Targacept, Inc. Common Stock ($0.001 Par Value) EQUITY UNDERWRITING AGREEMENT

Exhibit 1.1

Targacept, Inc.

Common Stock

($0.001 Par Value)

EQUITY UNDERWRITING AGREEMENT

May 19, 2011

Deutsche Bank Securities Inc.

As Representative of the

  Several Underwriters

60 Wall Street, 4^th Floor

New York, New York 10005

Ladies and Gentlemen:

Targacept, Inc., a Delaware corporation (the “Company”), proposes to sell to the several Underwriters (the “Underwriters”) named in Schedule I hereto for whom you are acting as representative (the “Representative” or “you”) an aggregate of 3,658,537 shares (the “Firm Shares”) of the Company’s common stock, $0.001 par value per share (the “Common Stock”), all of which will be sold by the Company. The respective amounts of the Firm Shares to be so purchased by the several Underwriters are set forth opposite their names in Schedule I hereto. The Company also proposes to sell at the Underwriters’ option an aggregate of up to 548,780 additional shares of the Company’s Common Stock (the “Option Shares”) as set forth below. The Firm Shares and the Option Shares (to the extent the aforementioned option is exercised) are herein collectively called the “Shares.”

As the Representative, you have advised the Company (a) that you are authorized to enter into this Agreement on behalf of the several Underwriters, and (b) that the several Underwriters are willing, acting severally and not jointly, to purchase the numbers of Firm Shares set forth opposite their respective names in Schedule I, plus their pro rata portion of the Option Shares if you elect to exercise the over-allotment option in whole or in part for the accounts of the several Underwriters.

In consideration of the mutual agreements contained herein and of the interests of the parties in the transactions contemplated hereby, the parties hereto agree as follows:

The Company represents and warrants to the Underwriters, as of the date hereof, as of the Applicable Time, as of the Closing Date and as of any Option Closing Date as follows:

(a) A registration statement on Form S-3 (File No. 333-171346) with respect to the Shares, including a form of prospectus (the “Base Prospectus”) has been prepared by the Company in conformity in all material respects with the requirements of the Securities Act of 1933, as amended (the “Act”), and the rules and regulations (the “Rules and Regulations”) of the Securities and Exchange Commission (the “Commission”) thereunder and has been filed with the Commission. The Company and the transactions contemplated by this Agreement meet the requirements and comply with the conditions for the use of Form S-3. The Registration

1

Statement meets the requirements of Rule 415(a)(1)(x) under the Act and complies in all material respects with said rule. Copies of such registration statement, including any amendments thereto, the Base Prospectus (meeting in all material respects the requirements of the Rules and Regulations) contained therein and the exhibits, financial statements and schedules, as finally amended and revised, have heretofore been delivered by the Company to you. Such registration statement, together with any registration statement filed by the Company pursuant to Rule 462(b) under the Act, is herein referred to as the “Registration Statement,” which term shall be deemed to include all information omitted therefrom in reliance upon Rules 430A, 430B or 430C under the Act and contained in the Prospectus referred to below. The Registration Statement has been declared effective under the Act and no post-effective amendment to the Registration Statement has been filed as of the date of this Agreement. The Company has prepared a prospectus supplement (the “Prospectus Supplement”) to the Base Prospectus setting forth the terms of the offering, sale and plan of distribution of the Shares. The term “Prospectus” as used in this Agreement means the Base Prospectus together with the Prospectus Supplement in the form filed with the Commission after the Applicable Time, pursuant to and within the time limits described in Rule 424(b) under the Act. Any preliminary prospectus supplement relating to the Shares in the form filed with the Commission at or prior to the Applicable Time, pursuant to and within the time limits described in Rule 424(b) under the Act, together with the Base Prospectus, is referred to as a “Preliminary Prospectus.” Any reference herein to the Registration Statement, to any Preliminary Prospectus, to the Prospectus or to any amendment or supplement to any of the foregoing documents shall be deemed to refer to and include any documents incorporated by reference therein and, in the case of any reference herein to the Prospectus, also shall be deemed to include any documents incorporated by reference therein, and any supplements or amendments thereto, filed with the Commission after the date of filing of the Prospectus under Rule 424(b) under the Act, and prior to the termination of the offering of the Shares by the Underwriters.

(b) No stop order suspending the effectiveness of the Registration Statement is in effect, and no proceedings for such purpose are pending before or, to the knowledge of the Company, threatened by the Commission; no order preventing or suspending the use of any Preliminary Prospectus, any Issuer Free Writing Prospectus (as defined below) or the Prospectus relating to the offering of the Shares is in effect, and no proceedings for such purpose or pursuant to Section 8A of the Act are pending before, or to the knowledge of the Company, threatened by the Commission.

(c)(i) The Registration Statement, when it was declared effective, did not contain and, as amended or supplemented, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading; (ii) the Registration Statement when it was declared effective complied, and the Prospectus complies, and, as amended or supplemented, if applicable, will comply in all material respects with the Act and the applicable rules and regulations of the Commission thereunder; (iii) the documents incorporated, or to be incorporated, by reference in the Prospectus at the time filed with the Commission conformed or will conform in all material respects to the requirements of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or the Act, as applicable, and the rules and regulations of the Commission thereunder; (iv) the General Use Free Writing Prospectus(es) (as defined below) issued at or prior to the Applicable Time (as defined below), the Preliminary Prospectus and the information included on Schedule II hereto, all considered together (collectively, the “General Disclosure Package”), as of the Applicable Time, did not contain and, as of the Closing Date or the Option Closing Date, as the case may be, as then amended or supplemented by the Company, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which

2

they were made, not misleading; (v) each individual Limited Use Free Writing Prospectus (as defined below), when considered together with the General Disclosure Package, as of the Applicable Time, did not contain and, as of the Closing Date or the Option Closing Date, as the case may be, as then amended or supplemented by the Company, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; and (vi) the Prospectus does not contain and, as amended or supplemented, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, except that the representations and warranties set forth in this paragraph do not apply to statements or omissions in the Registration Statement, the General Disclosure Package, any Issuer Free Writing Prospectus or the Prospectus based upon information relating to the Underwriters furnished to the Company in writing, including by email, by the Underwriters (or on behalf of the Underwriters by counsel), expressly for use therein, it being understood and agreed that the only such information is that described in Section 13 herein. As used in this subsection and elsewhere in this Agreement:

“Applicable Time” means 6:15 p.m. (New York time) on the date of this Agreement or such other time as agreed to by the Company and the Representative.

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

“General Use Free Writing Prospectus” means any Issuer Free Writing Prospectus that is identified on Schedule III to this Agreement.

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

(d) Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Shares or until any earlier date that the Company notified or notifies the Underwriters 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, any Preliminary Prospectus or the Prospectus, including any document incorporated by reference therein that has not been superseded or modified. 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 would, if made as of the date of the event, include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in light of the circumstances under which such statements were made, not misleading, the Company has notified or will notify promptly the Underwriters so that any use of such Issuer Free Writing Prospectus may cease until it is amended or supplemented. The foregoing two sentences do not apply to statements or omissions from any Issuer Free Writing Prospectus based upon and in conformity with written information furnished to the Company by the Representative on behalf of the Underwriters specifically for use therein.

(e) The Company has not, directly or indirectly, distributed and will not distribute any offering material in connection with the offering and sale of the Shares other than a Preliminary Prospectus, the Prospectus, any Permitted Free Writing Prospectus (as defined below) and other materials, if any, permitted under the Act and consistent with Section 4(a) below. The Company will comply with the filing requirements under Rule 433(d) under the Act with respect to each

3

Issuer Free Writing Prospectus. The Company has satisfied or will satisfy the conditions in Rule 433 under the Act to avoid a requirement to file with the Commission any electronic road show.

(f)(i) At the time of filing the Registration Statement and (ii) as of the date hereof (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 under the Act, without taking into account any determination by the Commission pursuant to Rule 405 under the Act that it is not necessary that the Company be considered an ineligible issuer), including, without limitation, for purposes of Rules 164 and 433 under the Act with respect to the offering of the Shares as contemplated by the Prospectus.

(g) The Company has been duly incorporated, is validly existing as a corporation in good standing under the laws of the jurisdiction of its incorporation, has the corporate power and authority to own its property and to conduct its business as described in the General Disclosure Package and the Prospectus and is duly qualified to transact business and is in good standing in each jurisdiction in which the conduct of its business or its ownership or leasing of property requires such qualification, except to the extent that the failure to be so qualified or to be in good standing would not have a material adverse effect on the Company.

(h) The Company has no subsidiaries.

(i) The Company has the full right, power and authority to enter into this Agreement and to perform and discharge its duties hereunder, and this Agreement has been duly authorized, executed and delivered by the Company.

(j) The authorized capital stock of the Company conforms as to legal matters to the description thereof contained in the Registration Statement, the General Disclosure Package and the Prospectus.

(k) The shares of Common Stock outstanding prior to the issuance of the Shares have been duly authorized and are validly issued, fully paid and non assessable. No person is entitled to preemptive or similar rights to acquire any securities of the Company, except rights that are not triggered by the issuance of the Shares. There are no outstanding securities convertible into or exchangeable for, or warrants, rights or options to purchase from the Company, or obligations of the Company to issue, any shares of its Common Stock or any other class of shares of capital stock of the Company, except for securities that have been issued pursuant to equity compensation plans of the Company as set forth in the General Disclosure Package and the Prospectus.

(l) The Shares have been duly authorized and, when issued, delivered and paid for in accordance with the terms of this Agreement, will be validly issued, fully paid and non-assessable.

(m) The execution and delivery by the Company of, and the performance by the Company of its obligations under, this Agreement will not contravene (i) any provision of applicable law, (ii) the certificate of incorporation or bylaws of the Company, in each case as amended and in effect as of the date hereof, (iii) any agreement or other instrument binding upon the Company that is material to the Company, or (iv) any judgment, order or decree of any governmental body, agency or court having jurisdiction over the Company, except, with respect to clauses (i), (iii) and (iv), for such contraventions which would not, singly or in the aggregate, result in a material adverse effect on the Company. No consent, approval, authorization or order of, or qualification with, any governmental body or agency is required for the performance by the Company of its obligations under this Agreement, except (i) such as may be required by the

4

securities or Blue Sky laws of the various states in connection with the offer and sale of the Shares, (ii) where the failure to obtain such would not have a material adverse effect on the power or ability of the Company to perform its obligations under this Agreement, or (iii) as may be required by the rules and regulations of the Financial Industry Regulatory Authority, Inc. (“FINRA”).

(n) Since the respective dates as of which information is given in the General Disclosure Package, and other than as set forth in the General Disclosure Package as of the Applicable Time, there has not occurred any material adverse change, or any development involving a prospective material adverse change, in the condition, financial or otherwise, or in the earnings, business or operations of the Company.

(o) There are no legal or governmental proceedings pending or, to the knowledge of the Company, threatened to which the Company is a party or to which any of the properties of the Company is subject that are required to be described in the Registration Statement or the Prospectus and are not so described, and there are no statutes, regulations, contracts or other documents that are required to be described in the Registration Statement, the General Disclosure Package or the Prospectus or to be filed as exhibits to the Registration Statement that are not described or filed as required.

(p) Each Preliminary Prospectus filed as part of the Registration Statement as originally filed or as part of any amendment thereto, or filed pursuant to Rule 424 under the Act, complied when so filed in all material respects with the Act and the applicable rules and regulations of the Commission thereunder.

(q) The Company is not, and after giving effect to the offering and sale of the Shares and the application of the proceeds thereof as described in the Prospectus will not be, required to register as an “investment company” as such term is defined in the Investment Company Act of 1940, as amended.

(r) The Company (i) is in compliance with any and all applicable foreign, federal, state and local laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (“Environmental Laws”), (ii) has received all permits, licenses or other approvals required of it under applicable Environmental Laws to conduct its business and (iii) is in compliance with all terms and conditions of any such permit, license or approval, except where such noncompliance with Environmental Laws, failure to receive required permits, licenses or other approvals or failure to comply with the terms and conditions of such permits, licenses or approvals would not, singly or in the aggregate, have a material adverse effect on the Company.

(s) There are no costs or liabilities associated with Environmental Laws (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) which would, singly or in the aggregate, have a material adverse effect on the Company.

(t) No person has the right to require the Company to include any securities of the Company with the Shares registered pursuant to the Registration Statement, except for such rights as have been waived.

(u) Subsequent to the respective dates as of which information is given in each of the Registration Statement, the General Disclosure Package and the Prospectus, (i) the Company has not incurred any material liability or obligation, direct or contingent, nor entered into any

5

material transaction not in the ordinary course of business; (ii) the Company has not purchased any of its outstanding capital stock, nor declared, paid or otherwise made any dividend or distribution of any kind on its capital stock, other than ordinary and customary dividends; and (iii) there has not been any material change in the capital stock, short-term debt or long-term debt of the Company, except in each case as described in each of the Registration Statement, the General Disclosure Package and the Prospectus, respectively.

(v) The Company does not own any real property. The Company has good and marketable title to all tangible personal property owned by it that is material to the business of the Company, in each case free and clear of all liens, encumbrances and defects, except such as are described in the General Disclosure Package and the Prospectus or such as do not materially affect the value of such property and do not interfere in any material respect with the use made and proposed to be made of such property by the Company; and any real property and buildings held under lease by the Company are held by it under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere in any material respect with the use made and proposed to be made of such property and buildings by the Company, in each case except as described in the General Disclosure Package and the Prospectus and except as enforceability may be limited by bankruptcy and other similar laws affecting the rights of creditors generally and general principles of equity.

(w) The Company owns or has valid, binding and enforceable licenses or other rights to the patents and patent applications, copyrights, trademarks, service marks, trade names, service names and trade secrets reasonably necessary or used in any material respect to conduct the business of the Company in the manner described in the General Disclosure Package and the Prospectus (collectively, the “Company Intellectual Property”), except as enforceability may be limited by bankruptcy and other similar laws affecting the rights of creditors generally and general principles of equity; the Company is not obligated to pay a royalty, grant a license, or provide other consideration to any third party in connection with the Company Intellectual Property other than as disclosed in the Registration Statement (including the exhibits thereto); except as disclosed in the General Disclosure Package and the Prospectus or except as would not reasonably be expected to have a material adverse effect on the Company, (i) the Company has not received any written notice of infringement or conflict with asserted rights of others with respect to any Company Intellectual Property, (ii) the discoveries, inventions, products or processes of the Company referred to in the General Disclosure Package and the Prospectus do not, to the knowledge of the Company, infringe, interfere or conflict with any right or patent claim of any third party, and (iii) no third party has any ownership right in or to any Company Intellectual Property that is owned by the Company, other than any co-owner of any patent constituting Company Intellectual Property who is listed on the records of the United States Patent and Trademark Office (the “PTO”) and any co-owner of any patent application constituting Company Intellectual Property who is named in such patent application, and, to the knowledge of the Company, no third party has any ownership right in or to any Company Intellectual Property that is licensed to the Company, other than any licensor of the Company of such Company Intellectual Property.

(x) All patent applications owned by the Company and filed with the PTO or any foreign or international patent authority (the “Company Patent Applications”) have been duly and properly filed; the Company has complied with its duty of candor and disclosure to the PTO for the Company Patent Applications; the Company is not aware of any facts required to be disclosed to the PTO that were not disclosed to the PTO and which would preclude the grant of a patent for the Company Patent Applications; and the Company has no knowledge of any facts which would preclude it from having clear title to the Company Patent Applications that have been identified by the Company as being exclusively owned by the Company.

6

(y) No material labor dispute with the employees of the Company exists, except as described in the General Disclosure Package and the Prospectus, or, to the knowledge of the Company, is imminent; and the Company is not aware of any existing, threatened or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers or contractors that could have a material adverse effect on the Company. The Company is not aware that any key employee or significant group of employees of the Company plans to terminate employment with the Company.

(z) The Company is insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as the Company believes are adequate for the conduct of its business at its current stage of development as described in the General Disclosure Package and the Prospectus and the value of its properties and as are customary in the business in which it is currently engaged; the Company has not been refused any insurance coverage sought or applied for; and the Company believes that it will be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that would not have a material adverse effect on the Company, except as described in the General Disclosure Package and the Prospectus.

(aa) The Company possesses all certificates, authorizations and permits issued by the appropriate federal, state or foreign regulatory authorities necessary to conduct its business as currently conducted, except where the lack of any such certificate, authorization or permit would not have a material adverse effect on the Company, including without limitation all such certificates, authorizations and permits required by the United States Food and Drug Administration (the “FDA”) or any other federal, state or foreign agencies or bodies engaged in the regulation of pharmaceuticals or biohazardous materials, and the Company has not received any notice of proceedings relating to the revocation or modification of any such certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would have a material adverse effect on the Company, except as described in the General Disclosure Package and the Prospectus.

(bb) The studies, tests and preclinical and clinical trials conducted by or on behalf of the Company that are described in the Registration Statement, the General Disclosure Package and the Prospectus were and, if still pending, are, to the Company’s knowledge, being conducted in all material respects in accordance with experimental protocols, procedures and controls pursuant to, where applicable, accepted professional and scientific standards for products or product candidates comparable to those being developed by the Company; the descriptions of the results of such studies, tests and trials contained in the Registration Statement, the General Disclosure Package and the Prospectus, to the knowledge of the Company, do not contain any misstatement of a material fact or omit to state a material fact necessary to make such statements not misleading; there have been no studies, tests or trials conducted by or, to the knowledge of the Company, on behalf of the Company not described in the Registration Statement, the General Disclosure Package and the Prospectus the results of which reasonably call into question the results of the studies, tests and trials described in the Registration Statement, the General Disclosure Package or the Prospectus; and the Company has not received any notices or correspondence from the FDA or any foreign, state or local governmental body exercising comparable entity or any Institutional Review Board or 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 on the Company.

7

(cc) The Company maintains a system of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences; and the Company is otherwise in compliance in all material respects with all effective provisions of the Sarbanes-Oxley Act of 2002 and any related rules and regulations promulgated by the Commission which are applicable to the Company and with which the Company is currently required to comply.

(dd) The Company has established and maintains “disclosure controls and procedures” (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act); the Company’s “disclosure controls and procedures” are reasonably designed to ensure that all information (both financial and non-financial) required to be disclosed by the Company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the rules and regulations of the Exchange Act, and that all such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure and to support the certifications of the Chief Executive Officer and Chief Financial Officer of the Company required under the Exchange Act with respect to such reports.

(ee) Except as disclosed in the Registration Statement, the General Disclosure Package and the Prospectus, the Company is not aware of (i) any material weakness in its internal control over financial reporting or (ii) change in internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

(ff) The financial statements of the Company (together with the related notes thereto) included in the Registration Statement, the General Disclosure Package and the Prospectus present fairly the financial position and results of the operations of the Company as of the respective dates indicated and for the respective periods specified; and such financial statements (together with the related notes thereto) have been prepared in conformity with generally accepted accounting principles, consistently applied throughout the periods involved except as otherwise stated therein, and all adjustments necessary for a fair presentation of results for such periods have been made. The summary and selected financial data included or incorporated by reference in the Registration Statement, the General Disclosure Package and the Prospectus present fairly the information shown therein and have been compiled on a basis consistent with that of the audited financial information included in the Registration Statement, the General Disclosure Package and the Prospectus and with the books and records of the Company. The Company does not have any material liabilities or obligations, direct or contingent (including any off-balance sheet obligations or any “variable interest entities” within the meaning of Financial Accounting Standards Board Accounting Standards Codification Topic 810, Consolidation), not disclosed in the Registration Statement. There are no financial statements (historical or pro forma) that are required to be included in the Registration Statement, the General Disclosure Package or the Prospectus that are not included as required.

(gg) To the Company’s knowledge, Ernst & Young LLP, who have certified certain of the financial statements filed with the Commission as part of, or incorporated by reference in, the Registration Statement, the General Disclosure Package and the Prospectus, is an independent registered public accounting firm with respect to the Company within the meaning of the Act

8

and the applicable Rules and Regulations and the Public Company Accounting Oversight Board (United States) (the “PCAOB”)

(hh) Each material contract, agreement and license to which the Company is bound is valid, binding, enforceable, and in full force and effect against the Company, and to the knowledge of the Company, each other party thereto, except as enforceability may be limited by bankruptcy and other similar laws affecting the rights of creditors generally and general principles of equity. Neither the Company nor, to the Company’s knowledge, any other party is in breach or default in any material respect with respect to any such contract, agreement and license, and, to the Company’s knowledge, no event has occurred which with notice or lapse of time would constitute a material breach or default, or permit termination, modification, or acceleration, under any such contract, agreement or license. No party has repudiated any material provision of any such contract, agreement or license.

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

(jj) Neither the Company nor, to the knowledge of the Company, any director, officer, agent, employee or other person associated with or acting on behalf of the Company has, while acting on behalf of the Company, (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; or (iii) violated or is in violation of any provision of the U.S. Foreign Corrupt Practices Act of 1977.

(kk) The Company is in compliance in all material respects with all presently applicable provisions of the Employee Retirement Income Security Act of 1974, as amended, including the regulations and published interpretations thereunder (“ERISA”); no “reportable event” (as defined in ERISA) has occurred with respect to any “pension plan” (as defined in ERISA) for which the Company would have any liability; the Company has not incurred and does not expect to incur any material liability under (i) Title IV of ERISA with respect to termination of, or withdrawal from any “pension plan” or (ii) Sections 412 or 4971 of the Internal Revenue Code of 1986, as amended, including the regulations and published interpretations thereunder ( the “Code”); and each “pension plan” for which the Company would have any liability that is intended to be qualified under Section 401(a) of the Code is so qualified in all material respects and nothing has occurred, whether by action or by failure to act, which could reasonably be expected to cause the loss of such qualification.

(ll) There are no transactions with related persons involving the Company that would be required to be disclosed pursuant to Item 404 of Regulation S-K which have not been so disclosed in the Registration Statement, the General Disclosure Package and the Prospectus in compliance in all material respects with Item 404.

(mm) Except for this Agreement, the Company is not a party to any contract, agreement or understanding with any person that would give rise to a valid claim against the Company or the Underwriters for a brokerage commission, finder’s fee or like payment in connection with the offering and sale of the Shares.

9

(nn) The statistical, industry-related and market-related data included in the Registration Statement, the General Disclosure Package and the Prospectus are based on or derived from sources that the Company reasonably and in good faith believes are reliable and accurate.

(oo) Neither the Company, nor to the Company’s knowledge, any of its affiliates, has taken or may take, directly or indirectly, any action designed to cause or result in, or which has constituted or which might reasonably be expected to constitute, the stabilization or manipulation of the price of the shares of Common Stock to facilitate the sale or resale of the Shares. The Company acknowledges that the Underwriters may engage in passive market making transactions in the Shares on the Nasdaq Global Select Market in accordance with Regulation M under the Exchange Act.

(pp) The Shares have been approved for listing subject to notice of issuance on the Nasdaq Global Select Market. The Company has taken no action designed to terminate, or likely to have the effect of terminating, the registration of the Common Stock under the Exchange Act or the listing of the Common Stock on the Nasdaq Global Select Market, nor has the Company received any notification that the Commission or the Nasdaq Global Select Market is contemplating terminating such registration or listing.

(qq) The registration of the Shares with the Commission could have been effected on Form S-3 under the Act pursuant to the standards for such Form S-3 in effect prior to October 21, 1992.

(a) On the basis of the representations, warranties and covenants herein contained, and subject to the conditions herein set forth, the Company agrees to sell to the Underwriters, and each Underwriter agrees, severally and not jointly, to purchase, the number of Firm Shares set forth opposite the name of each Underwriter in Schedule I hereof, at a price of $19.27 per share.

(b) Payment for the Firm Shares to be sold hereunder is to be made in Federal (same day) funds against delivery of certificates therefor to the Representative for the several accounts of the Underwriters. Such payment and delivery are to be made through the facilities of The Depository Trust Company, New York, New York at 10:00 a.m., New York time, on the third business day after the date of this Agreement or at such other time and date not later than five business days thereafter as you and the Company shall agree upon, such time and date being herein referred to as the “Closing Date.” (As used herein, “business day” means a day on which the New York Stock Exchange is open for trading and on which banks in New York are open for business and are not permitted by law or executive order to be closed.)

(c) In addition, on the basis of the representations and warranties herein contained and subject to the terms and conditions herein set forth, the Company hereby grants an option to the several Underwriters to purchase the Option Shares at the price per share as set forth in Section 2(a). The option granted hereby may be exercised in whole or in part by giving written notice (i) at any time before the Closing Date and (ii) only once thereafter within 30 days after the date of this Agreement, by you, as Representative of the several Underwriters, to the Company setting forth the number of Option Shares as to which the several Underwriters are exercising the option and the time and date at which such Option Shares are to be delivered. The time and date at which certificates for Option Shares are to be delivered shall be determined by the Representative but shall not be earlier than three nor later than 10 full business days after the exercise of such option, nor in any event prior to the Closing Date (such time and date being herein referred to as the “Option Closing Date”). If the date of exercise of the option is three or more days before the Closing Date, the notice of exercise shall set the

10

Closing Date as the Option Closing Date. The number of Option Shares to be purchased by each Underwriter shall be in the same proportion to the total number of Option Shares being purchased as the number of Firm Shares being purchased by such Underwriter bears to the total number of Firm Shares, adjusted by you in such manner as to avoid fractional shares. The option with respect to the Option Shares granted hereunder may be exercised only to cover over-allotments in the sale of the Firm Shares by the Underwriters. You, as Representative of the several Underwriters, may cancel such option at any time prior to its expiration by giving written notice of such cancellation to the Company. To the extent, if any, that the option is exercised, payment for the Option Shares shall be made on the Option Closing Date in Federal (same day funds) through the facilities of The Depository Trust Company in New York, New York drawn to the order of the Company.

It is understood that the several Underwriters are to make a public offering of the Firm Shares as soon as the Representative deems it advisable to do so. The Firm Shares are to be initially offered to the public at the initial public offering price set forth in the Prospectus. The Representative may from time to time thereafter change the public offering price and other selling terms.

It is further understood that you will act as the Representative for the Underwriters in the offering and sale of the Shares in accordance with a Master Agreement Among Underwriters entered into by you and the several other Underwriters.

The Company covenants and agrees with the Underwriters that:

(a) The Company will (A) prepare and timely file with the Commission under Rule 424(b) under the Act a Prospectus in a form approved by the Representative containing information previously omitted at the time of effectiveness of the Registration Statement in reliance on Rules 430A, 430B or 430C under the Act, (B) not file any amendment to the Registration Statement or distribute an amendment or supplement to the General Disclosure Package or the Prospectus or any document incorporated by reference therein of which the Underwriters shall not previously have been advised and furnished with a copy or to which the Representative shall have reasonably objected in writing or which is not in compliance with the Rules and Regulations and (C) file on a timely basis all reports and any definitive proxy or information statements required to be filed by the Company with the Commission subsequent to the date of the Prospectus and prior to the termination of the offering of the Shares by the Underwriters.

(b) The Company will (i) not make any offer relating to the Shares that would constitute an Issuer Free Writing Prospectus or that would otherwise constitute a “free writing prospectus” (as defined in Rule 405 under the Act) required to be filed by the Company with the Commission under Rule 433 under the Act unless the Representative approves its use in writing prior to first use (each, a “Permitted Free Writing Prospectus”); provided that the prior written consent of the Representative hereto shall be deemed to have been given in respect of the Issuer Free Writing Prospectus(es) included in Schedule III hereto, (ii) treat each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus, (iii) comply with the requirements of Rules 164 and 433 under the Act applicable to any Issuer Free Writing Prospectus, including the requirements relating to timely filing with the Commission, legending and record keeping and (iv) not take any action that would result in the Underwriters or the Company being required to file with the

11

Commission pursuant to Rule 433(d) under the Act a free writing prospectus prepared by or on behalf of the Underwriters that such Underwriters otherwise would not have been required to file thereunder. The Company will satisfy the conditions in Rule 433 under the Act to avoid a requirement to file with the Commission any electronic road show.

(c) The Company will advise the Underwriters promptly (A) when any post-effective amendment to the Registration Statement shall have been declared effective, (B) of receipt of any comments from the Commission, (C) of any request of the Commission for amendment of the Registration Statement or for supplement to the General Disclosure Package or the Prospectus or for any additional information, and (D) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or any order preventing or suspending the use of any Preliminary Prospectus, any Issuer Free Writing Prospectus or the Prospectus, or of the institution of any proceedings for that purpose or pursuant to Section 8A of the Act. The Company will use commercially reasonable efforts to prevent the issuance of any such order and to obtain as soon as possible the lifting thereof, if issued.

(d) The Company will cooperate with the Underwriters in endeavoring to qualify the Shares for sale under the securities laws of such jurisdictions as the Representative may reasonably have designated in writing and will make such applications, file such documents, and furnish such information as may be reasonably required for that purpose, provided the Company shall not be required to qualify as a foreign corporation or to file a general consent to service of process in any jurisdiction where it is not now so qualified or required to file such a consent. The Company will, from time to time, prepare and file such statements, reports, and other documents, as are or may be required to continue such qualifications in effect for so long a period as the Representative may reasonably request for distribution of the Shares.

(e) The Company will deliver to, or upon the order of, the Underwriters, from time to time, as many copies of any Preliminary Prospectus as the Underwriters may reasonably request. The Company will deliver to, or upon the order of, the Underwriters, from time to time, as many copies of any Issuer Free Writing Prospectus as the Underwriters may reasonably request. The Company will deliver to, or upon the order of, the Underwriters during the period when delivery of a Prospectus (or, in lieu thereof, the notice referred to under Rule 173(a) under the Act) (the “Prospectus Delivery Period”) is required under the Act, as many copies of the Prospectus in final form, or as thereafter amended or supplemented, as the Underwriters may reasonably request. The Company will deliver to the Underwriters at or before the Closing Date, four signed copies of the Registration Statement and all amendments thereto including all exhibits filed therewith, and will deliver to the Underwriters such number of copies of the Registration Statement (including such number of copies of the exhibits filed therewith that may reasonably be requested), including documents incorporated by reference therein, and of all amendments thereto, as the Underwriters may reasonably request.

(f) The Company will comply with the Act and the Rules and Regulations, and the Exchange Act and the rules and regulations of the Commission thereunder, so as to permit the completion of the distribution of the Shares as contemplated in this Agreement and the Prospectus. If during the period in which a prospectus (or, in lieu thereof, the notice referred to under Rule 173(a) under the Act) is required by law to be delivered by any Underwriter or a dealer, any event shall occur as a result of which, in the judgment of the Company or in the reasonable opinion of the Representative, it becomes necessary to amend or supplement the Prospectus in order to make the statements therein, in the light of the circumstances existing at the time the Prospectus is delivered to a purchaser, not misleading, or, if it is necessary at any time to amend or supplement the Prospectus to comply with any law, the Company promptly will either (i) prepare and file with the Commission an appropriate amendment to the

12

Registration Statement or supplement to the Prospectus or (ii) prepare and file with the Commission an appropriate filing under the Exchange Act which shall be incorporated by reference in the Prospectus so that the Prospectus as so amended or supplemented will not, in the light of the circumstances when it is so delivered, be misleading, or so that the Prospectus will comply with applicable law.

(g) If the General Disclosure Package is being used to solicit offers to buy the Shares at a time when the Prospectus is not yet available to prospective purchasers and any event shall occur as a result of which, in the judgment of the Company or in the reasonable opinion of the Representative, it becomes necessary to amend or supplement the General Disclosure Package in order to make the statements therein, in the light of the circumstances, not misleading, or to make the statements therein not conflict with the information contained in the Registration Statement then on file, or if it is necessary at any time to amend or supplement the General Disclosure Package to comply with any law, the Company promptly will either (i) prepare, file with the Commission (if required) and furnish to the Underwriters and any dealers an appropriate amendment or supplement to the General Disclosure Package or (ii) prepare and file with the Commission an appropriate filing under the Exchange Act which shall be incorporated by reference in the General Disclosure Package so that the General Disclosure Package as so amended or supplemented will not, in the light of the circumstances, be misleading or conflict with the Registration Statement then on file, or so that the General Disclosure Package will comply with applicable law.

(h) The Company will make generally available to its security holders, as soon as it is practicable to do so, but in any event not later than 16 months after the effective date of the Registration Statement, an earnings statement (which need not be audited) in reasonable detail, covering a period of at least 12 consecutive months beginning after the effective date of the Registration Statement, which earnings statement shall satisfy the requirements of Section 11(a) of the Act and Rule 158 under the Act.

(i) Prior to the Closing Date, the Company will furnish to the Underwriters, as soon as they have been prepared by or are available to the Company, a copy of any unaudited interim financial statements of the Company for any reportable period subsequent to the period covered by the most recent financial statements appearing in the Registration Statement and the Prospectus.

(j) No offering, sale, short sale or other disposition of any shares of Common Stock of the Company or other securities convertible into or exchangeable or exercisable for shares of Common Stock or derivative of Common Stock (or agreement for such) will be made for a period of 45 days after the date of the Prospectus, directly or indirectly, by the Company otherwise than hereunder or with the prior written consent of the Representative. The foregoing sentence shall not apply to (A) the Shares to be sold hereunder, (B) the issuance by the Company of shares of Common Stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof as described in or as contemplated by the Prospectus, or (C) the grant of options to purchase shares of Common Stock, or of restricted shares of Common Stock, pursuant to the Company’s 2006 Stock Incentive Plan, as amended and restated, provided that, prior to the grant of any such stock option or restricted shares of Common Stock, the Company shall cause the recipients of such grants who are directors or executive officers of the Company to execute and deliver to the Underwriters “lock-up” agreements, each substantially in the form of Exhibit A hereto.

(k) The Company will use its best efforts to list the Shares on the Nasdaq Global Select Market and its commercially reasonable efforts to maintain the listing of the Shares on the Nasdaq Global Select Market.

13

(l) The Company will use commercially reasonable efforts to cause each executive officer and director of the Company to furnish to the Underwriters, on or as soon as possible after the date of this agreement, a letter or letters, substantially in the form attached hereto as Exhibit A (the “Lockup Agreement”).

(m) The Company shall apply the net proceeds of its sale of the Shares as set forth in the Registration Statement, General Disclosure Package and the Prospectus.

(n) 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 to register as an investment company under the 1940 Act.

(o) The Company will maintain a transfer agent and, if necessary under the jurisdiction of incorporation of the Company, a registrar for the Common Stock.

(p) 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.

The Company will pay all costs, expenses and fees incident to the performance of the obligations of the Company under this Agreement, including, without limiting the generality of the foregoing, the following: accounting fees of the Company; the fees and disbursements of counsel for the Company; any roadshow expenses; the cost of printing and delivering to, or as requested by, the Underwriters copies of the Registration Statement, Preliminary Prospectuses, the Issuer Free Writing Prospectuses, the Prospectus, this Agreement, the Underwriters’ Selling Memorandum, the Underwriters’ Invitation Letter, the Nasdaq Additional Listing Application, if any, the Blue Sky Survey and any supplements or amendments thereto; the filing fees of the Commission; the filing fees and expenses (including legal fees and disbursements) incident to securing any required review by FINRA of the terms of the sale of the Shares; the Nasdaq Additional Listing Fee of the Nasdaq Global Select Market; the costs and expenses (including without limitation any damages or other amounts payable in connection with legal or contractual liability) associated with the reforming of any contracts for sale of the Shares made by the Underwriters caused by a breach of the representation in Section 1(c) and the expenses, including the fees and disbursements of counsel for the Underwriters, incurred in connection with the qualification of the Shares under state securities or Blue Sky laws. The Company shall not, however, be required to pay for any of the Underwriters’ expenses (other than those related to qualification under FINRA regulation and state securities or Blue Sky laws) except that, if this Agreement shall not be consummated because the conditions in Section 6 hereof are not satisfied, or because this Agreement is terminated by the Representative pursuant to Section 11 hereof, or by reason of any failure, refusal or inability on the part of the Company to perform any undertaking or satisfy any condition of this Agreement or to comply with any of the terms hereof on its part to be performed, unless such failure, refusal or inability is due primarily to the default or omission of any Underwriter, the Company shall reimburse the several Underwriters for reasonable out-of-pocket expenses, including fees and disbursements of counsel, reasonably incurred in connection with investigating, marketing and proposing to market the Shares or in contemplation of performing their obligations hereunder; but the Company shall not in any event be liable to any of the several Underwriters for damages on account of loss of anticipated profits from the sale by them of the Shares.

14

The several obligations of the Underwriters to purchase the Firm Shares on the Closing Date and the Option Shares, if any, on the Option Closing Date are subject to the accuracy, as of the Applicable Time, and the Closing Date or the Option Closing Date, as the case may be, of the representations and warranties of the Company contained herein, and to the performance by the Company of its covenants and obligations hereunder and to the following additional conditions:

(a) The Registration Statement and all post-effective amendments thereto shall have been declared effective and the Prospectus and each Issuer Free Writing Prospectus required shall have been filed as required by Rules 424, 430A, 430B, 430C or 433 under the Act, as applicable, within the time period prescribed by, and in compliance with, the Rules and Regulations, and any request of the Commission for additional information (to be included in the Registration Statement or otherwise) shall have been disclosed to the Underwriters and complied with to the reasonable satisfaction of the Representative. No stop order suspending the effectiveness of the Registration Statement, as amended from time to time, shall have been issued and no proceedings for that purpose or pursuant to Section 8A under the Act shall have been taken or, to the knowledge of the Company, shall be contemplated or threatened by the Commission and no injunction, restraining order or order of any nature by a Federal or state court of competent jurisdiction shall have been issued as of the Closing Date or the Option Closing Date, as the case may be, which would prevent the issuance of the Shares.

(b) The Underwriters shall have received on the Closing Date or the Option Closing Date, as the case may be, the opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., counsel for the Company, dated the Closing Date or the Option Closing Date, as the case may be, addressed to the Underwriters as to the matters set forth in Exhibit B.

(c) The Underwriters shall have received on the Closing Date or the Option Closing Date, as the case may be, the opinion of Womble Carlyle Sandridge & Rice, PLLC, outside corporate counsel for the Company, dated the Closing Date or the Option Closing Date, as the case may be, addressed to the Underwriters as to the matters set forth in Exhibit C.

(d) The Underwriters shall have received on the Closing Date or the Option Closing Date, as the case may be, the opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., special FDA counsel for the Company, dated the Closing Date or the Option Closing Date, as the case may be, addressed to the Underwriters as to the matters set forth in Exhibit D.

(e) The Underwriters shall have received on the Closing Date or the Option Closing Date, as the case may be, an opinion of Womble Carlyle Sandridge & Rice, PLLC, special intellectual property counsel to the Company, dated the Closing Date or the Option Closing Date, as the case may be, addressed to the Underwriters as to the matters set forth in Exhibit E.

(f) The Underwriters shall have received from Wilmer Cutler Pickering Hale and Dorr LLP, counsel for the Underwriters, an opinion dated the Closing Date or the Option Closing Date, as the case may be, in such form as shall be agreed to with the Underwriters.

(g) The Underwriters shall have received, on each of the date hereof, the Closing Date and, if applicable, the Option Closing Date, a letter dated the date hereof, the Closing Date or the Option Closing Date, as the case may be, in form and substance satisfactory to the Representative, of Ernst & Young LLP confirming that they are an independent registered public accounting firm with respect to the Company within the meaning of the Act and the applicable

15

Rules and Regulations and the PCAOB and stating that in their opinion the financial statements and schedules examined by them and included or incorporated by reference in the Registration Statement, the General Disclosure Package and the Prospectus comply in form in all material respects with the applicable accounting requirements of the Act and the related Rules and Regulations; and containing such other statements and information as is ordinarily included in accountants’ “comfort letters” to Underwriterss with respect to the financial statements and certain financial and statistical information contained in the Registration Statement, the General Disclosure Package and the Prospectus.

(h) The Underwriters shall have received on the Closing Date and, if applicable, the Option Closing Date, as the case may be, a certificate or certificates of the Company signed by the Chief Executive Officer and the Chief Financial Officer of the Company to the effect that, as of the Closing Date or the Option Closing Date, as the case may be:

(i) The representations and warranties of the Company contained in Section 1 hereof are true and correct as of the Closing Date or the Option Closing Date, as the case may be;

(ii) He or she has carefully examined the General Disclosure Package and any individual Limited Use Free Writing Prospectus and, in his or her view, as of the Applicable Time, the statements contained in the General Disclosure Package and any such individual Limited Use Free Writing Prospectus did not contain any untrue statement of a material fact, and such General Disclosure Package and any individual Limited Use Free Writing Prospectus, when considered together with the General Disclosure Package, did not 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;

(iii) He or she has carefully examined the Registration Statement and, in his or her view, as of the effective date of the Registration Statement, the Registration Statement and any amendments thereto did not contain any untrue statement of a material fact and did not omit to state a material fact necessary in order to make the statements therein not misleading;

(iv) He or she has carefully examined the Prospectus and, in his or her view, as of its date and the Closing Date or the Option Closing Date, as the case may be, the Prospectus and any amendments and supplements thereto did not contain any untrue statement of a material fact and did not 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; and

(v) Since the respective dates as of which information is given in the General Disclosure Package and the Prospectus, and other than as set forth in the General Disclosure Package as of the Applicable Time and the Prospectus, there has not been any material adverse change or any development involving a prospective material adverse change in or affecting the business, management, properties, assets, rights, operations, condition (financial or otherwise) or prospects of the Company, whether or not arising in the ordinary course of business.

(i) On the Closing Date or the Option Closing Date, as the case may be, the Company shall have furnished to the Underwriters a Secretary’s Certificate of the Company.

(j) The Company shall have furnished to the Underwriters such further certificates and documents confirming the representations and warranties, covenants and conditions contained herein and related matters as the Representative may reasonably have requested.

16

(k) The Firm Shares and Option Shares, if any, have been duly listed, subject to notice of issuance, on the Nasdaq Global Select Market.

(l) The Lockup Agreements described in Section 4(l) are in full force and effect.

The opinions and certificates mentioned in this Agreement shall be deemed to be in compliance with the provisions hereof only if they are in all material respects satisfactory to the Representative and to Wilmer Cutler Pickering Hale and Dorr LLP, counsel for the Underwriters.

If any of the conditions hereinabove provided for in this Section 6 shall not have been fulfilled when and as required by this Agreement to be fulfilled, the obligations of the Underwriters hereunder may be terminated by the Representative by notifying the Company of such termination in writing or by telegram at or prior to the Closing Date or the Option Closing Date, as the case may be.

In such event, the Company and the Underwriters shall not be under any obligation to each other (except to the extent provided in Sections 5 and 8 hereof).

The obligations of the Company to sell and deliver the portion of the Shares required to be delivered as and when specified in this Agreement are subject to the conditions that at the Closing Date or the Option Closing Date, as the case may be, no stop order suspending the effectiveness of the Registration Statement shall have been issued and in effect or proceedings therefor initiated or threatened.

(a) The Company agrees:

(1) to indemnify and hold harmless each Underwriter and each person, if any, who controls any Underwriter within the meaning of either Section 15 of the Act or Section 20 of the Exchange Act, against any losses, claims, damages or liabilities to which such Underwriter or any such controlling person may become subject under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions or proceedings in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of any material fact contained in the Registration Statement, any Preliminary Prospectus, any Issuer Free Writing Prospectus, the Prospectus or any amendment or supplement thereto, (ii) with respect to the Registration Statement or any amendment or supplement thereto, 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 or (iii) with respect to any Preliminary Prospectus, any Issuer Free Writing Prospectus, the Prospectus or any amendment or supplement thereto, 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 the light of the circumstances under which they were made; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement, or omission or alleged omission, made in the Registration Statement, any Preliminary Prospectus, any Issuer Free Writing Prospectus, the Prospectus, or such amendment or supplement, in reliance upon and in conformity with written information furnished to the Company by the Representative on behalf the Underwriters specifically for use therein, it being understood and agreed that the only such information furnished by the Underwriters consists of the information described as such in Section 13 herein; and

17

(2) to reimburse each Underwriter and each such controlling person upon demand for any legal or other out-of-pocket expenses reasonably incurred by such Underwriter or such controlling person in connection with investigating or defending any such loss, claim, damage or liability, action or proceeding or in responding to a subpoena or governmental inquiry related to the offering of the Shares, whether or not such Underwriter or controlling person is a party to any action or proceeding. In the event that it is finally judicially determined that the Underwriters were not entitled to receive payments for legal and other expenses pursuant to this subparagraph, the Underwriters will promptly return all sums that had been advanced pursuant hereto.

(b) Each Underwriter severally and not jointly will indemnify and hold harmless the Company, each of its directors, each of its officers who have signed the Registration Statement, and each person, if any, who controls the Company within the meaning of the Act, against any losses, claims, damages or liabilities to which the Company or any such director, officer, or controlling person may become subject under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions or proceedings in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of any material fact contained in the Registration Statement, any Preliminary Prospectus, any Issuer Free Writing Prospectus, the Prospectus or any amendment or supplement thereto, (ii) with respect to the Registration Statement or any amendment or supplement thereto, 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 or (iii) with respect to any Preliminary Prospectus, any Issuer Free Writing Prospectus, the Prospectus or any amendment or supplement thereto, 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 the light of the circumstances under which they were made; and will reimburse any legal or other expenses reasonably incurred by the Company or any such director, officer, or controlling person in connection with investigating or defending any such loss, claim, damage, liability, action or proceeding; provided, however, that each Underwriter will be liable in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission has been made in the Registration Statement, any Preliminary Prospectus, any Issuer Free Writing Prospectus, the Prospectus or such amendment or supplement, in reliance upon and in conformity with written information (including, without limitation, information transmitted by email) furnished to the Company by the Representative on behalf of the Underwriters specifically for use therein, it being understood and agreed that the only such information consists of the information described as such in Section 13 herein. This indemnity agreement will be in addition to any liability which the Underwriters may otherwise have.

(c) In case any proceeding (including any governmental investigation) shall be instituted involving any person in respect of which indemnity may be sought pursuant to this Section 8, such person (the “indemnified party”) shall promptly notify the person against whom such indemnity may be sought (the “indemnifying party”) in writing. No indemnification provided for in Section 8(a) or (b) shall be available to any party who shall fail to give notice as provided in this Section 8(c) if the party to whom notice was not given was unaware of the proceeding to which such notice would have related and was materially prejudiced by the failure to give such notice, but the failure to give such notice shall not relieve the indemnifying party or parties from any liability which it or they may have to the indemnified party for contribution or otherwise than on account of the provisions of Section 8(a) or (b). In case any such proceeding shall be brought against any indemnified party and it shall notify the indemnifying party of the commencement thereof, the indemnifying party shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified

18

party and shall pay as incurred the fees and disbursements of such counsel related to such proceeding. In any such proceeding, any indemnified party shall have the right to retain its own counsel at its own expense. Notwithstanding the foregoing, the indemnifying party shall pay as incurred (or within 30 days of presentation) the reasonable fees and expenses of the counsel retained by the indemnified party in the event (i) the indemnifying party and the indemnified party shall have mutually agreed to the retention of such counsel, (ii) the named parties to any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them or (iii) the indemnifying party shall have failed to assume the defense and employ counsel acceptable to the indemnified party within a reasonable period of time after notice of commencement of the action. It is understood that the indemnifying party shall not, in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the reasonable fees and expenses of more than one separate firm for all such indemnified parties. Such firm shall be designated in writing by the Representative in the case of parties indemnified pursuant to Section 8(a) and by the Company in the case of parties indemnified pursuant to Section 8(b). The indemnifying party shall not be liable for any settlement of any proceeding effected without its written consent but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party from and against any loss or liability by reason of such settlement or judgment. In addition, the indemnifying party will not, without the prior written consent of the indemnified party, settle or compromise or consent to the entry of any judgment in any pending or threatened claim, action or proceeding of which indemnification may be sought hereunder (whether or not any indemnified party is an actual or potential party to such claim, action or proceeding) unless such settlement, compromise or consent includes an unconditional release of each indemnified party from all liability arising out of such claim, action or proceeding.

(d) To the extent the indemnification provided for in this Section 8 is unavailable to or insufficient to hold harmless an indemnified party under Section 8(a) or (b) above in respect of any losses, claims, damages or liabilities (or actions or proceedings in respect thereof) referred to therein, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (or actions or proceedings in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Shares. If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities (or actions or proceedings in respect thereof), as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover page of the Prospectus. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company on the one hand or the Underwriters on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

19

The Company and the Underwriters agree that it would not be just and equitable if contributions pursuant to this Section 8(d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this Section 8(d). The amount paid or payable by an indemnified party as a result of the losses, claims, damages or liabilities (or actions or proceedings in respect thereof) referred to above in this Section 8(d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this subsection (d), (i) no Underwriter shall be required to contribute any amount in excess of the underwriting discounts and commissions applicable to the Shares purchased by such Underwriter and (ii) no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this Section 8(d) to contribute are several in proportion to their respective underwriting obligations and not joint.

(e) In any proceeding relating to the Registration Statement, any Preliminary Prospectus, any Issuer Free Writing Prospectus, the Prospectus or any supplement or amendment thereto, each party against whom contribution may be sought under this Section 8 hereby consents to the jurisdiction of any court having jurisdiction over any other contributing party, agrees that process issuing from such court may be served upon it by any other contributing party and consents to the service of such process and agrees that any other contributing party may join it as an additional defendant in any such proceeding in which such other contributing party is a party.

(f) Any losses, claims, damages, liabilities or expenses for which an indemnified party is entitled to indemnification or contribution under this Section 8 shall be paid by the indemnifying party to the indemnified party as such losses, claims, damages, liabilities or expenses are incurred. The indemnity and contribution agreements contained in this Section 8 and the representations and warranties of the Company set forth in this Agreement shall remain operative and in full force and effect, regardless of (i) any investigation made by or on behalf of any Underwriter or any person controlling any Underwriter, the Company, its directors or officers or any persons controlling the Company, (ii) acceptance of any Shares and payment therefor hereunder, and (iii) any termination of this Agreement. A successor to any Underwriter or any person controlling any Underwriter, or to the Company, its directors or officers, or any person controlling the Company, shall be entitled to the benefits of the indemnity, contribution and reimbursement agreements contained in this Section 8.

If on the Closing Date or the Option Closing Date, as the case may be, any Underwriter shall fail to purchase and pay for the portion of the Shares which such Underwriter has agreed to purchase and pay for on such date (otherwise than by reason of any default on the part of the Company), the Representative, shall use its reasonable efforts to procure within 36 hours thereafter one or more of the other Underwriters, or any others, to purchase from the Company such amounts as may be agreed upon and upon the terms set forth herein, the Shares which the defaulting Underwriter or Underwriters failed to purchase. If during such 36 hours the Representative shall not have procured such other Underwriters, or any others, to purchase the Shares agreed to be purchased by the defaulting Underwriter or Underwriters, then (a) if the aggregate number of shares with respect to which such default shall occur does not exceed 10% of the Shares to be purchased on the Closing Date or the Option Closing Date, as the case may be, the other Underwriters shall be obligated, severally, in proportion to the respective numbers

20

of Shares which they are obligated to purchase hereunder, to purchase the Shares which such defaulting Underwriter or Underwriters failed to purchase, or (b) if the aggregate number of shares of Shares with respect to which such default shall occur exceeds 10% of the Shares to be purchased on the Closing Date or the Option Closing Date, as the case may be, the Company or the Representative will have the right, by written notice given within the next 36-hour period to the parties to this Agreement, to terminate this Agreement without liability on the part of the non-defaulting Underwriters or of the Company except to the extent provided in Sections 5 and 8 hereof. In the event of a default by any Underwriter or Underwriters, as set forth in this Section 9, the Closing Date or Option Closing Date, as the case may be, may be postponed for such period, not exceeding seven days, as the Representative may determine in order that the required changes in the Registration Statement, the General Disclosure Package or in the Prospectus or in any other documents or arrangements may be effected. The term “Underwriter” includes any person substituted for a defaulting Underwriter. Any action taken under this Section 9 shall not relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

All communications hereunder shall be in writing and, except as otherwise provided herein, will be mailed, delivered, telecopied or telegraphed and confirmed as follows: (a) if to the Underwriters, to the Representative c/o Deutsche Bank Securities Inc., 60 Wall Street, 4^th Floor, New York, New York 10005; Attention: Syndicate Manager, with a copy to Deutsche Bank Securities Inc., 60 Wall Street, New York, New York 10005, Attention: General Counsel, with a copy (which shall not constitute notice) to Wilmer Cutler Pickering Hale and Dorr LLP, 399 Park Avenue, New York, New York 10022, Attention: Stuart R. Nayman and (b) if to the Company, to Targacept, Inc., 200 East First Street, Suite 300, Winston-Salem, North Carolina 27101, Attention: General Counsel.

This Agreement may be terminated by the Representative by notice to the Company:

(a) at any time prior to the Closing Date or any Option Closing Date (if different from the Closing Date and then only as to Option Shares) if any of the following has occurred: (i) since the respective dates as of which information is given in the Registration Statement, the General Disclosure Package and the Prospectus, any material adverse change or any development involving a prospective material adverse change in or affecting the earnings, business, management, properties, assets, rights, operations, condition (financial or otherwise) or prospects of the Company, whether or not arising in the ordinary course of business, (ii) any outbreak or escalation of hostilities or declaration of war or national emergency or other national or international calamity or crisis (including, without limitation, an act of terrorism) or change in economic or political conditions if the effect of such outbreak, escalation, declaration, emergency, calamity, crisis or change on the financial markets of the United States would, in the Representative’s judgment, materially impair the investment quality of the Shares, (iii) suspension of trading in securities generally on the New York Stock Exchange, the NYSE Amex or the Nasdaq Global Select Market or limitation on prices (other than limitations on hours or numbers of days of trading) for securities on any such trading market, (iv) the enactment, publication, decree or other promulgation of any statute, regulation, rule or order of any court or other governmental authority which in the Representative’s opinion materially and adversely affects or may materially and adversely affect the business or operations of the Company, (v) the declaration of a banking moratorium by United States or New York State authorities, (vi) any downgrading, or placement on any watch list for possible downgrading, in

21

the rating of any of the Company’s debt securities by any “nationally recognized statistical rating organization” (as defined for purposes of Rule 436(g) under the Exchange Act), (vii) the suspension of trading of the Company’s common stock by the Nasdaq Global Select Market, the Commission, or any other governmental authority or, (viii) the taking of any action by any governmental body or agency in respect of its monetary or fiscal affairs which in the Representative’s opinion has a material adverse effect on the securities markets in the United States; or

(b) as provided in Sections 6 and 9 of this Agreement.

This Agreement has been and is made solely for the benefit of the Underwriters and the Company and their respective successors, executors, administrators, heirs and assigns, and the officers, directors and controlling persons referred to herein, and no other person will have any right or obligation hereunder. No purchaser of any of the Shares from any Underwriter shall be deemed a successor or assign merely because of such purchase.

The Company and the Underwriters acknowledge and agree that the only information furnished or to be furnished by any Underwriters to the Company for inclusion in the Registration Statement, any Preliminary Prospectus, any Issuer Free Writing Prospectus or the Prospectus consists of the information set forth in the third and the ninth through thirteenth paragraphs under the caption “Underwriting” in the Prospectus.

The reimbursement, indemnification and contribution agreements contained in this Agreement and the representations, warranties and covenants in this Agreement shall remain in full force and effect regardless of (a) any termination of this Agreement, (b) any investigation made by or on behalf of any Underwriter or controlling person thereof, or by or on behalf of the Company or its directors or officers, and (c) delivery of and payment for the Shares under this Agreement.

The Company acknowledges and agrees that each Underwriter in providing investment banking services to the Company in connection with the offering, including in acting pursuant to the terms of this Agreement, has acted and is acting as an independent contractor and not as a fiduciary and the Company does not intend such Underwriter to act in any capacity other than as an independent contractor, including as a fiduciary or in any other position of higher trust.

This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

This Agreement shall be governed by, and construed in accordance with, the law of the State of New York, including, without limitation, Section 5-1401 of the New York General Obligations Law.

The Underwriters, on the one hand, and the Company (on its own behalf and, to the extent permitted by law, on behalf of its stockholders), on the other hand, waive any right to trial by jury in any action, claim, suit or proceeding with respect to your engagement as Underwriters or your role in connection herewith.

[signature page follows]

22

If the foregoing is in accordance with your understanding of our agreement, please sign and return to us the enclosed duplicates hereof, whereupon it will become a binding agreement among the Company and the several Underwriters in accordance with its terms.

SCHEDULE I

SCHEDULE OF UNDERWRITERS

SCHEDULE II

The number of Firm Shares being offered is 3,658,537 and the number of Option Shares is 548,780.

The price of the Shares to the public is $20.50 per Share.

The underwriting discount is 6%.

SCHEDULE III

None.

EXHIBIT A

LOCK-UP AGREEMENT

May     , 2011

Deutsche Bank Securities Inc.

As Representative of the several

 Underwriters

c/o Deutsche Bank Securities Inc.

60 Wall Street, 4th Floor

New York, New York 10005

Ladies and Gentlemen:

The undersigned understands that Deutsche Bank Securities Inc., as representative (the “Representative”) of the several underwriters (the “Underwriters”), proposes to enter into an Underwriting Agreement (the “Underwriting Agreement”) with Targacept, Inc. (the “Company”), providing for the public offering by the Underwriters, including the Representative, of common stock, par value $0.001 per share (the “Common Stock”), of the Company (the “Public Offering”).

To induce the Underwriters that may participate in the public offering to continue their efforts in connection with the Public Offering, the undersigned agrees that, without the prior written consent of the Representative, the undersigned will not, directly or indirectly, offer, sell, pledge, contract to sell (including any short sale), grant any option to purchase or otherwise dispose of any shares of Common Stock (including, without limitation, shares of Common Stock of the Company which may be deemed to be beneficially owned by the undersigned on the date hereof in accordance with the rules and regulations of the Securities and Exchange Commission, shares of Common Stock which may be issued upon exercise of a stock option or warrant and any other security convertible into or exchangeable for Common Stock) or enter into any Hedging Transaction (as defined below) relating to the Common Stock (each of the foregoing referred to as a “Disposition”) during the period commencing on the date of the final prospectus relating to the Public Offering and continuing until, and including, the date that is 45 days after the date of such final prospectus (the “Lock-Up Period”). The foregoing restriction is expressly intended to preclude the undersigned from engaging in any Hedging Transaction or other transaction which is designed to or reasonably expected to lead to or result in a Disposition during the Lock-Up Period even if the securities would be disposed of by someone other than the undersigned. “Hedging Transaction” means any short sale (whether or not against the box) or any purchase, sale or grant of any right (including, without limitation, any put or call option) with respect to any security (other than a broad-based market basket or index) that includes, relates to or derives any significant part of its value from the Common Stock.

The foregoing restrictions on Disposition shall not apply to (a) Dispositions made pursuant to 10b5-1 trading plans existing on the date hereof, (b) the entry into any 10b5-1 trading plan so long as no Dispositions may occur under such plan until the expiration of Lock-Up Period, (c) the sale of any Common Stock to the Underwriters pursuant to the Underwriting Agreement, (d) transactions relating to shares of Common Stock or other Company securities acquired in open market transactions after the completion of the Public Offering, (e) bona fide gifts or other transfers of shares of Common Stock for no consideration, (f) the Disposition in a transaction not involving a disposition for value to any trust for the direct or indirect benefit of the undersigned or a member of the “immediate family” of the undersigned, (g) the Disposition by

A-1

will or intestate succession to the legal representative or a member of the “immediate family” of the undersigned, (h) if the undersigned is a partnership or limited liability company, the distribution of shares of Common Stock to partners or members of the undersigned or to the estate of any deceased partner or member of the undersigned, (i) if the undersigned is a corporation, the transfer of shares of Common Stock in a transaction not involving a public distribution or public offering to any majority owned subsidiary of the undersigned, any holder of at least 50% of the outstanding voting power of the undersigned or any entity under common control with the undersigned or (j) if the undersigned is a trust, the distribution of shares of Common Stock to any beneficiary of the undersigned; provided, however, that in the case of any gift, transfer, disposition or distribution otherwise permitted by clauses (e), (f), (g), (h), (i) or (j), (1) each donee, transferee or distributee shall execute and deliver to the Underwriters a letter substantially in the form hereof agreeing to be bound by the terms hereof and (2) neither the undersigned nor any other party to the applicable transaction shall be required to file, or voluntarily file, a report under Section 16(a) of the Exchange Act other than a filing on Form 5 made after the expiration of the Lock-Up Period. For purposes hereof, the term “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

The undersigned agrees that the Company may, and that the undersigned will, (i) with respect to any shares of Common Stock or other Company securities for which the undersigned is the record holder, cause the transfer agent for the Company to note stop transfer instructions with respect to such securities on the transfer books and records of the Company and (ii) with respect to any shares of Common Stock or other Company securities for which the undersigned is the beneficial holder but not the record holder, cause the record holder of such securities to cause the transfer agent for the Company to note stop transfer instructions with respect to such securities on the transfer books and records of the Company.

In addition, the undersigned hereby waives any and all notice requirements and rights with respect to registration of securities pursuant to any agreement, understanding or otherwise setting forth the terms of any security of the Company held by the undersigned, including any registration rights agreement to which the undersigned and the Company may be party; provided that such waiver shall apply only to the proposed Public Offering, and any other action taken by the Company in connection with the proposed Public Offering.

The undersigned hereby agrees that, to the extent that the terms of this Lock-Up Agreement conflict with or are in any way inconsistent with any registration rights agreement to which the undersigned and the Company may be a party, this Lock-Up Agreement supersedes such registration rights agreement.

The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Lock-Up Agreement. All authority herein conferred or agreed to be conferred shall survive the death or incapacity of the undersigned and any obligations of the undersigned shall be binding upon the heirs, personal representatives, successors and assigns of the undersigned.

This Lock-Up Agreement shall terminate automatically on June 30, 2011 in the event that no shares of Common Stock have been purchased and paid for pursuant to the Underwriting Agreement by such date, or earlier if the Underwriting Agreement is otherwise terminated in accordance with its terms.

Signature:                                                                  

Print Name:                                                               

A-2

EXHIBIT B

[Form of Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.]

EXHIBIT C

[Form of Opinion of Womble Carlyle Sandridge & Rice, PLLC]

EXHIBIT D

[Form of FDA Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.]

EXHIBIT E

[Form of Intellectual Property Opinion of Womble Carlyle Sandridge & Rice, PLLC]