EMERGENT BIOSOLUTIONS INC.

Exhibit 1.1

EMERGENT BIOSOLUTIONS INC.

___Shares of Common Stock, par value $0.001 per share

UNDERWRITING AGREEMENT

                    , 2006

J.P. Morgan Securities Inc.
Cowen and Company, LLC
HSBC Securities (USA) Inc.
  As Representatives of the
  several Underwriters listed
  in Schedule I hereto
c/o J.P. Morgan Securities Inc.
277 Park Avenue
New York, New York 10172

Ladies and Gentlemen:

      Emergent BioSolutions Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several Underwriters listed in Schedule I hereto (the “Underwriters”), for whom you are acting as representatives (the “Representatives”), an aggregate of                      shares of common stock, par value $0.001 per share (the “Common Stock”), of the Company and, at the option of the Underwriters, up to an additional                      shares of Common Stock to cover over-allotments, if any, and the stockholders of the Company named in Schedule II hereto (the “Selling Stockholders”) propose to sell, at the option of the Underwriters, up to an additional                      shares of Common Stock to cover over-allotments, if any. The aggregate of                      shares to be sold by the Company are herein referred to as the “Underwritten Shares” and the aggregate of                      additional shares to be sold by the Company and the Selling Stockholders at the option of the Underwriters are herein referred to as the “Option Shares.” The Underwritten Shares and the Option Shares are herein referred to as the “Shares.” The shares of Common Stock of the Company to be outstanding after giving effect to the sale of the Shares are herein referred to as the “Stock.” The Stock, including the Shares, will have attached thereto rights (the “Rights”) to purchase shares of Series A Junior Participating Preferred Stock of the Company. The Rights are to be issued pursuant to a Rights Agreement (the “Rights Agreement”) dated as of [                    ] between the Company and American Stock Transfer & Trust Company, as Rights Agent.

      The Company and the Selling Stockholders hereby confirm their agreement with the several Underwriters concerning the purchase and sale of the Shares, as follows:

      1. Registration Statement. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Securities Act”), a

registration statement (File No. 333-136622) including a prospectus, relating to the Shares and the Rights. Such registration statement, as amended at the time it becomes effective, including the information, if any, deemed pursuant to Rule 430A or 430C under the Securities Act to be part of the registration statement at the time of its effectiveness (“Rule 430 Information”), is referred to herein as the “Registration Statement;” and as used herein, the term “Preliminary Prospectus” means each prospectus included in such registration statement (and any amendments thereto) before it becomes effective, any prospectus filed with the Commission pursuant to Rule 424(a) under the Securities Act and the prospectus included in the Registration Statement at the time of its effectiveness that omits Rule 430 Information, and the term “Prospectus” means the prospectus in the form first used (or made available to the Underwriters by the Company upon request of purchasers pursuant to Rule 173 under the Securities Act) in connection with confirmation of sales of the Shares. If the Company has filed an abbreviated registration statement pursuant to Rule 462(b) under the Securities Act (the “Rule 462 Registration Statement”), then any reference herein to the term “Registration Statement” shall be deemed to include such Rule 462 Registration Statement. Capitalized terms used but not defined herein shall have the meanings given to such terms in the Registration Statement and the Prospectus.

      At or prior to the time when sales of the Shares were first made (the “Time of Sale”), the Company had prepared the following information (collectively with the pricing information set forth on Annex B, the “Time of Sale Information”): a Preliminary Prospectus dated                                          2006, and each “free-writing prospectus” (as defined pursuant to Rule 405 under the Securities Act) listed on Annex B hereto.

      2. Purchase of the Shares by the Underwriters. (a) The Company agrees to issue and sell the Underwritten Shares to the several Underwriters as provided in this Agreement, and each Underwriter, on the basis of the representations, warranties and agreements set forth herein and subject to the conditions set forth herein, agrees, severally and not jointly, to purchase from the Company the respective number of Underwritten Shares set forth opposite such Underwriter’s name in Schedule I hereto at a price per share (the “Purchase Price”) of $                    . The public offering price of the Shares is not in excess of the price recommended by Cowen and Company, LLC, acting as a “qualified independent underwriter” within the meaning of Rule 2720 of the Rules of Conduct of the National Association of Securities Dealers, Inc.

      In addition, the Company as to                      of the Option Shares and each of the Selling Stockholders as and to the extent indicated in Schedule II hereto, agree, severally and not jointly, to sell the Option Shares to the several Underwriters as provided in this Agreement, and the Underwriters, on the basis of the representations, warranties and agreements set forth herein and subject to the conditions set forth herein, shall have the option to purchase, severally and not jointly, from the Company and each of the Selling Stockholders the Option Shares at the Purchase Price. If any Option Shares are to be purchased, the number of Option Shares to be purchased by each Underwriter shall be the number of Option Shares which bears the same ratio to the aggregate number of Option Shares being purchased as the number of Underwritten Shares set forth opposite the name of such Underwriter in Schedule I hereto bears to the aggregate number of Underwritten Shares being purchased from the Company by the several Underwriters, subject, however, to such adjustments to eliminate any fractional Shares as the Representative in its sole discretion shall make. Any such election to purchase Option Shares shall be made in

proportion to the maximum number of Option Shares to be sold by the Company and each Selling Stockholder as set forth in Schedule II hereto.

      The Underwriters may exercise the option to purchase the Option Shares at any time in whole, or from time to time in part, on or before the thirtieth day following the date of this Agreement, by written notice from the Representatives to the Company and the Attorneys-in-Fact (as defined below). Such notice shall set forth the aggregate number of Option Shares as to which the option is being exercised and the date and time when the Option Shares are to be delivered and paid for which may be the same date and time as the Closing Date (as hereinafter defined) but shall not be earlier than the Closing Date nor later than the tenth full business day (as hereinafter defined) after the date of such notice (unless such time and date are postponed in accordance with the provisions of Section 12 hereof). Any such notice shall be given at least two Business Days prior to the date and time of delivery specified therein. In the event of a partial exercise of the option to purchase the Option Shares, the Underwriters shall first purchase Option Shares from the Selling Shareholders on a pro rata basis until all Option Shares to be sold by the Selling Shareholders have been purchased before purchasing Option Shares to be sold by the Company.

      The Company and the Selling Stockholders understand that the Underwriters intend to make a public offering of the Shares as soon after the effectiveness of this Agreement as in the judgment of the Representatives is advisable, and initially to offer the Shares on the terms set forth in the Prospectus. The Company and the Selling Stockholders acknowledge and agree that the Underwriters may offer and sell Shares to or through any affiliate of an Underwriter and that any such affiliate may offer and sell Shares purchased by it to or through any Underwriter.

      (b) Payment for the Shares shall be made by wire transfer in immediately available funds to the respective accounts specified to the Representatives by the Company and, in the case of the Option Shares, the Attorneys-in-Fact at the offices of Dechert LLP, 30 Rockefeller Plaza, New York, NY at 10:00 A.M. New York City time on                     , 200   , or at such other time or place on the same or such other date, not later than the fifth business day thereafter, as the Representatives and the Company may agree upon in writing or, in the case of the Option Shares, on the date and at the time and place specified by the Representatives in the written notice of the Underwriters’ election to purchase such Option Shares. The time and date of such payment for the Underwritten Shares is referred to herein as the “Closing Date” and the time and date for such payment for the Option Shares, if other than the Closing Date, is herein referred to as the “Additional Closing Date.”

      Payment for the Shares to be purchased on the Closing Date or the Additional Closing Date, as the case may be, shall be made against delivery to the Representatives for the respective accounts of the several Underwriters of the Shares to be purchased on such date in definitive form registered in such names and in such denominations as the Representatives shall request in writing not later than two full business days prior to the Closing Date or the Additional Closing Date, as the case may be, with any transfer taxes payable in connection with the sale of the Shares duly paid by the Company or the Selling Stockholders as the case may be. The certificates for the Shares will be made available for inspection and packaging by the Representatives at the office of J.P. Morgan Securities Inc. set forth above not later than 1:00

P.M., New York City time, on the business day prior to the Closing Date or the Additional Closing Date, as the case may be.

      (c) Each of the Company and the Selling Stockholders acknowledges and agrees that the Underwriters are acting solely in the capacity of an arm’s length contractual counterparty to the Company and the Selling Stockholders 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 or a fiduciary to, or an agent of, the Company, the Selling Stockholders or any other person. Additionally, neither the Representatives nor any other Underwriter is advising the Company, the Selling Stockholders or any other person as to any legal, tax, investment, accounting or regulatory matters in any jurisdiction. The Company and the Selling Stockholders shall consult with their own advisors concerning such matters and shall be responsible for making their own independent investigation and appraisal of the transactions contemplated hereby, and the Underwriters shall have no responsibility or liability to the Company or the Selling Stockholders with respect thereto. Any review by the Underwriters of the Company, the transactions contemplated hereby or other matters relating to such transactions will be performed solely for the benefit of the Underwriters and shall not be on behalf of the Company or the Selling Stockholders.

      3. Representations and Warranties of the Company. The Company represents and warrants to each Underwriter and the Selling Stockholders that:

      (a) Preliminary Prospectus. No order preventing or suspending the use of any Preliminary Prospectus has been issued by the Commission, and each Preliminary Prospectus, at the time of filing thereof, complied in all material respects with the Securities Act and did not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use in any Preliminary Prospectus.

      (b) Time of Sale Information. The Time of Sale Information, at the Time of Sale did not, and at the Closing Date and as of the Additional Closing Date, as the case may be, will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use in such Time of Sale Information. No statement of material fact included in the Prospectus has been omitted from the Time of Sale Information and no statement of material fact included in the Time of Sale Information that is required to be included in the Prospectus has been omitted therefrom.

      (c) Issuer Free Writing Prospectus. Other than the Preliminary Prospectus and the Prospectus, the Company (including its agents and representatives, other than the Underwriters in their capacity as such) has not made, used, prepared, authorized, approved or referred to and

will not prepare, make, use, authorize, approve or refer to any “written communication” (as defined in Rule 405 under the Securities Act) that constitutes an offer to sell or solicitation of an offer to buy the Shares (each such communication by the Company or its agents and representatives (other than a communication referred to in clause (i) below) an “Issuer Free Writing Prospectus”) other than (i) any document not constituting a prospectus pursuant to Section 2(a)(10)(a) of the Securities Act or Rule 134 under the Securities Act or (ii) the documents listed on Annex B hereto and other written communications approved in writing in advance by the Representatives. Each such Issuer Free Writing Prospectus complied in all material respects with the Securities Act, has been filed in accordance with the Securities Act (to the extent required thereby) and, when taken together with the Preliminary Prospectus accompanying, or delivered prior to delivery of, such Issuer Free Writing Prospectus, did not, and at the Closing Date and as of the Additional Closing Date, as the case may be, will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to any statements or omissions made in each such Issuer Free Writing Prospectus in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use in any Issuer Free Writing Prospectus.

      (d) Registration Statement and Prospectus. The Registration Statement has been declared effective by the Commission. No order suspending the effectiveness of the Registration Statement has been issued by the Commission and, to the knowledge of the Company, no proceeding for that purpose or pursuant to Section 8A of the Securities Act against the Company or related to the offering has been initiated or threatened by the Commission; as of the applicable effective date of the Registration Statement and any amendment thereto, the Registration Statement complied and will comply in all material respects with the Securities Act, and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading; and as of the date of the Prospectus and any amendment or supplement thereto and as of the Closing Date and as of the Additional Closing Date, as the case may be, the Prospectus will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation and warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use in the Registration Statement and the Prospectus and any amendment or supplement thereto.

      (e) Financial Statements. The financial statements and the related notes thereto of the Company and its consolidated subsidiaries included in the Registration Statement, the Time of Sale Information and the Prospectus comply in all material respects with the applicable requirements of the Securities Act and the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Exchange Act”), as applicable, and present fairly the financial position of the Company and its subsidiaries as of the dates indicated and the results of their operations and the changes in their cash flows for the periods specified; such financial statements have been prepared in conformity with generally

accepted accounting principles applied on a consistent basis throughout the periods covered thereby, except in the case of unaudited financial statements, which are subject to normal year-end adjustments and do not contain certain footnotes as permitted by the applicable rules of the Commission; and the other historical financial information included in the Registration Statement, the Time of Sale Information and the Prospectus has been derived from the accounting records of the Company and its subsidiaries and presents fairly the information shown thereby.

      (f) No Material Adverse Change. Since the date of the most recent financial statements of the Company included in the Registration Statement, the Time of Sale Information and the Prospectus, except as disclosed therein or contemplated thereby, (i) except for the issuance of shares of Stock upon the exercise of outstanding options or under existing employee or director compensation or stock option plans and the grant of options or rights to purchase Stock under existing employee or director compensation or stock option plans, there has not been any change in the capital stock or increase in long-term debt of the Company or any of its subsidiaries, or any dividend or distribution of any kind declared, set aside for payment, paid or made by the Company on any class of capital stock, or any material adverse change or any development that would result in a material adverse change in the business, properties, management, financial position, stockholders’ equity or results of operations of the Company and its subsidiaries taken as a whole; (ii) neither the Company nor any of its subsidiaries has entered into any transaction or agreement that is material to the Company and its subsidiaries taken as a whole or incurred any liability or obligation, direct or contingent, that is material to the Company and its subsidiaries taken as a whole; and (iii) neither the Company nor any of its subsidiaries has sustained any loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor disturbance or dispute or any action, order or decree of any court or arbitrator or governmental or regulatory authority that is material to the Company and its subsidiaries taken as a whole, except in each case as otherwise disclosed in the Registration Statement, the Time of Sale Information and the Prospectus.

      (g) Organization and Good Standing. The Company and each of its subsidiaries have been duly organized and are validly existing and in good standing under the laws of their respective jurisdictions of organization, are duly qualified to do business and are in good standing in each jurisdiction in which their respective ownership or lease of property or the conduct of their respective businesses requires such qualification, and have all corporate, or such other comparable, power and authority necessary to own or hold their respective properties and to conduct the businesses in which they are engaged, except where the failure to be so qualified or have such power or authority would not, individually or in the aggregate, have a material adverse effect on the business, properties, management, financial position, stockholders’ equity, results of operations or prospects of the Company and its subsidiaries taken as a whole (a “Material Adverse Effect”). The Company does not own or control, directly or indirectly, any corporation, association or other entity other than the subsidiaries listed in Exhibit 21.1 to the Registration Statement.

      (h) Capitalization. The Company has an authorized capitalization as set forth in the Registration Statement, the Time of Sale Information and the Prospectus under the heading “Capitalization;” all the outstanding shares of capital stock of the Company (including the Option Shares to be sold by the Selling Stockholders) have been duly and validly authorized and

issued and are fully paid and non-assessable and are not subject to any pre-emptive or similar rights; except as described in or expressly contemplated by the Time of Sale Information and the Prospectus, there are no outstanding rights (including, without limitation, pre-emptive rights), warrants or options to acquire, or instruments convertible into or exchangeable for, any shares of capital stock or other equity interest in the Company or any of its subsidiaries, or any contract, commitment, agreement, understanding or arrangement of any kind relating to the issuance of any capital stock of the Company or any such subsidiary, any such convertible or exchangeable securities or any such rights, warrants or options; the capital stock of the Company conforms in all material respects to the description thereof contained in the Registration Statement, the Time of Sale Information and the Prospectus; and all the outstanding shares of capital stock or other equity interests of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and except as otherwise described in the Registration Statement, the Time of Sale Information and the Prospectus are owned directly or indirectly by the Company, free and clear of any lien, charge, encumbrance, security interest, restriction on voting or transfer or any other claim of any third party.

      (i) Due Authorization. The Company has full right, power and authority to execute and deliver this Agreement and to perform its obligations hereunder; and all action required to be taken for the due and proper authorization, execution and delivery by it of this Agreement and the consummation by it of the transactions contemplated hereby has been duly and validly taken.

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

      (k) The Shares. The Shares to be issued and sold by the Company hereunder have been duly authorized by the Company and, when issued and delivered and paid for as provided herein, will be duly and validly issued and will be fully paid and nonassessable and will conform in all material respects to the descriptions thereof in the Time of Sale Information and the Prospectus; the issuance of the Shares is not subject to any pre-emptive or similar rights; the Rights Agreement has been duly authorized, executed and delivered by the Company and constitutes a valid and legally binding agreement of the Company enforceable against the Company in accordance with its terms, subject to applicable bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium or similar laws affecting the enforcement of creditors’ rights or remedies generally and by equitable principles relating to enforceability, including principles of commercial reasonableness, good faith and fair dealing (regardless of whether enforcement is sought in a proceeding at law or in equity) (collectively, the “Enforceability Exceptions”); the Rights have been duly authorized by the Company and, when issued upon issuance of the Shares, will be validly issued; and the shares of Series A Junior Participating Preferred Stock issuable upon exercise of the Rights have been duly authorized by the Company and validly reserved for issuance and, upon the exercise of the Rights in accordance with the terms of the Rights Agreement and when issued and delivered and paid for as provided in the Rights Agreement, will be validly issued, fully paid and non-assessable.

      (l) No Violation or Default. Neither the Company nor any of its subsidiaries is (i) in violation of its charter or by-laws or similar organizational documents; (ii) in default, and no event has occurred that, 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 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; or (iii) in violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority having jurisdiction over the Company or any of its subsidiaries, except, in the case of clauses (ii) and (iii) above, for any such default or violation that would not, individually or in the aggregate, have a Material Adverse Effect.

      (m) No Conflicts. The execution, delivery and performance by the Company of each of this Agreement, the issuance by the Company of the Underwritten Shares and the Rights and the consummation by the Company of the transactions contemplated by this Agreement will not (i) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, any 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, (ii) result in any violation of the provisions of the charter or by-laws or similar organizational documents of the Company or any of its subsidiaries or (iii) result in the violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority having jurisdiction over the Company or any of its subsidiaries, except, in the case of clauses (i) and (iii) above, for any such conflict, breach or violation that would not, individually or in the aggregate, have a Material Adverse Effect.

      (n) No Consents Required. No consent, approval, authorization, order, registration or qualification of or with any court or arbitrator or governmental or regulatory authority is required for the execution, delivery and performance by the Company of this Agreement, the issuance by the Company of the Shares or the Rights and the consummation of the transactions contemplated by this Agreement, except for the registration of the Shares under the Securities Act and such consents, approvals, authorizations, orders and registrations or qualifications as have already been obtained or made or as may be required by the rules and regulations of the National Association of Securities Dealers, Inc. or the New York Stock Exchange or under applicable state securities laws in connection with the purchase and distribution of the Shares by the Underwriters.

      (o) Legal Proceedings. Except as described in the Registration Statement, the Time of Sale Information and the Prospectus, there are no legal, governmental or regulatory investigations, actions, suits or proceedings pending to which the Company or any of its subsidiaries is a party or to which any property of the Company or any of its subsidiaries is the subject that, individually or in the aggregate, if determined adversely to the Company or any of its subsidiaries could reasonably be expected to have a Material Adverse Effect or materially and adversely affect the ability of the Company to perform its obligations under this Agreement; to the knowledge of the Company, no such investigations, actions, suits or proceedings are threatened or contemplated by any governmental or regulatory authority or threatened by others; and (i) there are no current or pending legal, governmental or regulatory actions, suits or proceedings that are required under the Securities Act to be described in the Registration Statement that are not so described in the Registration Statement, the Time of Sale Information

and the Prospectus and (ii) there are no statutes, regulations or contracts or other documents that are required under the Securities Act to be filed as exhibits to the Registration Statement or described in the Registration Statement or the Prospectus that are not so filed as exhibits to the Registration Statement or described in the Registration Statement, the Time of Sale Information and the Prospectus.

      (p) Independent Accountants. Ernst & Young LLP, who have certified certain financial statements of the Company and its subsidiaries, are an independent registered public accounting firm with respect to the Company and its subsidiaries within the applicable rules and regulations adopted by the Commission and the Public Accounting Oversight Board (United States) and as required by the Securities Act.

      (q) Title to Real and Personal Property. Except as described in or expressly contemplated by the Registration Statement, the Time of Sale Information and the Prospectus, the Company and its subsidiaries have good and marketable title in fee simple to, or have valid rights to lease or otherwise use, all items of real and personal property that are material to each of the respective businesses of the Company and its subsidiaries taken as a whole, in each case free and clear of all liens, encumbrances, claims and defects and imperfections of title except those that (i) do not materially interfere with the use made and proposed to be made of such property by the Company and its subsidiaries or (ii) would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

      (r) Possession of Intellectual Property. Except as described in or expressly contemplated by the Registration Statement, the Time of Sale Information and the Prospectus, the Company owns or has valid, binding and enforceable licenses or other rights to use the Company Intellectual Property (as defined below), subject to the Enforceability Exceptions, and neither the Company nor any of its subsidiaries is obligated to pay a material royalty, grant a material license, or provide other material consideration to any third party in connection with the Company Intellectual Property. Except as described in the Registration Statement, the Time of Sale Information and the Prospectus or as would not reasonably be expected to have a Material Adverse Effect, (i) the Company has not received any written notice of any infringement with respect to the Company Intellectual Property or with respect to the Company’s products or processes described in the Registration Statement, the Time of Sale Information and the Prospectus, (ii) the discoveries, inventions, products or processes of the Company and its subsidiaries referred to in the Prospectus do not, to the knowledge of the Company, infringe or interfere with any patent claim of any third party and (iii) no third party has any ownership right in or to any Company Intellectual Property that is owned by the Company, other than any co-owner of any patent or patent application constituting Company Intellectual Property who is listed on the records of the U.S. Patent and Trademark Office (the “PTO”), and, to the knowledge of the Company, no third party has any ownership right in or to any Company Intellectual Property that is exclusively licensed to the Company, other than any licensor of the Company of such Company Intellectual Property. For purposes of this Agreement, “Intellectual Property” means patents, patent applications, copyrights, trade secrets, trademarks, service marks and trade names, and “Company Intellectual Property” means Intellectual Property reasonably necessary to conduct the business of the Company as described in the Prospectus.

      (s) PTO Matters. The Company has duly and properly filed or caused to be filed with the PTO and applicable foreign and international patent authorities all patent applications owned by the Company (the “Company Patent Applications”). To the knowledge of the Company, the Company has complied with the PTO’s duty of candor and disclosure and best mode requirement for the Company Patent Applications and has made no material misrepresentation in the Company Patent Applications. To the knowledge of the Company, the Company has complied with the relevant foreign filing requirements underlying patentability and enforceability of any resultant patents for the Company Patent Applications pending in countries outside the United States. The Company is not aware of any information material to a determination of patentability regarding the Company Patent Applications not called to the attention of the PTO or similar foreign authority. The Company is not aware of any information not called to the attention of the PTO or similar foreign authority which would preclude the grant of a patent for the Company Patent Applications. The Company has no knowledge of any information which would preclude the Company from having clear title to the Company Patent Applications.

      (t) Government Contracts and Government Bids. With respect to any Government Bid or Government Contract (in each case, as defined below) to which the Company or any of its Subsidiaries are a party, except as described in the Registration Statement, the Time of Sale Information and the Prospectus or as would not have a Material Adverse Effect, the Company and its subsidiaries have: (i) with full authority, duly and properly entered into such Government Contracts, and fully and completely complied in all material respects with the terms and conditions of such Government Contracts; (ii) in soliciting, submitting or entering into such Government Bid or Government Contract, and in all documentation associated with entering into such Government Bid or Government Contract, not knowingly made any false, incomplete or misleading statements, certifications or representations; (iii) in soliciting, submitting or entering into such Government Bid or Government Contract, and in all activities associated with entering into or performing under such Government Bid or Government Contract, to the knowledge of the Company, complied in all material respects with all applicable laws, regulations or agreements pertaining to such Government Bid or Government Contract; (iv) not been notified in writing by any governmental entity, prime contractor, subcontractor or other person that the Company or any of its subsidiaries is in material breach or default of any material obligation, agreement, certification, covenant or condition contained in any Government Contract, or breached or violated in any material respect any applicable law or regulation pertaining to such Government Contract; (v) not been notified in writing that it is the subject of a governmental investigation or audit, which remains ongoing or pending; (vi) not been notified in writing of any material cost, billing, schedule, technical or quality problems that would reasonably be expected to result in claims against the Company or any of its subsidiaries as a result of any violation or breach of any Government Contract (vii) not conducted or initiated any internal investigation, inspection or audit, or, to the Company’s or any of its subsidiaries’ knowledge, had reason to conduct, initiate or report any internal investigation, inspection or audit or made a voluntary disclosure to a government or regulatory agency, with respect to any alleged irregularity, misstatement, or acts committed or acts of omission in violation or breach of a Government Bid or Government Contract, nor, to the knowledge of the Company, are there any facts or circumstances that would reasonably be expected to give rise to such an investigation, inspection or audit; (viii) not been notified in writing of any intent to terminate, or any termination for convenience or termination for default with respect to a Government Contract, or received any written notifications to show

cause, cure, deficiency, default or similar notices relating to such Government Contract; (ix) not been notified in writing of any bid or award protest proceedings arising under or related to a Government Bid or Government Contract; (x) not been notified in writing that any money due to the Company pertaining to a Government Contract has been withheld or set off; (xi) not been notified in writing that the Company or any of its subsidiaries is being suspended or debarred from Government Bids or Government Contracts; and (xii) not been notified in writing of any material claims against the Company or any of its subsidiaries, which remain outstanding or pending, brought against the Company as a result of any violation or breach of any Government Bid or Government Contract. As used herein, “Government Bid” means, with respect to the Company or any subsidiary of the Company, any firm quotation, bid or proposal made by the Company, which if accepted or awarded, would lead to a Government Contract. “Government Contract” means, with respect to the Company or any subsidiary, any contract, including any prime contract, subcontract, facility contract, services contract, teaming agreement or arrangement, joint venture, basic ordering agreement, letter contract, purchase order, delivery order, change order or other contractual arrangement of any kind, between the Company or any subsidiary and (1) the United States federal government or the national government of any foreign country (acting on its own behalf or on behalf of another country or international organization), (2) any prime contractor of the United States federal government or the national government of any foreign country, but only with respect to a contract between such prime contractor and the United States federal government or the national government of any foreign country, or (3) any subcontractor with respect to any contract of a type described in clauses (1) or (2) above.

      (u) No Undisclosed Relationships. No relationship, direct or indirect, exists between or among the Company or any of its subsidiaries, on the one hand, and the directors, officers, stockholders, customers or suppliers of the Company or any of its subsidiaries, on the other, that is required by the Securities Act to be described in the Registration Statement and the Prospectus and that is not so described in such documents and in the Time of Sale Information.

      (v) Investment Company Act. The Company is not and, after giving effect to the offering and sale of the Shares and the application of the proceeds thereof as described in the Registration Statement, the Time of Sale Information and the Prospectus, will not be required to register as an “investment company” or an entity “controlled” by an “investment company” within the meaning of the Investment Company Act of 1940, as amended, and the rules and regulations of the Commission thereunder (collectively, “Investment Company Act”).

      (w) Taxes. The Company and its subsidiaries have filed all federal, state, local and foreign tax returns required to be filed through the date hereof and paid all taxes shown as due thereon, except for taxes being contested in good faith, in each case, except as would not have a Material Adverse Effect; and, except as otherwise disclosed in the Registration Statement, the Time of Sale Information and the Prospectus, there is no tax deficiency that has been, or would reasonably be expected to be, asserted against the Company or any of its subsidiaries or any of their respective properties or assets, in each case, except as would not have a Material Adverse Effect.

      (x) Licenses and Permits. The Company and its subsidiaries possess such permits, licenses, approvals, consents and other authorizations (collectively, “Governmental Licenses”)

issued by the appropriate federal, state, local or foreign regulatory agencies or bodies necessary to conduct the business of the Company as described in the Prospectus, including without limitation, all such registrations, approvals, certificates, authorizations and permits required by the United States Food and Drug Administration (the “FDA”) or any other federal, state, local or foreign agencies or bodies engaged in the regulation of clinical trials, pharmaceuticals, biologics or biohazardous substances or materials (“Governmental Regulatory Authority”), except where the failure so to possess would not, singly or in the aggregate, have a Material Adverse Effect. Neither the Company nor any Subsidiaries have received any notice of proceedings relating to the revocation or modification of any such Governmental Licenses, which, singly or in the aggregate, would have a Material Adverse Effect. The Company has not failed to submit to the FDA an Investigational New Drug Application that is required for a clinical trial it is conducting or sponsoring, except where such failure would not, singly or in the aggregate, have a Material Adverse Effect; all such submissions were in material compliance with applicable laws when submitted and no material deficiencies have been asserted by the FDA with respect to any such submissions, except any deficiencies which would not, singly or in the aggregate, have a Material Adverse Effect. Except as described in the Registration Statement, the Time of Sale Information and the Prospectus, the Company has not received from the FDA or any other Governmental Regulatory Authority any notice of adverse findings, notice of violations, Warning Letter, criminal proceeding notice under Section 305 of the Federal Food, Drug, and Cosmetic Act, or other similar communication from the FDA or other Governmental Authority alleging or asserting material noncompliance with applicable law or any Governmental Licenses, which remain outstanding or pending, and there are no seizures, recalls, market withdrawals, field notifications, notifications of misbranding or adulteration, safety alerts or similar actions relating to the safety or efficacy of the Company’s products being conducted, requested in writing or, to the knowledge of the Company, threatened by the FDA or other Governmental Authority relating to the products sold by the Company. Except as described in the Registration Statement, the Time of Sale Information and the Prospectus, since the FDA approval of a supplement to the Company’s manufacturing facility license for BioThrax in December 2001, the Company has not, either voluntarily or involuntarily, initiated, conducted, or issued or caused to be initiated, conducted or issued, any recall, market withdrawal, safety alert or other similar notice or action relating to the alleged lack of safety or efficacy of any of the Company’s products or any alleged product defect or violation, and the Company has no knowledge that any Governmental Authority has initiated, conducted or intends to initiate any such notice or action. Since the FDA approval of a supplement to the Company’s manufacturing facility license for BioThrax in December 2001, except as described in the Registration Statement, the Time of Sale Information and the Prospectus, the Company has not received notice of any proceeding seeking recall, suspension or seizure of any products being sold or intended to be sold by the Company.

      (y) Tests and Preclinical and Clinical Studies. The tests and preclinical and clinical studies conducted by or, to the Company’s knowledge, on behalf of the Company that are described in the Registration Statement and the Prospectus were and, if still pending, are being, conducted, where applicable, in all material respects in accordance with the protocols submitted to the FDA or any foreign government exercising comparable authority, procedures and controls pursuant to, where applicable, accepted professional and scientific standards for products or product candidates comparable to those being developed by the Company; the descriptions of the tests and preclinical and clinical studies, and results thereof, conducted by or, to the Company’s knowledge, on behalf of the Company contained in the Registration Statement and the

Prospectus do not contain any misstatement of a material fact or omit to state a material fact necessary to make such statements, in the light of the circumstances under which they were made, not misleading; the Company is not aware of any other trials, studies or tests not described in the Registration Statement and the Prospectus, the results of which reasonably call into question the results described in the Registration Statement and the Prospectus; and the Company has not received any written notice or correspondence from the FDA or any foreign, state or local governmental body exercising comparable authority requiring the termination, suspension, or clinical hold of any tests or preclinical or clinical studies, or such written notice or, where applicable, correspondence from any Institutional Review Board or comparable authority requiring the termination or suspension of a clinical study, conducted by or on behalf of the Company, which termination, suspension, or clinical hold would reasonably be expected to have a Material Adverse Effect.

      (z) No Labor Disputes. No labor disturbance by or dispute with employees of the Company or any of its subsidiaries exists or, to the knowledge of the Company, is contemplated or threatened and the Company is not aware of any existing or imminent labor disturbance by, or dispute with, the employees of any of its or its subsidiaries’ principal suppliers, contractors or customers, except in each case as would have a Material Adverse Effect.

      (aa) Compliance With Environmental Laws. Except as described in the Registration Statement, the Time of Sale Information and the Prospectus, (i) the Company and its subsidiaries (x) are in compliance with any and all applicable federal, state, local and foreign laws, rules, regulations, requirements, decisions and orders relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”); (y) have received and are in compliance with all permits, licenses, certificates or other authorizations or approvals required of them under applicable Environmental Laws to conduct their respective businesses; and (z) have not received notice of any actual or potential liability for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants, and (ii) there are no costs or liabilities associated with Environmental Laws of or relating to the Company or its subsidiaries, except in each case for any such failure to comply, or failure to receive required permits, licenses or approvals, or cost or liability, that would not, individually or in the aggregate, have a Material Adverse Effect.

      (bb) Compliance With ERISA. Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), that is maintained, administered or contributed to by the Company or any of its affiliates for employees or former employees of the Company and its affiliates has been maintained in compliance in all material respects with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Internal Revenue Code of 1986, as amended (the “Code”); and no prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred with respect to any such plan excluding transactions effected pursuant to a statutory or administrative exemption; and for each such plan that is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA, no “accumulated funding deficiency” as defined in Section 412 of the Code has been incurred, whether or not waived, and the fair market value of the assets of each such plan (excluding for

these purposes accrued but unpaid contributions) exceeds the present value of all benefits accrued under such plan determined using reasonable actuarial assumptions.

      (cc) Disclosure Controls. The Company and its subsidiaries maintain an effective system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of the Exchange Act) that is designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms, including controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure.

      (dd) Accounting Controls. The Company and its subsidiaries maintain systems of “internal control over financial reporting” (as defined in Rule 13a-15(f) of the Exchange Act) that comply with the requirements of the Exchange Act and have been designed by, or under the supervision of, their respective principal executive and principal financial officers, or persons performing similar functions, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles, including, but not limited to internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. Except as disclosed in the Registration Statement, the Time of Sale Information and the Prospectus, there are no material weaknesses in the Company’s internal controls.

      (ee) Insurance. Except as described in or expressly contemplated by the Registration Statement, the Time of Sale Information and the Prospectus, the Company and its subsidiaries have insurance covering their respective properties, operations, personnel and businesses, which insurance is in amounts and insures against such losses and risks as the Company reasonably believes are adequate to protect the Company and its subsidiaries and their respective businesses; and neither the Company nor any of its subsidiaries has (i) received notice from any insurer or agent of such insurer that material capital improvements or other expenditures are required or necessary to be made in order to continue such insurance, or (ii) any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage at reasonable cost from similar insurers as may be necessary to continue its business.

      (ff) No Unlawful Payments. Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or other person associated with or acting on behalf of the Company or any of its subsidiaries has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; (iii) violated or is in violation of any

provision of the Foreign Corrupt Practices Act of 1977, as amended; or (iv) made any unlawful bribe, rebate, payoff, influence payment, kickback or other unlawful payment.

      (gg) Compliance with Money Laundering Laws. 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 applicable money laundering statutes of all jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

      (hh) Compliance with OFAC. None of the Company, any of its subsidiaries or, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its subsidiaries is currently identified on the lists of sanctioned persons as being subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Department of the Treasury (“OFAC”); and the Company will not directly or indirectly use the proceeds of the offering of the Shares hereunder, 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 in violation of any U.S. sanctions administered by OFAC.

      (ii) No Restrictions on Subsidiaries. Except as described in or expressly contemplated by the Registration Statement, the Time of Sale Information and the Prospectus, no subsidiary of the Company is currently prohibited, directly or indirectly, under any agreement or other instrument to which it is a party or is subject, from paying any dividends to the Company, from making any other distribution on such subsidiary’s capital stock, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary’s properties or assets to the Company or any other subsidiary of the Company.

      (jj) No Broker’s Fees. 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 any of its subsidiaries or any Underwriter for a brokerage commission, finder’s fee or like payment in connection with the offering and sale of the Shares.

      (kk) No Registration Rights. Except as described in or expressly contemplated by the Registration Statement, the Time of Sale Information and the Prospectus, no person has the right to require the Company or any of its subsidiaries to register any securities for sale under the Securities Act by reason of the filing of the Registration Statement with the Commission or the issuance and sale of the Shares.

      (ll) No Stabilization. The Company has not taken, directly or indirectly, without giving effect to activities by the Underwriters, any action designed to or that would reasonably be expected to cause or result in any stabilization or manipulation of the price of the Shares.

      (mm) Business With Cuba. The Company has not done business in Cuba or with the Government of Cuba.

      (nn) Margin Rules. Neither the issuance, sale and delivery of the Shares nor the application of the proceeds thereof by the Company as described in the Registration Statement, the Time of Sale Information and the Prospectus will violate Regulation T, U or X of the Board of Governors of the Federal Reserve System or any other regulation of such Board of Governors.

      (oo) Forward Looking Statements. No forward looking statement (within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act) contained in the Registration Statement, the Time of Sale Information and the Prospectus has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith.

      (pp) Statistical and Market Data. Nothing has come to the attention of the Company that has caused the Company to believe that the statistical and market-related data included in the Registration Statement, the Time of Sale Information and the Prospectus is not based on or derived from sources that are reliable and accurate in all material respects.

      (qq) Sarbanes-Oxley Act. There is and has been no failure on the part of the Company or any of the Company’s directors or officers, in their capacities as such, to comply with any applicable provision of the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith (the “Sarbanes-Oxley Act”), including Section 402 related to loans.

      (rr) Off-Balance Sheet Arrangements. There are no transactions, arrangements or other relationships between or among the Company, its subsidiaries, any of its affiliates and any unconsolidated entity, including, but not limited to, any structured finance, special purpose or limited purpose entity that would reasonably be expected to materially affect the Company’s liquidity or the availability of or requirements for its capital resources that are required to be described in the Prospectus and that have not been described as required.

      (ss) Status under the Securities Act. The Company is not an ineligible issuer as defined under the Securities Act, in each case at the times specified in the Securities Act in connection with the offering of the Shares.

      4. Representations and Warranties of the Selling Stockholders. Each of the Selling Stockholders, severally and not jointly, represents and warrants to each Underwriter and the Company that:

      (a) Required Consents; Authority. All consents, approvals, authorizations and orders necessary for the execution and delivery by such Selling Stockholder of this Agreement and the Power of Attorney (the “Power of Attorney”) and the Custody Agreement (the “Custody Agreement”) hereinafter referred to, and for the sale and delivery of the Shares to be sold by such Selling Stockholder hereunder, have been obtained; and such Selling Stockholder has full right, power and authority to enter into this Agreement, the Power of Attorney and the Custody Agreement and to sell, assign, transfer and deliver the Shares to be sold by such Selling Stockholder hereunder; this Agreement, the Power of Attorney and the Custody Agreement have each been duly authorized, executed and delivered by such Selling Stockholder.

      (b) No Conflicts. The execution, delivery and performance by such Selling Stockholder of this Agreement, the Power of Attorney and the Custody Agreement, the sale of the Shares to be sold by such Selling Stockholder and the consummation by such Selling Stockholder of the transactions herein and therein contemplated will not (i) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of such Selling Stockholder pursuant to, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which such Selling Stockholder is a party or by which such Selling Stockholder is bound or to which any of the property or assets of such Selling Stockholder is subject, (ii) result in any violation of the provisions of the charter or by-laws or similar organizational documents of such Selling Stockholder or (iii) result in the violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory agency having jurisdiction over such Selling Stockholder.

      (c) Title to Shares. Such Selling Stockholder has good and valid title to the Shares to be sold at the Additional Closing Date by such Selling Stockholder hereunder, free and clear of all liens, encumbrances, equities or adverse claims; such Selling Stockholder will have, immediately prior to the Additional Closing Date, good and valid title to the Shares to be sold at the Additional Closing Date by such Selling Stockholder, free and clear of all liens, encumbrances, equities or adverse claims; and, upon delivery of the certificates representing such Shares and payment therefor pursuant hereto, good and valid title to such Shares, free and clear of all liens, encumbrances, equities or adverse claims, other than any such lien, encumbrance, equity or adverse claim created by or resulting from an action taken by any Underwriter, will pass to the several Underwriters.

      (d) No Stabilization. Such Selling Stockholder has not taken and will not take, directly or indirectly, without giving effect to activities by the Underwriters, any action designed to or that would reasonably be expected to cause or result in any stabilization or manipulation of the price of the Shares.

      (e) Time of Sale Information. The Time of Sale Information, at the Time of Sale did not, and at the Closing Date and as of the Additional Closing Date, as the case may be, will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that such Selling Stockholder makes no representation and warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use in such Time of Sale Information; provided, further, that the representations and warranties given in this paragraph by each Selling Stockholder only apply to statements or omissions in the Registration Statement, the Time of Sale Information or the Prospectus and any amendment or supplement thereto made in reliance upon and in conformity with information relating to such Selling Stockholder furnished to the Company or the Underwriters in writing by or on behalf of such Selling Stockholder expressly for use therein.

      (f) Issuer Free Writing Prospectus. Other than the Preliminary Prospectus and the Prospectus, such Selling Stockholder (including its agents and representatives, other than the Underwriters in their capacity as such) has not made, used, prepared, authorized, approved or

referred to and will not prepare, make, use, authorize, approve or refer to any Issuer Free Writing Prospectus, other than (i) any document not constituting a prospectus pursuant to Section 2(a)(10)(a) of the Securities Act or Rule 134 under the Securities Act or (ii) the documents listed on Annex B hereto and other written communications approved in writing in advance by the Company and the Representatives.

      (g) Registration Statement and Prospectus. As of the applicable effective date of the Registration Statement and any amendment thereto, the statements in the Registration Statement did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading; and as of the date of the Prospectus and any amendment or supplement thereto and as of the Closing Date and as of the Additional Closing Date, as the case may be, the Prospectus will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that such Selling Stockholder makes no representation and warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use in the Registration Statement, the Time of Sale Information and the Prospectus and any amendment or supplement thereto; provided, further, that the representations and warranties given in this paragraph by each Selling Stockholder only apply to statements or omissions in the Registration Statement, the Time of Sale Information or the Prospectus and any amendment or supplement thereto made in reliance upon and in conformity with information relating to such Selling Stockholder furnished to the Company or the Underwriters in writing by or on behalf of such Selling Stockholder expressly for use therein.

      (h) Material Information. As of the date hereof, as of the Closing Date and as of the Additional Closing Date, as the case may be, that the sale of the Shares by such Selling Stockholder is not and will not be prompted by any material information concerning the Company which is not set forth in the Registration Statement, the Time of Sale Information or the Prospectus. Each of the Selling Stockholders represents and warrants that certificates in negotiable form representing all of the Shares to be sold by such Selling Stockholders hereunder have been placed in custody under a Custody Agreement relating to such Shares, in the form heretofore furnished to you, duly executed and delivered by such Selling Stockholder to [ ], as custodian (the “Custodian”), and that such Selling Stockholder has duly executed and delivered Powers of Attorney, in the form heretofore furnished to you, appointing the person or persons indicated in Schedule II hereto, and each of them, as such Selling Stockholder’s Attorneys-in-fact (the “Attorneys-in-Fact” or any one of them the “Attorney-in Fact”) with authority to execute and deliver this Agreement on behalf of such Selling Stockholder, to determine the purchase price to be paid by the Underwriters to the Selling Stockholders as provided herein, to authorize the delivery of the Shares to be sold by such Selling Stockholder hereunder and otherwise to act on behalf of such Selling Stockholder in connection with the transactions contemplated by this Agreement and the Custody Agreement.

      Each of the Selling Stockholders, severally and not jointly, specifically agrees that the Shares represented by the certificates held in custody for such Selling Stockholder under the Custody Agreement, are subject to the interests of the Underwriters hereunder, and that the

arrangements made by such Selling Stockholder for such custody, and the appointment by such Selling Stockholder of the Attorneys-in-Fact by the Power of Attorney, are to that extent irrevocable. Each of the Selling Stockholders specifically agrees that the obligations of such Selling Stockholder hereunder shall not be terminated by operation of law, whether by the death or incapacity of any individual Selling Stockholder, or, in the case of an estate or trust, by the death or incapacity of any executor or trustee or the termination of such estate or trust, or in the case of a partnership, corporation or similar organization, by the dissolution of such partnership, corporation or organization, or by the occurrence of any other event. If any individual Selling Stockholder or any such executor or trustee should die or become incapacitated, or if any such estate or trust should be terminated, or if any such partnership, corporation or similar organization should be dissolved, or if any other such event should occur, before the delivery of the Shares hereunder, certificates representing such Shares shall be delivered by or on behalf of such Selling Stockholder in accordance with the terms and conditions of this Agreement and the Custody Agreement, and actions taken by the Attorneys-in-Fact pursuant to the Powers of Attorney shall be as valid as if such death, incapacity, termination, dissolution or other event had not occurred, regardless of whether or not the Custodian, the Attorneys-in-Fact, or any of them, shall have received notice of such death, incapacity, termination, dissolution or other event.

      5. Further Agreements of the Company. The Company covenants and agrees with each Underwriter that:

      (a) Required Filings. The Company will file the Prospectus with the Commission within the time periods specified by Rule 424(b) and Rule 430A or 430C under the Securities Act and will file any Issuer Free Writing Prospectus to the extent required by Rule 433 under the Securities Act; and the Company will furnish copies of the Prospectus and each Issuer Free Writing Prospectus (to the extent not previously delivered) to the Underwriters in New York City as soon as practicable but in no event later than 10:00 A.M., New York City time on the second business day succeeding the date of this Agreement in such quantities as the Representatives may reasonably request.

      (b) Delivery of Copies. The Company will deliver, without charge, (i) to the Representatives, four signed copies of the Registration Statement as originally filed and each amendment thereto, in each case including all exhibits and consents filed therewith; and (ii) to each Underwriter (A) a conformed copy of the Registration Statement as originally filed and each amendment thereto (without exhibits) and (B) during the Prospectus Delivery Period (as defined below), as many copies of the Prospectus (including all amendments and supplements thereto) and each Issuer Free Writing Prospectus as the Representatives may reasonably request. As used herein, the term “Prospectus Delivery Period” means such period of time after the first date of the public offering of the Shares as in the opinion of counsel for the Underwriters a prospectus relating to the Shares is required by law to be delivered (or required to be delivered but for Rule 172 under the Securities Act) in connection with sales of the Shares by any Underwriter or dealer.

      (c) Amendments or Supplements, Issuer Free Writing Prospectuses. Before preparing, using, authorizing, approving, referring to or filing any Issuer Free Writing Prospectus, and before filing any amendment or supplement to the Registration Statement or the Prospectus, the Company will furnish to the Representatives and counsel for the Underwriters a

copy of the proposed Issuer Free Writing Prospectus, amendment or supplement for review and will not prepare, use, authorize, approve, refer to or file any such Issuer Free Writing Prospectus or file any such proposed amendment or supplement to which the Representatives reasonably object.

      (d) Notice to the Representatives. The Company will advise the Representatives promptly, and confirm such advice in writing, (i) when the Registration Statement has become effective; (ii) when any amendment to the Registration Statement has been filed or becomes effective; (iii) when any supplement to the Prospectus or any Issuer Free Writing Prospectus or any amendment to the Prospectus has been filed; (iv) of any request by the Commission for any amendment to the Registration Statement or any amendment or supplement to the Prospectus or the receipt of any comments from the Commission relating to the Registration Statement or any other request by the Commission for any additional information; (v) of the issuance by the Commission of any order suspending the effectiveness of the Registration Statement or preventing or suspending the use of any Preliminary Prospectus or the Prospectus or the initiation or threatening of any proceeding for that purpose or pursuant to Section 8A of the Securities Act; (vi) of the occurrence of any event within the Prospectus Delivery Period as a result of which the Prospectus, the Time of Sale Information or any Issuer Free Writing Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances existing when the Prospectus, the Time of Sale Information or any such Issuer Free Writing Prospectus is delivered to a purchaser, not misleading; and (vii) of the receipt by the Company of any notice with respect to any suspension of the qualification of the Shares for offer and sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose; and the Company will use its best efforts to prevent the issuance of any such order suspending the effectiveness of the Registration Statement, preventing or suspending the use of any Preliminary Prospectus or the Prospectus or suspending any such qualification of the Shares and, if any such order is issued, will use its best efforts to obtain as soon as possible the withdrawal thereof.

      (e) Ongoing Compliance. (1) If during the Prospectus Delivery Period (i) any event shall occur or condition shall exist as a result of which the Prospectus as then amended or supplemented would include 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 the light of the circumstances existing when the Prospectus is delivered to a purchaser, not misleading or (ii) it is necessary to amend or supplement the Prospectus to comply with law, the Company will immediately notify the Underwriters thereof and forthwith prepare and, subject to paragraph (c) above, file with the Commission and furnish to the Underwriters and to such dealers as the Representatives may designate, such amendments or supplements to the Prospectus as may be necessary so that the statements in the Prospectus as so amended or supplemented will not, in the light of the circumstances existing when the Prospectus is delivered to a purchaser, be misleading or so that the Prospectus will comply with law and (2) if at any time prior to the Closing Date (i) any event shall occur or condition shall exist as a result of which the Time of Sale Information as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances, not misleading or (ii) it is necessary to amend or supplement the Time of Sale Information to comply with law, the Company will immediately notify the

Underwriters thereof and forthwith prepare and, subject to paragraph (c) above, file with the Commission (to the extent required) and furnish to the Underwriters and to such dealers as the Representatives may designate, such amendments or supplements to the Time of Sale Information as may be necessary so that the statements in the Time of Sale Information as so amended or supplemented will not, in the light of the circumstances, be misleading or so that the Time of Sale Information will comply with law.

      (f) Blue Sky Compliance. The Company will qualify the Shares for offer and sale under the securities or Blue Sky laws of such jurisdictions as the Representatives shall reasonably request and will continue such qualifications in effect so long as required for distribution of the Shares; provided that the Company shall not be required to (i) qualify as a foreign corporation or other entity or as a dealer in securities in any such jurisdiction where it would not otherwise be required to qualify, (ii) file any general consent to service of process in any such jurisdiction or (iii) subject itself to taxation in any jurisdiction if it is not otherwise so subject.

      (g) Earning Statement. The Company will make generally available to its security holders and the Representatives as soon as practicable an earning statement that satisfies the provisions of Section 11(a) of the Securities Act and Rule 158 of the Commission promulgated thereunder covering a period of at least twelve months beginning with the first fiscal quarter of the Company occurring after the “effective date” (as defined in Rule 158) of the Registration Statement.

      (h) Clear Market. For a period of 180 days after the date of the Prospectus, the Company will not (i) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or (ii) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise, without the prior written consent of J.P. Morgan Securities Inc. on behalf of the Representatives, other than (w) the Shares to be sold hereunder, (x) any shares of Common Stock issued upon the exercise of outstanding options or under existing employee or director compensation or stock option plans, (y) options or rights to purchase Common Stock granted under existing employee or director compensation or stock option plans and (z) up to an aggregate of 1,370,000 shares of Common Stock or securities convertible into or exercisable or exchangeable for Common Stock issued in connection with any transaction with an unaffiliated third party that includes a commercial relationship (including joint ventures, marketing or distributing arrangements, collaboration agreements or intellectual property license agreements) or any acquisition of assets or acquisition of a majority or controlling portion of the equity of another entity; provided, however, that any recipient of Common Stock or securities convertible into or exercisable or exchangeable for Common Stock pursuant to clause (z) above executes and delivers to the Representatives a “lock-up” agreement covering such Common Stock or securities for the remainder of the 180-day restricted period, or any extension thereof as described below, substantially in the form of Exhibit A hereto. Notwithstanding the foregoing, if (1) during the last 17 days of the 180-day restricted period, the Company issues an earnings release or material

news or a material event relating to the Company occurs; or (2) prior to the expiration of the 180-day restricted period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the 180-day period, the restrictions imposed by this Agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event.

      (i) Use of Proceeds. The Company will apply the net proceeds from the sale of the Shares in all material respects as described in the Registration Statement, the Time of Sale Information and the Prospectus under the heading “Use of proceeds.”

      (j) No Stabilization. The Company will not take, directly or indirectly, without giving effect to activities by the Underwriters, any action designed to or that would reasonably be expected to cause or result in any stabilization or manipulation of the price of the Shares.

      (k) Exchange Listing. The Company will use its best efforts to list the Shares on the New York Stock Exchange.

      (l) Reports. During a period of three years from the date hereof, the Company will furnish to the Representatives, as soon as they are available, copies of all reports or other communications (financial or other) furnished to holders of the Shares, and copies of any reports and financial statements furnished to or filed with the Commission or any national securities exchange or automatic quotation system; provided that any report, communication or financial statement furnished or filed with the Commission that is publicly available on the Commission’s EDGAR system shall be deemed to have been furnished to the Representatives at the time furnished or filed with the Commission.

      (m) Record Retention. The Company will, pursuant to reasonable procedures developed in good faith, retain copies of each Issuer Free Writing Prospectus that is not filed with the Commission in accordance with Rule 433 under the Securities Act.

      (n) Filings. The Company will file with the Commission such reports as may be required by Rule 463 under the Securities Act.

      6. Further Agreements of the Selling Stockholders. Each of the Selling Stockholders, severally and not jointly, covenants and agrees with each Underwriter that:

      (a) Clear Market. It will comply with the terms of the “lock-up” agreement, substantially in the form of Exhibit A hereto, entered into with the Underwriters on or before the date hereof.

      (b) Tax Form. It will deliver to the Representatives prior to or at the Closing Date a properly completed and executed United States Treasury Department Form W-9 (or other applicable form or statement specified by the Treasury Department regulations in lieu thereof) in order to facilitate the Underwriters’ documentation of their compliance with the reporting and withholding provisions of the Tax Equity and Fiscal Responsibility Act of 1982 with respect to the transactions herein contemplated.

      7. Certain Agreements of the Underwriters. Each Underwriter hereby represents and agrees that:

      (a) It has not and will not use, authorize use of, refer to, or participate in the planning for use of, any “free writing prospectus,” as defined in Rule 405 under the Securities Act (which term includes use of any written information furnished to the Commission by the Company and not incorporated by reference into the Registration Statement and any press release issued by the Company) other than (i) a free writing prospectus that contains no “issuer information” (as defined in Rule 433(h)(2) under the Securities Act) that was not included (including through incorporation by reference) in the Preliminary Prospectus or a previously filed Issuer Free Writing Prospectus, (ii) any Issuer Free Writing Prospectus listed on Annex B or prepared pursuant to Section 3(c) or Section 4(c) above, or (iii) any free writing prospectus prepared by such underwriter and approved by the Company in advance in writing (each such free writing prospectus referred to in clauses (i) or (iii), an “Underwriter Free Writing Prospectus”).

      (b) It has not and will not distribute any Underwriter Free Writing Prospectus referred to in clause (a)(i) in a manner reasonably designed to lead to its broad unrestricted dissemination.

      (c) It has not and will not, without the prior written consent of the Company, use any free writing prospectus that contains the final terms of the Shares unless such terms have previously been included in a free writing prospectus filed with the Commission; provided that Underwriters may use a term sheet substantially in the form of Annex C hereto without the consent of the Company; provided, further, that any Underwriter using such term sheet shall notify the Company, and provide a copy of such term sheet to the Company, prior to, or substantially concurrently with, the first use of such term sheet.

      (d) It will, pursuant to reasonable procedures developed in good faith, retain copies of each free writing prospectus used or referred to by it, in accordance with Rule 433 under the Securities Act.

      (e) It is not subject to any pending proceeding under Section 8A of the Securities Act with respect to the offering (and will promptly notify the Company if any such proceeding against it is initiated during the Prospectus Delivery Period).

      8. Conditions of Underwriters’ Obligations. The obligation of each Underwriter to purchase the Underwritten Shares on the Closing Date or the Option Shares on the Additional Closing Date, as the case may be, as provided herein is subject to the performance by the Company and each of the Selling Stockholders of their respective covenants and other obligations hereunder and to the following additional conditions:

      (a) Registration Compliance; No Stop Order. No order suspending the effectiveness of the Registration Statement shall be in effect, and no proceeding for such purpose or pursuant to Section 8A under the Securities Act shall be pending before or threatened by the Commission; the Prospectus and each Issuer Free Writing Prospectus shall have been timely filed with the Commission under the Securities Act (in the case of an Issuer Free Writing Prospectus, to the extent required by Rule 433 under the Securities Act) and in accordance with Section 4(a)

hereof; and all requests by the Commission for additional information shall have been complied with to the reasonable satisfaction of the Representatives.

      (b) Representations and Warranties. The respective representations and warranties of the Company and the Selling Stockholders contained herein shall be true and correct on the date hereof and on and as of the Closing Date or the Additional Closing Date, as the case may be; and the statements of the Company and its officers and each of the Selling Stockholders made in any certificates delivered pursuant to this Agreement shall be true and correct on and as of the Closing Date or the Additional Closing Date, as the case may be.

      (c) No Downgrade. Subsequent to the execution and delivery of this Agreement, (i) no downgrading shall have occurred in the rating accorded any debt securities or preferred stock of or guaranteed by the Company or any of its subsidiaries by any “nationally recognized statistical rating organization,” as such term is defined by the Commission for purposes of Rule 436(g)(2) under the Securities Act and (ii) no such organization shall have publicly announced that it has under surveillance or review, or has changed its outlook with respect to, its rating of any debt securities or preferred stock of or guaranteed by the Company or any of its subsidiaries (other than an announcement with positive implications of a possible upgrading).

      (d) No Material Adverse Change. No event or condition of a type described in Section 3(f)(i) hereof shall have occurred or shall exist, which event or condition is not described in the Time of Sale Information (excluding any amendment or supplement thereto) and the Prospectus (excluding any amendment or supplement thereto) and the effect of which in the judgment of the Representatives makes it impracticable or inadvisable to proceed with the offering, sale or delivery of the Shares on the Closing Date or the Additional Closing Date, as the case may be, on the terms and in the manner contemplated by this Agreement, the Time of Sale Information and the Prospectus.

      (e) Officer’s Certificate. The Representatives shall have received on and as of the Closing Date or the Additional Closing Date, as the case may be, (i) a certificate on behalf of the Company of the chief financial officer or chief accounting officer of the Company and one additional senior executive officer of the Company who is reasonably satisfactory to the Representatives (1) confirming that such officers have carefully reviewed the Registration Statement, the Time of Sale Information and the Prospectus and, to the knowledge of such officers, the representations of the Company set forth in Sections 3(b) and 3(d) hereof are true and correct, (2) confirming that the other representations and warranties of the Company in this Agreement are true and correct and that the Company has complied in all material respects with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date and (3) to the effect set forth in paragraphs (a), (c) and (d) above and (ii) one or more certificates on behalf of the Selling Stockholders of an officer or representative of each such Selling Stockholder who is reasonably satisfactory to the Representatives, (1) confirming that, to the knowledge of such officer or representative, the representations of such Selling Stockholders set forth in Sections 4(e), 4(f) and 4(g) hereof are true and correct and (2) confirming that the other representations and warranties of such Selling Stockholder in this agreement are true and correct and that such Selling Stockholder has complied in all material respects with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date.

      (f) Comfort Letters. On the date of this Agreement and on the Closing Date or the Additional Closing Date, as the case may be, Ernst & Young LLP shall have furnished to the Representatives, at the request of the Company, letters, dated the respective dates of delivery thereof and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement, the Time of Sale Information and the Prospectus; provided that the letter delivered on the Closing Date or the Additional Closing Date, as the case may be shall use a “cut-off” date no more than three business days prior to such Closing Date or such Additional Closing Date, as the case may be.

      (g) Opinion of Counsel for the Company. Wilmer Cutler Pickering Hale and Dorr LLP, counsel for the Company, shall have furnished to the Representatives, at the request of the Company, their written opinion, dated the Closing Date or the Additional Closing Date, as the case may be, and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Annex A hereto.

      (h) Opinions of Special Patent Counsel for Company. Gill Jennings & Every LLP, Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, and Sterne, Kessler, Goldstein & Fox P.L.L.C., special patent counsel for the Company, shall have each furnished to the Representatives, at the request of the Company, their written opinions, dated the Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Annex D hereto.

      (i) Opinion of Counsel for the Selling Stockholders. Thelen Reid & Priest LLP, counsel for the Selling Stockholders, shall have furnished to the Representatives, at the request of the Selling Stockholders, their written opinion, dated the Additional Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Annex E hereto.

      (j) Opinion of Special Regulatory Counsel for the Company. Thelen Reid & Priest LLP, special regulatory counsel for the Company, shall have furnished to the Representatives, at the request of the Selling Stockholders, their written opinion, dated the Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, to the effect set forth in Annex F hereto.

      (k) Opinion of Counsel for the Underwriters. The Representatives shall have received on and as of the Closing Date or the Additional Closing Date, as the case may be, an opinion of Dechert LLP, counsel for the Underwriters, with respect to such matters as the Representatives may reasonably request, and such counsel shall have received such documents and information as they may reasonably request to enable them to pass upon such matters.

      (l) No Legal Impediment to Issuance. No action shall have been taken and no statute, rule, regulation or order shall have been enacted, adopted or issued by any federal, state or foreign governmental or regulatory authority that would, as of the Closing Date or the Additional Closing Date, as the case may be, prevent the issuance or sale of the Shares; and no injunction or order of any federal, state or foreign court shall have been issued that would, as of the Closing

Date or the Additional Closing Date, as the case may be, prevent the issuance or sale of the Shares.

      (m) Good Standing. The Representatives shall have received on and as of the Closing Date or the Additional Closing Date, as the case may be, satisfactory evidence of the good standing of the Company and its subsidiaries in their respective jurisdictions of organization and their good standing as foreign entities in such other jurisdictions as the Representatives may reasonably request upon reasonable advance notice, in each case in writing or any standard form of telecommunication from the appropriate Governmental Authorities of such jurisdictions.

      (n) Exchange Listing. The Shares to be delivered on the Closing Date or the Additional Closing Date, as the case may be, shall have been approved for listing on the New York Stock Exchange, subject to official notice of issuance.

      (o) Lock-up Agreements. The “lock-up” agreements, each substantially in the form of Exhibit A hereto, between you and certain stockholders, officers and directors of the Company relating to sales and certain other dispositions of shares of Stock or certain other securities, delivered to you on or before the date hereof, shall be full force and effect on the Closing Date or the Additional Closing Date, as the case may be.

      (p) Additional Documents. On or prior to the Closing Date or the Additional Closing Date, as the case may be, the Company and the Selling Stockholders shall have furnished to the Representatives such further certificates and documents as the Representatives may reasonably request.

      All opinions, letters, certificates and evidence mentioned above or elsewhere in this Agreement shall be deemed to be in compliance with the provisions hereof only if they are in form and substance reasonably satisfactory to counsel for the Underwriters.

      9. Indemnification and Contribution.

      (a) Indemnification of the Underwriters by the Company. The Company agrees to indemnify and hold harmless each Underwriter, its affiliates, directors and officers and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any and all losses, claims, damages and liabilities (including, without limitation, reasonable legal fees and other reasonable expenses incurred in connection with any suit, action or proceeding or any claim asserted, as such fees and expenses are incurred), joint or several, that arise out of, or are based upon, (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary in order to make the statements therein, not misleading, (ii) or any untrue statement or alleged untrue statement of a material fact contained in the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Time of Sale Information (including any Time of Sale Information that has subsequently been amended), or caused by any omission or alleged omission to state therein a material fact necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading, in each case except insofar as such losses, claims, damages or liabilities arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in paragraph (c) below.

      The Company also agrees to indemnify and hold harmless, Cowen and Company, LLC, its affiliates, directors and officers and each person, if any, who controls Cowen and Company, LLC, within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any and all losses, claims, damages and liabilities incurred as a result of Cowen and Company, LLC’s participation as a “qualified independent underwriter” within the meaning of the Rules of Conduct of the National Association of Securities Dealers, Inc. in connection with the offering of the Shares.

      (b) Indemnification of the Underwriters by the Selling Stockholders. Each of the Selling Stockholders severally in proportion to the number of Shares to be sold by such Selling Stockholder hereunder agrees to indemnify and hold harmless each Underwriter, its affiliates, directors and officers and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the indemnity set forth in paragraph (a) above, but only with respect to any losses, claims, damages or liabilities that arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to such Selling Stockholder furnished to the Company in writing by or on behalf of such Selling Stockholder expressly for use in the Registration Statement, the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Time of Sale Information, it being understood and agreed upon that the only such information furnished by any Selling Stockholder consists of the information specifically relating to the Selling Stockholder under the caption “Principal and selling stockholders” in the Prospectus and the Preliminary Prospectus, in each case except insofar as such losses, claims, damages or liabilities

arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to any Underwriter furnished to the Company in writing by or on behalf of any Underwriter expressly for use in the Registration Statement, the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Time of Sale Information, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in paragraph (c) below.

      Each of the Selling Stockholders severally in proportion to the number of Shares to be sold by such Selling Stockholder hereunder also agrees to indemnify and hold harmless Cowen and Company, LLC, its affiliates, directors and officers and each person, if any, who controls Cowen and Company, LLC, within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any and all losses, claims, damages and liabilities incurred as a result of Cowen and Company, LLC’s participation as a “qualified independent underwriter” within the meaning of the Rules of Conduct of the National Association of Securities Dealers, Inc. in connection with the offering of the Shares, but only with respect to any losses, claims, damages or liabilities that arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to such Selling Stockholder furnished to the Company in writing by or on behalf of such Selling Stockholder expressly for use in the Registration Statement, the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Time of Sale Information, it being understood and agreed upon that the only such information furnished by any Selling Stockholder consists of the information specifically relating to the Selling Stockholder under the caption “Principal and selling stockholders” in the Prospectus and the Preliminary Prospectus.

      (c) Indemnification of the Company and the Selling Stockholders. Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, its directors, its officers who signed the Registration Statement 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 and each of the Selling Stockholders to the same extent as the indemnity set forth in paragraph (a) above, but only with respect to any losses, claims, damages or liabilities that arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to such Underwriter s furnished to the Company in writing by or on behalf of any Underwriter expressly for use in the Registration Statement, the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Time of Sale Information, it being understood and agreed upon that the only such information furnished by any Underwriter consists of: [___]

      (d) Notice and Procedures. If any suit, action, proceeding (including any governmental or regulatory investigation), claim or demand shall be brought or asserted against any person in respect of which indemnification may be sought pursuant to the preceding paragraphs of this Section 9 above, such person (the “Indemnified Person”) shall promptly notify the person against whom such indemnification may be sought (the “Indemnifying Person”) in writing; provided that the failure to notify the Indemnifying Person shall not relieve the Indemnifying Party from any liability that it may have under this Section 9 except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such

failure; and provided, further, that the failure to notify the Indemnifying Person shall not relieve it from any liability that it may have to an Indemnified Person otherwise than under this Section 9. If any such proceeding shall be brought or asserted against an Indemnified Person and it shall have notified the Indemnifying Person thereof, the Indemnifying Person shall be entitled to participate therein and, to the extent it wishes, jointly with any other similarly notified Indemnifying Person, to assume the defense thereof with counsel reasonably satisfactory to the Indemnified Person to represent the Indemnified Person and any others entitled to indemnification pursuant to this Section 9 that the Indemnifying Person may designate in such proceeding and shall pay the fees and expenses of such counsel related to such proceeding, as incurred. After notice from the Indemnifying Person to the Indemnified Person of its election to assume the defense of such proceeding, the Indemnifying Person shall not be liable to the Indemnified Person under this Section 9 for any legal or other expenses subsequently incurred by the Indemnified Person in connection with the defense thereof other than reasonable costs of investigation; provided, however, that in any such proceeding, any Indemnified Person shall have the right to retain its own counsel to participate in, but not control, the defense of such proceeding, but the fees and expenses of such counsel shall be at the expense of such Indemnified Person unless (i) the Indemnifying Person and the Indemnified Person shall have mutually agreed to the contrary or (ii) the Indemnifying Person has failed within a reasonable time to retain counsel reasonably satisfactory to the Indemnified Person. It is understood and agreed that the Indemnifying Person shall not, in connection with any proceeding or related proceeding in the same jurisdiction, be liable for the fees and expenses of more than one separate firm (in addition to any local counsel) for all Indemnified Persons, and that all such reasonable fees and expenses shall be paid or reimbursed as they are incurred; provided, however, that if indemnity may be sought pursuant to the second paragraph of Section 7(a) above in respect of such proceeding, then in addition to such separate firm for the Underwriters, their affiliates and such control persons of the Underwriters the indemnifying party shall be liable for the fees and expenses of not more than one separate firm (in addition to any local counsel) for Cowen and Company, LLC in its capacity as a “qualified independent underwriter,” its affiliates and all persons, if any, who control Cowen and Company, LLC within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act. Any such separate firm for any Underwriter, its affiliates, directors and officers and any control persons of such Underwriter shall be designated in writing by J.P. Morgan Securities Inc., any such separate firm for Cowen and Company, LLC, in its capacity as a “qualified independent underwriter,” shall be designated in writing by Cowen and Company, LLC, any such separate firm for the Company, its directors, its officers who signed the Registration Statement and any control persons of the Company shall be designated in writing by the Company and any separate firm for the Selling Stockholders shall be designated in writing by the Attorney-in-Fact. The Indemnifying Person 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 Person agrees to indemnify each Indemnified Person from and against any loss or liability by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an Indemnified Person shall have requested that an Indemnifying Person reimburse the Indemnified Person for fees and expenses of counsel as contemplated by this paragraph, the Indemnifying Person shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into (A) more than 60 days after receipt by the Indemnifying Person of such request and (B) more than 30 days after receipt by the Indemnifying Party of the proposed terms of such

settlement and (ii) the Indemnifying Person shall not have reimbursed the Indemnifying Person in accordance with such request prior to the date of such settlement. No Indemnifying Person shall, without the written consent of the Indemnified Person, effect any settlement of any pending or threatened proceeding in respect of which any Indemnified Person is or could have been a party and indemnification could have been sought hereunder by such Indemnified Person, unless such settlement (x) includes an unconditional release of such Indemnified Person, in form and substance reasonably satisfactory to such Indemnified Person, from all liability on claims that are the subject matter of such proceeding and (y) does not include any statement as to or any admission of fault, culpability or a failure to act by or on behalf of any Indemnified Person.

      (e) Contribution. If the indemnification provided for in paragraphs (a), (b) and (c) above is unavailable to an Indemnified Person or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each Indemnifying Person under such paragraph, in lieu of indemnifying such Indemnified Person thereunder, shall contribute to the amount paid or payable by such Indemnified Person as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Stockholders, on the one hand, and the Underwriters or Cowen and Company, LLC in its capacity as a “qualified independent underwriter,” as the case may be, on the other, from the offering of the Shares or (ii) if the allocation provided by clause (i) is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) but also the relative fault of the Company and the Selling Stockholders, on the one hand, and the Underwriters or Cowen and Company, LLC in its capacity as a “qualified independent underwriter,” as the case may be, on the other, in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company and the Selling Stockholders, on the one hand, and the Underwriters or Cowen and Company, LLC in its capacity as a “qualified independent underwriter,” as the case may be, on the other, shall be deemed to be in the same respective proportions as the net proceeds (before deducting expenses) received by the Company and the Selling Stockholders, as the case may be, from the sale of the Shares and the total underwriting discounts and commissions received by the Underwriters in connection therewith, in each case as set forth in the table on the cover of the Prospectus, bear to the aggregate offering price of the Shares. The relative fault of the Company and the Selling Stockholders, on the one hand, and the Underwriters or Cowen and Company, LLC in its capacity as a “qualified independent underwriter,” as the case may be, on the other, shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company and the Selling Stockholders or by the Underwriters or Cowen and Company, LLC in its capacity as a “qualified independent underwriter,” as the case may be, and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

      (f) Limitation on Liability. The Company, the Selling Stockholders and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 9 were determined by pro rata allocation (even if the Selling Stockholders or the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in paragraph (e) above. The amount paid or payable by an Indemnified Person as a result of the losses, claims, damages and liabilities

referred to in paragraph (e) above shall be deemed to include, subject to the limitations set forth above, any reasonable legal or other expenses incurred by such Indemnified Person in connection with any such action or claim. Notwithstanding the provisions of this Section 9, in no event shall an Underwriter be required to contribute any amount in excess of the amount by which the total underwriting discounts and commissions received by such Underwriter with respect to the offering of the Shares exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 9 are several in proportion to their respective purchase obligations hereunder and not joint. The Selling Stockholders’ obligations to contribute pursuant to this Section 9 are several in proportion to their respective receipt of net proceeds (before expenses) hereunder and not joint.

      (g) Non-Exclusive Remedies. The remedies provided for in this Section 9 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any Indemnified Person at law or in equity.

      10. Effectiveness of Agreement. This Agreement shall become effective upon the execution and delivery hereof by the parties hereto.

      11. Termination. This Agreement may be terminated in the absolute discretion of the Representatives, by notice to the Company and the Selling Stockholders, if after the execution and delivery of this Agreement and prior to the Closing Date or, in the case of the Option Shares, prior to the Additional Closing Date (i) trading generally shall have been suspended or materially limited on or by any of the New York Stock Exchange, the American Stock Exchange, the National Association of Securities Dealers, Inc., the Chicago Board Options Exchange, the Chicago Mercantile Exchange or the Chicago Board of Trade; (ii) trading of any securities issued or guaranteed by the Company shall have been suspended on any exchange or in any over-the-counter market; (iii) a general moratorium on commercial banking activities shall have been declared by federal or New York State authorities; or (iv) there shall have occurred any outbreak or escalation of hostilities or any change in financial markets or any calamity or crisis, either within or outside the United States, that, in the judgment of the Representatives, is material and adverse and makes it impracticable or inadvisable to proceed with the offering, sale or delivery of the Shares on the Closing Date or the Additional Closing Date, as the case may be, on the terms and in the manner contemplated by this Agreement, the Time of Sale Information and the Prospectus.

      12. Defaulting Underwriter. (a) If, on the Closing Date or the Additional Closing Date, as the case may be, any Underwriter defaults on its obligation to purchase the Shares that it has agreed to purchase hereunder on such date, the non-defaulting Underwriters may in their discretion arrange for the purchase of such Shares by other persons satisfactory to the Company and, with respect to the Option Shares, the Selling Stockholders on the terms contained in this Agreement. If, within 36 hours after any such default by any Underwriter, the non-defaulting Underwriters do not arrange for the purchase of such Shares, then the Company and, if applicable, the Selling Stockholders shall be entitled to a further period of 36 hours within which

to procure other persons satisfactory to the non-defaulting Underwriters to purchase such Shares on such terms. If other persons become obligated or agree to purchase the Shares of a defaulting Underwriter, either the non-defaulting Underwriters or the Company and the Selling Stockholders may postpone the Closing Date or the Additional Closing Date, as the case may be, for up to five full business days in order to effect any changes that in the opinion of counsel for the Company, counsel for the Selling Stockholders or counsel for the Underwriters may be necessary in the Registration Statement and the Prospectus or in any other document or arrangement, and the Company agrees to promptly prepare any amendment or supplement to the Registration Statement and the Prospectus that effects any such changes. As used in this Agreement, the term “Underwriter” includes, for all purposes of this Agreement unless the context otherwise requires, any person not listed in Schedule I hereto that, pursuant to this Section 12, purchases Shares that a defaulting Underwriter agreed but failed to purchase.

      (b) If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by the non-defaulting Underwriters and the Company and the Selling Stockholders as provided in paragraph (a) above, the aggregate number of Shares that remain unpurchased on the Closing Date or the Additional Closing Date, as the case may be does not exceed one-eleventh of the aggregate number of Shares to be purchased on such date, then the Company and the Selling Stockholders shall have the right to require each non-defaulting Underwriter to purchase the number of Shares that such Underwriter agreed to purchase hereunder on such date plus such Underwriter’s pro rata share (based on the number of Shares that such Underwriter agreed to purchase on such date) of the Shares of such defaulting Underwriter or Underwriters for which such arrangements have not been made.

      (c) If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by the non-defaulting Underwriters and the Company and the Selling Stockholders as provided in paragraph (a) above, the aggregate number of Shares that remain unpurchased on the Closing Date or the Additional Closing Date, as the case may be, exceeds one-eleventh of the aggregate amount of Shares to be purchased on such date, or if the Company and the Selling Stockholders shall not exercise the right described in paragraph (b) above, then this Agreement or, with respect to any Additional Closing Date, the obligation of the Underwriters to purchase Shares on the Additional Closing Date, as the case may be, shall terminate without liability on the part of the non-defaulting Underwriters. Any termination of this Agreement pursuant to this Section 12 shall be without liability on the part of the Company and the Selling Stockholders, except that the provisions of Section 9 hereof shall not terminate and shall remain in effect.

      (d) Nothing contained herein shall relieve a defaulting Underwriter of any liability it may have to the Company, the Selling Stockholders or any non-defaulting Underwriter for damages caused by its default.

      13. Payment of Expenses. (a) Whether or not the transactions contemplated by this Agreement are consummated or this Agreement is terminated, the Company will pay or cause to be paid all costs and expenses incident to the performance of its obligations hereunder, including without limitation, (i) the costs incident to the authorization, issuance, sale, preparation and delivery of the Shares and any taxes payable in that connection; (ii) the costs incident to the preparation, printing and filing under the Securities Act of the Registration Statement, the

Preliminary Prospectus, any Issuer Free Writing Prospectus, any Time of Sale Information and the Prospectus (including all exhibits, amendments and supplements thereto) and the distribution thereof; (iii) the costs of reproducing and distributing this Agreement; (iv) the fees and expenses of the Company’s counsel and independent accountants; (v) the fees and reasonable expenses, not exceeding $10,000 in the aggregate, incurred in connection with the registration or qualification and determination of eligibility for investment of the Shares under the laws of such jurisdictions as the Representatives may designate and the preparation, printing and distribution of a Blue Sky Memorandum (including the related reasonable fees and expenses of counsel for the Underwriters); (vi) the cost of preparing stock certificates; (vii) the costs and charges of any transfer agent and any registrar; (viii) all application fees and reasonable expenses incurred in connection with any filing with, and clearance of the offering by, the National Association of Securities Dealers, Inc. (including the fees and reasonable expenses of Cowen and Company, LLC acting as “qualified independent underwriter” within the meaning of the aforementioned Rule 2720 of The Rules of Conduct); (ix) all expenses incurred by the Company in connection with any “road show” presentation to potential investors; and (x) all expenses and application fees related to the listing of the Shares on the New York Stock Exchange.

      (b) If (i) this Agreement is terminated pursuant to clauses (ii) of Section 11, (ii) the Company or the Selling Stockholders for any reason fail to tender the Shares for delivery to the Underwriters or (iii) the Underwriters decline to purchase the Shares for any reason permitted under this Agreement (other than following termination of this Agreement pursuant to clause (i), (iii) or (iv) of Section 11), the Company agrees to reimburse the Underwriters for all out-of-pocket costs and expenses (including the reasonable fees and expenses of their counsel) reasonably incurred by the Underwriters in connection with this Agreement and the offering contemplated hereby.

      14. Persons Entitled to Benefit of Agreement. This Agreement shall inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and any controlling persons referred to in Section 9 hereof. Nothing in this Agreement is intended or shall be construed to give any other person any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision contained herein. No purchaser of Shares from any Underwriter shall be deemed to be a successor merely by reason of such purchase.

      15. Survival. The respective indemnities, rights of contribution, representations, warranties and agreements of the Company, the Selling Stockholders and the Underwriters contained in this Agreement or made by or on behalf of the Company, the Selling Stockholders or the Underwriters pursuant to this Agreement or any certificate delivered pursuant hereto shall survive the delivery of and payment for the Shares and shall remain in full force and effect, regardless of any termination of this Agreement or any investigation made by or on behalf of the Company, the Selling Stockholders or the Underwriters.

      16. Certain Defined Terms. For purposes of this Agreement, (a) except where otherwise expressly provided, the term “affiliate” has the meaning set forth in Rule 405 under the Securities Act; (b) the term “business day” means any day other than a day on which banks are permitted or required to be closed in New York City; (c) the term “subsidiary” has the meaning

set forth in Rule 405 under the Securities Act; and (d) the term “significant subsidiary” has the meaning set forth in Rule 1-02 of Regulation S-X under the Exchange Act.

      17. Miscellaneous. (a) Authority of the Representatives. Any action by the Underwriters hereunder may be taken by J.P. Morgan Securities Inc. on behalf of the Underwriters, and any such action taken by J.P. Morgan Securities Inc. shall be binding upon the Underwriters.

      (b) Notices. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given if mailed or transmitted and confirmed by any standard form of telecommunication. Notices to the Underwriters shall be given to the Representatives c/o J.P. Morgan Securities Inc., 277 Park Avenue, New York, New York 10172 (fax: (212)  ###-###-####); Attention: Equity Syndicate Desk. Notices to the Company shall be given to it at 300 Professional Drive, Suite 250, Gaithersburg, MD 20879 (fax: (301)  ###-###-####); Attention: Daniel J. Abdun-Nabi, Esquire, General Counsel. Notices to the Selling Stockholders shall be given to the Attorneys-in-Fact at                                         ,                                         ,                                          (fax:                     ); Attention:                    ;                      .

      (c) Governing Law. This Agreement shall be governed by and construed in accordance with the laws of the State of New York.

      (d) Counterparts. This Agreement may be signed in counterparts (which may include counterparts delivered by any standard form of telecommunication), each of which shall be an original and all of which together shall constitute one and the same instrument.

      (e) Amendments or Waivers. No amendment or waiver of any provision of this Agreement, nor any consent or approval to any departure therefrom, shall in any event be effective unless the same shall be in writing and signed by the parties hereto.

      (f) Headings. The headings herein are included for convenience of reference only and are not intended to be part of, or to affect the meaning or interpretation of, this Agreement.

      If the foregoing is in accordance with your understanding, please indicate your acceptance of this Agreement by signing in the space provided below.

Accepted:                     , 200   

J.P. MORGAN SECURITIES INC.

By		Authorized Signatory

For itself and on behalf of the
several Underwriters listed
in Schedule I hereto.

Schedule I

Underwriter		Number of Shares
J.P. Morgan Securities Inc.
Cowen and Company, LLC
HSBC Securities (USA) Inc.
Total

Schedule II

Selling Stockholders		Number of Option Shares

Annex A

      1. The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware and has the corporate power and authority to carry on its business and to own or lease its properties, as such business and properties are described in the Time of Sale Information and the Prospectus.

      2. The Company is duly qualified and is in good standing as a foreign corporation authorized to do business in the State of Maryland.

      3. Each of the subsidiaries of the Company listed on Schedule C attached hereto has been duly incorporated or formed and is validly existing as a corporation or limited liability company in good standing under the laws of the applicable jurisdiction as set forth on Schedule C attached hereto.

      4. Each of the subsidiaries of the Company listed on Schedule C attached hereto are duly qualified and in good standing as a foreign corporation or limited liability company authorized to do business in the applicable jurisdictions as set forth on Schedule C attached hereto.

      5. All the outstanding shares of capital stock of the Company have been duly authorized and are validly issued, fully paid and non-assessable.

      6. The Shares have been duly authorized and, when issued and delivered to the Underwriters against payment therefor as provided by the Underwriting Agreement, will be validly issued, fully paid and non-assessable, and the issuance of such Shares will not be subject to any preemptive rights under the Delaware General Corporation Law statute or the Certificate of Incorporation or By-laws or similar contractual rights granted by the Company pursuant to any contract or agreement that has been filed as an exhibit to the Registration Statement.

      7. The Underwriting Agreement has been duly authorized, executed and delivered by the Company.

      8. To our knowledge, no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose are pending before or threatened by the Commission.

      9. Except as may be required under the Securities Act and the rules and regulations of the Commission thereunder and the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission thereunder, no filing with, or authorization, approval, consent, license, order, registration, qualification or decree of, any United States federal governmental authority or agency is necessary for the issuance, sale and delivery of the Shares by the Company to the Underwriters pursuant to the Underwriting Agreement.

      10. The execution and delivery of the Underwriting Agreement by the Company and the consummation by the Company of the transactions contemplated thereby will not (A) conflict

with or constitute a breach of any of the terms or provisions of, or a default under, the Certificate of Incorporation or By-laws or any indenture, loan agreement, mortgage, lease or other agreement or instrument to which the Company is a party and that is filed as an exhibit to the Registration Statement or (B) violate or conflict with any United States federal or Massachusetts law, rule or regulation that in our experience is normally applicable in transactions of the type contemplated by the Underwriting Agreement, the Delaware General Corporation Law statute, or any judgment, order or decree specifically naming the Company of which we are aware.

      11. The statements in the Time of Sale Information and the Prospectus under the captions “Description of capital stock” and “Shares eligible for future sale” and in Item 14 of Part II of the Registration Statement, insofar as such statements constitute matters of law or legal conclusions or summarize the terms of agreements, are correct in all material respects.

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

      12. Except as described in the Time of Sale Information and the Prospectus, no contract or agreement that has been filed as an exhibit to the Registration Statement grants any person a right to require the Company to register pursuant to the Registration Statement any securities other than the Shares, except for any such right as has been waived.

      13 The Rights Agreement has been duly authorized, executed and delivered by the Company. The Rights have been duly authorized by the Company, and, when the Shares are issued and delivered to the Underwriters against payment therefor as provided in the Underwriting Agreement and the Rights are issued upon issuance of the Shares as provided in the Rights Agreement, the Rights applicable to the Shares will be validly issued. The shares of Series A Junior Participating Preferred Stock issuable upon exercise of the Rights have been duly authorized and reserved for issuance and, upon the exercise of the Rights in accordance with the terms of the Rights Agreement and when issued and delivered and paid for as provided in the Rights Agreement, will be validly issued, fully paid and non-assessable.

      In addition to the opinions provided above, we confirm to you as follows: In the course of acting as counsel for the Company in connection with the preparation of the Registration Statement, the Time of Sale Information and the Prospectus, we have participated in conferences with officers and other representatives of the Company, representatives of and counsel for the Underwriters and representatives of the registered independent public accounting firm of the Company, during which the contents of the Registration Statement, the Time of Sale Information and the Prospectus were discussed. While the limitations inherent in the independent verification of factual matters and the character of determinations involved in the registration process are such that we are not passing upon and do not assume any responsibility for the accuracy, completeness or fairness of the statements contained in the Registration Statement, the Time of Sale Information or the Prospectus (except to the extent expressly set forth in paragraph 11 above), subject to the foregoing and based on such participation and discussions:

      (a) the Registration Statement, as of the Effective Date, and the Prospectus, as of the date thereof (except for the financial statements, including the notes and schedules thereto, and other financial and accounting data and statistical data derived from such financial and accounting data included therein or omitted therefrom, as to which we express no view) appear on their face to be appropriately responsive in all material respects to the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder;

      (b) no facts have come to our attention that have caused us to believe that (i) the Registration Statement, as of the Effective Date, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading (except as set forth in the parenthetical in clause (a) above), (ii) the Time of Sale Information, as of the Time of Sale, contained an untrue statement of a material fact or omitted to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading (except as set forth in the parenthetical in clause (a) above) or (iii) the Prospectus, as of its date or as of the date hereof, contained or contains an untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading (except as set forth in the parenthetical in clause (a) above);

      (c) we are not aware of any contract or other document of a character required by the Securities Act and the applicable rules and regulations of the Commission thereunder to be filed as an exhibit to the Registration Statement that is not so filed; and

      (d) we are not aware of any action, proceeding or litigation pending, contemplated or threatened against the Company before any court or governmental or administrative agency or body that is required by the Securities Act or the rules and regulations thereunder to be described in the Registration Statement or the Prospectus that is not so described.

Annex B

a.		Time of Sale Information
b.		[Pricing Information Provided Orally by Underwriters]

Annex C

Emergent BioSolutions Inc.
Pricing Term Sheet

Annex D

1. To our actual knowledge, except as disclosed in the Registration Statement, we are not aware of any pending or threatened claims, action, suit, or proceeding asserting third party intellectual property rights against the Company. To our actual knowledge, we are not aware of any order, judgment, decree or injunction restricting the operation of the business of the Company. We have not, however, carried out an independent review to determine whether such matters may have arisen and make no representations in that regard.

2. To our actual knowledge, the issued patents [and patent applications] that the Company represents in the Intellectual Property and Licensing Section of the Registration Statement to have been duly maintained have not been abandoned, disclaimed or declared invalid or unenforceable by any court of competent jurisdiction. We have not, however, carried out an independent review of such patents [and patent applications] for the purposes of this Opinion and make no representations regarding matters beyond our actual knowledge.

3. To our actual knowledge, no person or entity other than the Company has asserted any inventorship or ownership rights in any of the patents or patent applications that we have handled for the Company (as set forth in Schedule A). We have not, however, carried out an independent review that we deem sufficient to express to the Underwriter any opinion concerning whether the inventors named in the [European][U.S.] patent applications that we handled for the Company (as set forth in Schedule A) were correctly determined.

Annex E

     (1) Each Selling Stockholder is the record, beneficial and lawful owner of all of the Shares to be sold by such Selling Stockholder and has valid and marketable title to such Shares, and upon delivery of and payment for the Shares, the Underwriters will acquire valid and marketable title to the shares, free and clear of any mortgage, pledge, security interest, lien, claim or other encumbrance or restriction on transferability or any adverse claim.

     (2) The sale of the Shares and the execution and delivery by the Selling Stockholder of, and the performance by the Selling Stockholder of its obligations under, the Underwriting Agreement, and the consummation of the transactions contemplated therein, (i) have been duly authorized on the part of each of the Selling Stockholders, and (ii) will not conflict with or result in a breach of any of the terms or provisions of, or constitute a default under, any indenture, mortgage, deed of trust, loan agreement or other material agreement or instrument, identified to us in any Selling Stockholder’s Certificate, to which any Selling Stockholder is a party or by which any Selling Stockholder is bound or to which any of the property or assets of any Selling Stockholder is subject, nor will any such action result in any violation of the provisions of the charter or bylaws or similar organizational documents of any Selling Stockholder or any applicable law or statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over such Selling Stockholder or any of its properties. No consent, approval, authorization, order, registration or qualification of or with any such court or governmental agency or body is required for the sale of the Shares or the consummation by the Selling Stockholders of the transactions contemplated by the Underwriting Agreement, except such consents, approvals, authorizations, registrations or qualifications as have been obtained under the Securities Act of 1933 and as may be required under state securities or Blue Sky laws in connection with the purchase and distribution of the Shares by the Underwriters.

     (3) The Power of Attorney and the Custody Agreement of each Selling Stockholder have been duly authorized, executed and delivered by such Selling Stockholder and constitute valid and legally binding obligations of each such Selling Stockholder, enforceable in accordance with their respective terms; and

     (4) The Underwriting Agreement has been duly authorized, executed and delivered by or on behalf of each Selling Stockholder.

Annex F

The statements in the Time of Sale Information and the Prospectus under the captions “Business — Government Contracts”, “Business — Government Regulation — Safety Act”, “Business — Government Regulation — Public Readiness and Emergency Preparedness Act”, insofar as such statements constitute matters of law or legal conclusions or summarize the terms of agreements, fairly summarize the matters described therein in all material respects.

Exhibit A

FORM OF LOCK-UP AGREEMENT

                        , 2006

J.P. Morgan Securities Inc.
Cowen & Co., LLC
HSBC Securities (USA) Inc.
As Representatives of
the several Underwriters listed in
Schedule I to the Underwriting
Agreement referred to below
c/o J.P. Morgan Securities Inc.
277 Park Avenue
New York, NY 10172

Re:		Emergent BioSolutions Inc. -— Public Offering

Ladies and Gentlemen:

      The undersigned understands that you, as Representatives of the several Underwriters, propose to enter into an Underwriting Agreement (the “Underwriting Agreement”) with Emergent BioSolutions Inc., a Delaware corporation (the “Company”), providing for the public offering (the “Public Offering”) by the several Underwriters named in Schedule I to the Underwriting Agreement (the “Underwriters”), of shares (the “Securities”) of the common stock, par value $0.01 per share, of the Company (the “Common Stock”). Capitalized terms used herein and not otherwise defined shall have the meanings set forth in the Underwriting Agreement.

      In consideration of the Underwriters’ agreement to purchase and make the Public Offering of the Securities, and for other good and valuable consideration receipt of which is hereby acknowledged, the undersigned hereby agrees that, without the prior written consent of J.P. Morgan Securities Inc. on behalf of the Underwriters, the undersigned will not, during the period ending 180 days after the date of the prospectus relating to the Public Offering (the “Prospectus”), (1) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock (including without limitation, Common Stock which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the Securities and

Exchange Commission and securities which may be issued upon exercise of a stock option or warrant) or (2) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise. In addition, the undersigned agrees that, without the prior written consent of J.P. Morgan Securities Inc. on behalf of the Underwriters, it will not, during the period ending 180 days after the date of the Prospectus, make any demand for or exercise any right with respect to, the registration of any shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock. Notwithstanding the foregoing, if (1) during the last 17 days of the 180-day restricted period, the Company issues an earnings release or material news or a material event relating to the Company occurs; or (2) prior to the expiration of the 180-day restricted period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the 180-day period, the restrictions imposed by this Letter Agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. The undersigned hereby further agrees that, prior to engaging in any transaction or taking any other action that is subject to the terms of this Letter Agreement during the period from the date of this Letter Agreement to and including the 34^th day following the expiration of the initial 180-day restricted period, it will give notice thereof to the Company and will not consummate such transaction or take any such action unless it has received written confirmation from the Company or J.P. Morgan Securities Inc. that the 180-day restricted period (as such may have been extended pursuant to this paragraph) has expired.

      The restrictions imposed by this Letter Agreement shall not apply to the transfer or disposition of shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock (1) as a bona fide gift, (2) to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned in a transaction not involving a disposition for value, (3) to any corporation, partnership, limited liability company or other entity all of the beneficial ownership interests of which are held by the undersigned or the immediate family of the undersigned in a transaction not involving a disposition for value, (4) by will, other testamentary document or intestate succession to the legal representative, heir, beneficiary or a member of the immediate family of the undersigned, (5) as a distribution to partners, members or stockholders of the undersigned in a transaction not involving a disposition for value or (6) to any affiliate of the undersigned or any investment fund or other entity controlled or managed by the undersigned in a transaction not involving a disposition for value; provided that, in each case, the transferee, distributee or donee agrees in writing to be bound by the terms of this Letter Agreement to the same extent as if a party hereto; and, provided further that, in the case of (3), (5) and (6) above, no filing pursuant to Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), reporting a reduction in the beneficial ownership of Common Stock shall be required or shall be voluntarily made in connection with such transfer (other than a filing on a Form 5 made after the expiration of the 180-day restricted period or any extension thereof pursuant to this Letter Agreement). In addition, the restrictions imposed by this Letter Agreement shall not apply to the sale of Securities by the undersigned pursuant to the Underwriting Agreement. Furthermore, notwithstanding the restrictions imposed by this Letter Agreement, the undersigned may, without the prior written consent of J.P. Morgan Securities Inc., (1) exercise an option to purchase shares of Common Stock granted under any

stock incentive plan or stock purchase plan of the Company, (2) establish a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of Common Stock, provided that such plan does not provide for any transfers of Common Stock during the 180-day restricted period or any extension thereof pursuant to this Letter Agreement, and (3) transfer shares of Common Stock acquired in the Public Offering or on the open market following the Public Offering. For purposes of this Letter Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

      In furtherance of the foregoing, the Company, and any duly appointed transfer agent for the registration or transfer of the securities described herein, are hereby authorized to decline to make any transfer of securities if such transfer would constitute a violation or breach of this Letter Agreement.

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

      If either J.P. Morgan Securities Inc., on the one hand, or the Company, on the other hand, informs the other, prior to the execution of the Underwriting Agreement, that it has determined not to proceed with the Public Offering, if the Public Offering is not completed by February 28, 2007, or if the Underwriting Agreement (other than the provisions thereof which survive termination) shall terminate or be terminated prior to payment for and delivery of the Common Stock to be sold thereunder, this Letter Agreement shall terminate automatically and be of no further force or effect. The undersigned understands that the Underwriters are entering into the Underwriting Agreement and proceeding with the Public Offering in reliance upon this Letter Agreement.

      This Letter 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.