Entry into a Material Definitive Agreement

Exhibit 1.1

16,000,000 Shares

ARIAD Pharmaceuticals, Inc.

Common Stock

($0.001 par value per Share)

UNDERWRITING AGREEMENT

October 25, 2010

JEFFERIES & COMPANY, INC.
OPPENHEIMER & CO. INC.
  as Representatives of the several
  Underwriters named in Schedule I hereto

c/o JEFFERIES & COMPANY, INC.
520 Madison Avenue
New York, New York 10022

c/o OPPENHEIMER & CO. INC.
300 Madison Avenue
New York, New York 10017

Ladies and Gentlemen:

     ARIAD Pharmaceuticals, Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions contained herein, to sell to you, Jefferies & Company, Inc. (“Jefferies”) and Oppenheimer & Co. Inc. (“OpCo”), acting as Representatives (the “Representatives”) of the underwriters named on Schedule I to this Agreement (the “Underwriters”), an aggregate of 16,000,000 shares (the “Firm Shares”) of the Company’s common stock, $0.001 par value per share (the “Common Stock”). In addition, the Company proposes to grant to the Underwriters an option to purchase up to an additional 2,400,000 shares (the “Option Shares”) of Common Stock from the Company for the purpose of covering over allotments in connection with the sale of the Firm Shares. Upon execution and delivery by the Representatives and the Company by 8:30 A.M. New York time on October 26, 2010 of a supplemental pricing agreement in the form attached hereto as Exhibit A, the aggregate number of Firm Shares to be purchased by the Underwriters and the aggregate number of Option Shares shall be increased as set forth on such supplemental pricing agreement. The execution and delivery of such supplemental pricing agreement shall not in any other way amend or modify the terms hereof; neither party hereto shall have any obligation to enter into a supplemental pricing agreement. The Firm Shares and the Option Shares are collectively called the “Shares.”

     The Company has prepared and filed in conformity with the requirements of the Securities Act of 1933, as amended (the “Securities Act”), and the published rules and regulations thereunder (the “Rules”) adopted by the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-3 declared effective by the Commission on January 21, 2010 (No. 333-164283), including a related prospectus dated January 21, 2010 (the “Base Prospectus”) relating to Common Stock that may be sold from time to time by the Company in accordance with Rule 415 of the Securities Act, and such amendments thereof as may have been required to the date of this Agreement. Copies of such Registration Statement (including all amendments thereof and all documents deemed incorporated by reference therein) and of the related Base Prospectus have heretofore been delivered by the Company or are otherwise available to you.

     The term “Registration Statement” as used in this Agreement means the registration statement, including all exhibits, financial schedules and all documents and information deemed to be part of the Registration Statement by incorporation by reference or otherwise, as amended from time to time, including the information (if any) contained in the form of final prospectus filed with the Commission pursuant to Rule 424(b) of the Rules and deemed to be part thereof at the time of effectiveness pursuant to Rule 430B of the Rules.

     If the Company has filed an abbreviated registration statement to register additional Shares pursuant to Rule 462(b) under the Rules (the “462(b) Registration Statement”), then any reference herein to the Registration Statement shall also be deemed to include such 462(b) Registration Statement. The term “Prospectus” means the Base Prospectus, any amendments or further supplements to such prospectus, and including, without limitation, the final prospectus supplement (the “Prospectus Supplement”), filed pursuant to and within the limits described in Rule 424(b) with the Commission in connection with the proposed sale of the Shares contemplated by this Agreement through the date of such prospectus supplement. The term “Effective Date” shall mean each date that the Registration Statement and any post-effective amendment or amendments thereto became or become effective. Unless otherwise stated herein, any reference herein to the Registration Statement, the Statutory Prospectus (as hereinafter defined) and the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein, including pursuant to Item 12 of Form S-3 under the Securities Act, which were filed under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) on or before the date hereof or are so filed hereafter. Any reference herein to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement, the Statutory Prospectus or the Prospectus shall be deemed to refer to and include any such document filed or to be filed under the Exchange Act after the date of the Registration Statement, the Statutory Prospectus or Prospectus, as the case may be, and deemed to be incorporated therein by reference.

     The Company understands that the Underwriters propose to make a public offering of the Shares, as set forth in and pursuant to the Statutory Prospectus and the Prospectus, as soon after the Effective Date and the date of this Agreement as the Representatives deem advisable. The Company hereby confirms that the Underwriters and dealers have been authorized to distribute or cause to be distributed the Base Prospectus and each Issuer Free Writing Prospectus (as hereinafter defined) and are authorized to distribute the Prospectus (as from time to time

amended or supplemented if the Company furnishes amendments or supplements thereto to the Underwriters).

     1. Sale, Purchase, Delivery and Payment for the Shares. On the basis of the representations, warranties and agreements contained in, and subject to the terms and conditions of, this Agreement:

          (a) The Company agrees to issue and sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at a purchase price of $3.61 per share (the “Initial Price”), the number of Firm Shares set forth opposite the name of such Underwriter under the column “Number of Firm Shares to be Purchased” on Schedule I to this Agreement, subject to adjustment in accordance with Section 9 hereof.

          (b) The Company hereby grants to the several Underwriters an option to purchase, severally and not jointly, all or any part of the Option Shares at the Initial Price. The number of Option Shares to be purchased by each Underwriter shall be the same percentage (adjusted by the Representatives to eliminate fractions) of the total number of Option Shares to be purchased by the Underwriters as such Underwriter is purchasing of the Firm Shares. Such option may be exercised only to cover over-allotments in the sales of the Firm Shares by the Underwriters and may be exercised in whole or in part at any time on or before 12:00 noon, New York City time, on the business day before the Firm Shares Closing Date (as defined below), and from time to time thereafter within 30 days after the date of this Agreement, in each case upon written, facsimile or telegraphic notice, or verbal or telephonic notice confirmed by written, facsimile or telegraphic notice, by the Representatives to the Company no later than 12:00 noon, New York City time, on the business day before the Firm Shares Closing Date or at least two business days before the Option Shares Closing Date (as defined below), as the case may be, setting forth the number of Option Shares to be purchased and the time and date (if other than the Firm Shares Closing Date) of such purchase.

          (c) Payment of the purchase price for, and delivery of certificates for, the Firm Shares shall be made at the offices of Jefferies & Company, Inc., 520 Madison Avenue, New York, New York 10022 (or at such other location as may be mutually acceptable), at 10:00 a.m., New York City time, on the third (or if the Shares are priced, as contemplated by Rule 15c6-1(c) under the Exchange Act, after 4:30 p.m. New York City time, the fourth) business day following the date of this Agreement or at such time on such other date, not later than ten (10) business days after the date of this Agreement, as shall be agreed upon by the Company and the Representatives (such time and date of delivery and payment are called the “Firm Shares Closing Date”). In addition, in the event that any or all of the Option Shares are purchased by the Representatives, payment of the purchase price, and delivery of the certificates, for such Option Shares shall be made at the above-mentioned offices, or at such other place as shall be agreed upon by the Representatives and the Company, on each date of delivery as specified in the notice from the Representatives to the Company (such time and date of delivery and payment are called the “Option Shares Closing Date”). The Firm Shares Closing Date and any Option Shares Closing Date are called, individually, a “Closing Date” and, together, the “Closing Dates.”

          (d) Payment shall be made to the Company by wire transfer of immediately available funds or by certified or official bank check or checks payable in New York Clearing House (same day) funds drawn to the order of the Company, against delivery of the certificates to the Representatives for the respective accounts of the Underwriters for the Shares to be purchased by them.

          (e) Certificates evidencing the Shares shall be registered in such names and shall be in such denominations as the Representatives shall request at least two full business days before the Firm Shares Closing Date or, in the case of Option Shares, on the day of notice of exercise of the option as described in Section 1(b) and shall be delivered by or on behalf of the Company to the Representatives through the facilities of the Depository Trust Company (“DTC”) for the account of the Underwriters. The Company will cause the certificates representing the Shares to be made available for checking and packaging, at such place as is designated by the Representatives, on the full business day before the Firm Shares Closing Date (or the Option Shares Closing Date in the case of the Option Shares).

     2. Representations and Warranties of the Company. The Company represents and warrants to each Underwriter as of the date hereof, as of the Firm Shares Closing Date and as of each Option Shares Closing Date (if any), as follows:

          (a) The Company meets the requirements for use of Form S-3 under the Securities Act, including the transaction requirements set forth in General Instruction 1.B.1 of such form. The Company filed with the Commission the Registration Statement on such Form, including a Base Prospectus, for registration under the Securities Act of the offering and sale of the Shares. When the Registration Statement or any amendment thereof or supplement thereto was or is declared effective and as of the date of the most recent amendment to the Registration Statement, it (i) complied or will comply, in all material respects, with the requirements of the Securities Act and the Rules and the Exchange Act and the rules and regulations of the Commission thereunder and (ii) did not or will not, contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein not misleading. When the Base Prospectus or the Prospectus was first filed with the Commission (whether filed as part of the Registration Statement or any amendment thereto or pursuant to Rule 424 of the Rules) and as of each Closing Date and when any amendment thereof or supplement thereto was first filed with the Commission and as of each Closing Date, such Base Prospectus or Prospectus as amended or supplemented complied in all material respects with the applicable provisions of the Securities Act and the Rules and did not as of the date thereof, does not, together with the Pricing Information (as defined below), as of the date hereof, and will not, together with the Pricing Information, as of the Closing Date, contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. If applicable, the Prospectus delivered to the Underwriters for use in connection with this offering was identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T. Notwithstanding the foregoing, none of the representations and warranties in this paragraph 2(a) shall apply to statements in, or omissions from, the Registration Statement or the Prospectus or any amendment thereof or supplement thereto made in reliance upon, and in conformity with, information herein or otherwise furnished in writing by the

Underwriters specifically for use in the Registration Statement or the Prospectus. With respect to the preceding sentence, the Company acknowledges that the only information furnished in writing by the Underwriters for use in the Registration Statement or the Prospectus is the statements contained in the first two sentences and the last sentence of the first paragraph under the section entitled “Commissions and Expenses” and the second, third and fifth paragraphs under the section entitled “Price Stabilization, Short Positions and Penalty Bids”, under the caption “Underwriting” in the Prospectus (collectively, the “Underwriting Information”).

          (b) As of the Applicable Time (as hereinafter defined), neither (i) the Statutory Prospectus (as hereinafter defined) together with each Issuer Free Writing Prospectus (as hereinafter defined) issued at or prior to the Applicable Time and the Pricing Information (as hereinafter defined) (collectively, the “General Disclosure Package”), nor (ii) any individual Issuer Free Writing Prospectus when considered together with the General Disclosure Package, included any untrue statement of a material fact or omitted to state any material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to statements in or omissions in the General Disclosure Package made in reliance upon and in conformity with the Underwriter Information.

          Each Issuer Free Writing Prospectus, including any electronic road show (including without limitation any “bona fide electronic road show” as defined in Rule 433(h)(5) under the Securities Act) (each, a “Road Show”) (i) is identified in Schedule III hereto and (ii) complied when issued, and complies, in all material respects with the requirements of the Securities Act and the Rules and the Exchange Act and the rules and regulations of the Commission thereunder.

          As used in this Section and elsewhere in this Agreement:

               “Applicable Time” means 4:07 p.m. (Eastern time) on the date of this Underwriting Agreement.

               “Statutory Prospectus” as of any time means the Base Prospectus that is included in the Registration Statement immediately prior to the Applicable Time, including any document incorporated by reference therein.

               “Issuer Free Writing Prospectus” means each “free writing prospectus” (as defined in Rule 405 of the Rules) prepared by or on behalf of the Company or used or referred to by the Company in connection with the offering of the Shares, including, without limitation, each Road Show.

               “Pricing Information” means the following information which will be conveyed orally by the Underwriters to each prospective purchaser of the Shares prior to the time of each sale of the Shares in connection with the offering: (i) the aggregate number of Firm Shares to be sold pursuant to this Agreement, (ii) the aggregate number of Option Shares that may be purchased by the Underwriters pursuant to the over-allotment option provided by this Agreement, and (iii) the public offering price per share of the Shares to be sold pursuant to this Agreement.

          (c) The Registration Statement is effective under the Securities Act and no stop order preventing or suspending the effectiveness of the Registration Statement or suspending or preventing the use of the Base Prospectus, the Prospectus or any “free writing prospectus”, as defined in Rule 405 under the Rules, has been issued by the Commission and, to the knowledge of the Company, no proceedings for that purpose have been instituted or are threatened under the Securities Act. Any required filing of the Base Prospectus and/or the Prospectus and any supplement thereto pursuant to Rule 424(b) of the Rules has been or will be made in the manner and within the time period required by such Rule 424(b). Any material required to be filed by the Company pursuant to Rule 433(d) of the Rules has been or will be made in the manner and within the time period required by such Rules.

          (d) The documents incorporated by reference in the Registration Statement, the Base Prospectus and the Prospectus, at the time they became effective or were filed with the Commission, as the case may be, complied in all material respects with the requirements of the Securities Act and the Rules or the Exchange Act and the rules and regulations of the Commission thereunder, as applicable, and none of such documents contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, and any further documents so filed and incorporated by reference in the Registration Statement, the Base Prospectus and the Prospectus, when such documents become effective or are filed with the Commission, as the case may be, will conform in all material respects to the requirements of the Securities Act and the Rules or the Exchange Act and the rules and regulations of the Commission thereunder, as applicable, and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they are made, not misleading.

          (e) Each Issuer Free Writing Prospectus, if any, 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 Representatives as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will conflict with the information contained in the Registration Statement, including any document incorporated by reference therein and any prospectus supplement deemed to be a part thereof that has not been superseded or modified, the Statutory Prospectus or the Prospectus.

          If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information contained in the Registration Statement, the Statutory Prospectus or the Prospectus or included or would include an untrue statement of a material fact or omitted or would omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances prevailing at the subsequent time, not misleading, the Company has promptly notified or will promptly notify the Representatives and has promptly amended or will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

          (f) None of the Company, its directors or its officers has distributed nor will distribute prior to the later of (i) the Firm Shares Closing Date, or the Option Shares Closing Date, and (ii) completion of the distribution of the Shares, any offering material in connection with the offering and sale of the Shares other than the Base Prospectus, the Prospectus, the Registration Statement and other materials, if any, permitted by the Securities Act and consistent with Section 5(d) below.

          (g) At the earliest time after the filing of the Registration Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) of the Rules) of the Shares and (ii) at the date hereof, the Company was not and is not an “ineligible issuer,” as defined in Rule 405 of the Rules, including (but not limited to) the Company or any other subsidiary in the preceding three years not having been convicted of a felony or misdemeanor or having been made the subject of a judicial or administrative decree or order as described in Rule 405 of the Rules.

          (h) The Company and each of its subsidiaries (as defined in Rule 405 of the Rules) has been duly organized and is validly existing as corporations or other legal entities in good standing (or the foreign equivalent thereof) under the laws of their respective jurisdictions of organization. The Company and each of its subsidiaries is duly qualified to do business and is in good standing as foreign corporations or other legal entities in each jurisdiction in which their respective ownership or lease of property or the conduct of their respective businesses require such qualification and have all power and authority (corporate or other) necessary to own or hold their respective properties and to conduct the businesses in which each is engaged, except where the failure to so qualify or have such power or authority (i) would not have, singularly or in the aggregate, a material adverse effect on the condition (financial or otherwise), results of operations, assets, business or prospects of the Company and its subsidiaries taken as a whole, or (ii) impair in any material respect the ability of the Company to perform its obligations under this Agreement or to consummate any transactions contemplated by the Agreement, the General Disclosure Package or the Prospectus (any such effect as described in clauses (i) or (ii), a “Material Adverse Effect”). The Company owns or controls, directly or indirectly, only the following corporations, partnerships, limited liability partnerships, limited liability companies, associations or other entities: (i) ARIAD Corporation, a Delaware corporation; (ii) ARIAD Pharma, S.A., a Greece company; and (iii) ARIAD Pharma, Ltd., a United Kingdom company.

          (i) The Company has the full right, power and authority to enter into this Agreement, and to perform and to discharge its obligations hereunder; and this Agreement has been duly authorized, executed and delivered by the Company, and constitutes a valid and binding obligation of the Company enforceable in accordance with its terms, except as rights to indemnity and contribution hereunder may be limited by federal or state securities laws and except as such enforceability may be limited by applicable bankruptcy, insolvency, reorganization or similar laws affecting the rights of creditors generally and subject to general principles of equity.

          (j) The Shares to be issued and sold by the Company to the Underwriters hereunder have been duly and validly authorized and, when issued and delivered against payment therefor as provided herein, will be duly and validly issued, fully paid and non-

assessable and free of any preemptive or similar rights and will conform to the description thereof contained in the General Disclosure Package and the Prospectus.

          (k) The Company has an authorized capitalization as set forth in the Statutory Prospectus, and all of the issued shares of capital stock of the Company have been duly and validly authorized and issued, are fully paid and non-assessable, have been issued in compliance with federal and state securities laws, and conform to the description thereof contained in the General Disclosure Package and the Prospectus. As of September 30, 2010, there were 110,836,282 shares of Common Stock issued and outstanding, no shares of Preferred Stock, par value $0.001, of the Company issued and outstanding, 2,782,300 shares of Common Stock were subject to outstanding restricted stock units (“RSUs”) and 16,864,065 shares of Common Stock were issuable upon the exercise of all options, warrants and convertible securities outstanding as of such date. Since such date, the Company has not issued any securities, other than Common Stock of the Company issued pursuant to the exercise of stock options previously outstanding under the Company’s stock plans or, the issuance of RSUs or restricted Common Stock under the Company’s stock plans, the issuance of Common Stock pursuant to employee stock purchase plans, and the issuance of shares of Common Stock issuable upon exercise of such warrants to certain purchasers pursuant to the Subscription Agreements entered into in connection with the Company’s registered offering in February 2009. All of the Company’s options, warrants and other rights to purchase or exchange any securities for shares of the Company’s capital stock have been duly authorized and validly issued and were issued in compliance with federal and state securities laws. The exercise price of each option to purchase Common Stock is no less than the fair market value of a share of Common Stock as determined on the date of grant of such option. All grants of options to purchase Common Stock were validly issued and properly approved by the Board of Directors of the Company in material compliance with the terms of the plans under which such options were issued and were recorded on the Company’s financial statements in accordance with generally accepted accounting principles in the United States (“GAAP”), and no such grants involved any “back dating”, “forward dating,” “spring loading” or similar practices with respect to the effective date of grant. The Common Stock and the Shares conform in all material respects to all statements in relation thereto contained in the Registration Statement and the Statutory Prospectus and the Prospectus. None of the outstanding shares of Common Stock was issued in violation of any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase securities of the Company. There are no authorized or outstanding shares of capital stock, options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any capital stock of the Company or any of its subsidiaries other than those described above or accurately described in the General Disclosure Package. The description of the Company’s stock option, stock bonus and other stock plans or arrangements, and the options or other rights granted thereunder, as described in the General Disclosure Package and the Prospectus, accurately and fairly present the information required to be shown with respect to such plans, arrangements, options and rights. Except as described in the General Disclosure Package and the Prospectus, the Company has not sold or issued any shares of Common Stock during the six-month period preceding the date of the Prospectus, including any sales pursuant to Rule 144A under, or Regulations D or S of, the Securities Act other than shares of Common Stock issued pursuant to employee benefit plans, qualified stock options plans or other employee compensation plans or pursuant to outstanding options, rights or warrants.

          (l) All the outstanding shares of capital stock of each subsidiary of the Company have been duly authorized and validly issued, are fully paid and nonassessable and, except to the extent set forth in the General Disclosure Package or the Prospectus, are owned by the Company directly or indirectly through one or more wholly-owned subsidiaries, free and clear of any claim, lien, encumbrance, security interest, restriction upon voting or transfer or any other claim of any third party, except as set forth in the security agreements, dated March 12, 2003 by and between the Company and certain subsidiaries and RBS Citizens, NA (formerly Citizens Bank of Massachusetts).

          (m) The execution, delivery and performance of this Agreement by the Company, the issue and sale of the Shares by the Company and the consummation of the transactions contemplated hereby will not (with or without notice or lapse of time or both) conflict with or result in a breach or violation of any of the terms or provisions of, constitute a default or Debt Repayment Triggering Event (as defined below) under, give rise to any right of termination or other right or the cancellation or acceleration of any right or obligation or loss of a benefit under, or give rise to the creation or imposition of any lien, encumbrance, security interest, claim or charge upon any property or assets of the Company or any subsidiary pursuant to, any material indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or assets of the Company or any of its subsidiaries is subject, nor will such actions result in any violation of the provisions of the charter or by-laws (or analogous governing instruments, as applicable) of the Company or any of its subsidiaries or any law, statute, rule, regulation, judgment, order or decree of any court or governmental agency or body, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their properties or assets. A “Debt Repayment Triggering Event” means any event or condition that gives, or with the giving of notice or lapse of time would give the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its subsidiaries.

          (n) Except for the registration of the Shares under the Securities Act and such consents, approvals, authorizations, registrations or qualifications as may be required under the Exchange Act and applicable state or foreign securities laws, the Financial Industry Regulatory Authority (“FINRA”) and the Nasdaq Global Market (“Nasdaq GM”) in connection with the offering and sale of the Shares by the Company, no consent, approval, authorization or order of, or filing, qualification or registration with, any court or governmental agency or body, foreign or domestic, which has not been made, obtained or taken and is not in full force and effect, is required for the execution, delivery and performance of this Agreement by the Company, the offer or sale of the Shares or the consummation of the transactions contemplated hereby.

          (o) Deloitte & Touche LLP (the “Auditor”), who have audited certain financial statements and related schedules included or incorporated by reference in the Registration Statement, the General Disclosure Package and the Prospectus, and have audited the Company’s internal control over financial reporting, is an independent registered public accounting firm as required by the Securities Act and the Rules and Regulations and the Public Company Accounting Oversight Board (United States). Except as pre-approved in accordance with the requirements set forth in Section 10A of the Exchange Act, Deloitte & Touche LLP has

not been engaged by the Company to perform any “prohibited activities” (as defined in Section 10A of the Exchange Act).

          (p) The financial statements, together with the related notes and schedules, included or incorporated by reference in the General Disclosure Package, the Prospectus and in the Registration Statement fairly present in all material respects the financial position and the results of operations, changes in stockholders’ equity, and cash flows of the Company and its consolidated subsidiaries and other consolidated entities at the respective dates or for the respective periods therein specified. Such statements and related notes and schedules have been prepared in accordance with GAAP applied on a consistent basis throughout the periods involved except as may be set forth in the related notes included or incorporated by reference in the General Disclosure Package and except that unaudited financial statements may not contain footnotes as required by GAAP. The financial statements, together with the related notes and schedules, included or incorporated by reference in the General Disclosure Package and the Prospectus comply in all material respects with the Securities Act, the Exchange Act, and the Rules and Regulations and the rules and regulations under the Exchange Act. No other financial statements or supporting schedules or exhibits are required by the Securities Act or the Rules and Regulations to be described, or included or incorporated by reference in the Registration Statement, the General Disclosure Package or the Prospectus. There is no pro forma or as adjusted financial information which is required to be included in the Registration Statement, the General Disclosure Package, or the Prospectus or a document incorporated by reference therein in accordance with the Securities Act and the Rules and Regulations which has not been included or incorporated as so required. Except as described in the Statutory Prospectus and the Prospectus, there are no material off-balance sheet arrangements (as defined in Item 303 of Regulation S-K) that have or are reasonably likely to have a material current or future effect on the Company’s financial condition, revenues or expenses, changes in financial condition, results of operations, liquidity, capital expenditures or capital resources. To the Company’s knowledge, no person who has been suspended or barred from being associated with a registered public accounting firm, or who has failed to comply with any sanction pursuant to Rule 5300 promulgated by the PCAOB, has participated in or otherwise aided the preparation of, or audited, the financial statements, supporting schedules or other financial data filed with the Commission as a part of the Registration Statement and included in the Prospectus.

          (q) Neither the Company nor any of its subsidiaries has sustained, since the date of the latest audited financial statements included or incorporated by reference in the General Disclosure Package, any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the General Disclosure Package; and, since such date, there has not been any change in the capital stock (other than the issuance of Common Stock issued pursuant to the exercise of stock options under the Company’s stock plans, the issuance of RSUs and restricted Common Stock under the Company’s stock plans, the issuance of Common Stock pursuant to employee stock purchase plans and the issuance of shares of Common Stock issuable upon exercise of such warrants to certain purchasers pursuant to the Subscription Agreements entered into in connection with the Company’s registered offering in February 2009) or long-term debt of the Company or any of its subsidiaries, or any material adverse changes, or any development involving a prospective material adverse change, in or affecting the business, assets, general

affairs, management, financial position, prospects, stockholders’ equity or results of operations of the Company and its subsidiaries taken as a whole, otherwise than as set forth or contemplated in the General Disclosure Package. Since the date of the latest balance sheet included in the Registration Statement and the Prospectus, except as disclosed therein, neither the Company nor its subsidiaries has (A) entered into any material transaction not in the ordinary course of business or (B) declared or paid any dividend or made any distribution on any shares of its stock or redeemed, repurchased or otherwise acquired or agreed to redeem, repurchase or otherwise acquire any shares of its capital stock.

          (r) Except as set forth in the General Disclosure Package, there is no legal or governmental action, suit, claim or proceeding pending to which the Company or any of its subsidiaries is a party or of which any property or assets of the Company or any of its subsidiaries is the subject which is required to be described in the Registration Statement, the General Disclosure Package or the Prospectus or a document incorporated by reference therein and is not described therein, or which, singularly or in the aggregate, if determined adversely to the Company or any of its subsidiaries, could have a Material Adverse Effect or prevent the consummation of the transactions contemplated hereby; and to the best of the Company’s knowledge, no such proceedings are threatened or contemplated by governmental authorities or threatened by others.

          (s) Neither the Company nor any of its subsidiaries is in (i) violation of its charter or by-laws (or analogous governing instrument, as applicable), (ii) default in any respect, and no event has occurred which, with notice or lapse of time or both, would constitute such a default, in the due performance or observance of any term, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which it is a party or by which it is bound or to which any of its property or assets is subject or (iii) violation in any respect of any law, ordinance, governmental rule, regulation or court order, decree or judgment to which it or its property or assets may be subject except, in the case of clauses (ii) and (iii) of this paragraph (s), for any violations or defaults which, singularly or in the aggregate, would not have a Material Adverse Effect.

          (t) The studies, tests and preclinical and clinical trials conducted by or on behalf of or sponsored by the Company and its subsidiaries or in which the Company or its product candidates have participated that are described in the General Disclosure Package and Prospectus or the results of which are referred to in the General Disclosure Package or Prospectus were and, if still pending, are being conducted (and with respect to such clinical trials being conducted on behalf of the Company, are, to the Company’s knowledge, being conducted) in all material respects in accordance with medical and scientific research procedures that the Company reasonably believes are appropriate and in compliance with all applicable laws and authorizations, including, without limitation, the Federal Food, Drug and Cosmetic Act and the rules and regulations promulgated thereunder. The descriptions in the General Disclosure Package and Prospectus of the results of such clinical trials are accurate and fairly present the data derived from such clinical trials, and the Company has no knowledge of any studies or tests performed by or on behalf of the Company the results of which are materially inconsistent with or otherwise materially call into question the results described or referred to in the General Disclosure Package and Prospectus. Except to the extent disclosed in the General Disclosure Package and the Prospectus, the Company has not received any notices or other correspondence

from the United States Food and Drug Administration (“FDA”) or any other governmental agency requiring the termination, suspension or modification of any clinical trials that are described in the General Disclosure Package or Prospectus or the results of which are referred to in the General Disclosure Package or Prospectus.

          (u) The Company and each of its subsidiaries possesses all licenses, certificates, authorizations and permits issued by, and have made all declarations and filings with, the appropriate local, state, federal or foreign regulatory agencies or bodies which are necessary or desirable for the ownership of their respective properties or the conduct of their respective businesses as described in the General Disclosure Package and the Prospectus (collectively, the “Governmental Permits”) except where any failures to possess or make the same, singularly or in the aggregate, would not have a Material Adverse Effect. The Company and its subsidiaries are in compliance with all such Governmental Permits; all such Governmental Permits are valid and in full force and effect, except where the validity or failure to be in full force and effect would not, singularly or in the aggregate, have a Material Adverse Effect. All such Governmental Permits are free and clear of any restriction or condition that are in addition to, or materially different from, those normally applicable to similar licenses, certificates, authorizations and permits. Neither the Company nor any subsidiary has received notification of any revocation or modification (or proceedings related thereto) of any such Governmental Permit and the Company has no reason to believe that any such Governmental Permit will not be renewed.

          (v) Neither the Company nor any of its subsidiaries is or, after giving effect to the offering of the Shares and the application of the proceeds thereof as described in the General Disclosure Package and the Prospectus, will become an “investment company” within the meaning of the Investment Company Act of 1940, as amended, and the rules and regulations of the Commission thereunder.

          (w) Neither the Company, its subsidiaries nor any of the Company’s or its subsidiaries’ officers, directors or affiliates has taken or will take, directly or indirectly, any action designed or intended to stabilize or manipulate the price of any security of the Company, or which caused or resulted in, or which might in the future reasonably be expected to cause or result in, stabilization or manipulation of the price of any security of the Company or any other actions which would directly or indirectly violate Regulation M of the Exchange Act (“Regulation M”). The Company acknowledges that the Underwriters may engage in passive market making transactions in the Common Stock on the Nasdaq GM in accordance with Regulation M.

          (x) To the knowledge of the Company, the Company and its subsidiaries own or possess the right to use all material patents, trademarks, trademark registrations, service marks, service mark registrations, trade names, copyrights, licenses, inventions, software, databases, know-how, Internet domain names, trade secrets and other unpatented and/or unpatentable proprietary or confidential information, systems or procedures, and other material intellectual property necessary to carry on their respective businesses as currently conducted, and as proposed to be conducted and described in the General Disclosure Package and the Prospectus (collectively, “Intellectual Property”), and, except as described in the General Disclosure Package and the Prospectus, the Company is not aware of any claim to the contrary or any

challenge by any other person to the rights of the Company and its subsidiaries with respect to the foregoing except for those that would not reasonably be expected to have a Material Adverse Effect. The Intellectual Property licenses described in the General Disclosure Package and the Prospectus are valid, binding upon, and enforceable by or against the parties thereto in accordance to its terms. The Company and each of its subsidiaries has complied in all material respects with, and is not in breach nor has received any asserted or threatened claim of breach of, any Intellectual Property license, except for any such breach that would not, singularly or in the aggregate, have a Material Adverse Effect, and the Company has no knowledge of any breach or anticipated breach by any other person to any Intellectual Property license. To the knowledge of the Company, the Company’s and each of its subsidiary’s businesses as now conducted and as proposed to be conducted does not infringe or conflict with any valid patents, trademarks, service marks, trade names, copyrights, trade secrets, licenses or other intellectual property or franchise right of any person. The Company has received no claim alleging the infringement by the Company or any of its subsidiaries of any patent, trademark, service mark, trade name, copyright, trade secret, license in or other intellectual property right or franchise right of any person. The Company and each of its subsidiaries has taken all reasonable steps to protect, maintain and safeguard its rights in all Intellectual Property, including the execution of appropriate nondisclosure and confidentiality agreements. The consummation of the transactions contemplated by this Agreement will not result in the loss or impairment of or payment of any additional amounts with respect to, nor require the consent of any other person in respect of, the Company’s or any of its subsidiaries’ right to own, use, or hold for use any of the Intellectual Property as owned, used or held for use in the conduct of its business as currently conducted. The granted and issued Intellectual Property owned by the Company and its subsidiaries and, to the Company’s knowledge, the granted and issued Intellectual Property licensed to the Company and its subsidiaries, have not been adjudged by a court of competent jurisdiction invalid or unenforceable, in whole or in part, and except as otherwise disclosed in the General Disclosure Package and Prospectus, there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others challenging the validity or scope of any such Intellectual Property. To the knowledge of the Company, the Company and each subsidiary has at all times complied with all applicable laws relating to privacy, data protection, and the collection and use of personal information collected, used, or held for use by the Company or any subsidiary in the conduct of the Company’s or any subsidiary’s business. No claims have been asserted or, to the Company’s knowledge, threatened against the Company or any subsidiary alleging a violation of any person’s privacy or personal information or data rights and the consummation of the transactions contemplated hereby will not breach or otherwise cause any violation of any law related to privacy, data protection, or the collection and use of personal information collected, used, or held for use by the Company or any of its subsidiaries in the conduct of the Company’s or any of its subsidiaries’ businesses. The Company and each of its subsidiaries take reasonable measures to ensure that such information is protected against unauthorized access, use, modification, or other misuse. The Company is not a party to or bound by any options, licenses or agreements with respect to the Intellectual Property of any other person or entity that are required to be set forth in the General Disclosure Package and Prospectus and are not described therein.

          (y) The Company and each of its subsidiaries has good and marketable title in fee simple to, or have valid rights to lease or otherwise use, all items of real or personal property which are material to the business of the Company and its subsidiaries taken as a whole, in each

case free and clear of all liens, encumbrances, security interests, claims and defects that do not, singularly or in the aggregate, materially affect the value of such property and do not interfere with the use made and proposed to be made of such property by the Company or any of its subsidiaries; and all of the leases and subleases material to the business of the Company and its subsidiaries, considered as one enterprise, and under which the Company or any of its subsidiaries holds properties described in the General Disclosure Package and the Prospectus, are in full force and effect, and neither the Company nor any subsidiary has received any notice of any material claim of any sort that has been asserted by anyone adverse to the rights of the Company or any subsidiary under any of the leases or subleases mentioned above, or affecting or questioning the rights of the Company or such subsidiary to the continued possession of the leased or subleased premises under any such lease or sublease.

          (z) No labor disturbance by the employees of the Company or any of its subsidiaries exists or, to the best of the Company’s knowledge, is threatened, and the Company is not aware of any existing or imminent labor disturbance by the employees of any of its or its subsidiaries’ principal suppliers, manufacturers, customers or contractors, that could reasonably be expected, singularly or in the aggregate, to have a Material Adverse Effect. The Company is not aware that any key employee or significant group of employees of the Company or any subsidiary plans to terminate employment with the Company or any such subsidiary. The Company is not aware of any threatened or pending litigation between the Company or its subsidiaries and any of its executive officers which, if adversely determined, could have a Material Adverse Effect.

          (aa) No “prohibited transaction” (as defined in Section 406 of the Employee Retirement Income Security Act of 1974, as amended, including the regulations and published interpretations thereunder (“ERISA”), or Section 4975 of the Internal Revenue Code of 1986, as amended from time to time (the “Code”)) or “accumulated funding deficiency” (as defined in Section 302 of ERISA) or any of the events set forth in Section 4043(b) of ERISA (other than events with respect to which the thirty (30)-day notice requirement under Section 4043 of ERISA has been waived) has occurred or could reasonably be expected to occur with respect to any employee benefit plan of the Company or any of its subsidiaries which could, singularly or in the aggregate, have a Material Adverse Effect. Each employee benefit plan of the Company or any of its subsidiaries is in compliance in all material respects with applicable law, including ERISA and the Code. The Company and its subsidiaries have not incurred and could not reasonably be expected to incur liability under Title IV of ERISA with respect to the termination of, or withdrawal from, any pension plan (as defined in ERISA). Each pension plan for which the Company or any of its subsidiaries would have any liability that is intended to be qualified under Section 401(a) of the Code is so qualified, and nothing has occurred, whether by action or by failure to act, which could, singularly or in the aggregate, cause the loss of such qualification.

          (bb) The Company and its subsidiaries are in compliance with all foreign, federal, state and local rules, laws and regulations relating to the use, treatment, storage and disposal of hazardous or toxic substances or waste and protection of health and safety or the environment which are applicable to their businesses (“Environmental Laws”), except where the failure to comply would not, singularly or in the aggregate, have a Material Adverse Effect. There has been no storage, generation, transportation, handling, treatment, disposal, discharge, emission, or other release of any kind of toxic or other wastes or other hazardous substances by,

due to, or caused by the Company or any of its subsidiaries (or, to the Company’s knowledge, any other entity for whose acts or omissions the Company or any of its subsidiaries is or may otherwise be liable) upon any of the property now or previously owned or leased by the Company or any of its subsidiaries, or upon any other property, in violation of any law, statute, ordinance, rule, regulation, order, judgment, decree or permit or which would, under any law, statute, ordinance, rule (including rule of common law), regulation, order, judgment, decree or permit, give rise to any liability, except for any violation or liability which would not have, singularly or in the aggregate with all such violations and liabilities, a Material Adverse Effect; and there has been no disposal, discharge, emission or other release of any kind onto such property or into the environment surrounding such property of any toxic or other wastes or other hazardous substances with respect to which the Company has knowledge, except for any such disposal, discharge, emission, or other release of any kind which would not have, singularly or in the aggregate with all such discharges and other releases, a Material Adverse Effect. In the ordinary course of business, the Company and its subsidiaries conducts periodic reviews of the effect of Environmental Laws on their business and assets, in the course of which they identify and evaluate associated costs and liabilities (including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws or Governmental Permits issued thereunder, any related constraints on operating activities and any potential liabilities to third parties). On the basis of such reviews, the Company and its subsidiaries have reasonably concluded that such associated costs and liabilities would not have, singularly or in the aggregate, a Material Adverse Effect.

          (cc) The Company and its subsidiaries, each (i) has timely filed all necessary federal, state, local and foreign tax returns, and all such returns were true, complete and correct, (ii) has paid all federal, state, local and foreign taxes, assessments, governmental or other charges due and payable for which it is liable, including, without limitation, all sales and use taxes and all taxes which the Company or any of its subsidiaries is obligated to withhold from amounts owing to employees, creditors and third parties, and (iii) does not have any tax deficiency or claims outstanding or assessed or, to the best of its knowledge, proposed against any of them, except those, in each of the cases described in clauses (i), (ii) and (iii) of this paragraph (cc), that would not, singularly or in the aggregate, have a Material Adverse Effect. There are no tax audits or investigations pending, which if adversely determined would have a Material Adverse Effect. The Company and its subsidiaries, each has not engaged in any transaction which is a corporate tax shelter or which could be characterized as such by the Internal Revenue Service or any other taxing authority. The accruals and reserves on the books and records of the Company and its subsidiaries in respect of tax liabilities for any taxable period not yet finally determined are adequate to meet any assessments and related liabilities for any such period, and since December 31, 2009, the Company and its subsidiaries each has not incurred any liability for taxes other than in the ordinary course.

          (dd) The Company and each of its subsidiaries carries, or is covered by, insurance in such amounts and covering such risks as is adequate for the conduct of their respective businesses and the value of their respective properties and as is customary for companies engaged in similar businesses in similar industries. The Company has no reason to believe that it or any subsidiary will not be able (i) to renew its existing insurance coverage as and when such policies expire or (ii) to obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that

would not result in a Material Adverse Effect. Neither the Company nor any of its subsidiaries has been denied any insurance coverage that they have sought or for which they have applied.

          (ee) The Company and its subsidiaries each maintains a system of internal accounting and other controls sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain accountability for assets; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences. Except as described in the General Disclosure Package, since the end of the Company’s most recent audited fiscal year, there has been (A) no material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (B) no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting. The Company is not aware of (A) any significant deficiency in the design or operation of internal controls which could materially and adversely affect the Company’s ability to record, process, summarize and report financial data; or (B) any fraud, whether or not material, that involves management or other employees who have a role in the Company’s internal controls.

          (ff) The minute books of the Company and each of its subsidiaries that would be a “significant subsidiary” within the meaning of Rule 1-02(w) of Regulation S-X under the Exchange Act (such a significant subsidiary of the Company, a “Significant Subsidiary”) have been made available to the Underwriters and counsel for the Underwriters, and such books (i) contain a complete summary of all meetings and actions of the board of directors (including each board committee) and shareholders of the Company (or analogous governing bodies and interest holders, as applicable), and each of its Significant Subsidiaries since the time of its respective incorporation or organization through the date of the latest meeting and action, and (ii) accurately in all material respects reflect all transactions referred to in such minutes.

          (gg) There is no franchise, lease, contract, agreement or document required by the Securities Act or by the Rules and Regulations to be described in the General Disclosure Package and in the Prospectus or a document incorporated by reference therein or to be filed as an exhibit to the Registration Statement or a document incorporated by reference therein which is not described or filed therein as required; and all descriptions of any such franchises, leases, contracts, agreements or documents contained in the Registration Statement or in a document incorporated by reference therein are accurate and complete descriptions of such documents in all material respects. Other than as described in the General Disclosure Package and in the Prospectus, no such franchise, lease, contract or agreement has been suspended or terminated for convenience or default by the Company or any of its subsidiaries or any of the other parties thereto, and neither the Company nor any of its subsidiaries has received notice nor does the Company have any other knowledge of any such pending or threatened suspension or termination, except for such pending or threatened suspensions or terminations that would not reasonably be expected to, singularly or in the aggregate, have a Material Adverse Effect.

          (hh) No relationship or transaction, direct or indirect, exists between or among the Company and any of its subsidiaries on the one hand, and the directors, officers, stockholders

(or analogous interest holders), customers or suppliers of the Company or any of its subsidiaries or any of their affiliates on the other hand, which is required to be described in the General Disclosure Package and the Prospectus or a document incorporated by reference therein and which is not so described.

          (ii) No person or entity has the right to require registration of shares of Common Stock or other securities of the Company or any of its subsidiaries because of the filing or effectiveness of the Registration Statement or otherwise, except for persons and entities who have expressly waived such right in writing or who have been given timely and proper written notice and have failed to exercise such right within the time or times required under the terms and conditions of such right. Except as described in the General Disclosure Package, there are no persons with registration rights or similar rights to have any securities registered or to include such securities with the shares of Common Stock registered by the Company or any of its subsidiaries under the Securities Act. Each director and executive officer of the Company listed on Schedule II has delivered to the Representatives his or her executed written lock-up agreement in the form attached to this Agreement as Exhibit B hereto (“Lock-Up Agreement”).

          (jj) Neither the Company nor any of its subsidiaries owns any “margin securities” as that term is defined in Regulation U of the Board of Governors of the Federal Reserve System (the “Federal Reserve Board”), and none of the proceeds of the sale of the Shares will be used, directly or indirectly, for the purpose of purchasing or carrying any margin security, for the purpose of reducing or retiring any indebtedness which was originally incurred to purchase or carry any margin security or for any other purpose which might cause any of the Shares to be considered a “purpose credit” within the meanings of Regulation T, U or X of the Federal Reserve Board.

          (kk) Neither the Company nor any of its subsidiaries is a party to any contract, agreement or understanding with any person (other than this Agreement) 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 or any transaction contemplated by this Agreement, the Registration Statement, the General Disclosure Package or the Prospectus.

          (ll) No forward-looking statement (within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act) contained in either the General Disclosure Package or the Prospectus has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith.

          (mm) The Company is subject to and in compliance in all material respects with the reporting requirements of Section 13 or Section 15(d) of the Exchange Act. The Common Stock is registered pursuant to Section 12(b) of the Exchange Act and is listed on the Nasdaq GM, and the Company has taken no action designed to, or reasonably likely to have the effect of, terminating the registration of the Common Stock under the Exchange Act or delisting the Common Stock from the Nasdaq GM, nor has the Company received any notification that the Commission or the Nasdaq Stock Market LLC (“Nasdaq”) is contemplating terminating such registration or listing. No consent, approval, authorization or order of, or filing, notification or registration with, the Nasdaq GM is required for the listing and trading of the shares of Common

Stock on the Nasdaq GM, except for (i) a Notification Form: Listing of Additional Shares and (ii) a Notification Form: Change in the Number of Shares Outstanding.

          (nn) The Company and its directors and officers, in their capacities as such are in compliance in all material respects with all applicable provisions of the Sarbanes-Oxley Act of 2002 and all applicable rules and regulations promulgated thereunder or implementing the provisions thereof.

          (oo) The Company is in compliance in all material respects with all applicable corporate governance requirements set forth in the Nasdaq Marketplace Rules.

          (pp) Neither the Company nor any of its subsidiaries nor any employee or agent of the Company or any subsidiary, has made any contribution or other payment to any official of, or candidate for, any federal, state, local or foreign office in violation of any law or of the character required to be disclosed in the Registration Statement, the General Disclosure Package or the Prospectus or a document incorporated by reference therein. Neither the Company nor any of its subsidiaries nor, to the Company’s knowledge, any director, officer, agent, employee, affiliate or other person acting on behalf of the Company or any of its subsidiaries is aware of or has taken any action, directly or indirectly, that has resulted or would result in a violation of the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder (the “FCPA”), including, without limitation, making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any “foreign official” (as such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA; and the Company and its subsidiaries and, to the Company’s knowledge, the Company’s affiliates have conducted their respective businesses in compliance with the FCPA and have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith.

          (qq) There are no transactions, arrangements or other relationships between and/or among the Company, any of its affiliates (as such term is defined in Rule 405 of the Securities Act) and any unconsolidated entity, including, but not limited to, any structured finance, special purpose or limited purpose entity that could reasonably be expected to materially affect the Company’s or any of its subsidiaries’ liquidity or the availability of or requirements for their capital resources required to be described in the General Disclosure Package and the Prospectus or a document incorporated by reference therein which have not been described as required.

          (rr) The statistical 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 believes to be reliable and accurate, and such data agree with the sources from which they are derived.

          (ss) The operations of the Company and its subsidiaries are and have been conducted at all times in compliance in all material respects with applicable financial

recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, and any other applicable money laundering statutes and applicable rules and regulations thereunder (collectively, the “Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending, or to the best knowledge of the Company, threatened.

          (tt) Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its subsidiaries 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.

          (uu) Neither the Company nor any subsidiary nor any of their affiliates (within the meaning of FINRA Conduct Rule 2720(b)(1)(a)) directly or indirectly controls, are controlled by, or is under common control with, or is an associated person (within the meaning of Article I, Section 1(ee) of the By-laws of FINRA) of, any member firm of FINRA.

          (vv) The Company satisfies the pre-1992 eligibility requirements for the use of a registration statement on Form S-3 in connection with the Offering contemplated thereby (the pre-1992 eligibility requirements for the use of the registration statement on Form S-3 include (i) having a non-affiliate, public common equity float of at least $150 million or a non-affiliate, public common equity float of at least $100 million and annual trading volume of at least three million shares and (ii) having been subject to the Exchange Act reporting requirements for a period of 36 months).

          (ww) No approval of the shareholders of the Company under the rules and regulations of Nasdaq is required for the Company to issue and deliver to the Underwriters the Shares.

          (xx) The Company has established and maintains disclosure controls and procedures (as such term is defined in Rule 13a-15 under the Exchange Act), which: (i) are designed to ensure that material information relating to the Company is made known to the Company’s principal executive officer and its principal financial officer by others within the Company, particularly during the periods in which the periodic reports required under the Exchange Act are required to be prepared; (ii) provide for the periodic evaluation of the effectiveness of such disclosure controls and procedures at the end of the periods in which the periodic reports are required to be prepared; and (iii) are effective in all material respects to perform the functions for which they were established.

          (yy) The documents incorporated or deemed to be incorporated by reference in the Prospectus, at the time they were or hereafter are filed with the Commission, complied and will comply in all material respects with the requirements of the Exchange Act, and, when read together with the other information in the Prospectus, at the time the Registration Statement and

any amendments thereto become effective and at the Firm Shares Closing Date and the applicable Option Shares Closing Date, as the case may be, will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading.

          (zz) Since the adoption of Section 13(k) of the Exchange Act, neither the Company nor any of its subsidiaries has extended or maintained credit, arranged for the extension of credit, or renewed any extension of credit, in the form of a personal loan, to or for any director or executive officer (or equivalent thereof) of the Company and/or such subsidiary except for such extensions of credit as are expressly permitted by Section 13(k) of the Exchange Act.

          (aaa) The Company has not been advised, and has no reason to believe, that it and each of its subsidiaries are not conducting business in compliance with all applicable laws, rules and regulations of the jurisdictions in which it is conducting business, except where failure to be so in compliance would not result in a Material Adverse Effect. The Company has not received any FDA Form 483, notice of adverse finding, warning letter, untitled letter or other correspondence or notice from the FDA or any other governmental authority alleging or asserting noncompliance with any laws applicable to the Company.

     Any certificate contemplated hereby and signed by any officer of the Company or any of its subsidiaries and delivered to the Representatives or to counsel for the Underwriters shall be deemed a representation and warranty by the Company to each Underwriter as to the matters covered thereby.

     The Company acknowledges that the Underwriters and, for purposes of the opinions to be delivered pursuant to Section 4 hereof, counsel to the Company and counsel to the Underwriters, will rely upon the accuracy and truthfulness of the foregoing representations and hereby consents to such reliance.

     3. [RESERVED]

     4. Conditions of the Underwriters’ Obligations. The obligations of the Underwriters under this Agreement are several and not joint. The respective obligations of the Underwriters to purchase the Shares are subject to each of the following terms and conditions:

          (a) Notification that the Registration Statement has become effective shall have been received by the Representatives and the Prospectus shall have been timely filed with the Commission in accordance with Section 5(a) of this Agreement and any material required to be filed by the Company pursuant to Rule 433(d) of the Rules shall have been timely filed with the Commission in accordance with such Rule.

          (b) No order preventing or suspending the use of the Base Prospectus, the Prospectus or any “free writing prospectus” (as defined in Rule 405 of the Rules), shall have been or shall be in effect and no order suspending the effectiveness of the Registration Statement shall be in effect and no proceedings for such purpose shall be pending before or threatened by

the Commission, and any requests for additional information on the part of the Commission (to be included in the Registration Statement or the Prospectus or otherwise) shall have been complied with to the satisfaction of the Commission and the Representatives. If the Company has elected to rely upon Rule 430B, information previously omitted from the effective Registration Statement pursuant to Rule 430B shall have been transmitted to the Commission for filing pursuant to Rule 424(b) within the prescribed time period and the Company shall have provided evidence satisfactory to the Representatives of such timely filing, or a post-effective amendment providing such information shall have been promptly filed and declared effective in accordance with the requirements of Rule 430B.

          (c) The representations and warranties of the Company contained in this Agreement and in the certificates delivered pursuant to Section 4(d) shall be true and correct when made and in all material respects on and as of each Closing Date as if made on such date; provided, however, that such materiality qualifier shall not be applicable to any representation or warranty that is already qualified or modified by materiality or Material Adverse Effect in the text thereof. The Company shall have performed all covenants and agreements in all material respects and satisfied all the conditions contained in this Agreement required to be performed or satisfied by them at or before such Closing Date.

          (d) The Representatives shall have received on each Closing Date a certificate, addressed to the Representatives and dated such Closing Date, of the chief executive or chief operating officer and the chief financial officer or chief accounting officer of the Company to the effect that: (i) the representations, warranties and agreements of the Company in this Agreement were true and correct when made and are true and correct in all material respects as of such Closing Date; provided, however, that such materiality qualifier shall not be applicable to any representation or warranty that is already qualified or modified by materiality or Material Adverse Effect in the text thereof; (ii) the Company has performed all of its covenants and agreements in all material respects and satisfied all conditions contained herein required to be performed or satisfied by the Company; (iii) they have carefully examined the Registration Statement, the Prospectus, the General Disclosure Package, and any individual Issuer Free Writing Prospectus and, in their opinion (A) as of the Effective Date the Registration Statement and Prospectus did not include, and as of the Applicable Time, neither (i) the General Disclosure Package, nor (ii) any individual Issuer Free Writing Prospectus, when considered together with the General Disclosure Package, included, any untrue statement of a material fact and as of the times described above such documents did not omit to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, and (B) since the Effective Date no event has occurred which should have been set forth in a supplement or otherwise required an amendment to the Registration Statement, the Statutory Prospectus or the Prospectus; and (iv) no stop order suspending the effectiveness of the Registration Statement has been issued and, to their knowledge, no proceedings for that purpose have been instituted or are pending under the Securities Act.

          (e) The Representatives shall have received: (i) simultaneously with the execution of this Agreement a signed letter from the Auditor addressed to the Representatives and dated the date of this Agreement, in form and substance reasonably satisfactory to the Representatives, containing statements and information of the type ordinarily included in

accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement and the General Disclosure Package, and (ii) on each Closing Date, a signed letter from the Auditor addressed to the Representatives and dated the date of such Closing Date(s), in form and substance reasonably satisfactory to the Representatives containing statements and information of the type ordinarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement and the Prospectus. To the extent those sections of the comfort letter relating to the quarter ended September 30, 2010 do not cover the entire quarter, the Representatives shall have received a certificate, addressed to the Representatives and dated as of the date of each delivery of a comfort letter, of the chief financial officer of the Company, that covers those portions of the quarter ended September 30, 2010 that are not covered by the applicable comfort letter.

          (f) The Representatives shall have received on each Closing Date from Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., counsel for the Company, (i) an opinion, addressed to the Representatives and dated such Closing Date, stating in effect the matters set forth on Exhibit C-1 hereto, and (ii) a negative assurance letter, addressed to the Representatives and dated such Closing Date, stating in effect the matters set forth on Exhibit C-2 hereto.

          (g) The Representatives shall have received on each Closing Date from David L Berstein, Esq., Senior Vice President and Chief Intellectual Property Officer of the Company, an opinion, addressed to the Representatives and dated such Closing Date, stating in effect the matters set forth on Exhibit D hereto.

          (h) The Representatives shall have received from Latham & Watkins LLP, a favorable opinion, addressed to the Representatives and dated such Closing Date, covering such matters as are customarily covered in transactions of this type, and the Company shall have furnished to Latham & Watkins LLP such documents as they may reasonably request for the purpose of enabling them to pass upon such matters.

          (i) All proceedings taken in connection with the sale of the Firm Shares and the Option Shares as herein contemplated shall be reasonably satisfactory in form and substance to the Representatives and their counsel.

          (j) The Representatives shall have received copies of the Lock-up Agreements executed by each entity or person listed on Schedule II hereto.

          (k) The Shares shall have been approved for listing on The Nasdaq GM, subject only to official notice of issuance.

          (l) The Representatives shall be reasonably satisfied that since the respective dates as of which information is given in the Registration Statement, the Statutory Prospectus, the General Disclosure Package and the Prospectus, (i) there shall not have been any material change in the capital stock of the Company (other than as a result of the exercise of outstanding stock options or other equity-based rights described in the Registration Statement, the Statutory Prospectus, the General Disclosure Package and the Prospectus) or any material change in the indebtedness (other than in the ordinary course of business) of the Company, (ii) except as set

forth or contemplated by the Registration Statement, the Statutory Prospectus, the General Disclosure Package or the Prospectus, no material oral or written agreement or other transaction shall have been entered into by the Company that is not in the ordinary course of business or that could reasonably be expected to result in a material reduction in the future earnings of the Company, (iii) no loss or damage (whether or not insured) to the property of the Company shall have been sustained that had or could reasonably be expected to have a Material Adverse Effect, (iv) no legal or governmental action, suit or proceeding affecting the Company or any of its properties that is material to the Company or that affects or could reasonably be expected to affect the transactions contemplated by this Agreement shall have been instituted or threatened and (v) there shall not have been any material change in the assets, properties, condition (financial or otherwise), or in the results of operations, business affairs or business prospects of the Company or its subsidiaries considered as a whole that makes it impractical or inadvisable in the Representatives’ judgment to proceed with the purchase or offering of the Shares as contemplated hereby.

          (m) The Company shall have furnished or caused to be furnished to the Representatives such further certificates or documents as the Representatives shall have reasonably requested.

     5. Covenants and other Agreements of the Company and the Underwriters.

          (a) The Company covenants and agrees as follows:

     (i) The Company will use its best efforts to cause the Registration Statement, if not effective at the time of execution of this Agreement, and any amendments thereto, to become effective as promptly as possible. The Company shall prepare the Prospectus in a form approved by the Representatives and file such Prospectus pursuant to Rule 424(b) under the Securities Act not later than the Commission’s close of business on the second business day following the execution and delivery of this Agreement, or, if applicable, such earlier time as may be required by the Rules. The Company will file with the Commission all Issuer Free Writing Prospectuses in the time and manner required under Rule 433(d).

     (ii) The Company shall promptly advise the Representatives in writing (A) when any post-effective amendment to the Registration Statement shall have become effective or any supplement to the Prospectus shall have been filed, (B) of any request by the Commission for any amendment of the Registration Statement or the Prospectus or for any additional information, (C) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any order preventing or suspending the use of the Base Prospectus or any “free writing prospectus”, as defined in Rule 405 of the Rules, or the institution or threatening of any proceeding for that purpose and (D) of the receipt by the Company of any notification with respect to the suspension of the qualification of the Shares for sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose. The Company shall not file any amendment of the Registration Statement or supplement to the Prospectus or any

document incorporated by reference in the Registration Statement or any Issuer Free Writing Prospectus unless the Company has furnished the Representatives a copy for their review prior to filing and shall not file any such proposed amendment or supplement to which the Representatives reasonably object. The Company shall use its best efforts to prevent the issuance of any such stop order and, if issued, to obtain as soon as possible the withdrawal thereof.

     (iii) If, at any time when a prospectus relating to the Shares (or, in lieu thereof, the notice referred to in Rule 173(a) of the Rules) is required to be delivered under the Securities Act and the Rules, any event occurs as a result of which the Prospectus as then amended or supplemented includes any untrue statement of a material fact or omits to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made not misleading, or if it shall be necessary to amend or supplement the Prospectus to comply with the Securities Act or the Rules, the Company promptly shall prepare and file with the Commission, subject to the second sentence of paragraph (ii) of this Section 5(a), an amendment or supplement which shall correct such statement or omission or an amendment which shall effect such compliance.

     (iv) If at any time following issuance of an Issuer Free Writing Prospectus there occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicts with the information contained in the Registration Statement or includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances prevailing at the subsequent time, not misleading, the Company will promptly notify the Representatives and will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

     (v) The Company shall make generally available (through EDGAR or otherwise) to its security holders and to the Representatives as soon as practicable, but not later than 45 days after the end of the 12 month period beginning at the end of the fiscal quarter of the Company during which the most recent Effective Date occurs (or 90 days if such 12 month period coincides with the Company’s fiscal year), an earning statement (which need not be audited) of the Company, covering such 12 month period, which shall satisfy the provisions of Section 11(a) of the Securities Act and Rule 158 of the Rules.

     (vi) Upon written request, the Company shall furnish to the Representatives and counsel for the Underwriters, without charge, signed copies of the Registration Statement (including all exhibits thereto and amendments thereof) and to each other Underwriter, without charge, a copy of the Registration Statement (without exhibits thereto) and all amendments thereof and, so long as delivery of a prospectus by an Underwriter or dealer may be required by the Securities Act or the Rules, as many copies of any the Base Prospectus, any Issuer

Free Writing Prospectus and the Prospectus and any amendments thereof and supplements thereto as the Representatives may reasonably request. If applicable, the copies of the Registration Statement, the Base Prospectus, any Issuer Free Writing Prospectus and Prospectus and each amendment and supplement thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

     (vii) The Company shall cooperate with the Representatives and counsel for the Underwriters in endeavoring to qualify the Shares for offer and sale in connection with the offering under the laws of such jurisdictions in the U.S. as the Representatives may designate and shall maintain such qualifications in effect so long as required for the distribution of the Shares; provided, however, that the Company shall not be required in connection therewith, as a condition thereof, to qualify as a foreign corporation or to execute a general consent to service of process in any jurisdiction or subject itself to taxation as doing business in any jurisdiction.

     (viii) The Company, during the period when the Prospectus (or in lieu thereof, the notice referred to in Rule 173(a) of the Rules) is required to be delivered under the Securities Act and the Rules or the Exchange Act, will file all reports and other documents required to be filed with the Commission pursuant to Section 13, 14 or 15 of the Exchange Act within the time periods required by the Exchange Act and the regulations promulgated thereunder.

     (ix) Without the prior written consent of the Representatives, for a period of 90 days after the date of this Agreement, the Company shall not issue, sell or register with the Commission (other than on Form S-8 or on any successor form), or otherwise dispose of, directly or indirectly, any equity securities of the Company (or any securities convertible into, exercisable for or exchangeable for equity securities of the Company), except for the issuance of the Shares pursuant to the Registration Statement and the issuance of shares pursuant to the Company’s existing stock option plan or bonus plan or upon exercise of warrants outstanding as of the date hereof as described in the Registration Statement and the Prospectus. In the event that during this period, (A) any shares are issued pursuant to the Company’s existing equity incentive plans or bonus plans that are exercisable during such 90-day period or (B) any registration is effected on Form S-8 or on any successor form relating to shares that are exercisable during such 90-day period, the Company shall obtain the written agreement of such grantee or purchaser or holder of such registered securities that, for a period of 90 days after the date of this Agreement, such person will not, without the prior written consent of the Representatives, offer for sale, sell, distribute, grant any option for the sale of, or otherwise dispose of, directly or indirectly, or exercise any registration rights with respect to, any shares of Common Stock (or any securities convertible into, exercisable for, or exchangeable for any shares of Common Stock) owned by such person; provided, however, that the obligation of the Company to obtain such an agreement shall only apply if such grantee or purchaser or holder of such

registered securities is an officer or director of the Company, listed on Schedule II hereto. Notwithstanding the foregoing, (i) the Company represents and warrants that each such grantee or purchaser or holder of such registered securities listed on Schedule II hereto shall be subject to similar lockup restrictions as set forth on Exhibit B attached hereto and the Company shall enforce such rights and impose stop-transfer restrictions on any such sale or other transfer or disposition of such shares until the end of the applicable period and (ii) if (x) during the last 17 days of the 90-day period described in this Section 5(a)(ix) the Company issues an earnings release or material news or a material event relating to the Company occurs; or (y) prior to the expiration of such 90-day period, the Company announces that it will release earnings results during the 16 day period beginning on the last day of the 90-day period; the restrictions imposed by this Section 5(a)(ix) shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event; provided, however, that this sentence shall not apply if the research published or distributed on the Company is compliant under Rule 139 of the Securities Act and the Company’s securities are actively traded as defined in Rule 101(c)(1) of Regulation M.

     (x) On or before completion of this offering, the Company shall make all filings required under applicable securities laws and by The Nasdaq GM (including any required registration under the Exchange Act) provided, however, the Company shall make all filings required by Nasdaq that may be filed after the completion of the offering of the Shares within the period required by Nasdaq. The Company shall engage and maintain, at its expense, a registrar and transfer agent for the Shares. The Company will use its best efforts to list, subject to notice of issuance, the Shares on The Nasdaq GM and to maintain the listing of the Shares on The Nasdaq GM.

     (xi) Prior to the Closing Date, the Company will issue no press release or other communications directly or indirectly and hold no press conference with respect to the Company, the condition, financial or otherwise, or the earnings, business affairs of any of them, or the offering of the Shares without the prior written consent of the Representatives unless in the judgment of the Company and its counsel, and after notification to the Representatives, such press release or communication is required by law.

     (xii) The Company will apply the net proceeds from the offering of the Shares in the manner set forth under “Use of Proceeds” in the Prospectus.

     (xiii) If, immediately prior to the third anniversary of the initial effective date of the Registration Statement, any of the Shares remain unsold by the Underwriters, the Company will, upon written notice from the Underwriters at least 30 days prior to that third anniversary file, if it has not already done so, a new shelf registration statement relating to the Shares, in a form satisfactory to the Representatives, will use its best efforts to cause such registration statement to be declared effective within 180 days after that third anniversary, and will take all

other action necessary or appropriate to permit the public offering and sale of the Shares to continue as contemplated in the expired Registration Statement. References herein to the “Registration Statement” shall include such new shelf registration statement with respect to the Shares that remain unsold.

     (xiv) The Company shall cause to be prepared and delivered, at its expense, within one business day from the effective date of this Agreement, to Jefferies an “electronic Prospectus” to be used by the Underwriters in connection with the offering and sale of the Shares. As used herein, the term “electronic Prospectus” means a form of Prospectus, and any amendment or supplement thereto, that meets each of the following conditions: (i) it shall be encoded in an electronic format, satisfactory to Jefferies, that may be transmitted electronically by Jefferies and the other Underwriters to offerees and purchasers of the Shares; (ii) it shall disclose the same information as the paper Prospectus, except to the extent that graphic and image material cannot be disseminated electronically, in which case such graphic and image material shall be replaced in the electronic Prospectus with a fair and accurate narrative description or tabular representation of such material, as appropriate; and (iii) it shall be in or convertible into a paper format or an electronic format, satisfactory to Jefferies, that will allow investors to store and have continuously ready access to the Prospectus at any future time, without charge to investors (other than any fee charged for subscription to the Internet as a whole and for on-line time). The Company hereby confirms that it has included or will include in the Prospectus filed pursuant to EDGAR or otherwise with the Commission and in the Registration Statement at the time it was declared effective an undertaking that, upon receipt of a request by an investor or his or her representative, the Company shall transmit or cause to be transmitted promptly, without charge, a paper copy of the Prospectus.

     (xv) The Company shall not invest, or otherwise use the proceeds received by the Company from its sale of the Shares in such a manner as would require the Company or any of its subsidiaries to register as an investment company under the Investment Company Act.

     (xvi) The Company will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of the Shares or any other reference security, whether to facilitate the sale or resale of the Shares or otherwise, and the Company will, and shall cause each of its affiliates to, comply with all applicable provisions of Regulation M. If the limitations of Rule 102 of Regulation M (“Rule 102”) do not apply with respect to the Shares or any other reference security pursuant to any exception set forth in Section (d) of Rule 102, then promptly upon notice from the Representatives (or, if later, at the time stated in the notice), the Company will, and shall cause each of its affiliates to, comply with Rule 102 as though such exception were not available but the other provisions of Rule 102 (as interpreted by the Commission) did apply.

     (xvii) During the period the Lock-up Agreements are in effect, the Company will enforce all existing agreements between the Company and any of its security holders that prohibit the sale, transfer, assignment, pledge or hypothecation of any of the Company’s securities. In addition, the Company will direct the transfer agent to place stop transfer restrictions upon any such securities of the Company that are bound by such existing “lock-up” agreements for the duration of the periods contemplated in such agreements, including, without limitation, the Lock-up Agreements entered into by the Company’s officers and directors pursuant to Section 4(j).

          (b) The Company agrees to pay, or reimburse if paid by the Representatives, whether or not the transactions contemplated hereby are consummated or this Agreement is terminated, all costs and expenses incident to the public offering of the Shares and the performance of the obligations of the Company under this Agreement including those relating to: (i) the preparation, printing, reproduction, filing and distribution of the Registration Statement including all exhibits thereto, the Base Prospectus, the Prospectus, any Issuer Free Writing Prospectus, all amendments and supplements thereto and any document incorporated by reference therein, and the printing, filing and distribution of this Agreement; (ii) the preparation and delivery of certificates for the Shares to the Underwriters; (iii) the registration or qualification of the Shares for offer and sale under the securities or Blue Sky laws of the various jurisdictions referred to in Section 5(a)(vii), including the reasonable fees and disbursements of counsel for the Underwriters in connection with such registration and qualification and the preparation, printing, distribution and shipment of preliminary and supplementary Blue Sky memoranda; (iv) the furnishing (including costs of shipping and mailing) to the Underwriters of copies of the Base Prospectus, the Prospectus and all amendments or supplements to the Prospectus, any Issuer Free Writing Prospectus, and of the several documents required by this Section 5(b) to be so furnished, as may be reasonably requested for use in connection with the offering and sale of the Shares by the Underwriters or by dealers to whom Shares may be sold; (v) any filing fees of FINRA in connection with its review of the terms of the public offering and reasonable fees and disbursements of counsel for the Underwriters in connection with such review; (vi) inclusion of the Shares for listing on The Nasdaq GM; (vii) all transfer taxes, if any, with respect to the sale and delivery of the Shares by the Company to the Underwriters; and (viii) all filing fees, attorneys’ fees and expenses incurred by the Company or the Underwriters in connection with qualifying or registering (or obtaining exemptions from the qualification or registration of) all or any part of the Shares for offer and sale under the provincial securities laws of Canada, and, if requested by the Representatives, preparing and printing a “Canadian wrapper”, and any supplements thereto and advising the Underwriters of such qualifications, registrations, determinations and exemptions, provided such fees and expenses related to distribution in Canada do not exceed $7,000 in the aggregate. Subject to the provisions of Section 8, the Underwriters agree to pay, whether or not the transactions contemplated hereby are consummated or this Agreement is terminated, all costs and expenses incident to the performance of the obligations of the Underwriters under this Agreement not payable by the Company pursuant to the preceding sentence, including, without limitation, the fees and disbursements of counsel for the Underwriters (other than as contemplated in (iii) and (viii) above).

          (c) The Company acknowledges and agrees that the Underwriters have acted and are acting solely in the capacity of a principal in an arm’s length transaction between the Company, on the one hand, and the Underwriters, on the other hand, with respect to the offering of Shares contemplated hereby (including in connection with determining the terms of the offering) and not as a financial advisor, agent or fiduciary to the Company or any other person. Additionally, the Company acknowledges and agrees that the Underwriters have not and will not advise the Company or any other person as to any legal, tax, investment, accounting or regulatory matters in any jurisdiction. The Company has consulted with its own advisors concerning such matters and shall be responsible for making its own independent investigation and appraisal of the transactions contemplated hereby, and the Underwriters shall have no responsibility or liability to the Company or any other person with respect thereto, whether arising prior to or after the date hereof. Any review by the Underwriters of the Company, the transactions contemplated hereby or other matters relating to such transactions have been and will be performed solely for the benefit of the Underwriters and shall not be on behalf of the Company. The Company agrees that it will not claim that the Underwriters, or any one of them, has rendered advisory services of any nature or respect, or owes a fiduciary duty to the Company or any other person in connection with any such transaction or the process leading thereto.

          (d) The Company represents and agrees that, unless it obtains the prior consent of the Representatives, and each of the Underwriters represents and agrees that, unless it obtains the prior consent of the Company and the Representatives, it has not made and will not make any offer relating to the Shares that would constitute an “issuer free writing prospectus,” as defined in Rule 433, or that would otherwise constitute a “free writing prospectus,” as defined in Rule 405, required to be filed with the Commission. The Company has complied and will comply with the requirements of Rule 433 under the Securities Act applicable to any Issuer Free Writing Prospectus, including timely filing with the Commission where required, legending and record keeping. The Company represents that is has satisfied and agrees that it will satisfy the conditions set forth in Rule 433 of the Rules to avoid a requirement to file with the Commission any Road Show.

     6. Indemnification.

          (a) The Company agrees to indemnify and hold harmless each Underwriter, its officers and employees, and each person, if any, who controls any Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act against any and all losses, claims, damages and liabilities, joint or several (including any reasonable investigation, legal and other expenses incurred in connection with, and any amount paid in settlement of, any action, suit or proceeding or any claim asserted), to which they, or any of them, may become subject under the Securities Act, the Exchange Act or other Federal or state law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the Base Prospectus, the Registration Statement, the Statutory Prospectus (considered together with the Pricing Information), the Prospectus, any Issuer Free Writing Prospectus or any “issuer-information” filed or required to be filed pursuant to Rule 433(d) of the Rules, any amendment thereof or supplement thereto, or in any Blue Sky application or other information or other documents executed by the Company filed in any state or other jurisdiction to qualify any or all of the Shares under the securities laws thereof (any such

application, document or information being hereinafter referred to as a “Blue Sky Application”) or arise out of or are based upon any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading; provided, however, that such indemnity shall not inure to the benefit of any Underwriter (or any person controlling such Underwriter) on account of any losses, claims, damages or liabilities arising from the sale of the Shares to any person by such Underwriter if such untrue statement or omission or alleged untrue statement or omission was made in the Base Prospectus, the Registration Statement, the Prospectus, the Statutory Prospectus (considered together with the Pricing Information), any Issuer Free Writing Prospectus or any “issuer-information” filed or required to be filed pursuant to Rule 433(d) of the Rules or such amendment or supplement thereto, or in any Blue Sky Application in reliance upon and in conformity with the Underwriter Information. This indemnity agreement will be in addition to any liability which the Company may otherwise have.

          (b) Each Underwriter agrees to indemnify and hold harmless the Company, its officers and employees, and each person, if any, who controls the Company within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, each director of the Company, and each officer of the Company who signs the Registration Statement, against any losses, claims, damages or liabilities (including any reasonable investigation, legal and other expenses incurred in connection with, and any amount paid in settlement of, any action, suit or proceeding or any claim asserted) to which such party may become subject, under the Securities Act, the Exchange Act or other Federal or state law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in the Base Prospectus, the Registration Statement, the Statutory Prospectus (considered together with the Pricing Information) or the Prospectus, or any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in the Base Prospectus, the Registration Statement, the Statutory Prospectus (considered together with the Pricing Information) or the Prospectus or any such amendment or supplement in reliance upon and in conformity with the Underwriter Information; provided, however, that the obligation of each Underwriter to indemnify the Company (including any controlling person, director or officer thereof) shall be limited to the net proceeds received by the Company from such Underwriter.

          (c) Any party that proposes to assert the right to be indemnified under this Section 6 will, promptly after receipt of notice of commencement of any action, suit or proceeding against such party in respect of which a claim is to be made against an indemnifying party or parties under this Section 6, notify each such indemnifying party of the commencement of such action, suit or proceeding, enclosing a copy of all papers served. No indemnification provided for in Section 6(a) or 6(b) shall be available to any party who shall fail to give notice as provided in this Section 6(c) if the party to whom notice was not given was unaware of the action, suit or proceeding to which such notice would have related and was prejudiced in a material manner by the failure to give such notice but the omission so to notify such indemnifying party of any such action, suit or proceeding shall not relieve it from any liability that it may have to any indemnified party for contribution or otherwise than under this Section 6.

In case any such action, suit or 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 in, and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel reasonably satisfactory to such indemnified party, and after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof and the approval by the indemnified party of such counsel, the indemnifying party shall not be liable to such indemnified party for any legal or other expenses, except as provided below and except for the reasonable costs of investigation subsequently incurred by such indemnified party in connection with the defense thereof. The indemnified party shall have the right to employ its counsel in any such action, but the fees and expenses of such counsel shall be at the expense of such indemnified party unless (i) the employment of counsel by such indemnified party has been authorized in writing by the indemnifying parties, (ii) the indemnified party shall have been advised by counsel that there may be one or more legal defenses available to it which are different from or in addition to those available to the indemnifying party (in which case the indemnifying parties shall not have the right to direct the defense of such action on behalf of the indemnified party) or (iii) the indemnifying parties shall not have employed counsel to assume the defense of such action within a reasonable time after notice of the commencement thereof, in each of which cases the fees and expenses of counsel shall be at the expense of the indemnifying parties.

          The indemnifying party under this Section 6 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 against any loss, claim, damage, liability or expense by reason of such settlement or judgment to the extent set forth herein. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement, compromise or consent to the entry of judgment in any pending or threatened action, suit or proceeding in respect of which any indemnified party is a party or could be named and indemnity was or would be sought hereunder by such indemnified party, unless such settlement, compromise or consent (a) includes an unconditional release of such indemnified party from all liability for claims that are the subject matter of such action, suit or proceeding and (b) does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

     7. Contribution. In order to provide for just and equitable contribution in circumstances in which the indemnification provided for in Section 6(a) or 6(b) is due in accordance with its terms but for any reason is unavailable to or insufficient to hold harmless an indemnified party in respect to any losses, liabilities, claims, damages or expenses referred to therein, then each indemnifying party shall contribute to the aggregate losses, liabilities, claims, damages and expenses (including any investigation, legal and other expenses reasonably incurred in connection with, and any amount paid in settlement of, any action, suit or proceeding or any claims asserted, but after deducting any contribution received by any person entitled hereunder to contribution from any person who may be liable for contribution) incurred by such indemnified party, as incurred, in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other hand from the offering of the Shares pursuant to this Agreement or, if such allocation is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to above but also the relative fault of the Company on the one hand and the Underwriters on the other hand in

connection with the statements or omissions which resulted in such losses, liabilities, claims, damages or expenses, as well as any other relevant equitable considerations. The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation or by any other method of allocation which does not take account of the equitable considerations referred to above. The aggregate amount of losses, liabilities, claims, damages and expenses incurred by an indemnified party and referred to above shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue or alleged untrue statement or omission or alleged omission. Notwithstanding the provisions of this Section 7, (i) no Underwriter (except as may be provided in the Agreement Among Underwriters) shall be required to contribute any amount in excess of the underwriting discounts and commissions received by such Underwriter in connection with the Shares underwritten by it and distributed to the public. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. For purposes of this Section 7, each person, if any, who controls an Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement, and each person, if any, who controls the Company within the meaning of the Section 15 of the Securities Act or Section 20 of the Exchange Act, shall have the same rights to contribution as the Company. Any party entitled to contribution will, promptly after receipt of notice of commencement of any action, suit or proceeding against such party in respect of which a claim for contribution may be made against another party or parties under this Section 7, notify such party or parties from whom contribution may be sought, but the omission so to notify such party or parties from whom contribution may be sought shall not relieve the party or parties from whom contribution may be sought from any other obligation it or they may have hereunder or otherwise than under this Section 7. No party shall be liable for contribution with respect to any action, suit, proceeding or claim settled without its written consent. Each Underwriter’s obligations to contribute pursuant to this Section 7 are several in proportion to their respective underwriting commitments and not joint.

     8. Termination.

          (a) This Agreement may be terminated with respect to the Shares to be purchased on a Closing Date by the Representatives by notifying the Company at any time at or before a Closing Date in the absolute discretion of the Representatives if: (i) in the judgment of the Representatives there has occurred any material adverse change in the securities markets or any event, act or occurrence that has materially disrupted, or will in the future materially disrupt, the securities markets or there shall be such a material adverse change in general financial, political or economic conditions or the effect of international conditions on the financial markets in the U.S. is such as to make it, in the judgment of the Representatives, inadvisable or impracticable to market the Shares or enforce contracts for the sale of the Shares; (ii) there has occurred any outbreak or material escalation of hostilities or other calamity or crisis the effect of which on the financial markets of the U.S. is such as to make it, in the judgment of the Representatives, inadvisable or impracticable to market the Shares or enforce contracts for the

sale of the Shares; (iii) trading in the Shares or any securities of the Company has been suspended or materially limited by the Commission or Nasdaq or trading generally on the New York Stock Exchange, Inc. or The Nasdaq GM has been suspended or materially limited, or minimum or maximum ranges for prices for securities shall have been fixed, or maximum ranges for prices for securities have been required, by any of said exchanges or by order of the Commission, FINRA, or any other governmental or regulatory authority; (iv) a banking moratorium has been declared by any state or Federal authority; or (v) in the judgment of the Representatives, there has been, since the time of execution of this Agreement or since the respective dates as of which information is given in the Prospectus, any material adverse change in the assets, properties, condition, financial or otherwise, or in the results of operations, business affairs or business prospects of the Company and its subsidiaries considered as a whole, whether or not arising in the ordinary course of business.

          (b) If this Agreement is terminated pursuant to any of its provisions, the Company shall not be under any liability to any Underwriter, and no Underwriter shall be under any liability to the Company, except that (y) if this Agreement is terminated by the Representatives or the Underwriters because of any failure, refusal or inability on the part of the Company to comply with the terms or to fulfill any of the conditions of this Agreement or as a result of the events set forth in Section 8(a)(v), the Company will reimburse the Underwriters for all out of-pocket expenses (including the reasonable fees and disbursements of their counsel) incurred by them in connection with the proposed purchase and sale of the Shares or in contemplation of performing their obligations hereunder and (z) no Underwriter who shall have failed or refused to purchase the Shares agreed to be purchased by it under this Agreement, without some reason sufficient hereunder to justify cancellation or termination of its obligations under this Agreement, shall be relieved of liability to the Company or any other Underwriter for damages occasioned by its failure or refusal.

     9. Substitution of Underwriters. If any Underwriter shall default in its obligation to purchase on any Closing Date the Shares agreed to be purchased hereunder on such Closing Date, the Representatives shall have the right, within 36 hours thereafter, to make arrangements for one or more of the non-defaulting Underwriters, or any other underwriters, to purchase such Shares on the terms contained herein. If, however, the Representatives shall not have completed such arrangements within such 36-hour period, then the Company shall be entitled to a further period of thirty-six hours within which to procure another party or other parties satisfactory to the Underwriters to purchase such Shares on such terms. If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by the Representatives and the Company as provided above, the aggregate number of Shares which remains unpurchased on such Closing Date does not exceed one-eleventh of the aggregate number of all the Shares that all the Underwriters are obligated to purchase on such date, then the Company shall have the right to require each non-defaulting Underwriter to purchase the number of Shares which such Underwriter agreed to purchase hereunder at such date and, in addition, to require each non-defaulting Underwriter to purchase its pro rata share (based on the number of Shares which such Underwriter agreed to purchase hereunder) of the Shares of such defaulting Underwriter or Underwriters for which such arrangements have not been made; but nothing herein shall relieve a defaulting Underwriter from liability for its default. In any such case, either the Representatives or the Company shall have the right to postpone the applicable Closing Date for a period of not more than seven days in order to effect any necessary changes and

arrangements (including any necessary amendments or supplements to the Registration Statement or Prospectus or any other documents), and the Company agrees to file promptly any amendments to the Registration Statement or the Prospectus which in the opinion of the Company and the Underwriters and their counsel may thereby be made necessary.

     If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by the Representatives and the Company as provided above, the aggregate number of such Shares which remains unpurchased exceeds 10% of the aggregate number of all the Shares to be purchased at such date, then this Agreement, or, with respect to a Closing Date which occurs after the Firm Share Closing Date, the obligations of the Underwriters to purchase and of the Company, as the case may be, to sell the Option Shares to be purchased and sold on such date, shall terminate, without liability on the part of any non-defaulting Underwriter to the Company, and without liability on the part of the Company, except as provided in Sections 5(b), 6, 7 and 8. The provisions of this Section 9 shall not in any way affect the liability of any defaulting Underwriter to the Company or the nondefaulting Underwriters arising out of such default. The term “Underwriter” as used in this Agreement shall include any person substituted under this Section 9 with like effect as if such person had originally been a party to this Agreement with respect to such Shares

     10. Miscellaneous. The respective agreements, representations, warranties, indemnities and other statements of the Company and the Underwriter, as set forth in this Agreement or made by or on behalf of them pursuant to this Agreement, shall remain in full force and effect, regardless of any investigation (or any statement as to the results thereof) made by or on behalf of any Underwriter or the Company or the or any of their respective officers, directors or controlling persons referred to in Sections 6 and 7 hereof, and shall survive delivery of and payment for the Shares. In addition, the provisions of Sections 5(b), 6, 7 and 8 shall survive the termination or cancellation of this Agreement.

     This Agreement has been and is made for the benefit of the Underwriters, the Company and their respective successors and assigns, and, to the extent expressed herein, for the benefit of persons controlling any of the Underwriters, or the Company, and directors and officers of the Company, and their respective successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement. The term “successors and assigns” shall not include any purchaser of Shares from any Underwriter merely because of such purchase.

     All notices and communications hereunder shall be in writing and mailed or delivered or by telephone or telegraph if subsequently confirmed in writing, (a) if to the Representatives, to Jefferies & Company, Inc., 520 Madison Avenue, New York, New York 10022 Attention: General Counsel, and Oppenheimer & Co. Inc., 300 Madison Avenue, New York, New York 10017 Attention: Equity Capital Markets, with a copy to Oppenheimer & Co. Inc., 300 Madison Avenue, New York, New York 10017 Attention: R. Wade Dougherty, and a copy to Latham & Watkins LLP, 12636 High Bluff Drive, Suite 400, San Diego, CA 92130 Attention: Cheston J. Larson, and (b) if to the Company, to ARIAD Pharmaceuticals, Inc., 26 Landsdowne Street, Cambridge, MA 02139 Attention: Raymond T. Keane, Esq., Senior Vice President, General Counsel with a copy to Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., One Financial Center, Boston, MA 02111 Attention: Jonathan L. Kravetz.

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

     With respect to any Related Proceeding, each party irrevocably waives, to the fullest extent permitted by applicable law, all immunity (whether on the basis of sovereignty or otherwise) from jurisdiction, service of process, attachment (both before and after judgment) and execution to which it might otherwise be entitled in the Specified Courts, and with respect to any Related Judgment, each party waives any such immunity in the Specified Courts or any other court of competent jurisdiction, and will not raise or claim or cause to be pleaded any such immunity at or in respect of any such Related Proceeding or Related Judgment, including, without limitation, any immunity pursuant to the United States Foreign Sovereign Immunities Act of 1976, as amended.

     The invalidity or unenforceability of any Section, paragraph or provision of this Agreement shall not affect the validity or enforceability of any other Section, paragraph or provision hereof. If any Section, paragraph or provision of this Agreement is for any reason determined to be invalid or unenforceable, there shall be deemed to be made such minor changes (and only such minor changes) as are necessary to make it valid and enforceable.

     Each of the parties hereto acknowledges that it is a sophisticated business person who was adequately represented by counsel during negotiations regarding the provisions hereof, including, without limitation, the indemnification provisions of Section 6 and the contribution provisions of Section 7, and is fully informed regarding said provisions. Each of the parties hereto further acknowledges that the provisions of Sections 6 and 7 hereto fairly allocate the risks in light of the ability of the parties to investigate the Company, its affairs and its business in order to assure that adequate disclosure has been made in the Registration Statement, the Base Prospectus, each free writing prospectus and the Prospectus (and any amendments and supplements thereto), as required by the Securities Act and the Exchange Act.

     [REMAINDER OF PAGE LEFT BLANK INTENTIONALLY]

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

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

SCHEDULE I

		Number of
		Firm Shares to
Name		Be Purchased
Jefferies & Company, Inc.			8,000,000
Oppenheimer & Co. Inc.			8,000,000
Total			16,000,000

Schedule I

SCHEDULE II

Lock-up Signatories

Harvey J. Berger, M.D.
David L. Berstein, Esq.
Daniel M. Bollag, Ph.D.
Timothy P. Clackson, Ph.D.
Pierre F. Dodion, M.D.
Edward M. Fitzgerald
Frank G. Haluska
Raymond T. Keane, Esq.
Jay R. LaMarche
Athanase Lavidas, Ph.D.
Massimo Radaelli, Ph.D.
A. Collier Smyth, M.D
Robert M. Whelan, Jr.
Wayne Wilson

Schedule II

SCHEDULE III

Issuer Free Writing Prospectus

Free Writing Prospectus filed by ARIAD Pharmaceuticals, Inc. on October 25, 2010 (File No. 333-164283)

Schedule III

Exhibit A

SUPPLEMENTAL PRICING AGREEMENT

______________, 2010

          Pursuant to the introductory paragraph of the Underwriting Agreement dated October 25, 2010 by and among ARIAD Pharmaceuticals, Inc., Jefferies & Company, Inc. and Oppenheimer & Co. Inc. (the “Underwriting Agreement”), the undersigned hereby agree to increase the number of Firm Shares to                      and the number of Option Shares to                     . Upon execution and delivery of this Supplemental Pricing Agreement, references in the Underwriting Agreement to Firm Shares shall refer to                      shares of Common Stock, references to Option Shares shall refer to                      shares of Common Stock and the number of Firm Shares set forth opposite the name of each Underwriter on Schedule I to the Underwriting Agreement shall be as set forth on Schedule I hereto. All other terms and provisions of the Underwriting Agreement remain unchanged.

          Capitalized terms used in this Supplemental Pricing Agreement but not defined herein shall have the meanings ascribed to them in the Underwriting Agreement.

          The foregoing Supplemental Pricing Agreement is hereby confirmed and accepted by the Representatives in New York, New York as of the date first above written.

Exhibit A

SCHEDULE I

		Number of
		Firm Shares to
Name		Be Purchased
Jefferies & Company, Inc.
Oppenheimer & Co. Inc.
Total

Exhibit A

Exhibit B

FORM OF LOCK-UP AGREEMENT

JEFFERIES & COMPANY, INC.
OPPENHEIMER & CO. INC.

c/o JEFFERIES & COMPANY, INC.
520 Madison Avenue
New York, New York 10022

c/o OPPENHEIMER & CO. INC.
300 Madison Avenue
New York, New York 10017

Re:      ARIAD Pharmaceuticals, Inc. — Public Offering

Dear Sirs:

          In order to induce Jefferies & Company, Inc. (“Jefferies”) and Oppenheimer & Co. Inc. (“OpCo” and together with Jefferies, the “Representatives”), to enter in to a certain underwriting agreement with ARIAD Pharmaceuticals, Inc., a Delaware corporation (the “Company”), with respect to the public offering of the Company’s Common Stock, par value $0.001 per share (“Common Stock”), and/or other securities of the Company (the “Offering”), the undersigned hereby agrees that for a period (the “Lock-up Period”) of ninety (90) days following the date of the final prospectus filed by the Company with the Securities and Exchange Commission in connection with such public offering, the undersigned will not, without the prior written consent of the Representatives, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract or grant an option to sell, or otherwise dispose of or agree to dispose of, any shares of Common Stock or securities convertible into or exercisable or exchangeable for Common Stock (including, without limitation, shares of Common Stock or any such securities which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933, as the same may be amended or supplemented from time to time (such shares or securities, the “Beneficially Owned Shares”)), (ii) enter into any swap, hedge or other agreement or arrangement that transfers in whole or in part, the economic risk of ownership of any Beneficially Owned Shares, Common Stock or securities convertible into or exercisable or exchangeable for Common Stock, (iii) engage in any short selling of any Beneficially Owned Shares, Common Stock or securities convertible into or exercisable or exchangeable for Common Stock or (iv) publicly announce an intention to effect a transaction specified in clause (i), (ii) or (iii).

          If (i) the Company issues an earnings release or material news or a material event relating to the Company occurs during the last seventeen (17) days of the Lock-up Period, or (ii) prior to the expiration of the Lock-up Period, the Company announces that it will release earnings results during the sixteen (16)-day period beginning on the last day of the Lock-up Period, the restrictions imposed by this agreement (“Agreement”) shall continue to apply until the expiration

Exhibit B

of the eighteen (18)-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event.

          Notwithstanding the foregoing, the undersigned may transfer Beneficially Owned Shares (i) as a bona fide gift or gifts, (ii) to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, or (iii) by will or intestate succession; provided, that (A) each donee, transferee or distributee shall execute and deliver a letter substantially in the form hereof agreeing to be bound by the terms hereof and (B) 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 Securities Exchange Act of 1934, as amended (the “Exchange Act”), other than a filing on Form 5 made after the expiration of the Lock-up Period. For purposes of this Agreement, the term “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

          In addition, notwithstanding the foregoing, the restrictions set forth herein shall not apply to the establishment of a trading plan that complies with Rule 10b5-1 under the Exchange Act; provided however, that the restrictions shall apply in full force to sales pursuant to the trading plan during the Lock-up Period. Furthermore, notwithstanding anything herein to the contrary, this lock up will not apply to the sale of shares of Common Stock pursuant to a trading plan that complies with Rule 10b5-1 and existing on the date of this Agreement.

          Anything contained herein to the contrary notwithstanding, any person to whom shares of Common Stock, securities convertible into or exercisable or exchangeable for Common Stock or Beneficially Owned Shares are transferred from the undersigned shall be bound by the terms of this Agreement.

          In addition, the undersigned hereby waives, from the date hereof until the expiration of the ninetieth (90th) day following the date of the Company’s final prospectus, any and all rights, if any, to request or demand registration pursuant to the Securities Act of 1933, as amended, of any shares of Common Stock or securities convertible into or exercisable or exchangeable for Common Stock that are registered in the name of the undersigned or that are Beneficially Owned Shares. In order to enable the aforesaid covenants to be enforced, the undersigned hereby consents to the placing of legends and/or stop transfer orders with the transfer agent of the Common Stock with respect to any shares of Common Stock, securities convertible into or exercisable or exchangeable for Common Stock or Beneficially Owned Shares.

          It is understood that, if the Company notifies Jefferies that it does not intend to proceed with the Offering or if the Offering is not consummated by November 30, 2010, this Agreement shall terminate and the undersigned will be released from their obligations hereunder. This Agreement shall be governed by and construed in accordance with the laws of the State of New York, without regard to the conflict of laws principles thereof.

          The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Agreement. This Agreement is irrevocable and 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.

Exhibit B