectively, “Agreements and Instruments”) except for such defaults that would not result in a Material Adverse Effect; and the execution, delivery and performance of this Agreement, the issuance and sale of the Offered Securities and the consummation of the transactions contemplated herein and in the Registration Statement (including the use of the proceeds from the sale of the Offered 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 pursuant to, the Agreements and Instruments (except for such conflicts, breaches, defaults or Repayment Events or liens, charges or encumbrances that would not result in 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 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 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.

(m) Absence of Labor Dispute. No labor dispute with the employees of the Company exists or, to the knowledge of the Company, is imminent, and the Company is not aware of any existing or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers, customers or contractors, which, in either case, would result in a Material Adverse Effect.

(n) Absence of Proceedings. There is no action, suit, proceeding, inquiry or investigation before or brought by any court or governmental agency or body, domestic or foreign, now pending, or, to the knowledge of the Company, threatened, against or affecting the Company, which is required to be disclosed in the Registration Statement (other than as disclosed therein), or which would result in a Material Adverse Effect, or which would materially and adversely affect the properties or assets thereof or the consummation of the transactions contemplated in this Agreement or the performance by the Company of its obligations hereunder; the aggregate of all pending legal or governmental proceedings to which the Company is a party or of which any of its property or assets is the subject which are not described in the Registration Statement, the General Disclosure Package or the Prospectus, including ordinary routine litigation incidental to the business, could not result in a Material Adverse Effect.

(o) Accuracy of Exhibits. There are no contracts or documents which are required to be described in the Registration Statement or the Prospectus or to be filed as exhibits thereto which have not been so described and filed as required.

(p) Possession of Intellectual Property. Except as described in the General Disclosure Package and the Prospectus, or as would not have a Material Adverse Effect, (a) the Company owns, possesses or has all rights necessary to use the Company Intellectual Property (as defined below), (b) the Company has not received any written notice, nor to the Company’s knowledge, any non-written notice, of any infringement

of, or conflict with, any Intellectual Property (as defined below) of any third party, (c) no third party, including any academic or governmental organization, possesses or could obtain rights to the Company Intellectual Property which, if exercised, could enable such party to develop products competitive with those of the Company, and (d) 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. Except as described in the General Disclosure Package and the Prospectus or as would not have a Material Adverse Effect, (1) the Company is not aware of any facts or circumstances concerning its business, as now operated and as planned to be operated by the Company as described in the Prospectus, that constitute or will 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 concerning its business, as now operated and as planned to be operated by the Company as described in the Prospectus, that constitute or will constitute an infringement by the Company of, or conflict with, any non-patented Intellectual Property right of any third party, (3) the Company is not aware of any facts or circumstances that would render any Company Intellectual Property invalid or unenforceable, (4) the Company is not in breach of any of its obligations under any options, licenses, or agreements with respect to the Company Intellectual Property and, to the Company’s knowledge, no other party to such options, licenses or agreements is in breach thereof, (5) none of the technology employed by the Company has been obtained or is being used by the Company in violation of any contractual obligation binding on the Company or, to the Company’s knowledge, any of its officers, directors, employees, consultants or otherwise in violation of the rights of any persons, and (6) to the Company’s knowledge, there is no material infringement by third parties of any Company Intellectual Property. The Company is not a party to or bound by any options, licenses or agreements with respect to the Intellectual Property rights of any other person or entity that are required to be set forth in the Registration Statement and are not described therein accurately in all material respects. For purposes of this Agreement, “Intellectual Property” means patents, patent rights, trademarks, servicemarks, copyrights, trade 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 necessary to carry on the business now operated and as planned to be operated by the Company as described in the Prospectus.

(q) PTO Applications. The Company has duly and properly filed or caused to be filed with the United States Patent and Trademark Office (the “PTO”) and applicable foreign patent authorities all patent applications owned by the Company or which the Company is prosecuting on behalf of the owner of such patent applications (the “Company Patent Applications”). To the knowledge of the Company, the Company has complied with the PTO’s duty of candor and disclosure for the Company Patent Applications and has made no material misrepresentation in the Company Patent Applications. To the knowledge of the Company, the Company has complied with the duty of candor and disclosure for the Company Patent Applications pending in countries outside the United States. The Company is not aware of any information material to a determination of patentability regarding the Company Patent Applications not called to the attention of the PTO or similar foreign authority that requires such disclosures. The Company is not aware of any information not called to the attention of the PTO or similar foreign authority requiring disclosure of such information which the Company believes would preclude the grant of a patent for the Company Patent Applications. The Company has no knowledge of any information that would preclude the Company from having clear title to the Company Patent Applications that are purported to be owned by the Company.

(r) Absence of Further Requirements. No filing with, or authorization, approval, consent, license, order, registration, qualification or decree of, any court or governmental authority or agency is necessary or required for the performance by the Company of its obligations hereunder, in connection with the offering, issuance or sale of the Offered Securities hereunder, except such as have been already 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 (“FINRA”).

(s) Absence of Manipulation. Neither the Company nor, to the knowledge of the Company, any affiliate of the Company has taken, nor will the Company or any affiliate take, directly or indirectly, any

action which is designed to or which has constituted or which would 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 Offered Securities.

(t) Possession of Licenses and Permits. The Company possesses such permits, licenses, approvals, consents and other authorizations (collectively, “Governmental Licenses”) issued by the appropriate federal, state, local or foreign regulatory agencies or bodies necessary to conduct the business of the Company as described in the Prospectus, including without limitation, all such registrations, approvals, certificates, authorizations and permits required by the United States Food and Drug Administration (the “FDA”), the United States Drug Enforcement Administration, and/or other federal, state, local or foreign agencies or bodies engaged in the regulation of clinical trials, pharmaceuticals, biologics or biohazardous substances or materials, except where the failure so to possess would not, singly or in the aggregate, result in 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, result in 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, result in a Material Adverse Effect; and the Company has not received any 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 result in a Material Adverse Effect. The Company has no reason to believe that any party granting any such Governmental Licenses is considering limiting, suspending or revoking the same in any material respect. Where 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, except where such failure would not, singly or in the aggregate, have a Material Adverse Effect; 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, except any deficiencies which could not, singly or in the aggregate, have a Material Adverse Effect.

(u) Tests and Preclinical and Clinical Studies. 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 and clinical studies conducted by or, to the Company’s knowledge, on behalf of the Company that are described in the Registration Statement and the Prospectus were, and, if still pending, are being, conducted in all material respects in accordance with the protocols submitted to the FDA and all applicable laws and regulations; the descriptions of the tests and preclinical and clinical studies, and results thereof, conducted by or, to the Company’s knowledge, on behalf of the Company contained in the Registration Statement and the Prospectus are accurate and complete in all material respects; the Company is not aware of any other trials or studies, the results of which reasonably call into question the results described or referred to in the Registration Statement and the Prospectus; the Company is not in receipt of any communications from the FDA or any foreign, state or local governmental body exercising comparable authority that reasonably call into question the results of the trials or studies described or referred to in the Registration Statement and the Prospectus; and the Company has not received any notice or correspondence from the FDA or any foreign, state or local governmental body exercising comparable authority requiring the termination, suspension, or clinical hold of any tests or preclinical or clinical studies, or such notice or correspondence from any Institutional Review Board or comparable authority requiring the termination or suspension of a clinical study, conducted by or on behalf of the Company, which termination, suspension, or clinical hold would reasonably be expected to have a Material Adverse Effect.

(v) Title to Property. The Company has good and marketable title to all real property owned by the Company and good title to all other properties owned by it, 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 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 of such property by the Company; and all of the leases and subleases material to the business of the Company and under which the Company holds properties described in the Prospectus, are in full force and effect, and the Company has no notice of any material claim of any sort that has been asserted by anyone adverse to the rights of the Company under any of the leases or subleases mentioned above, or affecting or questioning the rights of the Company to the continued possession of the leased or subleased premises under any such lease or sublease.

(w) Investment Company Act. The Company is not required, and upon the issuance and sale of the Offered 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”).

(x) Environmental Laws. Except as described in the Prospectus and except as would not, singly or in the aggregate, result in a Material Adverse Effect, (A) the Company is not in violation of any federal, state, local or foreign statute, law, rule, regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof, including any judicial or administrative order, consent, decree or judgment, relating to pollution or protection of human health, the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface-strata) or wildlife, including, without limitation, laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum or petroleum products, asbestos containing materials or mold (collectively, “Hazardous Materials”) or to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental Laws”), (B) the Company has all permits, authorizations and approvals required under any applicable Environmental Laws and is in compliance with their requirements, (C) there are no pending or, to the knowledge of the Company, threatened administrative, regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of noncompliance or violation, investigation or proceedings relating to any Environmental Law against the Company and (D) to the knowledge of the Company, there are no events or circumstances that would reasonably be expected to form the basis of an order for clean-up or remediation, or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company relating to Hazardous Materials or any Environmental Laws.

(y) Registration Rights. There are no persons with rights to have any securities registered pursuant to the Registration Statement, which rights have not been waived or complied with, nor, except as specifically set forth in the Prospectus, are there any persons with rights to have any securities otherwise registered by the Company under the 1933 Act.

(z) Accounting Controls and Disclosure Controls.

(i) The Company maintains a system of internal accounting controls sufficient to provide reasonable assurances that (A) transactions are executed in accordance with management’s general or specific authorization; (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 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.

(ii) The Company employs disclosure controls and procedures that are designed to ensure that information required to be disclosed by the Company in the reports that it files or submits under

the 1934 Act is recorded, processed, summarized and reported, within the time periods specified in the Commission’s rules and forms, and is accumulated and communicated to the Company’s management, including its principal executive officer or officers and the principal financial officer or officers, as appropriate, to allow timely decisions regarding disclosure.

(aa) Compliance with the Sarbanes-Oxley Act. There is and has been no failure on the part of the Company or any of the Company’s officers or directors, in their capacities as such, to comply in all material respects with any provision of the Sarbanes-Oxley Act of 2002 and all rules and regulations promulgated thereunder or implementing the provisions thereof (the “Sarbanes-Oxley Act”), including Section 402 related to loans and Sections 302 and 906 related to certifications.

(bb) FINRA Matters. Except as disclosed in writing to the Representatives, neither the Company nor, to the Company’s knowledge, the Company’s officers, directors, securityholders or any of its affiliates (within the meaning of FINRA Conduct Rule 2720(b)(1)(a)), directly or indirectly controls, is controlled by, or is under common control with, or is an associated person (within the meaning of Article I, Section 1(dd) of the By-laws of FINRA) of, any member firm of FINRA.

(cc) Payment of Taxes. All United States federal income tax returns of the Company required by law to be filed have been filed and all taxes shown by such returns or otherwise assessed, which are due and payable, have been paid, except assessments against which appeals have been or will be promptly taken and as to which adequate reserves have been provided. The United States federal income tax returns of the Company through the fiscal year ended December 31, 2009 have been settled and no assessment in connection therewith has been made against the Company. The Company has filed all other tax returns that are required to have been filed by it pursuant to applicable foreign, state, local or other law except insofar as the failure to file such returns would not result in a Material Adverse Effect, and has paid all taxes due pursuant to such returns or pursuant to any assessment received by the Company, except for such taxes, if any, as are being contested in good faith and as to which adequate reserves have been provided. The charges, accruals and reserves on the books of the Company in respect of any income and corporation tax liability for any years not finally determined are adequate to meet any assessments or re-assessments for additional income tax for any years not finally determined, except to the extent of any inadequacy that would not result in a Material Adverse Effect.

(dd) Insurance. The Company carries or is 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 will not be able (i) to renew its existing insurance coverage as and when such policies expire or (ii) to 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 result in a Material Adverse Effect. The Company has not been denied any insurance coverage which it has sought or for which it has applied.

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

(ff) 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.

(gg) Money Laundering Laws. The operations of the Company are and have been conducted at all times in compliance with applicable financial recordkeeping 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 with respect to the Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

(hh) 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.

(ii) No Finder’s Fee. 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 this offering.

(jj) Accurate Disclosure. The statements in the General Disclosure Package and the Final Prospectus under the headings “Description of Common Stock,” “Certain Provisions of Delaware Law and of the Company’s Certificate of Incorporation and Bylaws,” “Business—Intellectual Property,” “Business—Collaboration and Licensing Agreements,” “Business—Third-Party Reimbursement,” “Business—Government Regulation,” “Risk Factors—Our development and commercialization strategy depends upon access to findings of safety and effectiveness based on data not developed by us but which the FDA may reference in reviewing our U.S. marketing applications…,” “Risk Factors—Healthcare reform measures could hinder or prevent our product candidates’ commercial success” and “Risk Factors—Risks Related to Intellectual Property,” insofar as such statements summarize legal matters, agreements, documents or proceedings discussed therein, are, in all material respects, accurate and fair summaries of such legal matters, agreements, documents or proceedings and present the information required to be shown.

(kk) Officer’s Certificates. Any certificate signed by any officer of the Company 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.

3. Purchase, Sale and Delivery of Offered Securities. On the basis of the representations, warranties and agreements and subject to the terms and conditions set forth herein, the Company agrees to sell to the several Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at a purchase price of $5.17 per share, the respective number of shares of Firm Securities set forth opposite the names of the Underwriters in Schedule A hereto, plus any additional number of shares of Firm Securities which such Underwriters may become obligated to purchase pursuant to the provisions of Section 9 hereof.

The Company will deliver the Firm Securities to or as instructed by the Representatives for the accounts of the several Underwriters in a form reasonably acceptable to the Representatives against payment of the purchase price by the Underwriters in Federal (same day) funds by wire transfer to an account at a bank acceptable to the Representatives drawn to the order of Orexigen Therapeutics, Inc. at the

office of Ropes & Gray LLP, Three Embarcadero Center, San Francisco, CA 94111, at 9:00 a.m., New York time, on October 30, 2012 , or at such other time not later than seven full business days thereafter as the Representatives and the Company determine, such time being herein referred to as the “First Closing Date”. For purposes of Rule 15c6-1 under the 1934 Act, the First Closing Date (if later than the otherwise applicable settlement date) shall be the settlement date for payment of funds and delivery of securities for all the Offered Securities sold pursuant to the offering. The Firm Securities so to be delivered or evidence of their issuance will be made available for checking at the above office at least 24 hours prior to the First Closing Date.

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

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

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

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

(a) Filing of Prospectuses. The Company has filed or will file each Statutory Prospectus (including the Prospectus) pursuant to and in accordance with Rule 424(b)(2) (or, if applicable and consented to by the Representatives, subparagraph (5)) not later than the second business day following the earlier of the date it is first used or the execution and delivery of this Agreement. The Company has complied and will comply with Rule 433.

(b) Filing of Amendments; Response to Commission Requests. The Company will promptly advise the Representatives of any proposal to amend or supplement the Registration Statement or any Statutory Prospectus at any time and will offer the Representatives a reasonable opportunity to comment on any such amendment or supplement; and the Company will also advise the Representatives promptly of (i) the filing of any such amendment or supplement, (ii) any request by the Commission or its staff for any amendment to the Registration Statement, for any supplement to any Statutory Prospectus or for any additional information, (iii) the institution by the Commission of any stop order proceedings in respect of the Registration Statement or the

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

(c) Continued Compliance with Securities Laws. If, at any time when a prospectus relating to the Offered Securities is (or but for the exemption in Rule 172 would be) required to be delivered under the 1933 Act by any Underwriter or dealer, any event occurs as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, or if it is necessary at any time to amend the Registration Statement or supplement the Prospectus to comply with the 1933 Act, the Company will promptly notify the Representatives of such event and will promptly prepare and file with the Commission and furnish, at its own expense, to the Underwriters and the dealers and any other dealers upon request of the Representatives, an amendment or supplement which will correct such statement or omission or an amendment which will effect such compliance. Neither the Representatives’ consent to, nor the Underwriters’ delivery of, any such amendment or supplement shall constitute a waiver of any of the conditions set forth in Section 7 hereof.

(d) Rule 158. As soon as practicable, but not later than 16 months, after the date of this Agreement, the Company will make generally available to its securityholders an earnings statement covering a period of at least 12 months beginning after the date of this Agreement and satisfying the provisions of Section 11(a) of the 1933 Act and Rule 158.

(e) Furnishing of Prospectuses. The Company will furnish to the Representatives copies of the Registration Statement, including all exhibits, any Statutory Prospectus, the Prospectus and all amendments and supplements to such documents, in each case as soon as available and in such quantities as the Representatives reasonably request. The Company will pay the expenses of printing and distributing to the Underwriters all such documents.

(f) Blue Sky Qualifications. The Company will use its best efforts to arrange for the qualification of the Offered Securities for sale under the laws of such jurisdictions as the Representatives designate and will continue such qualifications in effect so long as required for the distribution; provided, that in connection therewith, the Company will not be required to file a 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 subject itself to taxation for doing business in any jurisdiction in which it is not otherwise so subject.

(g) Reporting Requirements. During the period when the Prospectus is required to be delivered under the 1933 Act, the Company will furnish, upon request, to each of the Representatives and the other Underwriters, as soon as practicable after the end of each fiscal year, a copy of its annual report to stockholders for such year; and the Company will furnish to the Representatives as soon as available, a copy of each report and any definitive proxy statement of the Company filed with the Commission under the 1934 Act or mailed to stockholders. However, so long as the Company is subject to the reporting requirements of either Section 13 or Section 15(d) of the 1934 Act and is timely filing reports with the Commission on EDGAR, it is not required to furnish such reports or statements to the Representatives or the Underwriters.

(h) Payment of Expenses. The Company will pay all expenses incident to the performance of its obligations under this Agreement, including but not limited to any filing fees and other expenses (including reasonable fees and disbursements of counsel to the Underwriters) incurred in connection with qualification of the Offered Securities for sale and determination of their eligibility for investment under the laws of such jurisdictions as the Representatives designate and

the preparation and printing of memoranda relating thereto, costs and expenses relating to investor presentations or any “road show” in connection with the offering and sale of the Offered Securities including, without limitation, any travel expenses of the Company’s officers and employees and any other expenses of the Company including the chartering of airplanes, fees and expenses incident to listing the Offered Securities on the NASDAQ Stock Market, fees and expenses in connection with the registration of the Offered Securities under the 1934 Act, and expenses incurred in distributing preliminary prospectuses and the Prospectus (including any amendments and supplements thereto) to the Underwriters and for expenses incurred for preparing, printing and distributing any Issuer Free Writing Prospectuses to investors or prospective investors.

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

(j) Restriction on Sale of Common Stock. For the period specified below (the “Lock-Up Period”), the Company will not, directly or indirectly, take any of the following actions with respect to its shares of Common Stock or any securities convertible into or exchangeable or exercisable for any of its shares of Common Stock (“Lock-Up Securities”): (i) offer, sell, issue, contract to sell, pledge or otherwise dispose of Lock-Up Securities, (ii) offer, sell, issue, contract to sell, contract to purchase or grant any option, right or warrant to purchase Lock-Up Securities, (iii) enter into any swap, hedge or any other agreement that transfers, in whole or in part, the economic consequences of ownership of Lock-Up Securities, (iv) establish or increase a put equivalent position or liquidate or decrease a call equivalent position in Lock-Up Securities within the meaning of Section 16 of the 1934 Act or (v) file with the Commission a registration statement under the 1933 Act relating to Lock-Up Securities, or publicly disclose the intention to take any such action, without the prior written consent of Credit Suisse Securities (USA) LLC (“Credit Suisse”) and Merrill Lynch, Pierce, Fenner & Smith Incorporated (“Merrill Lynch”). The foregoing sentence shall not apply to (A) the Offered Securities to be sold hereunder, (B) issuances of Lock-Up Securities pursuant to the conversion or exchange of convertible or exchangeable securities or the exercise of warrants or options, in each case outstanding on the date hereof and referred to in the Statutory Prospectus, (C) grants of employee stock options pursuant to the terms of a plan in effect on the date hereof and issuances of Lock-Up Securities pursuant to the exercise of such options and (D) up to an aggregate of 5% of the total outstanding shares of Common Stock of the Company immediately following the completion of this offering of Offered Securities issued to licensors, licensees, collaborators, vendors, manufacturers, distributors, customers, lenders or other similar parties at a price greater than or equal to the then market price of the shares of Common Stock; provided, however, that in the case of this subclause (D), the recipients of such shares of Common Stock agree to execute a Lock-Up Agreement in the form attached as Exhibit A hereto for the remainder of the term of the Lock-Up Period. The initial Lock-Up Period will commence on the date hereof and continue for 45 days after the date hereof or such earlier date that Credit Suisse and Merrill Lynch consent to in writing; provided, however, that if (1) during the last 17 days of the initial Lock-Up Period, the Company releases earnings results or material news or a material event relating to the Company occurs or (2) prior to the expiration of the initial Lock-Up Period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the initial Lock-Up Period, then in each case the Lock-Up Period will be extended until the expiration of the 18-day period beginning on the date of release of the earnings results or the occurrence of the materials news or material event, as applicable, unless Credit Suisse and Merrill Lynch waive, in writing, such extension. The Company will provide Credit Suisse and Merrill Lynch with notice of any announcement described in clause (2) of the preceding sentence that gives rise to an extension of the Lock-Up Period.

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

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

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

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

(b) Filing of Prospectus. The Prospectus shall have been filed with the Commission in accordance with the rules and regulations of the Commission and Section 5(a) hereof. No stop order suspending the effectiveness of the Registration Statement or of any part thereof shall have been issued and no proceedings for that purpose shall have been instituted or, to the knowledge of the Company or any Underwriter, shall be contemplated by the Commission.

(c) No Material Adverse Change. Subsequent to the execution and delivery of this Agreement, there shall not have occurred (i) change, or any development or event involving a prospective change, in the condition (financial or otherwise), results of operations, business, properties, of the Company which, in the judgment of the Representatives, is material and adverse and makes it impractical or inadvisable to market the Offered Securities; (ii) any material adverse change in U.S. or international financial, political or economic conditions or currency exchange rates or exchange controls the effect of which is such as to make it, in the judgment of the Representatives, impractical to market or to enforce contracts for the sale of the Offered Securities, whether in the primary market or in respect of dealings in the secondary market; (iii) any suspension or material limitation of trading in any securities of the Company by the Commission or the Nasdaq Global Market or any suspension or material limitation of trading in securities generally on the New York Stock Exchange or the American Stock Exchange, or any setting of minimum or maximum prices for trading on such exchange; (iv) any banking moratorium declared by any U.S. federal or New York authorities; (v) any material disruption of settlements of securities, payment, or clearance services in the United States or (vi) any attack on, outbreak or escalation of hostilities or act of terrorism involving the United States, any declaration of war by Congress or any other national or international calamity or emergency if, in the judgment of the Representatives, the effect of any such attack, outbreak, escalation, act, declaration, calamity or emergency is such as to make it impractical or inadvisable to market the Offered Securities or to enforce contracts for the sale of the Offered Securities.

(d) Opinion of Counsel for Company. The Representatives shall have received an opinion and negative assurance letter, dated such Closing Date, of Latham & Watkins LLP, counsel for the Company, in form and substance satisfactory to the Representatives, together with signed or reproduced copies of such letters for each of the other Underwriters with respect to such matters as the Representatives may reasonably request.

(e) Opinion of Counsel for Underwriters. The Representatives shall have received an opinion and negative assurance letter, dated such Closing Date, of Ropes & Gray LLP, counsel for the Underwriters, with respect to such matters as the Representatives may reasonably request.

(f) Officer’s Certificate. The Representatives shall have received a certificate, dated such Closing Date, of an executive officer of the Company and a principal financial or accounting officer of the Company in which such officers shall state that: the representations and warranties of the Company in this Agreement are true and correct; the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date; no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or, to the best of their knowledge, are contemplated by the Commission; and, subsequent to the respective dates of the most recent financial statements in the General Disclosure Package, there has been no material adverse change in the condition (financial or otherwise), results of operations, business, properties or prospects of the Company, except as set forth in the General Disclosure Package or as described in such certificate.

(g) Approval of Listing. On the Closing Date, the Offered Securities shall have been approved for inclusion in the NASDAQ Global Market, subject only to official notice of issuance.

(h) Lock-Up Agreements. As of the date hereof, the Representatives shall have received a lock-up agreement substantially in the form of Exhibit A hereto signed by the persons listed on Schedule C hereto.

(i) CBO Certificate. The Representatives shall have received a certificate, dated such Closing Date, of the Chief Business Officer of the Company substantially in the form of Exhibit B hereto.

(j) Additional Documents. On the Closing Date, 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 Offered 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 Offered Securities as herein contemplated shall be satisfactory in form and substance to the Representatives and counsel for the Underwriters.

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

8. Indemnification and Contribution. (a) Indemnification of Underwriters. The Company will indemnify and hold harmless each Underwriter, its partners, members, directors, officers, employees, agents, affiliates and each person, if any, who controls such Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act (each, an “Indemnified Party”), against any and all losses, claims, damages or liabilities, joint or several, to which such Indemnified Party may become subject, under

the 1933 Act, the 1934 Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in any part of the Registration Statement at any time, any Statutory Prospectus as of any time, the Prospectus or any Issuer Free Writing Prospectus, or arise out of or are based upon the omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein not misleading, and will reimburse each Indemnified Party for any legal or other expenses reasonably incurred by such Indemnified Party in connection with investigating or defending against any loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Indemnified Party is a party thereto), whether threatened or commenced, and in connection with the enforcement of this provision with respect to any of the above as such expenses are incurred; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement in or omission or alleged omission from any of such documents in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in subsection (b) below.

(b) Indemnification of Company. Each Underwriter will severally and not jointly indemnify and hold harmless the Company, each of its directors and each of its officers who signs a Registration Statement and each person, if any, who controls the Company within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act (each, an “Underwriter Indemnified Party”), against any losses, claims, damages or liabilities to which such Underwriter Indemnified Party may become subject, under the 1933 Act, the 1934 Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in any part of the Registration Statement at any time, any Statutory Prospectus as of any time, the Prospectus, or any Issuer Free Writing Prospectus, or arise out of or are based upon the omission or the alleged omission of a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in reliance upon and in conformity with written information furnished to the Company by such Underwriter through the Representatives specifically for use therein, and will reimburse any legal or other expenses reasonably incurred by such Underwriter Indemnified Party in connection with investigating or defending against any such loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Underwriter Indemnified Party is a party thereto), whether threatened or commenced, based upon any such untrue statement or omission, or any such alleged untrue statement or omission as such expenses are incurred, it being understood and agreed that the only such information furnished by any Underwriter consists of the following information in the Prospectus furnished on behalf of each Underwriter: the concession and reallowance figures appearing in the fourth paragraph under the caption “Underwriting” and the information contained in the eleventh and twelfth paragraphs under the caption “Underwriting”.

(c) Actions against Parties; Notification. Promptly after receipt by an indemnified party under this Section of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under subsection (a) or (b) above, notify the indemnifying party of the commencement thereof; but the failure to notify the indemnifying party shall not relieve it from any liability that it may have under subsection (a) or (b) above except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure; and provided further that the failure to notify the indemnifying party shall not relieve it from any liability that it may have to an indemnified party otherwise than under subsection (a) or (b) above. In case any such action is brought against any indemnified party and it notifies the indemnifying party of the commencement thereof, the indemnifying party will be entitled to participate therein and, to the extent that it may wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be

counsel to the indemnifying party), and after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party will not be liable to such indemnified party under this Section for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof other than reasonable costs of investigation. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened action in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party unless such settlement (i) includes an unconditional release of such indemnified party from all liability on any claims that are the subject matter of such action and (ii) does not include a statement as to, or an admission of, fault, culpability or a failure to act by or on behalf of an indemnified party.

(d) Contribution. If the indemnification provided for in this Section is unavailable or insufficient to hold harmless an indemnified party under subsection (a) or (b) above, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of the losses, claims, damages or liabilities referred to in subsection (a) or (b) above (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Offered Securities or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The amount paid by an indemnified party as a result of the losses, claims, damages or liabilities referred to in the first sentence of this subsection (d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any action or claim which is the subject of this subsection (d). Notwithstanding the provisions of this subsection (d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Offered Securities underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the 1933 Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this subsection (d) to contribute are several in proportion to their respective underwriting obligations and not joint. The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 8(d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to in this Section 8(d).

9. Default of Underwriters. If any Underwriter or Underwriters default in their obligations to purchase Offered Securities hereunder on either the First or any Optional Closing Date and the aggregate number of shares of Offered Securities that such defaulting Underwriter or Underwriters agreed but failed to purchase does not exceed 10% of the total number of shares of Offered Securities that the Underwriters are obligated to purchase on such Closing Date, Credit Suisse and Merrill Lynch may make arrangements satisfactory to the Company for the purchase of such Offered Securities by other persons, including any of the Underwriters, but if no such arrangements are made by such Closing Date, the non-defaulting Underwriters shall be obligated severally, in proportion to their respective commitments hereunder, to purchase the Offered Securities that such defaulting Underwriters agreed but failed to purchase on such Closing Date. If any Underwriter or Underwriters so default and the aggregate number of shares of Offered

Securities with respect to which such default or defaults occur exceeds 10% of the total number of shares of Offered Securities that the Underwriters are obligated to purchase on such Closing Date and arrangements satisfactory to Credit Suisse, Merrill Lynch and the Company for the purchase of such Offered Securities by other persons are not made within 36 hours after such default, this Agreement will terminate without liability on the part of any non-defaulting Underwriter or the Company, except as provided in Section 10 (provided that if such default occurs with respect to Optional Securities after the First Closing Date, this Agreement will not terminate as to the Firm Securities or any Optional Securities purchased prior to such termination). As used in this Agreement, the term “Underwriter” includes any person substituted for an Underwriter under this Section. Nothing herein will relieve a defaulting Underwriter from liability for its default.

10. Survival of Certain Representations and Obligations. The respective indemnities, agreements, representations, warranties and other statements of the Company or its officers and of the several Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation, or statement as to the results thereof, made by or on behalf of any Underwriter, the Company or any of their respective representatives, officers or directors or any controlling person, and will survive delivery of and payment for the Offered Securities. If the purchase of the Offered Securities by the Underwriters is not consummated due to a failure of the Company to perform its obligations under Section 7 hereof, the Company will reimburse the Underwriters for all out-of-pocket expenses (including fees and disbursements of counsel) reasonably incurred by them in connection with the offering of the Offered Securities, and the respective obligations of the Company and the Underwriters pursuant to Section 8 hereof shall remain in effect; provided, however that, if such failure to consummate shall take place after the First Closing Date with respect to any Optional Securities, such reimbursement will be limited to the reasonable out of pocket expenses incurred after the First Closing Date solely with respect to such Optional Securities. In addition, if any Offered Securities have been purchased hereunder, the representations and warranties in Section 2 and all obligations under Section 5 shall also remain in effect.

11. Notices. All communications hereunder will be in writing and, if sent to the Underwriters, will be mailed, delivered or telegraphed and confirmed to the Representatives, c/o Credit Suisse Securities (USA) LLC, Eleven Madison Avenue, New York, N.Y. 10010-3629, Attention: LCD-IBD, or, if sent to the Company, will be mailed, delivered or telegraphed and confirmed to it at Orexigen Therapeutics, Inc., 3344 N. Torrey Pines Ct., La Jolla, CA 92037, Attention: General Counsel; provided, however, that any notice to an Underwriter pursuant to Section 8 will be mailed, delivered or telegraphed and confirmed to such Underwriter.

12. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and controlling persons referred to in Section 8, and no other person will have any right or obligation hereunder.

13. Representation of Underwriters. The Representatives will act for the several Underwriters in connection with this financing, and any action under this Agreement taken by all the Representatives jointly or jointly by Credit Suisse and Merrill Lynch will be binding upon all the Underwriters.

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

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

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

(b) Arms’ Length Negotiations. The price of the Offered Securities set forth in this Agreement was established by the Company following discussions and arms-length negotiations with the Representatives and the Company is capable of evaluating and understanding and understands and accepts the terms, risks and conditions of the transactions contemplated by this Agreement;

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

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

16. Applicable Law. This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York. The Company hereby submits to the non-exclusive jurisdiction of the Federal and state courts in the Borough of Manhattan in The City of New York in any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. The Company irrevocably and unconditionally waives any objection to the laying of venue of any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby in Federal and state courts in the Borough of Manhattan in The City of New York and irrevocably and unconditionally waives and agrees not to plead or claim in any such court that any such suit or proceeding in any such court has been brought in an inconvenient forum.

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


Very truly yours,

	OREXIGEN THERAPEUTICS, INC.

	By:	/s/ Joseph Hagan
	Name:	Joseph Hagan
	Title:	C.B.O.


The foregoing Underwriting Agreement is hereby confirmed and accepted as of the date first above written.

	CREDIT SUISSE SECURITIES (USA) LLC

		By:	/s/ Charles Newton
			Name:	Charles Newton
			Title:	Managing Director

	MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED

		By:	/s/ Edmund Baxter
			Name:	Edmund Baxter
			Title:	Managing Director

	LEERINK SWANN LLC

		By:	/s/ Bryan Giraudo
			Name:	Bryan Giraudo
			Title:	Managing Director

			Acting on behalf of themselves and as the Representatives of the several Underwriters

[Signature Page to Underwriting Agreement]

SCHEDULE A


Underwriters	Number of Firm Securities

Credit Suisse Securities (USA) LLC		4,950,000

Merrill Lynch, Pierce, Fenner & Smith Incorporated		3,850,000

Leerink Swann LLC		2,200,000


Total		11,000,000

SCHEDULE B

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

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

1. Issuer Free Writing Prospectus dated October 25, 2012 filed by Orexigen Therapeutics, Inc. on October 25, 2012 pursuant to Rule 433 of the Securities Act of 1933, as amended.

2.	Other Information Included in the General Disclosure Package

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

None

SCHEDULE C

Michael Narachi

Jay Hagan

Mark Booth

Heather Turner

Preston Klassen

Dawn Viveash

Eckard Weber

Louis Bock

Brian Dovey

Patrick Mahaffy

Peter Honig

Wendy Dixon

Lota Zoth