ACADIA Pharmaceuticals Inc. 4,947,229 Shares Common Stock UNDERWRITING AGREEMENT dated April 27, 2006 Banc of America Securities LLC Lehman Brothers Inc. Piper Jaffray & Co. JMP Securities LLC Canaccord Adams Inc.

Exhibit 1.1

ACADIA Pharmaceuticals Inc.

4,947,229 Shares

Common Stock

UNDERWRITING AGREEMENT

dated April 27, 0000

Xxxx xx Xxxxxxx Securities LLC

Xxxxxx Brothers Inc.

Xxxxx Xxxxxxx & Co.

JMP Securities LLC

Canaccord Xxxxx Inc.

Underwriting Agreement

April 27, 0000

XXXX XX XXXXXXX SECURITIES LLC

XXXXXX BROTHERS INC.

As Representatives of the several Underwriters

c/o BANC OF AMERICA SECURITIES LLC

0 Xxxx 00xx Xxxxxx

Xxx Xxxx, XX 00000

c/x XXXXXX BROTHERS INC.

000 Xxxxxxx Xxxxxx

Xxx Xxxx, Xxx Xxxx 00000

Ladies and Gentlemen:

Introductory. ACADIA Pharmaceuticals Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 4,947,229 shares (the “Firm Shares”) of its Common Stock, par value $0.0001 per share (the “Common Stock”). In addition, the Company has granted to the Underwriters an option to purchase up to an additional 742,084 shares (the “Optional Shares”) of Common Stock, as provided in Section 2. The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Shares”. Banc of America Securities LLC (“BAS”) and Xxxxxx Brothers Inc. have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Shares.

To the extent there are no additional Underwriters listed on Schedule A other than you, the terms Representatives and Underwriters as used herein shall mean you, as Underwriters. The terms Representatives and Underwriters shall mean either the singular or plural as the context requires.

The Company hereby confirms its agreements with the Underwriters as follows:

Section 1. Representations and Warranties of the Company. The Company hereby represents and warrants to, and covenants with, each Underwriter as follows:

(a) The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-3 (File No. 333-131079), which contains a base prospectus (the “Base Prospectus”), to be used in connection with the public offering and sale of the Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, at each time of effectiveness under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including any required information deemed to be a part

thereof at the time of effectiveness pursuant to Rule 430B under the Securities Act or the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of the Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. Any preliminary prospectus supplement to the Base Prospectus that describes the Shares and the offering thereof and is used prior to filing of the Prospectus is called, together with the Base Prospectus, a “preliminary prospectus.” The term “Prospectus” shall mean the final prospectus relating to the Shares that is first filed pursuant to Rule 424(b) after the date and time that this Agreement is executed and delivered by the parties hereto (the “Execution Time”). Any reference herein to the Registration Statement, any preliminary prospectus, the Disclosure Package (as defined herein) or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the Securities Act; any reference to any amendment or supplement to any preliminary prospectus or the Prospectus shall be deemed to refer to and include any documents filed after the date of such preliminary prospectus or Prospectus, as the case may be, under the Exchange Act, and incorporated by reference in such preliminary prospectus or Prospectus, as the case may be; and any reference to any amendment to the Registration Statement shall be deemed to refer to and include any annual report of the Company filed pursuant to Section 13(a) or 15(d) of the Exchange Act after the effective date of the Registration Statement that is incorporated by reference in the Registration Statement.

(b) Compliance with Registration Requirements. The Registration Statement has been declared effective by the Commission under the Securities Act. The Company has complied to the Commission’s satisfaction with all requests of the Commission for additional or supplemental information. No stop order suspending the effectiveness of the Registration Statement is in effect, the Commission has not issued any order or notice preventing or suspending the use of the Registration Statement, any preliminary prospectus or the Prospectus and no proceedings for such purpose have been instituted or are pending or, to the best knowledge of the Company, are contemplated or threatened by the Commission.

Each preliminary prospectus and the Prospectus when filed complied in all material respects with the Securities Act. Each of the Registration Statement and any post-effective amendment thereto, at each time of effectiveness and at the date hereof, complied and will comply in all material respects with the Securities Act and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading. The Prospectus (including any Prospectus wrapper), as amended or supplemented, as of its date, at the date hereof, at the time of any filing pursuant to Rule 424(b), at the Closing Date (as defined herein) and at any Subsequent Closing Date (as defined herein), did not and will not contain any untrue statement of a material fact or 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. The representations and warranties set forth in the two immediately preceding sentences do not apply to statements in or omissions from the Registration Statement or any post-effective amendment thereto, or the Prospectus, or any amendments or supplements thereto, made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing

by the Representatives expressly for use therein, it being understood and agreed that the only such information furnished by the Representatives consists of the information described as such in Section 8(b) hereof. There is no contract or other document required to be described in the Prospectus or to be filed as an exhibit to the Registration Statement as of the time of the Prospectus that has not been described or filed as required.

(c) Documents Incorporated by Reference. The documents incorporated by reference in the Prospectus, when they became effective or were filed with the Commission, as the case may be, conformed in all material respects to the requirements of the Securities Act or the Exchange Act, as applicable. Any further documents so filed and incorporated by reference in the Prospectus or any further amendment or supplement thereto, when such documents become effective or are filed with the Commission, as the case may be, will conform in all material respects to the requirements of the Securities Act or the Exchange Act, as applicable, and the rules and regulations of the Commission thereunder.

(d) Disclosure Package. The term “Disclosure Package” shall mean (i) any preliminary prospectus, (ii) the issuer free writing prospectuses as defined in Rule 433 of the Securities Act prepared by or on behalf of the Company or used or referred to by the Company in connection with the offering of the Shares (each, an “Issuer Free Writing Prospectus”), if any, identified in Schedule B hereto, (iii) any other “free writing prospectus” (as defined in Rule 405 of the Securities Act) that the Representatives and the Company shall hereafter expressly agree in writing to treat as part of the Disclosure Package, and (iv) Schedule C hereto, which indicates the number of Shares being sold and the price at which the Shares will be sold to the public in accordance with this Agreement and the estimated net proceeds to the Company from the sale of the Shares. As of 9:00 pm (Eastern time) on the date of execution and delivery of this Agreement (the “Applicable Time”), the Disclosure Package did not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the Disclosure Package based 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 or on behalf of any Underwriter consists of the information described as such in Section 8(b) hereof.

(e) Company Not Ineligible Issuer. (i) At the earliest time after the filing of the Registration Statement relating to the Shares that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) of the Securities Act) and (ii) as of the date of the execution and delivery of this Agreement (with such date being used as the determination date for purposes of this clause (ii)), the Company was not and is not an Ineligible Issuer (as defined in Rule 405 of the Securities Act), without taking account of any determination by the Commission pursuant to Rule 405 of the Securities Act that it is not necessary that the Company be considered an Ineligible Issuer.

(f) Issuer Free Writing Prospectuses. Each Issuer Free Writing Prospectus identified in Schedule B hereto, as of its issue date and at all subsequent times through the completion of the offering of Shares under this Agreement or until any earlier date that the Company notified or notifies the Representatives as described in the next sentence, did not, does not and will not

include any information that conflicted, conflicts or will conflict with the information contained in the Registration Statement. If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information contained in the Registration Statement, the Company has promptly notified or will promptly notify the Representatives and has promptly amended or supplemented or will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict. The foregoing two sentences do not apply to statements in or omissions from any Issuer Free Writing Prospectus based upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(g) Distribution of Offering Material By the Company. The Company has not distributed and will not distribute, prior to the later of the last Subsequent Closing Date (as defined below) and the completion of the Underwriters’ distribution of the Shares, any offering material in connection with the offering and sale of the Shares other than a preliminary prospectus, the Prospectus, any Issuer Free Writing Prospectus reviewed and consented to by the Representatives or included in Schedule B hereto or the Registration Statement.

(h) The Underwriting Agreement. This Agreement has been duly authorized, executed and delivered by the Company.

(i) Authorization of the Shares. The Shares to be purchased by the Underwriters from the Company have been duly authorized for issuance and sale pursuant to this Agreement and, when issued and delivered by the Company pursuant to this Agreement, will be validly issued, fully paid and nonassessable.

(j) No Applicable Registration or Other Similar Rights. There are no persons with registration or other similar rights to have any equity or debt securities registered for sale under the Registration Statement or included in the offering contemplated by this Agreement, except for such rights as have been duly waived.

(k) No Material Adverse Change. Except as otherwise disclosed in the Disclosure Package, subsequent to the respective dates as of which information is given in the Disclosure Package: (i) there has been no material adverse change, or any development that could reasonably be expected to result in a material adverse change, in the condition, financial or otherwise, or in the earnings, business, operations or business prospects of the Company and its subsidiaries, considered as one entity, whether or not arising from transactions in the ordinary course of business (any such change is called a “Material Adverse Change”); (ii) the Company and its subsidiaries, considered as one entity, have not incurred any material liability or obligation, indirect, direct or contingent, not in the ordinary course of business nor entered into any material transaction or agreement not in the ordinary course of business; (iii) there has been no dividend or distribution of any kind declared, paid or made by the Company or, except for dividends paid to the Company or other subsidiaries, any of its subsidiaries on any class of capital stock or repurchase or redemption by the Company or any of

its subsidiaries of any class of capital stock.; and (iv) there has not been any change in the capital stock, short-term debt or long-term debt of the Company and its subsidiaries, taken as a whole, other than such changes that occur in the ordinary course of business.

(l) Independent Accountants. PricewaterhouseCoopers LLP, who have expressed their opinion with respect to the financial statements (which term as used in this Agreement includes the related notes thereto) filed with the Commission as a part of the Registration Statement and included in the Disclosure Package and the Prospectus, are independent public accountants as required by the Securities Act.

(m) Preparation of the Financial Statements. The financial statements filed with the Commission as a part of the Registration Statement and included in the Disclosure Package and the Prospectus present fairly the consolidated financial position of the Company and its subsidiaries as of and at the dates indicated and the results of their operations and cash flows for the periods specified. Such financial statements have been prepared in conformity with generally accepted accounting principles as applied in the United States applied on a consistent basis throughout the periods involved, except as may be expressly stated in the related notes thereto. No other financial statements or supporting schedules are required to be included in the Registration Statement. The financial data set forth in the preliminary prospectus and the Prospectus under the captions “Summary Consolidated Financial Data” and “Capitalization” fairly present the information set forth therein on a basis consistent with that of the audited financial statements included in the Registration Statement.

(n) Incorporation and Good Standing of the Company and its Subsidiaries. Each of the Company and its subsidiaries has been duly incorporated and is validly existing as a corporation in good standing under the laws of the jurisdiction of its incorporation and has corporate power and authority to own or lease, as the case may be, and operate its properties and to conduct its business as described in the Disclosure Package and the Prospectus and, in the case of the Company, to enter into and perform its obligations under this Agreement. The Company is duly qualified as a foreign corporation to transact business and is in good standing in the State of California and 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 for such jurisdictions (other than the State of California) where the failure to so qualify or to be in good standing would not, individually or in the aggregate, result in a material adverse effect, on the condition, financial or otherwise, or on the earnings, business, operations or business prospects of the Company and its subsidiaries, considered as one entity whether or not arising from transactions in the ordinary course of business (a “Material Adverse Effect”). All of the issued and outstanding capital stock of each subsidiary has been duly authorized and validly issued, is fully paid and nonassessable and is owned by the Company, directly or through subsidiaries, free and clear of any security interest, mortgage, pledge, lien, encumbrance or claim. The Company does not own or control, directly or indirectly, any corporation, association or other entity other than the subsidiaries listed in Exhibit 21.1 to the Registration Statement.

(o) Capitalization and Other Capital Stock Matters. The authorized, issued and outstanding capital stock of the Company is as set forth in the Disclosure Package and the Prospectus under the caption “Capitalization” (other than for subsequent issuances, if any, pursuant to employee benefit plans described in the Disclosure Package and the Prospectus or

upon exercise of outstanding options or warrants described in the Disclosure Package and the Prospectus, as the case may be). The Common Stock (including the Shares) conforms in all material respects to the description thereof contained in the Disclosure Package and the Prospectus. All of the issued and outstanding shares of Common Stock have been duly authorized and validly issued, are fully paid and nonassessable and have been issued in compliance with federal and state securities laws. None of the outstanding shares of Common Stock were issued in violation of any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase securities of the Company. There are no authorized or outstanding options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any capital stock of the Company or any of its subsidiaries other than those accurately described in the Disclosure Package and the Prospectus. The description of the Company’s stock option, stock bonus and other stock plans or arrangements, and the options or other rights granted thereunder, set forth or incorporated by reference in the Disclosure Package and the Prospectus accurately and fairly presents the information required to be shown with respect to such plans, arrangements, options and rights.

(p) Quotation. The Shares have been approved for quotation on the Nasdaq Stock Market, Inc., subject only to official notice of issuance.

(q) Non-Contravention of Existing Instruments; No Further Authorizations or Approvals Required. Neither the Company nor any of its subsidiaries is (i) in violation or in default (or, with the giving of notice or lapse of time, would be in default) (“Default”) under its charter or bylaws, or (ii) in Default under any indenture, mortgage, loan or credit agreement, note, contract, franchise, lease or other agreement or instrument to which the Company or such subsidiary is a party or by which it may be bound, or to which any of the property or assets of the Company or any of its subsidiaries is subject (each, an “Existing Instrument”), except with respect to clause (ii) only, for such Defaults as would not, individually or in the aggregate, have a Material Adverse Effect. The Company’s execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby, by the Disclosure Package and by the Prospectus (i) have been duly authorized by all necessary corporate action and will not result in any Default under the charter or bylaws of the Company or any subsidiary, (ii) will not conflict with or constitute a breach of, or Default or a Debt Repayment Triggering 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, or require the consent of any other party to, any Existing Instrument, except for such conflicts, breaches, Defaults, liens, charges or encumbrances as would not, individually or in the aggregate, have a Material Adverse Effect and (iii) will not result in any violation of any law, administrative regulation or administrative or court decree applicable to the Company or any of its subsidiaries. No consent, approval, authorization or other order of, or registration or filing with, any court or other governmental or regulatory authority or agency is required for the Company’s execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby, by the Disclosure Package and by the Prospectus, except such as have been obtained or made by the Company and are in full force and effect under the Securities Act, applicable state securities or blue sky laws and from the NASD, Inc. (the “NASD”). As used herein, a “Debt Repayment Triggering Event” means any event or condition which gives, or with the giving of notice or lapse of time would give, the holder of any note,

debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its subsidiaries.

(r) No Material Actions or Proceedings. Other than as set forth in the Disclosure Package and the Prospectus, there are no legal or governmental actions, suits or proceedings pending or, to the best of the Company’s knowledge, threatened (i) against or affecting the Company or any of its subsidiaries, (ii) which has as the subject thereof any officer or director of, or property owned or leased by, the Company or any of its subsidiaries or (iii) relating to environmental or discrimination matters, where in any such case (A) there is a reasonable possibility that such action, suit or proceeding might be determined adversely to the Company or such subsidiary, or any officer or director of, or property owned or leased by, the Company or any of its subsidiaries and (B) any such action, suit or proceeding, if so determined adversely, would reasonably be expected to have a Material Adverse Effect or adversely affect the consummation of the transactions contemplated by this Agreement. No material labor dispute with the employees of the Company or any of its subsidiaries exists or, to the best of the Company’s knowledge, is threatened or imminent.

(s) Intellectual Property Rights. Except as set forth in the Disclosure Package and the Prospectus, the Company and its subsidiaries own or possess the right to use sufficient trademarks, trade names, patent rights, copyrights, domain names, licenses, approvals, trade secrets, inventions, technology, know-how and other similar rights (collectively, “Intellectual Property Rights”) as are necessary or material (i) to conduct their businesses as now conducted, (ii) in connection with the commercialization of the drug candidates described in the Prospectus as being under development by the Company independently and (iii) in connection with the development of the drug candidates described in the Prospectus as being under development by the Company in collaboration with third parties. Except as set forth in the Disclosure Package and the Prospectus, (a) there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding, or claim by others challenging the Company’s rights in or to any Intellectual Property Rights, and the Company is unaware of any facts which would form a reasonable basis for any such claim; (b) there is no pending, or to the Company’s knowledge, threatened action, suit, proceeding, or claim by others that the Company infringes, misappropriates, or otherwise violates any Intellectual Property Rights of others, and the Company is unaware of any other facts which would form a reasonable basis for any such claim; (c) there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding, or claim by others challenging the validity or scope of any such Intellectual Property Rights owned by the Company and the Company is unaware of any facts which would form a reasonable basis for any such claim; (d) to the Company’s knowledge, the operation of Company’s business as now conducted and in connection with the development and commercialization of the drug candidates described in the Prospectus, as being under development by the Company (either independently or in collaboration with third parties), does not infringe any claim of any patent or published patent application; (e) there is no prior art of which the Company is aware that may render any patent owned or licensed by the Company invalid or any patent application owned or licensed by the Company unpatentable which has not been disclosed to the applicable government patent office; and (f) the patents, trademarks, and copyrights granted or issued to the Company have been duly maintained and are in full force and in effect, and none of such patents, trademarks and copyrights have been adjudged invalid or unenforceable in whole or in part. 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 Prospectus and are not described therein in all material respects.

(t) Patent Applications. The Company has duly and properly filed or caused to be filed with the U.S. Patent and Trademark Office (the “PTO”) and applicable foreign and international patent authorities all patent applications owned by the Company (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 Company’s knowledge, the Company Patent Applications disclose patentable subject matters, and the Company has not been notified of any inventorship challenges nor has any interference been declared or provoked nor is any material fact known by the Company that would preclude the issuance of patents with respect to the Company Patent Applications or would render such patents invalid or unenforceable. To the Company’s knowledge, no third party possesses rights to the Company’s Intellectual Property Rights that, if exercised, could enable such party to develop products competitive to those the Company intends to develop as described in the Prospectus.

(u) Trials. The studies, tests and preclinical and clinical trials conducted by or on behalf of the Company that are described in 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. The descriptions of such studies, tests and trials contained in the Registration Statement and the Prospectus are accurate in all material respects. Neither the Company nor any third party or consultant engaged by the Company in connection with the conduct of the Company’s studies, tests, preclinical and clinical trials have received any notices or correspondence from the U.S. Food and Drug Administration (the “FDA”) or any foreign, state or local governmental or self-regulatory body exercising comparable authority requiring the termination, suspension or material modification of any studies, tests or preclinical or clinical trials conducted by or on behalf of the Company, which termination, suspension or material modification would reasonably be expected to have a Material Adverse Effect. To the Company’s knowledge, there is no termination, suspension or material indemnification of any studies, tests or preclinical or clinical trials conducted by others on any active ingredient contained in the existing products of the Company, or the drug candidates described in the Prospectus as being under development.

(v) Proposed FDA or PTO Rules. To the best of the Company’s knowledge, there are no rulemaking or similar proceedings before the FDA or PTO which affect or involve the Company or any of the processes or drug candidates that the Company has developed, is developing or proposes to develop or uses or proposes to use which, if the subject of an action unfavorable to the Company, would have a Material Adverse Effect.

(w) All Necessary Permits, etc. The Company and each subsidiary possess such valid and current certificates, authorizations or permits issued by the appropriate state, federal or foreign regulatory or self-regulatory agencies or bodies necessary to conduct their respective businesses including, without limitation, all such certificates, authorizations and permits required by the FDA and any state, federal or foreign or self-regulatory agencies or bodies engaged in the regulation of pharmaceuticals or biohazardous materials, and neither the Company nor any

subsidiary has received any notice of proceedings relating to the revocation or modification of, or non-compliance with, any such certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, could have a Material Adverse Effect.

(x) Title to Properties. Except as otherwise disclosed in the Disclosure Package and the Prospectus, the Company and each of its subsidiaries has good and marketable title to all the properties and assets reflected as owned in the financial statements referred to in Section 1(m) above (or elsewhere in the Disclosure Package and the Prospectus), in each case free and clear of any security interests, mortgages, liens, encumbrances, equities, claims and other defects, except such as do not materially and adversely affect the value of such property and do not materially interfere with the use made or proposed to be made of such property by the Company or such subsidiary. The real property, improvements, equipment and personal property held under lease by the Company or any subsidiary are held under valid and enforceable leases, with such exceptions as are not material and do not materially interfere with the use made or proposed to be made of such real property, improvements, equipment or personal property by the Company or such subsidiary.

(y) Tax Law Compliance. The Company and its consolidated subsidiaries have filed all necessary federal, state and foreign income and franchise tax returns or have properly requested extensions thereof and have paid all taxes required to be paid by any of them and, if due and payable, any related or similar assessment, fine or penalty levied against any of them, except for any taxes, assessments, fines or penalties as may be being contested in good faith and by appropriate proceedings. The Company has made appropriate provisions in the applicable financial statements referred to in Section 1(m) above in respect of all federal, state and foreign income and franchise taxes for all periods as to which the tax liability of the Company or any of its consolidated subsidiaries has not been finally determined.

(z) Company Not an “Investment Company”. The Company has been advised of the rules and requirements under the Investment Company Act of 1940, as amended (the “Investment Company Act”). The Company is not, and after receipt of payment for the Shares and the application of the proceeds thereof as contemplated under the caption “Use of Proceeds” in the Disclosure Package and the Prospectus will not be, an “investment company” within the meaning of the Investment Company Act and will conduct its business in a manner so that it will not become subject to the Investment Company Act.

(aa) Insurance. Each of the Company and its subsidiaries are insured by recognized, financially sound and reputable institutions with policies in such amounts and with such deductibles and covering such risks as are generally deemed adequate and customary for their businesses including, but not limited to, policies covering real and personal property owned or leased by the Company and its subsidiaries against theft, damage, destruction, and acts of vandalism. The Company has no reason to believe that it or any subsidiary 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 have a Material Adverse Effect. Neither of the Company nor any subsidiary has been denied any insurance coverage which it has

sought or for which it has applied, other than such denials that would not have a Material Adverse Effect.

(bb) No Price Stabilization or Manipulation. The Company has not taken and will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of the Common Stock to facilitate the sale or resale of the Shares.

(cc) Related Party Transactions. There are no business relationships or related-party transactions involving the Company or any subsidiary or any other person required to be described in the Disclosure Package or the Prospectus that have not been described as required.

(dd) Disclosure Controls and Procedures. The Company has established and maintains disclosure controls and procedures (as such term is defined in Rule 13a 15(e) under the Exchange Act), which (i) are designed to ensure that material information relating to the Company, including its consolidated subsidiaries, is made known to the Company’s principal executive officer and its principal financial officer by others within those entities, particularly during the periods in which the periodic reports required under the Exchange Act will be prepared, (ii) have been evaluated for effectiveness as of the end of the Company’s most recent fiscal quarter and (iii) are effective in all material respects to perform the functions for which they were established. Based on the evaluation of the Company’s disclosure controls and procedures described above, the Company is not aware of any material deficiencies in the design or operation of the Company’s disclosure controls and procedures.

(ee) No Unlawful Contributions or Other Payments. Neither the Company nor any of its subsidiaries nor, to the best of the Company’s knowledge, any employee or agent of the Company or any subsidiary, has made any contribution or other payment to any official of, or candidate for, any federal, state or foreign office in violation of any law or of the character required to be disclosed in the Disclosure Package and the Prospectus.

(ff) Internal Controls and Procedures. The Company maintains (i) effective internal control over financial reporting as defined in Rule 13a-15 under the Exchange Act, and (ii) 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 generally accepted accounting principles as applied in the United States and to maintain asset accountability; (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.

(gg) No Material Weakness in Internal Controls. Since the end of the Company’s most recent audited fiscal year, there has been (i) no material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (ii) 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.

(hh) Compliance with Environmental Laws. Except as would not, individually or in the aggregate, result in a Material Adverse Effect, (i) neither the Company nor any of its subsidiaries is in violation of any federal, state, local or foreign law or regulation relating to pollution or protection of human health or 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 emissions, discharges, releases or threatened releases of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum and petroleum products (collectively, “Materials of Environmental Concern”), or otherwise relating to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Materials of Environment Concern (collectively, “Environmental Laws”), which violation includes, but is not limited to, noncompliance with any permits or other governmental authorizations required for the operation of the business of the Company or its subsidiaries under applicable Environmental Laws, or noncompliance with the terms and conditions thereof, nor has the Company or any of its subsidiaries received any written communication, whether from a governmental authority, citizens group, employee or otherwise, that alleges that the Company or any of its subsidiaries is in violation of any Environmental Law; (ii) there is no claim, action or cause of action filed with a court or governmental authority, no investigation with respect to which the Company has received written notice, and no written notice to the Company by any person or entity alleging potential liability for investigatory costs, cleanup costs, governmental responses costs, natural resources damages, property damages, personal injuries, attorneys’ fees or penalties arising out of, based on or resulting from the presence, or release into the environment, of any Material of Environmental Concern at any location owned, leased or operated by the Company or any of its subsidiaries, now or in the past (collectively, “Environmental Claims”), pending or, to the best of the Company’s knowledge, threatened against the Company or any of its subsidiaries or any person or entity whose liability for any Environmental Claim the Company or any of its subsidiaries has retained or assumed either contractually or by operation of law; and (iii) to the best of the Company’s knowledge, there are no past or present actions, activities, circumstances, conditions, events or incidents, including, without limitation, the release, emission, discharge, presence or disposal of any Material of Environmental Concern, that reasonably could result in a violation of any Environmental Law or form the basis of a potential Environmental Claim against the Company or any of its subsidiaries or against any person or entity whose liability for any Environmental Claim the Company or any of its subsidiaries has retained or assumed either contractually or by operation of law.

(ii) Periodic Review of Costs of Environmental Compliance. In the ordinary course of its business, the Company conducts a periodic review of the effect of Environmental Laws on the business, operations and properties of the Company and its subsidiaries, in the course of which it identifies and evaluates associated costs and liabilities (including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws or any permit, license or approval, any related constraints on operating activities and any potential liabilities to third parties). On the basis of such review and the amount of its established reserves, the Company has reasonably concluded that such associated costs and liabilities would not, individually or in the aggregate, have a Material Adverse Effect.

(jj) ERISA Compliance. None of the following events has occurred or exists: (i) a failure to fulfill the obligations, if any, under the minimum funding standards of Xxxxxxx 000 xx

xxx Xxxxxx Xxxxxx Employee Retirement Income Security Act of 1974, as amended (“ERISA”), and the regulations and published interpretations thereunder with respect to a Plan, determined without regard to any waiver of such obligations or extension of any amortization period; (ii) an audit or investigation by the Internal Revenue Service, the U.S. Department of Labor, the Pension Benefit Guaranty Corporation or any other federal or state governmental agency or any foreign regulatory agency with respect to the employment or compensation of employees of the Company that would have a Material Adverse Effect; (iii) any breach of any contractual obligation, or any violation of law or applicable qualification standards, with respect to the employment or compensation of employees of the Company that would have a Material Adverse Effect. None of the following events has occurred: (i) a material increase in the aggregate amount of contributions required to be made to all Plans in the current fiscal year of the Company compared to the amount of such contributions made in the Company’s most recently completed fiscal year; (ii) a material increase in the Company’s “accumulated post-retirement benefit obligations” (within the meaning of Statement of Financial Accounting Standards 106) compared to the amount of such obligations in the Company’s most recently completed fiscal year; (iii) any event or condition giving rise to a liability under Title IV of ERISA that would have a Material Adverse Effect; or (iv) except as included in the Disclosure Package and the Prospectus, the filing of a claim by one or more employees or former employees of the Company related to their employment that would have a Material Adverse Effect. For purposes of this paragraph, the term “Plan” means a plan (within the meaning of Section 3(3) of ERISA) subject to Title IV of ERISA with respect to which any member of the Company may have any liability.

(kk) Brokers. Except as provided herein, there is no broker, finder or other party that is entitled to receive from the Company any brokerage or finder’s fee or other fee or commission as a result of any transactions contemplated by this Agreement.

(ll) No Outstanding Loans or Other Indebtedness. There are no outstanding loans, advances (except normal advances for business expenses in the ordinary course of business) or guarantees or indebtedness by the Company to or for the benefit of any of the officers or directors of the Company or any of the members of any of them, except as disclosed in the Disclosure Package and the Prospectus.

(mm) Strategic Agreements. Except as otherwise disclosed in the Disclosure Package and Prospectus, each of the collaboration or strategic alliance agreements, including without limitation, license and supply agreements, described in the Disclosure Package and Prospectus under the caption “Business – Collaboration Agreements,” (collectively, the “Strategic Agreements”) is in full force and effect and constitutes a valid and binding agreement between the parties thereto, enforceable in accordance with its terms, subject, as to enforcement, to bankruptcy, insolvency and reorganization, and there has not occurred any breach or default under any such Strategic Agreement or any event that with the giving of notice or lapse of time would constitute a breach or default thereunder.

(nn) Accuracy of Statements. The statements set forth in the Disclosure Package and Prospectus under the caption “Business—Collaboration Agreements,” insofar as they purport to describe the provisions of the agreements referred to therein, under the caption “Business — Government Regulation,” insofar as they purport to describe the provisions of the laws and regulations referred to therein, and under the caption “Underwriting,” insofar as they purport to

describe the provisions of the laws and documents referred to therein, are accurate descriptions or summaries in all material respects.

(oo) Xxxxxxxx-Xxxxx Compliance. There is and has been no material failure on the part of the Company and, to the knowledge of the Company, any of the Company’s directors or officers, in their capacities as such, to comply with any provision of the Xxxxxxxx-Xxxxx Act of 2002 and the rules and regulations promulgated in connection therewith (the “Xxxxxxxx-Xxxxx Act”), including Section 402 related to loans and Sections 302 and 906 related to certifications.

(pp) Compliance with Laws. The Company has not been advised, and has no reason to believe, that it and each of its subsidiaries are not conducting business in compliance with all applicable laws, rules and regulations of the jurisdictions in which it is conducting business, except where failure to be so in compliance would not have a Material Adverse Effect.

(qq) Statistical Data. The statistical and market-related data included in the Registration Statement and the Prospectus are based on or derived from sources which the Company reasonably and in good faith believes are reliable and accurate, and such data agree with the sources from which they are derived.

Any certificate signed by an officer of the Company and delivered to the Representatives or to counsel for the Underwriters shall be deemed to be a representation and warranty by the Company to each Underwriter as to the matters set forth therein.

The Company acknowledges that the Underwriters and, for purposes of the opinions to be delivered pursuant to Section 5 hereof, counsel to the Company and counsel to the Underwriters, will rely upon the accuracy and truthfulness of the foregoing representations and hereby consents to such reliance.

Section 2. Purchase, Sale and Delivery of the Shares.

(a) The Firm Shares. The Company agrees to issue and sell to the several Underwriters the Firm Shares upon the terms herein set forth. On the basis of the representations, warranties and agreements herein contained, and upon the terms but subject to the conditions herein set forth, the Underwriters agree, severally and not jointly, to purchase from the Company the respective number of Firm Shares set forth opposite their names on Schedule A. The purchase price per Firm Common Share to be paid by the several Underwriters to the Company shall be $11.28 per share.

(b) The Closing Date. Delivery of the Firm Shares to be purchased by the Underwriters and payment therefor shall be made at the offices of Xxxxxx Godward LLP, 0000 Xxxxxxxx Xxxx, Xxx Xxxxx, Xxxxxxxxxx (or such other place as may be agreed to by the Company and the Representatives) at 6:00 a.m. San Diego time, on May 3, 2006, or such other time and date not later than 10:30 a.m. San Diego time, on May 3, 2006, as the Representatives shall designate by notice to the Company (the time and date of such closing are called the “Closing Date”).

(c) The Optional Shares; the Subsequent Closing Date. In addition, on the basis of the representations, warranties and agreements herein contained, and upon the terms but subject to the conditions herein set forth, the Company hereby grants an option to the several Underwriters to purchase, severally and not jointly, up to an aggregate of 742,084 Optional Shares from the Company at the purchase price per share to be paid by the Underwriters for the Firm Shares. The option granted hereunder may be exercised at any time and from time to time upon notice by the Representatives to the Company, which notice may be given at any time within 30 days from the date of this Agreement. Such notice shall set forth (i) the aggregate number of Optional Shares as to which the Underwriters are exercising the option, and (ii) the time, date and place at which such closing will occur (which time and date may be simultaneous with, but not earlier than, the Closing Date; and in such case the term “Closing Date” shall refer to the time and date of delivery of the Firm Shares and the Optional Shares). Such time and date of delivery, if subsequent to the Closing Date, is called a “Subsequent Closing Date” and shall be determined by the Representatives and shall not be earlier than three nor later than five full business days after delivery of such notice of exercise. Any Optional Shares would cover sales by the Underwriters which exceed the total number of Firm Shares. If any Optional Shares are to be purchased, each Underwriter agrees, severally and not jointly, to purchase the number of Optional Shares (subject to such adjustments to eliminate fractional shares as the Representatives may determine) that bears the same proportion to the total number of Optional Shares to be purchased as the number of Firm Shares set forth on Schedule A opposite the name of such Underwriter bears to the total number of Firm Shares. The Representatives, on behalf of the several Underwriters, may, in their sole discretion, cancel the option at any time prior to its expiration by giving written notice of such cancellation to the Company; provided that the option cannot be cancelled as to any Optional Shares for which a notice of exercise has been delivered to the Company.

(d) Public Offering of the Shares. The Representatives hereby advise the Company that the Underwriters intend to offer for sale to the public, as described in the Prospectus, their respective portions of the Shares as soon after this Agreement has been executed and the Registration Statement has been declared effective as the Representatives, in their sole judgment, have determined is advisable and practicable.

(e) Payment for the Shares. Payment for the Shares shall be made at the Closing Date (and, if applicable, at any Subsequent Closing Date) by wire transfer of immediately available funds to the order of the Company.

It is understood that the Representatives have been authorized, for their own account and the accounts of the several Underwriters, to accept delivery of and receipt for, and make payment of the purchase price for, the Firm Shares and any Optional Shares the Underwriters have agreed to purchase. BAS, individually and not as the Representative of the Underwriters, may (but shall not be obligated to) make payment for any Shares to be purchased by any Underwriter whose funds shall not have been received by the Representatives by the Closing Date or any Subsequent Closing Date, as the case may be, for the account of such Underwriter, but any such payment shall not relieve such Underwriter from any of its obligations under this Agreement.

(f) Delivery of the Shares. Delivery of the Firm Shares and the Optional Shares shall be made against the irrevocable release of a wire transfer of immediately available funds for the

amount of the purchase price therefor through the facilities of The Depository Trust Company unless the Representatives shall otherwise instruct prior to the Closing Date or Subsequent Closing Date, as applicable. Time shall be of the essence, and delivery at the time and place specified in this Agreement is a further condition to the obligations of the Underwriters.

(g) Delivery of Prospectus to the Underwriters. Not later than 10:00 a.m. on the second business day following the date the Shares are first released by the Underwriters for sale to the public, the Company shall deliver or cause to be delivered, copies of the Prospectus in such quantities and at such places as the Representatives shall request.

Section 3. Covenants of the Company. The Company covenants and agrees with each Underwriter as follows:

(a) Representatives’ Review of Proposed Amendments and Supplements. During the period beginning at the Applicable Time and ending on the later of the Closing Date or such date, as in the reasonable opinion of counsel for the Underwriters, the Prospectus is no longer required by law to be delivered in connection with sales by an Underwriter or dealer, including in circumstances where such requirement may be satisfied pursuant to Rule 172 (the “Prospectus Delivery Period”), prior to amending or supplementing the Registration Statement, the Disclosure Package or the Prospectus (including any amendment or supplement through incorporation by reference of any report filed under the Exchange Act), the Company shall furnish to the Representatives for review a copy of each such proposed amendment or supplement, and the Company shall not file or use any such proposed amendment or supplement to which the Representatives reasonably object.

(b) Securities Act Compliance. During the Prospectus Delivery Period, the Company shall promptly advise the Representatives in writing (i) of the receipt of any comments of, or requests for additional or supplemental information from, the Commission, (ii) of the time and date of any filing of any post-effective amendment to the Registration Statement or any amendment or supplement to any preliminary prospectus or the Prospectus, (iii) of the time and date that any post-effective amendment to the Registration Statement becomes effective and (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any order or notice preventing or suspending the use of the Registration Statement, any preliminary prospectus or the Prospectus, or of any proceedings to remove, suspend or terminate from listing or quotation the Common Stock from any securities exchange upon which it is listed for trading or included or designated for quotation, or of the threatening or initiation of any proceedings for any of such purposes. If the Commission shall enter any such stop order or issue any such notice at any time, the Company will use its best efforts to obtain the lifting or reversal of such order or notice at the earliest possible moment. Additionally, the Company agrees that it shall comply with the provisions of Rules 424(b) and 430B, as applicable, under the Securities Act, including with respect to the timely filing of documents thereunder, and will use its reasonable efforts to confirm that any filings made by the Company under such Rule 424(b) were received in a timely manner by the Commission.

(c) Amendments and Supplements to the Registration Statement, Disclosure Package and Prospectus and Other Securities Act Matters. If, during the Prospectus Delivery Period, any event or development shall occur or condition exist as a result of which the Disclosure Package or the Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein in the light of the circumstances under which they were made or then prevailing, as the case may be, not misleading, or if it shall be necessary to amend or supplement the Disclosure Package or the Prospectus, or to file under the Exchange Act any document incorporated by reference in the Disclosure Package or the Prospectus, in order to make the statements therein, in the light of the circumstances under which they were made or then prevailing, as the case may be, not misleading, or if in the reasonable opinion of the Representatives it is otherwise necessary or advisable to amend or supplement the Registration Statement, the Disclosure Package or the Prospectus, or to file a new registration statement containing the Prospectus, in order to comply with law, including in connection with the delivery of the Prospectus, the Company agrees to promptly prepare (subject to Section 3(a) and 3(d) hereof), file with the Commission and furnish at its own expense to the Underwriters and to dealers, amendments or supplements to the Registration Statement, the Disclosure Package or the Prospectus, or any new registration statement, necessary in order to make the statements in the Disclosure Package or the Prospectus as so amended or supplemented, in the light of the circumstances under which they were made or then prevailing, as the case may be, not misleading or so that the Registration Statement, the Disclosure Package or the Prospectus, as amended or supplemented, will comply with law.

(d) Permitted Free Writing Prospectuses. The Company represents that it has not made, and agrees that, unless it obtains the prior written consent of the Representatives, it will not make, any offer relating to the Shares that constitutes or would constitute an Issuer Free Writing Prospectus or that otherwise constitutes or would constitute a “free writing prospectus” (as defined in Rule 405 of the Securities Act) or a portion thereof, in each case, required to be filed by the Company with the Commission or retained by the Company under Rule 433 of the Securities Act; provided that the prior written consent of the Representatives hereto shall be deemed to have been given in respect of the Free Writing Prospectuses included in Schedule B hereto and any electronic road show. Any such free writing prospectus consented to by the Representatives is hereinafter referred to as a “Permitted Free Writing Prospectus”. The Company agrees that (i) it has treated and will treat, as the case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus, for purposes of compliance with Rule 433 of the Securities Act and (ii) has complied and will comply, as the case may be, with the requirements of Rules 164 and 433 of the Securities Act applicable to any Permitted Free Writing Prospectus, including in respect of timely filing with the Commission and legending, in each case if required by Rule 433, and record keeping.

(e) Copies of any Amendments and Supplements to the Prospectus. The Company agrees to furnish the Representatives, without charge, during the Prospectus Delivery Period, as many copies of the Prospectus and any amendments and supplements thereto and the Disclosure Package as the Representatives may request.

(f) Copies of the Registration Statement and the Prospectus. The Company will furnish to the Representatives and counsel for the Underwriters upon request signed copies of the Registration Statement (including exhibits thereto) and, so long as delivery of a prospectus by an

Underwriter or dealer may be required by the Securities Act, as many copies of each preliminary prospectus, the Prospectus and any supplement thereto and the Disclosure Package as the Representatives may reasonably request.

(g) Blue Sky Compliance. The Company shall cooperate with the Representatives and counsel for the Underwriters to qualify or register the Shares for sale under (or obtain exemptions from the application of) the state securities or blue sky laws or Canadian provincial Securities laws or other foreign laws of those jurisdictions reasonably designated by the Representatives, shall comply with such laws and shall continue such qualifications, registrations and exemptions in effect so long as required for the distribution of the Shares. The Company shall not be required to qualify as a foreign corporation or to take any action that would subject it to general service of process in any such jurisdiction where it is not presently qualified or where it would be subject to taxation as a foreign corporation. The Company will advise the Representatives promptly of the suspension of the qualification or registration of (or any such exemption relating to) the Shares for offering, sale or trading in any jurisdiction or any initiation or threat of any proceeding for any such purpose, and in the event of the issuance of any order suspending such qualification, registration or exemption, the Company shall use its best efforts to obtain the withdrawal thereof at the earliest possible moment.

(h) Use of Proceeds. The Company shall apply the net proceeds from the sale of the Shares sold by it in the manner described under the caption “Use of Proceeds” in the Disclosure Package and the Prospectus.

(i) Transfer Agent. The Company shall engage and maintain, at its expense, a registrar and transfer agent for the Common Stock.

(j) Earnings Statement. As soon as practicable, the Company will make generally available to its security holders and to the Representatives an earnings statement (which need not be audited) covering the twelve-month period ending March 31, 2007 that satisfies the provisions of Section 11(a) of the Securities Act and Rule 158 under the Securities Act.

(k) Periodic Reporting Obligations. During the Prospectus Delivery Period the Company shall file, on a timely basis, with the Commission and the Nasdaq Stock Market, Inc. all reports and documents required to be filed under the Exchange Act.

(l) Quotation. The Company will use its reasonable best efforts to quote, subject to notice of issuance, the Shares on the Nasdaq Stock Market, Inc.

(m) Agreement Not to Offer or Sell Additional Shares. During the period commencing on the date hereof and ending on the 90th day following the date of the Prospectus (the “Lock-up Period”), the Company will not, without the prior written consent of the Representatives (which consent may be withheld at the sole discretion of the Representatives), directly or indirectly, sell, offer, contract or grant any option to sell, pledge, transfer or establish an open “put equivalent position” or liquidate or decrease a “call equivalent position” within the meaning of Rule 16a-1(h) under the Exchange Act, or otherwise dispose of or transfer (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition of), or announce the offering of, or file any registration statement under the Securities Act in respect of,

any shares of Common Stock, options or warrants to acquire shares of the Common Stock or securities exchangeable or exercisable for or convertible into shares of Common Stock (other than as contemplated by this Agreement with respect to the Shares); provided, however, that (i) the Company may file a registration statement on Form S-8 and issue shares of its Common Stock or options to purchase its Common Stock, other stock awards, or Common Stock upon exercise of options or other stock awards, pursuant to any stock option, stock bonus or other stock plan or arrangement described in the Disclosure Package and Prospectus, (ii) the Company may file a registration statement on Form S-8 and issue shares of its Common Stock or options to purchase its Common Stock, other stock awards, or Common Stock upon exercise of options or other stock awards, pursuant to any stock option, stock bonus or other stock plan or arrangement not described in the Disclosure Package and Prospectus, so long as the aggregate amount of such issuances pursuant to this clause (ii) does not exceed three percent (3.0 %) of the Company’s outstanding capital stock measured as of the Closing Date, including the Shares to be issued and sold hereunder, and (iii) the Company may issue shares of Common Stock or securities exercisable for shares of Common Stock in connection with a strategic partnership, licensing, joint venture, collaboration, lending or other similar arrangements, or in connection with the acquisition or license by the Company of any business, products or technologies, so long as the aggregate amount of such issuances pursuant to this clause (iii) does not exceed ten percent (10.0 %) of the Company’s outstanding capital stock measured as of the Closing Date, including the Shares to be issued and sold hereunder, provided, further, that in each of clause (ii) and (iii), such shares of Common Stock, options, other stock awards or securities exercisable for shares of Common Stock shall not be re-sellable during the Lock-up Period (including any extension thereof). Notwithstanding the foregoing, if (x) during the last 17 days of the 90-day restricted period the Company issues an earnings release or material news or a material event relating to the Company occurs, or (y) prior to the expiration of the 90-day restricted period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the 90-day period, the restrictions imposed in this clause shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. The Company will provide the Representatives and each individual subject to the restricted period pursuant to the lockup letters described in Section 5(i) with prior notice of any such announcement that gives rise to an extension of the restricted period.

(n) Compliance with Laws. The Company will comply in all material respects with all applicable securities and other laws, rules and regulations, including, without limitation, the Xxxxxxxx-Xxxxx Act, and use its best efforts to cause the Company’s directors and officers, in their capacities as such, to comply in all material respects with such laws, rules and regulations, including, without limitation, the provisions of the Xxxxxxxx-Xxxxx Act.

(o) Future Reports to Stockholders. To furnish to its stockholders as soon as practicable after the end of each fiscal year an annual report (including a balance sheet and statements of income, stockholders’ equity and cash flows of the Company and its consolidated subsidiaries certified by independent public accountants) and, as soon as practicable after the end of each of the first three quarters of each fiscal year (beginning with the fiscal quarter ending after the effective date of the Registration Statement), to make available to its stockholders consolidated summary financial information of the Company and its subsidiaries for such quarter in reasonable detail.

(p) Investment Limitation. Prior to the date that is one year from the date hereof, the Company shall not invest, or otherwise use the proceeds received by the Company from its sale of the Shares in such a manner as would require the Company or any of its subsidiaries to register as an investment company under the Investment Company Act.

(q) No Manipulation of Price. Prior to the date that is three years from the date hereof, the Company will not take, directly or indirectly, any action designed to cause or result in, or that has constituted or might reasonably be expected to constitute the stabilization or manipulation of the price of any securities of the Company.

(r) Existing Lock-Up Agreement. The Company will enforce all existing agreements between the Company and any of its security holders that prohibit the sale, transfer, assignment,

pledge or hypothecation of any of the Company’s securities in connection with this offering of Shares for the duration of the periods contemplated in such agreements. In addition, the Company will direct the transfer agent to place stop transfer restrictions upon any such securities of the Company that are bound by such existing “lock-up” agreements for the duration of the periods contemplated in such agreements.

The Representatives, on behalf of the several Underwriters, may, in their sole discretion, waive in writing the performance by the Company of any one or more of the foregoing covenants or extend the time for their performance. Notwithstanding the foregoing, the Representatives agree not to consent to any action proposed to be taken by the Company or any other holder of the Company’s securities that would otherwise be prohibited by, or to waive compliance by the Company or any such other security holder with the provisions of, Section 3(n) above or any lock-up agreement delivered pursuant to Section 5(i) below without giving the other Representative at least 17 days prior notice (or such shorter notice as the other Representative may deem acceptable to permit compliance with applicable provisions of NASD Conduct Rule 2711(f) restricting publication and distribution of research and public appearances by research analysts before and after the expiration, waiver or termination of a lock-up agreement).

Section 4. Payment of Expenses. The Company agrees to pay all costs, fees and expenses incurred in connection with the performance of its obligations hereunder and in connection with the transactions contemplated hereby, including without limitation (i) all expenses incident to the issuance and delivery of the Shares (including all printing and engraving costs), (ii) all fees and expenses of the registrar and transfer agent of the Common Stock, (iii) all necessary issue, transfer and other stamp taxes in connection with the issuance and sale of the Shares to the Underwriters, (iv) all fees and expenses of the Company’s counsel, independent public or certified public accountants and other advisors, (v) all costs and expenses incurred in connection with the preparation, printing, filing, shipping and distribution of the Registration Statement (including financial statements, exhibits, schedules, consents and certificates of experts), each Issuer Free Writing Prospectus, each preliminary prospectus and the Prospectus, and all amendments and supplements thereto, and this Agreement, (vi) all filing fees, attorneys’ fees and expenses incurred by the Company or the Underwriters in connection with qualifying or registering (or obtaining exemptions from the qualification or registration of) all or any part of the Shares for offer and sale under the state securities or blue sky laws or the provincial securities laws of Canada, and, if requested by the Representatives, preparing and printing a “Blue Sky Survey” or memorandum, and any supplements thereto, advising the Underwriters of such qualifications, registrations and exemptions, (vii) the filing fees incident to, and the reasonable fees and expenses of counsel for the Underwriters in connection with, the NASD’s review and approval of the Underwriters’ participation in the offering and distribution of the Shares, (viii) the fees and expenses associated with quotation of the Shares on the Nasdaq Stock Market, Inc., (ix) all transportation and other expenses incurred in connection with presentations to prospective purchasers of the Shares, and (x) all other fees, costs and expenses referred to in Item 14 of Part II of the Registration Statement. Except as provided in this Section 4, Section 6, Section 8 and Section 9 hereof, the Underwriters shall pay their own expenses, including the fees and disbursements of their counsel.

Section 5. Conditions of the Obligations of the Underwriters. The obligations of the several Underwriters to purchase and pay for the Shares as provided herein on the Closing Date

and, with respect to the Optional Shares, any Subsequent Closing Date, shall be subject to the accuracy of the representations and warranties on the part of the Company set forth in Section 1 hereof as of the date hereof and as of the Closing Date as though then made and, with respect to the Optional Shares, as of any Subsequent Closing Date as though then made, to the accuracy of the statements of the Company made in any certificates pursuant to the provisions hereof, to the timely performance by the Company of its covenants and other obligations hereunder, and to each of the following additional conditions:

(a) Accountants’ Comfort Letter. On the date hereof, the Representatives shall have received from PricewaterhouseCoopers LLP, independent public accountants for the Company, in form and substance satisfactory to the Underwriters and PricewaterhouseCoopers LLP, a letter dated the date hereof addressed to the 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 Disclosure Package and Prospectus, except that the specified date referred to therein for the carrying out of procedures shall be no more than three business days prior to the Closing Date.

(b) Compliance with Registration Requirements; No Stop Order; No Objection from NASD. For the period from and after effectiveness of this Agreement and prior to the Closing Date and, with respect to the Optional Shares, any Subsequent Closing Date:

(i) the Company shall have filed the Prospectus with the Commission (including the information required by Rule 430B under the Securities Act) in the manner and within the time period required by Rule 424(b) under the Securities Act; or the Company shall have filed a post-effective amendment to the Registration Statement containing the information required by such Rule 430B, and such post-effective amendment shall have become effective;

(ii) all material required to be filed by the Company pursuant to Rule 433(d) under the Securities Act shall have been filed with the Commission within the applicable time periods prescribed for such filings under such Rule 433;

(iii) no stop order suspending the effectiveness of the Registration Statement, any Rule 462(b) Registration Statement, or any post-effective amendment to the Registration Statement, shall be in effect and no proceedings for such purpose shall have been instituted or threatened by the Commission; and

(iv) the NASD shall have raised no objection to the fairness and reasonableness of the underwriting terms and arrangements.

(c) No Material Adverse Change. For the period from and after the date of this Agreement and prior to the Closing Date and, with respect to the Optional Shares, any Subsequent Closing Date, in the judgment of the Representatives, there shall not have occurred any Material Adverse Change.

(d) Opinion of Counsel for the Company. On each of the Closing Date and any Subsequent Closing Date, the Representatives shall have received the opinion of Cooley

Godward LLP, counsel for the Company, dated as of such Closing Date, the form of which is attached as Exhibit A.

(e) Opinion of Special Patent Counsel for the Company. On each of the Closing Date and any Subsequent Closing Date, the Representatives shall have received the opinion of Xxxxxx Martens Xxxxx & Bear, LLP, special patent counsel for the Company, dated as of such Closing Date, in the form which is attached as Exhibit B.

(f) Opinion of Counsel for the Underwriters. On each of the Closing Date and any Subsequent Closing Date, the Representatives shall have received the favorable opinion of Shearman & Sterling LLP, counsel for the Underwriters, dated as of such Closing Date, in form and substance satisfactory to, and addressed to, the Representatives, with respect to the issuance and sale of the Shares, the Registration Statement, the Prospectus (together with any supplement thereto), the Disclosure Package and other related matters as the Representatives may reasonably require.

(g) Officers’ Certificate. On each of the Closing Date and any Subsequent Closing Date, the Representatives shall have received a written certificate executed by the Chief Executive Officer of the Company and the Chief Financial Officer of the Company, dated as of such Closing Date, to the effect set forth in subsection (b)(iii) of this Section 5, and further to the effect that:

(i) for the period from and after the date of this Agreement and prior to such Closing Date, there has not occurred any Material Adverse Change;

(ii) the representations, warranties and covenants of the Company set forth in Section 1 of this Agreement are true and correct on and as of the Closing Date with the same force and effect as though expressly made on and as of such Closing Date; and

(iii) the Company has complied with all the agreements hereunder and satisfied all the conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date.

(h) Bring-down Comfort Letter. On each of the Closing Date and any Subsequent Closing Date, the Representatives shall have received from PricewaterhouseCoopers LLP, independent public accountants for the Company, a letter dated such date, in form and substance satisfactory to the Representatives and PricewaterhouseCoopers LLP, to the effect that they reaffirm the statements made in the letter furnished by them pursuant to subsection (a) of this Section 5, except that the specified date referred to therein for the carrying out of procedures shall be no more than three business days prior to the Closing Date or Subsequent Closing Date, as the case may be.

(i) Lock-Up Agreement from Certain Securityholders of the Company. On or prior to the date hereof, the Company shall have furnished to the Representatives an agreement in the form of Exhibit C hereto from each party listed on Exhibit D hereto, and such agreement shall be in full force and effect on the Closing Date and any Subsequent Closing Date.

(j) Additional Documents. On or before each of the Closing Date and any Subsequent Closing Date, the Representatives and counsel for the Underwriters shall have received such information, documents and opinions as they may reasonably require for the purposes of enabling them to pass upon the issuance and sale of the Shares as contemplated herein, or in order to evidence the accuracy of any of the representations and warranties, or the satisfaction of any of the conditions or agreements, herein contained.

If any condition specified in this Section 5 is not satisfied when and as required to be satisfied, this Agreement may be terminated by the Representatives by notice to the Company at any time on or prior to the Closing Date and, with respect to the Optional Shares, at any time prior to any Subsequent Closing Date, which termination shall be without liability on the part of any party to any other party, except that Section 4, Section 6, Section 8 and Section 9 shall at all times be effective and shall survive such termination.

Section 6. Reimbursement of Underwriters’ Expenses. If this Agreement is terminated by the Representatives pursuant to Section 5, Section 7, Section 10 or Section 11, or if the sale to the Underwriters of the Shares on the Closing Date is not consummated because of any refusal, inability or failure on the part of the Company to perform any agreement herein or to comply with any provision hereof, the Company agrees to reimburse the Representatives and the other Underwriters (or such Underwriters as have terminated this Agreement with respect to themselves), severally, upon demand for all out-of-pocket expenses that shall have been reasonably incurred by the Representatives and the Underwriters in connection with the proposed purchase and the offering and sale of the Shares, including but not limited to fees and disbursements of counsel, printing expenses, travel expenses, postage, facsimile and telephone charges.

Section 7. Effectiveness of this Agreement. This Agreement shall not become effective until the execution of this Agreement by the parties hereto. Prior to such effectiveness, this Agreement may be terminated by any party by notice to each of the other parties hereto, and any such termination shall be without liability on the part of (a) the Company to any Underwriter, except that the Company shall be obligated to reimburse the expenses of the Representatives and the Underwriters pursuant to Sections 4 and 6 hereof, (b) of any Underwriter to the Company or (c) any party hereto to any other party except that the provisions of Section 8 and Section 9 shall at all times be effective and shall survive such termination.

Section 8. Indemnification.

(a) Indemnification of the Underwriters. The Company agrees to indemnify and hold harmless each Underwriter, its officers, employees, directors and agents, and each person, if any, who controls any Underwriter within the meaning of the Securities Act and the Exchange Act against any loss, claim, damage, liability or expense, as incurred, to which such Underwriter or such controlling person may become subject under the Securities Act, the Exchange Act, or other federal or state statutory law or regulation, insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based (i) upon any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, or any amendment thereto, including any information deemed to be a part thereof pursuant to Rule 430B or Rule 430C under the Securities Act, 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; (ii) upon any untrue statement or alleged untrue statement of a material fact contained in any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto) or any “road show” (as defined in Rule 433) not constituting an Issuer Free Writing Prospectus (a “Non-IFWP Road Show”), or the omission or alleged omission therefrom of a material fact, in each case, necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, (iii) in whole or in part upon inaccuracy in the representations and warranties of the Company contained herein, (iv) in whole or in part upon any failure of the Company to perform its obligations hereunder or under law, or (v) any act or failure to act or any alleged act or failure to act by any Underwriter in connection with, or relating in any manner to, the Shares or the offering contemplated hereby, and which is included as part of or referred to in any loss, claim, damage, liability or action arising out of or based upon any matter covered by clause (i) or (ii) above, provided that the Company shall not be liable under this clause (v) to the extent that a court of competent jurisdiction shall have determined by a final judgment that such loss, claim, damage, liability or action resulted directly from any such acts or failures to act undertaken or omitted to be taken by any Underwriter through its bad faith or willful misconduct; and to reimburse each Underwriter, its officers, directors, employees, agents and each such controlling person for any and all expenses (including the fees and disbursements of counsel chosen by the Representatives) as such expenses are reasonably incurred by such Underwriter, or its officers, directors, employees, agents or such controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action; provided however, that the foregoing indemnity agreement shall not apply to any loss, claim, damage, liability or expense to the extent, but only to the extent, arising out of or based upon any untrue statement or alleged untrue statement or omission or alleged omission made in reliance upon and in conformity with written information furnished to the Company by the Representatives expressly for use in the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto) or any Non-IFWP Road Show. The indemnity agreement set forth in this Section 8(a) shall be in addition to any liabilities that the Company may otherwise have.

(b) Indemnification of the Company, its Directors and Officers. Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, each of its directors, each of its officers who signed the Registration Statement and each person, if any, who controls the Company within the meaning of the Securities Act or the Exchange Act, against any loss, claim, damage, liability or expense, as incurred, to which the Company, or any such director, officer or controlling person may become subject, under the Securities Act, the Exchange Act, or other federal or state statutory law or regulation, or at common law or otherwise (including in settlement of any litigation, if such settlement is effected with the written consent of such Underwriter), insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based upon any untrue or alleged untrue statement of a material fact contained in the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus, the Prospectus (or any amendment or supplement thereto) or any Non-IFWP Road Show, or arises out of or is based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, and only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in

the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto) or any Non-IFWP Road Show, in reliance upon and in conformity with written information furnished to the Company by the Representatives expressly for use therein; and to reimburse the Company, or any such director, officer or controlling person for any legal and other expense reasonably incurred by the Company, or any such director, officer or controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action. The Company hereby acknowledges that the only information that the Underwriters have furnished to the Company expressly for use in the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto) or any Non-IFWP Road Show are the statements set forth in the table in the first paragraph under the caption “Underwriting” in the Prospectus, the statements set forth under the captions “Underwriting – Stabilization” and “Underwriting – Market Making” in the Prospectus and the Underwriters confirm that such statements are correct. The indemnity agreement set forth in this Section 8(b) shall be in addition to any liabilities that each Underwriter may otherwise have.

(c) Notifications and Other Indemnification Procedures. Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof, but the failure to so notify the indemnifying party (i) will not relieve it from liability which it may have to any indemnified party for contribution or otherwise than under the indemnity agreement contained in this Section 8 or to the extent it is not prejudiced as a proximate result of such failure. In case any such action is brought against any indemnified party and such indemnified party seeks or intends to seek indemnity from an indemnifying party, the indemnifying party will be entitled to participate in, and, to the extent that it shall elect, jointly with all other indemnifying parties similarly notified, by written notice delivered to the indemnified party promptly after receiving the aforesaid notice from such indemnified party, to assume the defense thereof with counsel reasonably satisfactory to such indemnified party; provided, however, if the defendants in any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that a conflict may arise between the positions of the indemnifying party and the indemnified party in conducting the defense of any such action or that there may be legal defenses available to it and/or other indemnified parties that are different from or additional to those available to the indemnifying party, the indemnified party or parties shall have the right to select separate counsel to assume such legal defenses and to otherwise participate in the defense of such action on behalf of such indemnified party or parties. Upon receipt of notice from the indemnifying party to such indemnified party of such indemnifying party’s election so to assume the defense of such action and approval by the indemnified party of counsel, the indemnifying party will not be liable to such indemnified party under this Section 8 for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof unless (i) the indemnified party shall have employed separate counsel in accordance with the proviso to the preceding sentence (it being understood, however, that the indemnifying party shall not be liable for the expenses of more than one separate counsel (together with local counsel), approved by the indemnifying party (the Representatives in the case of Section 8(b) and Section 9), representing the indemnified parties who are parties to such action) or (ii) the indemnifying party shall not have employed counsel

satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of commencement of the action, in each of which cases the fees and expenses of counsel shall be at the expense of the indemnifying party.

(d) Settlements. The indemnifying party under this Section 8 shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there is a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party against any loss, claim, damage, liability or expense by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as contemplated by Section 8(c) hereof, the indemnifying party agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed the indemnified party in accordance with such request prior to the date of such settlement. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement, compromise or consent to the entry of judgment in any pending or threatened action, suit or proceeding in respect of which any indemnified party is or could have been a party and indemnity was or could have been sought hereunder by such indemnified party, unless such settlement, compromise or consent includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such action, suit or proceeding.

Section 9. Contribution. If the indemnification provided for in Section 8 is for any reason unavailable to or otherwise insufficient to hold harmless an indemnified party in respect of any losses, claims, damages, liabilities or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount paid or payable by such indemnified party, as incurred, as a result of any losses, claims, damages, liabilities or expenses referred to therein (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 Shares pursuant to this Agreement 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 hand, in connection with the statements or omissions or inaccuracies in the representations and warranties herein which resulted in such losses, claims, damages, liabilities 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 Shares pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Shares 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 front cover page of the Prospectus bear to the aggregate initial public offering price of the Shares as set forth on such cover. 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 or any such inaccurate or alleged inaccurate representation or warranty relates to information supplied by the Company, on the one hand, or the Underwriters, on the other hand, and the

parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The amount paid or payable by a party as a result of the losses, claims, damages, liabilities and expenses referred to above shall be deemed to include, subject to the limitations set forth in Section 8(c), any legal or other fees or expenses reasonably incurred by such party in connection with investigating or defending any action or claim. The provisions set forth in Section 8(c) with respect to notice of commencement of any action shall apply if a claim for contribution is to be made under this Section 9; provided, however that no additional notice shall be required with respect to any action for which notice has been given under Section 8(c) for purposes of indemnification.

The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 9 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 that does not take account of the equitable considerations referred to in this Section 9.

Notwithstanding the provisions of this Section 9, no Underwriter shall be required to contribute any amount in excess of the underwriting commissions received by such Underwriter in connection with the Shares underwritten by it and distributed to the public. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 9 are several, and not joint, in proportion to their respective underwriting commitments as set forth opposite their names in Schedule A. For purposes of this Section 9, each officer, director, agent or employee of an Underwriter and each person, if any, who controls an Underwriter within the meaning of the Securities Act and the Exchange Act 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 the Securities Act and the Exchange Act shall have the same rights to contribution as the Company.

Section 10. Default of One or More of the Several Underwriters. If, on the Closing Date or any Subsequent Closing Date, as the case may be, any one or more of the several Underwriters shall fail or refuse to purchase Shares that it or they have agreed to purchase hereunder on such date, and the aggregate number of Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase does not exceed 10% of the aggregate number of the Shares to be purchased on such date, the other Underwriters shall be obligated, severally, in the proportions that the number of Firm Shares set forth opposite their respective names on Schedule A bears to the aggregate number of Firm Shares set forth opposite the names of all such non-defaulting Underwriters, or in such other proportions as may be specified by the Representatives with the consent of the non-defaulting Underwriters, to purchase the Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase on such date. If, on the Closing Date or any Subsequent Closing Date, as the case may be, any one or more of the Underwriters shall fail or refuse to purchase Shares and the aggregate number of Shares with respect to which such default occurs exceeds 10% of the aggregate number of Shares to be purchased on such date, and arrangements satisfactory to the Representatives and the

Company for the purchase of such Shares are not made within 48 hours after such default, this Agreement shall terminate without liability of any party to any other party except that the provisions of Section 4, Section 6, Section 8 and Section 9 shall at all times be effective and shall survive such termination. In any such case either the Representatives or the Company shall have the right to postpone the Closing Date or any Subsequent Closing Date, as the case may be, but in no event for longer than seven days in order that the required changes, if any, to the Registration Statement and the Prospectus or any other documents or arrangements may be effected.

As used in this Agreement, the term “Underwriter” shall be deemed to include any person substituted for a defaulting Underwriter under this Section 10. Any action taken under this Section 10 shall not relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

Section 11. Termination of this Agreement. Prior to the Closing Date this Agreement may be terminated by the Representatives by notice given to the Company if at any time (i) trading or quotation in any of the Company’s securities shall have been suspended or limited by the Commission or by the Nasdaq Stock Market, Inc., or trading in securities generally on the New York Stock Exchange or the Nasdaq Stock Market, Inc. shall have been suspended or limited, or minimum or maximum prices shall have been generally established on any of such stock exchanges by the Commission or the NASD; (ii) a general banking moratorium shall have been declared by federal, New York, Delaware or California authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States has occurred; (iii) there shall have occurred any outbreak or escalation of national or international hostilities or any crisis or calamity, or any change in the United States or international financial markets, or any substantial change or development involving a prospective substantial change in United States’ or international political, financial or economic conditions, as in the judgment of the Representatives is material and adverse and makes it impracticable to market the Shares in the manner and on the terms described in the Prospectus or to enforce contracts for the sale of securities, (iv) in the judgment of the Representatives there shall have occurred a Material Adverse Change, or (v) the Company shall have sustained a loss by strike, fire, flood, earthquake, accident or other calamity of such character as in the judgment of the Representatives may interfere materially with the conduct of the business and operations of the Company regardless of whether or not such loss shall have been insured. Any termination pursuant to this Section 11 shall be without liability on the part of (a) the Company to any Underwriter, except that the Company shall be obligated to reimburse the expenses of the Representatives and the Underwriters pursuant to Sections 4 and 6 hereof, (b) any Underwriter to the Company, or (c) any party hereto to any other party hereto except that the provisions of Section 8 and Section 9 shall at all times be effective and survive such termination.

Section 12. No Advisory or Fiduciary Responsibility. The Company acknowledges and agrees that: (i) the purchase and sale of the Shares pursuant to this Agreement, including the determination of the public offering price of the Shares and any related discounts and commissions, is an arm’s-length commercial transaction between the Company, on the one hand, and the several Underwriters, on the other hand, 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; (ii) in connection with each transaction contemplated hereby

and the process leading to such transaction each Underwriter is and has been acting solely as a principal and is not the financial advisor, agent or fiduciary of the Company, or its affiliates, stockholders, creditors or employees or any other party; (iii) no Underwriter has assumed or will assume an advisory, agency or fiduciary responsibility in favor of the Company with respect to any of the transactions 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; (iv) the several 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 that the several Underwriters have no obligation to disclose any of such interests by virtue of any advisory, agency or fiduciary relationship; and (v) 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 legal, accounting, regulatory and tax advisors to the extent itndeemed appropriate.

This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the several Underwriters, or any of them, with respect to the subject matter hereof. The Company hereby waives and releases, to the fullest extent permitted by law, any claims that the Company may have against the several Underwriters with respect to any breach or alleged breach of agency or fiduciary duty.

Section 13. Representations and Indemnities to Survive Delivery. The respective indemnities, agreements, representations, warranties and other statements of the Company, of 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 made by or on behalf of any Underwriter or the Company or any of its or their partners, officers or directors or any controlling person, and will survive delivery of and payment for the Shares sold hereunder and any termination of this Agreement.

Section 14. Notices. All communications hereunder shall be in writing and shall be mailed, hand delivered or telecopied and confirmed to the parties hereto as follows:

If to the Representatives:

Banc of America Securities LLC

000 Xxxxxxx Xxxxxx

Xxx Xxxx, XX 00000

Facsimile: (000) 000-0000

Attention: Syndicate Department

with a copy to:

Banc of America Securities LLC

0 Xxxx 00xx Xxxxxx

Xxx Xxxx, Xxx Xxxx 00000

Facsimile: (000) 000-0000

Attention: Legal Department

and:

Xxxxxx Brothers Inc.

000 Xxxxxxx Xxxxxx

Xxx Xxxx, Xxx Xxxx 00000

Fax: (000) 000-0000

Attention: Syndicate Department

and:

Shearman & Sterling LLP

000 Xxxxxxxxx Xxxxxx

Xxx Xxxx, Xxx Xxxx 00000

Facsimile: (000) 000-0000

Attention: Xxxxx Xxxxxxx, Esq.

If to the Company:

ACADIA Pharmaceuticals Inc.

0000 Xxxxxxxx Xxxxxx Xxxxxxxxx

Xxx Xxxxx, Xxxxxxxxxx 00000

Facsimile: (000) 000-0000

Attention: Chief Financial Officer

with a copy to:

Xxxxxx Godward LLP

0000 Xxxxxxxx Xxxx

Xxx Xxxxx, Xxxxxxxxxx 00000-0000

Facsimile: (000) 000-0000

Attention: Xxxxxxx Xxxx, Esq.

Any party hereto may change the address for receipt of communications by giving written notice to the others.

Section 15. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto, including any substitute Underwriters pursuant to Section 10 hereof, and to the benefit of the employees, officers and directors and controlling persons referred to in Section 8 and Section 9, and in each case, their respective successors, and no other person will have any right or obligation hereunder. The term “successors” shall not include a purchaser of any of the Shares from any of the several Underwriters merely because of such purchase.

Section 16. Partial Unenforceability. The invalidity or unenforceability of any Section, paragraph or provision of this Agreement shall not affect the validity or enforceability of any other Section, paragraph or provision hereof. If any Section, paragraph or provision of this Agreement is for any reason determined to be invalid or unenforceable, there shall be deemed to

be made such minor changes (and only such minor changes) as are necessary to make it valid and enforceable.

Section 17. Governing Law Provisions. (a) THIS AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED IN SUCH STATE.

(b) Consent to Jurisdiction. Any legal suit, action or proceeding arising out of or based upon this Agreement or the transactions contemplated hereby (“Related Proceedings”) may be instituted in the federal courts of the United States of America located in the City and County of New York, Borough of Manhattan, or the courts of the State of New York in each case located in the City and County of New York, Borough of Manhattan (collectively, the “Specified Courts”), and each party irrevocably submits to the exclusive jurisdiction (except for proceedings instituted in regard to the enforcement of a judgment of any such court (a “Related Judgment”), as to which such jurisdiction is non-exclusive) of such courts in any such suit, action or proceeding. Service of any process, summons, notice or document by mail to such party’s address set forth above shall be effective service of process for any suit, action or other proceeding brought in any such court. The parties irrevocably and unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the Specified Courts and irrevocably and unconditionally waive and agree not to plead or claim in any such court that any such suit, action or other proceeding brought in any such court has been brought in an inconvenient forum.

Section 18. General Provisions. This Agreement constitutes the entire agreement of the parties to this Agreement and supersedes all prior written or oral and all contemporaneous oral agreements, understandings and negotiations with respect to the subject matter hereof. This Agreement may be executed in two or more counterparts, each one of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement may not be amended or modified unless in writing by all of the parties hereto, and no condition herein (express or implied) may be waived unless waived in writing by each party whom the condition is meant to benefit. The Section headings herein are for the convenience of the parties only and shall not affect the construction or interpretation of this Agreement.

Each of the parties hereto acknowledges that it is a sophisticated business person who was adequately represented by counsel during negotiations regarding the provisions hereof, including, without limitation, the indemnification provisions of Section 8 and the contribution provisions of Section 9, and is fully informed regarding said provisions. Each of the parties hereto further acknowledges that the provisions of Sections 8 and 9 hereto fairly allocate the risks in light of the ability of the parties to investigate the Company, its affairs and its business in order to assure that adequate disclosure has been made in the Registration Statement, any preliminary prospectus and the Prospectus (and any amendments and supplements thereto), as required by the Securities Act and the Exchange Act.

If the foregoing is in accordance with your understanding of our agreement, kindly sign and return to the Company the enclosed copies hereof, whereupon this instrument, along with all counterparts hereof, shall become a binding agreement in accordance with its terms.


Very truly yours, ACADIA PHARMACEUTICALS INC.

By:		/s/ Xxx Xxxxxxxx
		Name: Xxx Xxxxxxxx Title: Chief Executive Officer

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


BANC OF AMERICA SECURITIES LLC XXXXXX BROTHERS INC. Acting as Representatives of the several Underwriters named in the attached Schedule A.

By:		Banc of America Securities LLC

By:		/s/ Xxxxxxx X. Xxxxxxxx
		Xxxxxxx X. Xxxxxxxx Managing Director

By:		Xxxxxx Brothers Inc.

By:		/s/ Xxxx Xxxxxx
		Xxxx Xxxxxx
		Vice President

SCHEDULE A


Underwriters		Number of Firm Shares to be Purchased
Banc of America Securities LLC		1,682,058

Xxxxxx Brothers Inc.		1,682,058

Xxxxx Xxxxxxx & Co.		742,084

JMP Securities LLC		692,612

Canaccord Xxxxx Inc.		148,417

Total		4,947,229

SCHEDULE B

Schedule of Free Writing Prospectuses included in the Disclosure Package

SCHEDULE C

Number and Price of Shares



Price per share:		$12.00

Offering size:		4,947,229 shares or 5,689,313 shares if the Underwriters exercise their option to purchase additional shares in full

Use of proceeds:		The estimated net proceeds to the Company from the offering of the Shares will be approximately $55.6 million ($64.0 million if the underwriters’ option to purchase additional shares is exercised in full), after payment of underwriting discounts and commissions and estimated expenses.

Closing date:		May 3, 2006

EXHIBIT A

Form of Opinion of Counsel for the Company

A-1

EXHIBIT B

Form of Opinion of IP Counsel

C-1

EXHIBIT C

April , 0000

Xxxx xx Xxxxxxx Securities LLC

Xxxxxx Brothers Inc.

As Representatives of the Several Underwriters

c/o Banc of America Securities LLC

0 Xxxx 00xx Xxxxxx

Xxx Xxxx, XX 00000

Re:	ACADIA Pharmaceuticals Inc. (the “Company”)

Ladies and Gentlemen:

The undersigned is an owner of record or beneficially of certain shares of Common Stock of the Company (“Common Stock”) or securities convertible into or exchangeable or exercisable for Common Stock. The Company proposes to carry out a public offering of Common Stock (the “Offering”) for which you will act as the representatives of the underwriters. The undersigned recognizes that the Offering will be of benefit to the undersigned and will benefit the Company. The undersigned acknowledges that you and the other underwriters are relying on the representations and agreements of the undersigned contained in this letter in carrying out the Offering and in entering into underwriting arrangements with the Company with respect to the Offering.

In consideration of the foregoing, the undersigned hereby agrees that the undersigned will not, (and will cause any spouse or immediate family member of the spouse or the undersigned living in the undersigned’s household not to), without the prior written consent of Banc of America Securities LLC and Xxxxxx Brothers Inc. (collectively, the “Representatives”) (which consent may be withheld in their sole discretion), directly or indirectly, sell, offer, contract or grant any option to sell (including without limitation any short sale), pledge, transfer, establish an open “put equivalent position” or liquidate or decrease a “call equivalent position” within the meaning of Rule 16a-1(h) under the Securities Exchange Act of 1934, as amended (the “Exchange Act’), or otherwise dispose of or transfer (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition of) including the filing (or participation in the filing of) of a registration statement with the Securities and Exchange Commission in respect of, any shares of Common Stock, options or warrants to acquire shares of Common Stock, or securities exchangeable or exercisable for or convertible into shares of Common Stock currently or hereafter owned either of record or beneficially (as defined in Rule 13d-3 under the Exchange Act) by the undersigned (or such spouse or family member), or publicly announce an intention to do any of the foregoing, for a period commencing on the date hereof and continuing through the close of trading on the date 90 days after the date of the Prospectus (the “Lock-Up Period”). In addition, the undersigned agrees that, without the prior written consent of the Representatives, it will not, during the Lock-Up Period, make any demand for or exercise any right with respect to, the registration of any shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock.

C-2

The lock-up restriction described in the previous paragraph shall not apply to: (1) bona fide gifts to, or transfers to a trust for, the direct or indirect benefit of the undersigned or the immediate family of the undersigned, (2) any shares of Common Stock sold pursuant to any 10b5-1 plan existing on or prior to the date hereof, and (3) the entering into a 10b5-1 plan during the Lock-Up Period so long as no shares of Common Stock are sold pursuant to such 10b5-1 plan during the Lock-Up Period; provided that in any transaction described in clause (1) above, (x) prior to such donation, transfer or distribution, such donee, transferee, or distributee shall execute and deliver to the Representatives a duplicate form of this lock-up agreement and (y) the undersigned shall not be required to, and shall not voluntarily, file a report under Section 16(a) of the Exchange Act. For purposes of this lock-up agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

If (i) the Company issues an earnings release or material news, or a material event relating to the Company occurs, during the last 17 days of the lock-up period, or (ii) prior to the expiration of the lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the lock-up period, the restrictions imposed by this agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event, unless the Representatives 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 Section 14 of the Underwriting Agreement) and agrees that any such notice properly delivered will be deemed to have given to, and received by, the undersigned. 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. 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 shares of Common Stock or securities convertible into or exchangeable or exercisable for Common Stock held by the undersigned except in compliance with the foregoing restrictions.

With respect to the Offering only, the undersigned waives any registration rights relating to registration under the Securities Act of any Common Stock owned either of record or beneficially by the undersigned, including any rights to receive notice of the Offering.

C-3

This agreement is irrevocable and will be binding on the undersigned and the respective successors, heirs, personal representatives, and assigns of the undersigned.

Printed Name of Holder


By:
Signature

Printed Name of Person Signing

(and indicate capacity of person signing if

signing as custodian, trustee, or on behalf of an

entity)

C-4

EXHIBIT D

LIST OF PARTIES TO LOCK-UP AGREEMENTS

Xxxxxx X Xxxxxxx, Ph.D.

Xxxxxx Xxxxxx

Xxxxxxx Xxxxx

Xxxx X. Xxxxx, Ph.D.

Xxxx Xxx Xxxx, Ph.D.

Xxx Xxxxxxxx, Ph.D.

Xxxxxx X. Xxxxxx, Ph.D.

Xxxxxxx Xxxxxxxxx

Xxxx X. Xxxxxx, Ph.D.

Xxxxxx X. Xxxxx

Xxxxx Xxxxxxxxx

Bo-Xxxxxx Xxxx, Ph.D.

D-1

Document Metadata

Table of Contents

ACADIA Pharmaceuticals Inc. 4,947,229 Shares Common Stock UNDERWRITING AGREEMENT dated April 27, 2006 Banc of America Securities LLC Lehman Brothers Inc. Piper Jaffray & Co. JMP Securities LLC Canaccord Adams Inc.

Document Metadata