SECURITIES PURCHASE AGREEMENT

Exhibit 4.5

SECURITIES PURCHASE AGREEMENT

SECURITIES PURCHASE AGREEMENT (the “Agreement”), dated as of August 7, 2007, by and among NPS Pharmaceuticals, Inc., a Delaware corporation, with headquarters located at 300 Interpace Parkway, Building B, Parsippany, New Jersey 07054 (the “Company”, “Our” or “We”), and the investors listed on the Schedule of Buyers attached hereto (individually, a “Buyer” or “Holder” and collectively, the “Buyers” or “Holders”).

WHEREAS:

A. The Company and each Buyer is executing and delivering this Agreement in reliance upon the exemption from securities registration afforded by Section 4(2) of the Securities Act of 1933, as amended (the “1933 Act”), and Rule 506 of Regulation D (“Regulation D”) as promulgated by the United States Securities and Exchange Commission (the “SEC”) under the 1933 Act.

B. The Company has authorized a new series of senior subordinated convertible notes of the Company, in the form attached hereto as Exhibit A (the “Notes”), which Notes shall be convertible into the Company’s common stock, par value $0.001 per share (the “Common Stock”) (as converted, the “Conversion Shares”), in accordance with the terms of the Notes.

C. Each Buyer wishes to purchase, and the Company wishes to sell, upon the terms and conditions stated in this Agreement, (i) that aggregate principal amount of the Notes set forth opposite such Buyer’s name in column (3) on the Schedule of Buyers attached hereto (which aggregate amount for all Buyers shall be $50,000,000).

D. Contemporaneously with the execution and delivery of this Agreement, the parties hereto are executing and delivering a Registration Rights Agreement, substantially in the form attached hereto as Exhibit B (the “Registration Rights Agreement”), pursuant to which the Company will agree to provide certain registration rights with respect to the Registrable Securities (as defined in the Registration Rights Agreement) under the 1933 Act and the rules and regulations promulgated thereunder, and applicable state securities laws.

E. The Notes and the Conversion Shares collectively are referred to herein as the “Securities”.

NOW, THEREFORE, the Company and each Buyer hereby agree as follows:

1. PURCHASE AND SALE OF NOTES.

(a) Purchase of Notes.

(i) Notes. Subject to the satisfaction (or waiver) of the conditions set forth in Sections 6 and 7 below, the Company shall issue and sell to each Buyer, and each Buyer severally, but not jointly, agrees to purchase from the Company on the Closing Date (as defined below), a principal amount of Notes as is set forth opposite such Buyer’s name in column (3) on the Schedule of Buyers (the “Closing”).

(ii) Closing. The date and time of the Closing (the “Closing Date”) shall be 10:00 a.m., New York City time, on the date hereof (or such later date as is mutually agreed to by the Company and each Buyer) after notification of satisfaction (or waiver) of the conditions to the Closing set forth in Sections 6 and 7 below at the offices of Chadbourne & Parke LLP, 30 Rockefeller Plaza, New York, New York 10112.

(iii) Purchase Price. The aggregate purchase price for the Notes to be purchased by each such Buyer at the Closing (the “Purchase Price”) shall be the amount set forth opposite each Buyer’s name in column (5) of the Schedule of Buyers. Each Buyer shall pay $1,000 for each $1,000 of principal amount of Notes to be purchased by such Buyer at the Closing.

(b) Form of Payment. On the Closing Date, (i) each Buyer shall pay its Purchase Price to the Company for the Notes to be issued and sold to such Buyer at the Closing, by wire transfer of immediately available funds in accordance with the Company’s written wire instructions and (ii) the Company shall deliver to each Buyer the Notes (allocated in the principal amounts as such Buyer shall request) which such Buyer is then purchasing hereunder duly executed on behalf of the Company and registered in the name of such Buyer or its designee.

2. BUYER’S REPRESENTATIONS AND WARRANTIES. Each Buyer represents and warrants with respect to only itself that:

(a) No Sale or Distribution. Such Buyer is acquiring the Notes and upon conversion of the Notes will acquire the Conversion Shares issuable upon conversion of the Notes for its own account and not with a view towards, or for resale in connection with, the public sale or distribution thereof, except pursuant to sales registered or exempted under the 1933 Act; provided, however, that by making the representations herein, such Buyer does not agree to hold any of the Securities for any minimum or other specific term and reserves the right to dispose of the Securities at any time in accordance with or pursuant to a registration statement or an exemption under the 1933 Act and pursuant to the applicable terms of the Transaction Documents (as defined in Section 3(b)). Such Buyer is acquiring the Securities hereunder in the ordinary course of its business. Such Buyer does not presently have any agreement or understanding, directly or indirectly, with any Person (as defined in Section 3(p)) to distribute any of the Securities.

(b) Accredited Investor Status. Such Buyer is an “accredited investor” as that term is defined in Rule 501(a) of Regulation D.

(c) Reliance on Exemptions. Such Buyer understands that the Securities are being offered and sold to it in reliance on specific exemptions from the registration requirements of United States federal and state securities laws and that the Company is relying in part upon the truth and accuracy of, and such Buyer’s compliance with, the representations, warranties, agreements, acknowledgments and understandings of such Buyer set forth herein in order to determine the availability of such exemptions and the eligibility of such Buyer to acquire the Securities.

(d) Information. Such Buyer and its advisors, if any, have been furnished with all materials relating to the business, finances and operations of the Company and materials relating to the offer and sale of the Securities that have been requested by such Buyer. Such Buyer and its advisors, if any, have been afforded the opportunity to ask questions of the Company. Neither such inquiries nor any other due diligence investigations conducted by such Buyer or its advisors, if any, or its representatives shall modify, amend or affect such Buyer’s right to rely on the Company’s representations and warranties contained herein. Such Buyer understands that its investment in the Securities involves a high degree of risk and is able to afford a complete loss of such investment. Such Buyer has sought such accounting, legal and tax advice as it has considered necessary to make an informed investment decision with respect to its acquisition of the Securities.

(e) No Governmental Review. Such Buyer understands that no United States federal or state agency or any other government or governmental agency has passed on or made any recommendation or endorsement of the Securities or the fairness or suitability of the investment in the Securities nor have such authorities passed upon or endorsed the merits of the offering of the Securities.

(f) Transfer or Resale. Such Buyer understands that except as provided in the Registration Rights Agreement: (i) the Securities have not been and are not being registered under the 1933 Act or any state securities laws, and may not be offered for sale, sold, assigned or transferred unless (A) subsequently registered thereunder, (B) such Buyer shall have delivered to the Company an opinion of counsel, in a generally acceptable form, to the effect that such Securities to be sold, assigned or transferred may be sold, assigned or transferred pursuant to an exemption from such registration, or (C) such Buyer provides the Company with reasonable assurance that such Securities can be sold, assigned or transferred pursuant to Rule 144 or Rule 144A promulgated under the 1933 Act, as amended (or a successor rule thereto) (collectively, “Rule 144”); (ii) any sale of the Securities made in reliance on Rule 144 may be made only in accordance with the terms of Rule 144 and further, if Rule 144 is not applicable, any resale of the Securities under circumstances in which the seller (or the Person through whom the sale is made) may be deemed to be an underwriter (as

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that term is defined in the 1933 Act) may require compliance with some other exemption under the 1933 Act or the rules and regulations of the SEC thereunder; and (iii) neither the Company nor any other Person is under any obligation to register the Securities under the 1933 Act or any state securities laws or to comply with the terms and conditions of any exemption thereunder. The Securities may be pledged in connection with a bona fide margin account or other loan or financing arrangement secured by the Securities and such pledge of Securities shall not be deemed to be a transfer, sale or assignment of the Securities hereunder, and no Buyer effecting a pledge of Securities shall be required to provide the Company with any notice thereof or otherwise make any delivery to the Company pursuant to this Agreement or any other Transaction Document, including without limitation, this Section 2(f).

(g) Legends. Such Buyer understands that the certificates or other instruments representing the Notes and, until such time as the resale of the Conversion Shares have been registered under the 1933 Act as contemplated by the Registration Rights Agreement, the stock certificates representing the Conversion Shares except as set forth below, shall bear any legend as required by the “blue sky” laws of any state and a restrictive legend in substantially the following form (and a stop-transfer order may be placed against transfer of such stock certificates):

[NEITHER THE ISSUANCE AND SALE OF THE SECURITIES REPRESENTED BY THIS CERTIFICATE NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE CONVERTIBLE HAVE BEEN][THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN] REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS. THE SECURITIES MAY NOT BE OFFERED FOR SALE, SOLD, TRANSFERRED OR ASSIGNED (I) IN THE ABSENCE OF (A) AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR (B) AN OPINION OF COUNSEL, IN A GENERALLY ACCEPTABLE FORM, THAT REGISTRATION IS NOT REQUIRED UNDER SAID ACT OR (II) UNLESS SOLD PURSUANT TO RULE 144 OR RULE 144A UNDER SAID ACT. NOTWITHSTANDING THE FOREGOING, THE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN OR FINANCING ARRANGEMENT SECURED BY THE SECURITIES.

The legend set forth above shall be removed and the Company shall issue a certificate without such legend to the holder of the Securities upon which it is stamped, if, unless otherwise required by law, (i) such Securities are registered for resale under the 1933 Act, (ii) in connection with a sale, assignment or other transfer, such holder provides the Company with an opinion of a law firm reasonably acceptable to the Company, in a generally acceptable form, to the effect that such sale, assignment or transfer of the Securities may be made without registration under the applicable requirements of the 1933 Act, or (iii) such holder provides the Company with assurance reasonably acceptable to the Company that the Securities can be sold, assigned or transferred pursuant to Rule 144 or Rule 144A.

(h) Validity; Enforcement. The Transaction Documents to which it is a party have been duly and validly authorized, executed and delivered on behalf of such Buyer and shall constitute the legal, valid and binding obligations of such Buyer enforceable against such Buyer in accordance with their respective terms, except as such enforceability may be limited by general principles of equity or to applicable bankruptcy, insolvency, reorganization, moratorium, liquidation and other similar laws relating to, or affecting generally, the enforcement of applicable creditors’ rights and remedies.

(i) No Conflicts. The execution, delivery and performance by such Buyer of the Transaction Documents to which it is a party and the consummation by such Buyer of the transactions contemplated hereby and thereby will not (i) result in a violation of the organizational documents of such Buyer or (ii) conflict with, or constitute a default (or an event which with notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration or cancellation of, any agreement, indenture or instrument to which such Buyer is a party, or (iii) result in a violation of any law, rule, regulation, order, judgment or decree (including federal and state securities laws) applicable to such Buyer, except in the case of clauses (ii) and (iii) above, for such conflicts, defaults, rights or violations which would not, individually or in the aggregate, reasonably be expected to have a material adverse effect on the ability of such Buyer to perform its obligations hereunder.

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(j) Residency. Such Buyer is a resident of that jurisdiction specified below its address on the Schedule of Buyers.

3. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company represents and warrants to each of the Buyers that as of the date hereof:

(a) Organization and Qualification. The Company and its “Subsidiaries” (which for purposes of this Agreement means any entity in which the Company, directly or indirectly, owns a majority of the capital stock or similar equity interest) are entities duly organized and validly existing and, to the extent legally applicable, in good standing under the laws of the jurisdiction in which they are formed, and have the requisite power and authorization to own their properties and to carry on their business as now being conducted. Each of the Company and its Subsidiaries is duly qualified as a foreign entity to do business and to the extent legally applicable, is in good standing in every jurisdiction in which its ownership of property or the nature of the business conducted by it makes such qualification necessary, except to the extent that the failure to be so qualified or be in good standing would not have a Material Adverse Effect. As used in this Agreement, “Material Adverse Effect” means any material adverse effect on the business, properties, assets, operations, results of operations, condition (financial or otherwise) or prospects of the Company and its Subsidiaries, taken as a whole, or on the transactions contemplated hereby and the other Transaction Documents or by the agreements and instruments to be entered into in connection herewith or therewith, or on the authority or ability of the Company to perform its obligations under the Transaction Documents.

(b) Authorization; Enforcement; Validity. The Company has the requisite corporate power and authority to enter into and perform its obligations under this Agreement, the Notes, the Registration Rights Agreement, the Irrevocable Transfer Agent Instructions (as defined in Section 5(b)) and each of the other agreements entered into by the parties hereto in connection with the transactions contemplated by this Agreement (collectively, the “Transaction Documents”) and to issue the Securities in accordance with the terms hereof and thereof. The execution and delivery of the Transaction Documents by the Company and the consummation by the Company of the transactions contemplated hereby and thereby, including, without limitation, the issuance of the Notes and the reservation for issuance and the issuance of the Conversion Shares issuable upon conversion of the Notes have been duly authorized by the Company’s Board of Directors and other than as set forth in Section 3(e), no further filing, consent or authorization is required by the Company, its Board of Directors or its stockholders. This Agreement and the other Transaction Documents of even date herewith have been duly executed and delivered by the Company, and constitute the legal, valid and binding obligations of the Company enforceable against the Company in accordance with their respective terms, except as such enforceability may be limited by general principles of equity or applicable bankruptcy, insolvency, reorganization, moratorium, liquidation or similar laws relating to, or affecting generally, the enforcement of applicable creditors’ rights and remedies.

(c) Issuance of Securities. The issuance of the Notes are duly authorized and are free from all taxes, liens and charges with respect to the issue thereof. As of the Closing, a number of shares of Common Stock shall have been duly authorized and reserved for issuance which equals or exceeds the number of Conversion Shares. Upon conversion in accordance with the Notes, the Conversion Shares respectively, will be validly issued, fully paid and nonassessable and free from all preemptive or similar rights, taxes, liens and charges with respect to the issue thereof, with the holders being entitled to all rights accorded to a holder of Common Stock. Assuming the accuracy of each of the representations and warranties set forth in Section 2 of this Agreement, the offer and issuance by the Company of the Securities is exempt from registration under the 1933 Act.

(d) No Conflicts. The execution, delivery and performance of the Transaction Documents by the Company and the consummation by the Company of the transactions contemplated hereby and thereby (including, without limitation, the issuance of the Notes and reservation for issuance and issuance of the Conversion Shares will not (i) result in a violation of any certificate of incorporation, certificate of formation, any certificate of designations or other constituent documents of the Company or any of its Subsidiaries, any capital stock of the Company or any of its Subsidiaries or bylaws of the Company or any of its Subsidiaries or (ii) conflict with, or constitute a default (or an event which with notice or lapse of time or both would become a default) in any

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respect under, or give to others any rights of termination, amendment, acceleration or cancellation of, any agreement, indenture or instrument to which the Company or any of its Subsidiaries is a party filed as an exhibit to the SEC Documents (as defined in Section 3(i), or (iii) result in a violation of any law, rule, regulation, order, judgment or decree (including foreign, federal and state securities laws and regulations and the rules and regulations of the Nasdaq Global Market (the “Principal Market”) applicable to the Company or any of its Subsidiaries or by which any property or asset of the Company or any of its Subsidiaries is bound or affected, except, with respect to clauses (ii) and (iii), could not reasonably be expected to result in a Material Adverse Effect.

(e) Consents. Neither the Company nor any of its Subsidiaries is required to obtain any consent, authorization or order of, or make any filing or registration with, any court, governmental agency or any regulatory or self-regulatory agency or any other Person in order for it to execute, deliver or perform any of its obligations under or contemplated by the Transaction Documents, in each case in accordance with the terms hereof or thereof, except for the following consents, authorizations, orders, filings and registrations: (i) the filing with the SEC of one or more Registration Statements (as defined in the Registration Rights Agreement) in accordance with the requirements of the Registration Rights Agreement, (ii) the filing of a notification and a listing application for the Conversion Shares with the Principal Market, which shall be done pursuant to the rules of the Principal Market, (iii) the filing of a notice of Sale of Securities on Form D with the SEC under Regulation D, and (iv) the filing of a Form 8-K pursuant to the 1934 Act. The Company and its Subsidiaries are unaware of any facts or circumstances that might prevent the Company from obtaining or effecting any of the registration, application or filings pursuant to the preceding sentence. The Company is not in violation of the listing requirements of the Principal Market and has no knowledge of any facts that would reasonably lead to delisting or suspension of the Common Stock in the foreseeable future.

(f) Acknowledgement Regarding Buyer’s Purchase of Securities. The Company acknowledges and agrees that each Buyer is acting solely in the capacity of an arm’s length purchaser with respect to the Transaction Documents and the transactions contemplated hereby and thereby and that no Buyer is (i) an officer or director of the Company, (ii) to the knowledge of the Company, an “affiliate” of the Company or any of its subsidiaries (as defined in Rule 144 of the 1933 Act or (iii) to the knowledge of the Company, a “beneficial owner” of more than 10% of the shares of Common Stock (as defined for purposed of Rule 13d-3 of the Securities Exchange Act of 1934, as amended (the “1934 Act”)). The Company further acknowledges that no Buyer is acting as a financial advisor or fiduciary of the Company or any of its Subsidiaries (or in any similar capacity) with respect to the Transaction Documents and the transactions contemplated hereby and thereby, and any advice given by a Buyer or any of its representatives or agents in connection with the Transaction Documents and the transactions contemplated hereby and thereby is merely incidental to such Buyer’s purchase of the Securities. The Company further represents to each Buyer that the Company’s decision to enter into the Transaction Documents has been solely based on the independent evaluation by the Company and its representatives.

(g) No General Solicitation; Placement Agent’s Fees. Neither the Company, nor any of its affiliates, nor any Person acting on its or their behalf, has engaged in any form of general solicitation or general advertising (within the meaning of Regulation D) in connection with the offer or sale of the Securities. Neither the Company nor any of its Subsidiaries has engaged any placement agent or other agent in connection with the sale of the Securities.

(h) No Integrated Offering. None of the Company, its Subsidiaries, any of their affiliates, and any Person acting on their behalf has, directly or indirectly, made any offers or sales of any security or solicited any offers to buy any security, under circumstances that would require registration of any of the Securities under the 1933 Act or cause this offering of the Securities to be integrated with prior offerings by the Company for purposes of the 1933 Act or any applicable stockholder approval provisions, including, without limitation, under the rules and regulations of any exchange or automated quotation system on which any of the securities of the Company are listed or designated. None of the Company, its Subsidiaries, their affiliates and any Person acting on their behalf will take any action or steps referred to in the preceding sentence that would require registration of any of the Securities under the 1933 Act or cause the offering of the Securities to be integrated with other offerings.

(i) SEC Documents; Financial Statements. During the three (3) years prior to the date hereof, the Company has filed all reports, schedules, forms, statements and other documents required to be filed by it with the SEC pursuant to the reporting requirements of the 1934 Act (all of the foregoing filed prior to the date hereof and all exhibits included therein and financial

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statements, notes and schedules thereto and documents incorporated by reference therein being hereinafter referred to as the “SEC Documents”). As of their respective dates, the SEC Documents complied in all material respects with the requirements of the 1934 Act and the rules and regulations of the SEC promulgated thereunder applicable to the SEC Documents, and none of the SEC Documents, at the time they were filed with the SEC, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. As of their respective dates, the financial statements of the Company included in the SEC Documents complied as to form in all material respects with applicable accounting requirements and the published rules and regulations of the SEC with respect thereto. Such financial statements have been prepared in accordance with U.S. generally accepted accounting principles, consistently applied, during the periods involved (except (i) as may be otherwise indicated in such financial statements or the notes thereto, or (ii) in the case of unaudited interim statements, to the extent they may exclude footnotes or may be condensed or summary statements) and fairly presented in all material respects the financial position of the Company as of the dates thereof and the results of its operations and cash flows for the periods then ended (subject, in the case of unaudited statements, to normal year-end audit adjustments).

(j) Absence of Certain Changes. Except as disclosed in the SEC Documents, and the $100 million of notes to be issued on the date hereof by the Company’s subsidiary, Cinacalcet Royalty Sub LLC, (the “Subsidiary Notes”) pursuant to that certain Indenture dated as of December 22, 2004, as amended, since the date of the latest audited financial statements included within the SEC Documents (i) there has been no event, occurrence or development that has had or that could reasonably be expected to result in a Material Adverse Effect, (ii) the Company has not incurred any liabilities (contingent or otherwise) other than (A) trade payables, accrued expenses and other liabilities incurred in the ordinary course of business consistent with past practice and (B) liabilities not required to be reflected in the Company’s financial statements pursuant to U.S. generally accepted accounting principals or required to be disclosed in filings made with the SEC, (iii) the Company has not altered its method of accounting or the identity of its auditors, (iv) the Company has not declared or made any dividend or distribution of cash or other property to its stockholders or purchased, redeemed or made any agreements to purchase or redeem any shares of its capital stock and (v) the Company has not issued any equity securities to any officer, director or Affiliate, except pursuant to existing Company equity compensation plans. The Company has not taken any steps to seek protection pursuant to any bankruptcy law nor does the Company have any knowledge or reason to believe that its creditors intend to initiate involuntary bankruptcy proceedings or any actual knowledge of any fact that would reasonably lead a creditor to do so. The Company and its Subsidiaries, individually and on a consolidated basis, are not as of the date hereof, and after giving effect to the transactions contemplated hereby to occur at the Closing, will not be Insolvent (as defined below). For purposes of this Section 3(j), “Insolvent” means, with respect to any Person, (i) the present fair saleable value of such Person’s assets is less than the amount required to pay such Person’s total Indebtedness (as defined in Section 3(p)), (ii) such Person is unable to pay its debts and liabilities, subordinated, contingent or otherwise, as such debts and liabilities become absolute and matured, (iii) such Person intends to incur or believes that it will incur debts that would be beyond its ability to pay as such debts mature or (iv) such Person has unreasonably small capital with which to conduct the business in which it is engaged as such business is now conducted and is proposed to be conducted.

(k) No Undisclosed Events, Liabilities, Developments or Circumstances. No event, liability, development or circumstance has occurred or exists, or is contemplated to occur, with respect to the Company, its Subsidiaries or their respective business, properties, prospects, operations or financial condition, that would be required to be disclosed by the Company under applicable securities laws on a registration statement of Form S-1 filed with the SEC relating to an issuance and sale by the Company of its Common Stock and which has not been publicly announced except for the issuance of the Subsidiary Notes.

(l) Conduct of Business; Regulatory Permits. Neither the Company nor its Subsidiaries are in violation of any term of or in default under its Certificate of Incorporation, any certificate of designations of any outstanding series of preferred stock of the Company or Bylaws or their organizational charter or bylaws, respectively. Neither the Company nor any of its Subsidiaries is in violation of any judgment, decree or order or any statute, ordinance, rule or regulation applicable to the Company or its Subsidiaries, and neither the Company nor any of its Subsidiaries will conduct its business in violation of any of the foregoing, except for possible violations which could not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. Without limiting the generality of the foregoing, the Company is not in violation of any of the rules, regulations or requirements of the

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Principal Market and has no knowledge of any facts or circumstances that would reasonably lead to delisting or suspension of the Common Stock by the Principal Market in the foreseeable future. The Company and its Subsidiaries possess all certificates, authorizations and permits issued by the appropriate regulatory authorities necessary to conduct their respective businesses, except where the failure to possess such certificates, authorizations or permits would not have, individually or in the aggregate, a Material Adverse Effect, and neither the Company nor any such Subsidiary has received any notice of proceedings relating to the revocation or modification of any such certificate, authorization or permit.

(m) Foreign Corrupt Practices. Neither the Company, nor any of its Subsidiaries, nor any director, officer, agent, employee or other Person acting on behalf of the Company or any of its Subsidiaries has, in the course of its actions for, or on behalf of, the Company or any of its Subsidiaries (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expenses 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 U.S. Foreign Corrupt Practices Act of 1977, as amended; or (iv) made any unlawful bribe, rebate, payoff, influence payment, kickback or other unlawful payment to any foreign or domestic government official or employee.

(n) Sarbanes-Oxley Act. The Company is in compliance in all material respects with any and all applicable requirements of the Sarbanes-Oxley Act of 2002 that are effective as of the date hereof, and any and all applicable rules and regulations promulgated by the SEC thereunder that are effective as of the date hereof.

(o) Equity Capitalization. As of the date hereof, the authorized capital stock of the Company consists of 105,000,000 shares of Common Stock, of which as of August 2, 2007, 46,379,163 shares are issued and outstanding, 5,707,489 shares are reserved for issuance pursuant to the Company’s equity compensation plans and agreements and 5,248,051 shares are reserved for issuance pursuant to securities (other than the aforementioned equity compensation plans and agreements and the Notes) exercisable or exchangeable for, or convertible into, shares of Common Stock and 5,000,000 shares of preferred stock, par value $0.001 per share, of which as of the date hereof none are issued and outstanding. All of such outstanding shares have been, or upon issuance will be, validly issued and are fully paid and nonassessable. Except as disclosed in the SEC Documents, (i) none of the Company’s capital stock is subject to preemptive rights or any other similar rights or any liens or encumbrances suffered or permitted by the Company; (ii) there are no outstanding options, warrants, scrip, rights to subscribe to, calls or commitments of any character whatsoever relating to, or securities or rights convertible into, or exercisable or exchangeable for, any capital stock of the Company or any of its Subsidiaries, or contracts, commitments, understandings or arrangements by which the Company or any of its Subsidiaries is or may become bound to issue additional capital stock of the Company or any of its Subsidiaries or options, warrants, scrip, rights to subscribe to, calls or commitments of any character whatsoever relating to, or securities or rights convertible into, or exercisable or exchangeable for, any capital stock of the Company or any of its Subsidiaries; (iii) and except for the Subsidiary Notes, there are no outstanding debt securities, notes, credit agreements, credit facilities or other agreements, documents or instruments evidencing Indebtedness of the Company or any of its Subsidiaries or by which the Company or any of its Subsidiaries is or may become bound, (iv) there are no agreements or arrangements under which the Company or any of its Subsidiaries is obligated to register the sale of any of their securities under the 1933 Act (except pursuant to the Registration Rights Agreement); (v) and except for the Subsidiary Notes, there are no outstanding securities or instruments of the Company or any of its Subsidiaries which contain any redemption or similar provisions, and there are no contracts, commitments, understandings or arrangements by which the Company or any of its Subsidiaries is or may become bound to redeem a security of the Company or any of its Subsidiaries; (vi) there are no securities or instruments containing anti-dilution or similar provisions that will be triggered by the issuance of the Securities and (vii) and except for the Subsidiary Notes, the Company and its Subsidiaries have no liabilities or obligations required to be disclosed in the SEC Documents but not so disclosed in the SEC Documents, other than those incurred in the ordinary course of the Company’s or its Subsidiaries’ respective businesses and which, individually or in the aggregate, do not or would not have a Material Adverse Effect.

(p) Indebtedness and Other Contracts. Except as disclosed in the SEC Documents or Schedule 3(p), neither the Company nor any of its Subsidiaries (i) has any outstanding Indebtedness (as defined below), (ii) is in violation of any term of or in default under any contract, agreement or instrument relating to any Indebtedness, except where such violations and defaults would not result, individually or in the aggregate, in a Material Adverse Effect, or (iii) is a party to any contract, agreement or instrument relating to

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any Indebtedness, the performance of which, in the judgment of the Company’s officers, has or is expected to have a Material Adverse Effect. For purposes of this Agreement: (x) “Indebtedness” of any Person means, without duplication (A) all indebtedness for borrowed money, (B) all obligations issued, undertaken or assumed as the deferred purchase price of property or services, including (without limitation) “capital leases” in accordance with generally accepted accounting principals (other than trade payables entered into in the ordinary course of business), (C) all reimbursement or payment obligations with respect to letters of credit, surety bonds and other similar instruments, (D) all obligations evidenced by notes, bonds, debentures or similar instruments, including obligations so evidenced incurred in connection with the acquisition of property, assets or businesses, (E) all indebtedness created or arising under any conditional sale or other title retention agreement, or incurred as financing, in either case with respect to any property or assets acquired with the proceeds of such indebtedness (even though the rights and remedies of the seller or bank under such agreement in the event of default are limited to repossession or sale of such property), (F) all monetary obligations under any leasing or similar arrangement which, in connection with generally accepted accounting principles, consistently applied for the periods covered thereby, is classified as a capital lease, (G) all indebtedness referred to in clauses (A) through (F) above secured by (or for which the holder of such Indebtedness has an existing right, contingent or otherwise, to be secured by) any mortgage, lien, pledge, charge, security interest or other encumbrance upon or in any property or assets (including accounts and contract rights) owned by any Person, even though the Person which owns such assets or property has not assumed or become liable for the payment of such indebtedness, and (H) all Contingent Obligations in respect of indebtedness or obligation of others of the kinds referred to in clauses (A) through (G) above; (y) “Contingent Obligation” means, as to any Person, any direct or indirect liability, contingent or otherwise, of the Person with respect to any indebtedness, lease, dividend or other obligation of another Person if the primary purpose or intent of the Person incurring such liability, or the primary effect thereof, is to provide assurance to the obligee of such liability that such liability will be paid or discharged, or that any agreements relating thereto will be complied with, or that the holders of such liability will be protected (in whole or in part) against loss with respect thereto; and (z) “Person” means an individual, a limited liability company, a partnership, a joint venture, a corporation, a trust, an unincorporated organization and a government or any department or agency thereof.

(q) Absence of Litigation. Except as disclosed in the SEC Documents, there is no action, suit, proceeding, inquiry or investigation before or by the Principal Market, any court, public board, government agency, self-regulatory organization or body pending or, to the knowledge of the Company, threatened against or affecting the Company or any of its Subsidiaries, the Common Stock or any of the Company’s or its Subsidiaries, officers or directors that could reasonably be excepted to have a Material Adverse Effect.

(r) Intellectual Property Rights. The Company and its Subsidiaries own or possess adequate rights or licenses to use all trademarks, service marks and all applications and registrations therefor, trade names, patents, patent rights, copyrights, original works of authorship, inventions, trade secrets and other intellectual property rights necessary to conduct their respective businesses as now conducted (“Intellectual Property Rights”) except as could not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect. The Company does not have any knowledge of any infringement by the Company or its Subsidiaries of Intellectual Property Rights of others. To the knowledge of the Company, there is no claim, action or proceeding being threatened, against the Company or its Subsidiaries regarding its Intellectual Property Rights except as could not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect. The Company is unaware of any facts or circumstances which might give rise to any of the foregoing infringements or claims, actions or proceedings except as could not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect. The Company and its Subsidiaries have taken reasonable security measures to protect the secrecy, confidentiality and value of all of their Intellectual Property Rights.

(s) Environmental Laws. The Company and its Subsidiaries (i) are in compliance with any and all Environmental Laws (as hereinafter defined), (ii) have received all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses and (iii) are in compliance with all terms and conditions of any such permit, license or approval where, in each of the foregoing clauses (i), (ii) and (iii), the failure to so comply could be reasonably expected to have, individually or in the aggregate, a Material Adverse Effect. The term “Environmental Laws” means all federal, state, local or foreign laws relating to pollution or protection of human health or the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata), including, without limitation, laws relating to emissions, discharges, releases or threatened releases

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of chemicals, pollutants, contaminants, or toxic or hazardous substances or wastes (collectively, “Hazardous Materials”) into the environment, or otherwise relating to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials, as well as all authorizations, codes, decrees, demands or demand letters, injunctions, judgments, licenses, notices or notice letters, orders, permits, plans or regulations issued, entered, promulgated or approved thereunder.

(t) Subsidiary Rights. Except as provided in the indenture under which the Subsidiary Notes are issued, the Company or one of its Subsidiaries has the unrestricted right to vote, and (subject to limitations imposed by applicable law) to receive dividends and distributions on, all capital securities of its Subsidiaries as owned by the Company or such Subsidiary.

(u) Internal Accounting and Disclosure Controls. The Company and each of its Subsidiaries maintain a system of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset and liability accountability, (iii) access to assets or incurrence of liabilities is permitted only in accordance with management’s general or specific authorization and (iv) the recorded accountability for assets and liabilities is compared with the existing assets and liabilities at reasonable intervals and appropriate action is taken with respect to any difference. The Company maintains disclosure controls and procedures (as such term is defined in Rule 13a-14 under the 1934 Act) which it has concluded are effective in ensuring that information required to be disclosed by the Company in the reports that it files or submits under the 1934 Act is recorded, processed, summarized and reported, within the time periods specified in the rules and forms of the SEC, including, without limitation, controls and procedures designed in to ensure that information required to be disclosed by the Company in the reports that it files or submits under the 1934 Act is accumulated and communicated to the Company’s management, including its principal executive officer or officers and its principal financial officer or officers, as appropriate, to allow timely decisions regarding required disclosure.

(v) Ranking of Notes. Other than the Company’s outstanding 3% Convertible Notes due 2008 or as set forth on Schedule 3(v), no Indebtedness of the Company is senior to or ranks pari passu with the Notes in right of payment, whether with respect of payment of redemptions, interest, damages or upon liquidation or dissolution or otherwise. No Indebtedness of the Company is secured by any assets of the Company.

(w) Investment Company Status. The Company is not, and upon consummation of the sale of the Securities will not be, an “investment company,” a company controlled by an “investment company” or an “affiliated person” of, or “promoter” or “principal underwriter” for, an “investment company” as such terms are defined in the Investment Company Act of 1940, as amended.

(x) Form S-3 Eligibility. The Company is eligible to register the Conversion Shares for resale by the Buyers using Form S-3 promulgated under the 1933 Act.

(y) Transfer Taxes. On the Closing Date, all stock transfer or other taxes (other than income or similar taxes) which are required to be paid in connection with the sale and transfer of the Securities to be sold to each Buyer hereunder will be, or will have been, fully paid or provided for by the Company, and all laws imposing such taxes will be or will have been complied with.

(z) Manipulation of Price. The Company has not, and to its knowledge no one acting on its behalf has, (i) taken, directly or indirectly, any action designed to cause or to result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of any of the Securities, (ii) sold, bid for, purchased, or paid any compensation for soliciting purchases of, any of the Securities, or (iii) paid or agreed to pay to any person any compensation for soliciting another to purchase any other securities of the Company.

(aa) FDA Compliance. The Company and each of the Subsidiaries are conducting their business in compliance with the rules and regulations of the United States Food and Drug Administration (the “FDA”) and all applicable federal, state and local laws, orders, rules, regulations, directives, decrees and judgments of each of the jurisdictions in which it is conducting business, including, without limitation, all applicable local, state and federal laws and regulations governing health, sanitation, safety, zoning and land use,

9

except where the failure to be so in compliance would not reasonably be expected to have a Material Adverse Effect. Except as disclosed in the SEC Documents, there are no pending or threatened administrative, regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of noncompliance or violation, investigation or proceedings before the FDA or any other federal, state, local or foreign governmental bodies that involve or effect the Company, its existing products, product candidates or any of its Subsidiaries which, individually or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would be reasonably likely to result in a Material Adverse Effect.

(bb) License Agreements. Neither the Company nor any Subsidiary is in breach or default (nor has any event occurred which with notice, lapse of time, or both would result in any breach of, or constitute a default) under any license agreements granting to the Company or such Subsidiary any right to incorporate any Intellectual Property Rights into any commercial product of the Company filed as an exhibit to the SEC Documents (collectively, the “Inbound License Agreements”) or any license agreements under which the Company or such Subsidiary licenses or grants a third party rights to incorporate any rights under any Company Intellectual Property Rights into any commercial product of such third party filed as an exhibit to the SEC Documents (collectively, the “Outbound License Agreements”), except in each case as would not, individually or in the aggregate, be reasonably expected to result in a Material Adverse Effect.

(cc) Protection of Intellectual Property. The Company has taken reasonable steps to protect the material Intellectual Property Rights of the Company and the Subsidiaries.

(dd) No Infringement or Prospective Infringement by the Company. To the knowledge of the Company, none of the products manufactured, marketed, used, sold or licensed by the Company and/or as anticipated to be manufactured, marketed, used, sold or licensed by the Company or any Subsidiary, and none of the Intellectual Property Rights used by the Company or any Subsidiary in the conduct of the Company’s business as described in the SEC Documents infringes upon, violates or constitutes the unauthorized use of any valid and enforceable rights owned or controlled by any third party.

(ee) No Pending or Threatened Infringement Claims. No litigation to which the Company or any Subsidiary is a party is now pending and no notice or other claim in writing has been received by the Company (i) alleging that the Company or any Subsidiary has engaged in any activity or conduct that infringes upon, violates or constitutes the unauthorized use of the Intellectual Property Rights of any third party or (ii) challenging the ownership, use, validity or enforceability of any Intellectual Property Rights owned by or exclusively licensed to or by the Company or any Subsidiary. No Intellectual Property Rights, used or likely to be used in the business of the Company (y) that is owned by the Company or a Subsidiary is subject to any outstanding order, judgment, decree, stipulation or agreement materially restricting the use, sale, transfer, assignment or licensing thereof by the Company or such Subsidiary, except as may be specifically provided in any such Outbound License Agreement or other licenses or agreements, or (z) that is the subject of an Inbound License Agreement is subject to any outstanding judgment, decree, stipulation or agreement materially restricting the use, sale, transfer, assignment or licensing thereof by the Company or any Subsidiary, except as provided in the Inbound License Agreements or other licenses or agreements.

(ff) No Infringement by Third Parties. To the knowledge of the Company, no third party is misappropriating, infringing, diluting or violating any Intellectual Property Rights of the Company or any Subsidiary, that is used or is likely to be used in the business of the Company as described in the SEC Documents, and no such claims have been brought against any third party by the Company or any Subsidiary.

4. COVENANTS.

(a) Best Efforts. Each party shall use commercially reasonable efforts timely to satisfy each of the conditions to be satisfied by it as provided in Sections 6 and 7 of this Agreement.

(b) Form D and Blue Sky. The Company agrees to file a Form D with respect to the Securities as required under Regulation D and to provide a copy thereof to each Buyer promptly after such filing. The Company shall make all filings and reports relating to the offer and sale of the Securities required under applicable securities or “Blue Sky” laws of the states of the United States following the Closing Date.

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(c) Use of Proceeds. The Company will use the proceeds from the sale of the Securities for general corporate purposes, but not for the redemption or repurchase of any of its or its Subsidiaries’ equity securities or payment of any dividend to its equity holders.

(d) Financial Information. The Company agrees to send the following to each Investor (as defined in the Registration Rights Agreement) during the period required by Section 8 of the Registration Rights Agreements unless the following are filed with the SEC through EDGAR and are available to the public through the EDGAR system, within one (1) Business Day after the filing thereof with the SEC, (i) a copy of its Annual Reports on Form 10-K or 10-KSB, Quarterly Reports on Form 10-Q or 10-QSB, any Current Reports on Form 8-K and any registration statements (other than on Form S-8) or amendments filed pursuant to the 1933 Act, and (ii) copies of any notices and other information made available or given to the stockholders of the Company generally, contemporaneously with the making available or giving thereof to the stockholders. As used herein, “Business Day” means any day other than Saturday, Sunday or other day on which commercial banks in The City of New York are authorized or required by law to remain closed.

(e) Placement Fees. The Company shall be responsible for the payment of any placement agent’s fees, financial advisory fees, or broker’s commissions relating to or arising out of the transactions contemplated hereby. The Company shall pay, and hold each Buyer harmless against, any liability, loss or expense (including, without limitation, reasonable attorney’s fees and out-of-pocket expenses) arising in connection with any claim relating to any such payment.

(f) Pledge of Securities. The Company acknowledges and agrees that the Securities may be pledged by an Investor in connection with a bona fide margin agreement or other loan or financing arrangement that is secured by the Securities. The pledge of Securities shall not be deemed to be a transfer, sale or assignment of the Securities hereunder, and no Investor effecting a pledge of Securities shall be required to provide the Company with any notice thereof or otherwise make any delivery to the Company pursuant to this Agreement or any other Transaction Document, including, without limitation, Section 2(f) hereof; provided that an Investor and its pledgee shall be required to comply with the provisions of Section 2(f) hereof in order to effect a sale, transfer or assignment of Securities to such pledgee. The Company hereby agrees to execute and deliver such documentation as a pledgee of the Securities may reasonably request in connection with a pledge of the Securities to such pledgee by an Investor.

(g) Disclosure of Transactions and Other Material Information. The Company shall make all filings with the SEC as required as a result of the Transaction documents within the time periods required for such filings.

(h) Additional Registration Statements. Until 30 days after the date that the Registration Statement is first declared effective by the SEC, the Company shall not file a registration statement under the 1933 Act relating to securities that are not the Securities other than a Registration Statement on Form S-8.

(i) Additional Notes; Dilutive Issuances. So long as any Buyer beneficially owns any Securities, the Company will not issue any Notes other than to the Buyers as contemplated hereby and the Company shall not issue any other securities that would cause a breach or default under the Notes.

(j) Reservation of Shares. The Company shall take all action necessary to at all times have authorized, and reserved for the purpose of issuance, the number of shares of Common Stock issuable upon conversion of the Notes (without taking into account any limitations on the Conversion of the Notes set forth in the Notes).

(k) Make Whole Premium Upon Change of Control. (i) If a Change of Control (as defined below) occurs, the Company will pay, to the extent described below, a make whole premium if the holder converts Notes in connection with any such transaction by increasing the Conversion Rate (as defined in the Note) applicable to such Notes if and as required below. A conversion of the Notes by a holder will be deemed for these purposes to be “in connection with” a Change of Control if the Conversion Notice (as defined in the Note) is received by the conversion agent on or subsequent to the date 15 trading days prior to the date announced by the Company as the anticipated effective date of the Change of Control but before the close of business on the business day

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immediately preceding the effective date of the related Change of Control. Any make whole premium will have the effect of increasing the amount of any cash, securities or other assets otherwise due to holders of Notes upon conversion. Any increase in the applicable Conversion Rate (as defined in the Note) will be determined by reference to the table below and is based on the date on which the Change of Control becomes effective, which we refer to as the “effective date,” and the price, which we refer to as the “stock price”, paid, or deemed to be paid, per share of the Company’s Common Stock in the transaction constituting the Change of Control, subject to adjustment as described below. If holders of the Company’s Common Stock receive only cash in the Change of Control, the stock price shall be the cash amount paid per share of the Company’s Common Stock. In all other cases, the stock price shall be the average of the closing prices of the Company’s Common Stock for each of the 10 trading days immediately prior to but not including the effective date of the Change of Control.

The following table shows the amount, if any, by which the applicable Conversion Rate will increase for each hypothetical stock price and effective date set forth below (if the Conversion Rate of the Notes is adjusted in accordance with the terms of the Notes, the Conversation Rates and hypothetical stock prices set forth below shall be equitably adjusted by the Company; any dispute with respect to any such adjustment shall be resolved in accordance with Section 21 of the Notes).

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Number of Additional Shares (per $1,000 principal amount of Notes)

The exact applicable price and effective date may not be as set forth in the table above, in which case:

if the actual applicable price is between two applicable prices listed in the table above, or the actual effective date is between two dates listed in the table above, we will determine the number of additional shares by linear interpolation between the numbers of additional shares set forth for the two applicable prices, or for the two dates based on a 365-day year, as applicable;

if the actual applicable price is greater than $14.00 per share (subject to adjustment), we will not increase the conversion rate; and

if the actual applicable price is less than $4.18 per share (subject to adjustment), we will not increase the conversion rate.

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(ii) A “Change of Control” will be deemed to occur at such time as:

(A) any “person” or “group” (as those terms are used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934) is or becomes the “beneficial owner” (as that term is used in Rule 13d-3 under the Securities Exchange Act of 1934), directly or indirectly, of 50% or more of the total outstanding voting power of all classes of the Company’s capital stock entitled to vote generally in the election of directors (“voting stock”);

(B) there occurs a sale, transfer, lease, conveyance or other disposition of all or substantially all of the Company’s property or assets to any “person” or “group” (as those terms are used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934), including any group acting for the purpose of acquiring, holding, voting or disposing of securities within the meaning of Rule 13d-5(b)(1) under the Securities Exchange Act of 1934;

(C) the Company consolidates with, or merges with or into, another person or any person consolidates with, or merges with or into, the Company, unless either:

(i) the persons that “beneficially owned”, directly or indirectly, the shares of the Company’s voting stock immediately prior to such consolidation or merger “beneficially own”, directly or indirectly, immediately after such consolidation or merger, shares of the surviving or continuing corporation’s voting stock representing at least a majority of the total outstanding voting power of all outstanding classes of voting stock of the surviving or continuing corporation; or

(ii) both of the following conditions are satisfied:

(a) at least 90% of the consideration (other than cash payments for fractional shares or pursuant to statutory appraisal rights) in such consolidation or merger consists of common stock and any associated rights traded on a U.S. national securities exchange (or which will be so traded when issued or exchanged in connection with such consolidation or merger); and

(b) as a result of such consolidation or merger, the Notes become convertible into cash and, if applicable, solely such common stock and associated rights;

(D) the following persons cease for any reason to constitute a majority of the Company’s board of directors:

(i) individuals who on the first issue date of the Notes constituted the Company’s board of directors; and

(ii) any new directors whose election to the Company’s board of directors or whose nomination for election by the Company’s stockholders was approved by at least a majority of the Company’s directors then still in office either who were directors on such first issue date of the Notes or whose election or nomination for election was previously so approved; or

(E) the Company is liquidated or dissolved or holders of the Company’s capital stock approve any plan or proposal for the Company’s liquidation or dissolution.

(iii) All adjustments to the Conversion Rate in accordance with this Section 4(k) shall be subject to the provisions of Section 3(d)(ii) of the Notes.

5. REGISTER; TRANSFER AGENT INSTRUCTIONS.

(a) Register. The Company shall maintain at its principal executive offices (or such other office or agency of the Company as it may designate by notice to each holder of Securities), a register for the Notes in which the Company shall record the name and address of the Person in whose name the Notes have been issued (including the name and address of each transferee), the principal

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amount of Notes held by such Person, the number of Conversion Shares issuable upon conversion of the Notes held by such Person. The Company shall keep the register open and available at all times during business hours for inspection of any Buyer or its legal representatives.

(b) Transfer Agent Instructions. The Company shall issue irrevocable instructions to its transfer agent, and any subsequent transfer agent, to issue certificates or credit shares to the applicable balance accounts at The Depository Trust Company (“DTC”), registered in the name of each Buyer or its respective nominee(s), for the Conversion Shares issued upon conversion of the Notes in such amounts as specified from time to time by each Buyer to the Company upon conversion of the Notes in the form of Exhibit C attached hereto (the “Irrevocable Transfer Agent Instructions”). The Company warrants that no instruction other than the Irrevocable Transfer Agent Instructions referred to in this Section 5(b), and stop transfer instructions to give effect to Section 2(g) hereof, will be given by the Company to its transfer agent, and that the Securities shall otherwise be freely transferable on the books and records of the Company as and to the extent provided in this Agreement and the other Transaction Documents. If a Buyer effects a sale, assignment or transfer of the Securities in accordance with Section 2(f), the Company shall permit the transfer and shall promptly instruct its transfer agent to issue one or more certificates or credit shares to the applicable balance accounts at DTC in such name and in such denominations as specified by such Buyer to effect such sale, transfer or assignment. In the event that such sale, assignment or transfer involves Conversion Shares sold, assigned or transferred pursuant to an effective registration statement or pursuant to Rule 144, the transfer agent shall issue such Securities to the Buyer, assignee or transferee, as the case may be, without any restrictive legend.

6. CONDITIONS TO THE COMPANY’S OBLIGATION TO SELL. The obligation of the Company hereunder to issue and sell the Notes to the Buyers at the Closing is subject to the satisfaction, at or before the Closing Date, of each of the following conditions, provided that these conditions are for the Company’s sole benefit and may be waived by the Company at any time in its sole discretion by providing each Buyer with prior written notice thereof:

(a) Each Buyer shall have executed each of the Transaction Documents to which it is a party and delivered the same to the Company.

(b) Each Buyer and each other Buyer shall have delivered to the Company the Purchase Price for the Notes being purchased by each Buyer at the Closing by wire transfer of immediately available funds pursuant to the wire instructions provided by the Company.

(c) The representations and warranties of each Buyer shall be true and correct in all material respects (except for those representations and warranties that are qualified by materiality, which shall be true and correct in all respects) as of the date when made and as of the Closing Date as though made at that time (except for representations and warranties that speak as of a specific date), and each Buyer shall have performed, satisfied and complied in all material respects with the covenants, agreements and conditions required by this Agreement to be performed, satisfied or complied with by each Buyer at or prior to the Closing Date.

7. CONDITIONS TO EACH BUYER’S OBLIGATION TO PURCHASE. The obligation of each Buyer hereunder to purchase the Notes at the Closing is subject to the satisfaction, at or before the Closing Date, of each of the following conditions, provided that these conditions are for each Buyer’s sole benefit and may be waived by such Buyer at any time in its sole discretion by providing the Company with prior written notice thereof:

(a) The Company shall have duly executed and delivered to such Buyer (i) each of the Transaction Documents and (ii) the Notes (allocated in such principal amounts as such Buyer shall request), being purchased by such Buyer at the Closing pursuant to this Agreement.

(b) The Company shall have delivered to such Buyer a copy of the Irrevocable Transfer Agent Instructions, in the form of Exhibit C attached hereto, which instructions shall have been delivered to the Company’s transfer agent.

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(c) The representations and warranties of the Company shall be true and correct in all material respects (except for those representations and warranties that are qualified by materiality or Material Adverse Effect, which shall be true and correct in all respects) as of the date when made and as of the Closing Date as though made at that time (except for representations and warranties that speak as of a specific date) and the Company shall have performed, satisfied and complied in all material respects with the covenants, agreements and conditions required by the Transaction Documents to be performed, satisfied or complied with by the Company at or prior to the Closing Date. Such Buyer shall have received a certificate, executed by an officer of the Company, dated as of the Closing Date, to the foregoing effect in the form attached hereto as Exhibit D.

(d) The Common Stock (i) shall be designated for quotation or listed on the Principal Market and (ii) shall not have been suspended, as of the Closing Date, by the SEC or the Principal Market from trading on the Principal Market nor shall suspension by the SEC or the Principal Market have been threatened, as of the Closing Date, either (A) in writing by the SEC or the Principal Market or (B) by falling below the minimum listing maintenance requirements of the Principal Market.

(e) The Company shall have obtained all governmental, regulatory or third party consents and approvals, if any, necessary for the sale of the Securities.

8. TERMINATION. In the event that the Closing shall not have occurred with respect to a Buyer on or before five (5) Business Days from the date hereof due to the Company’s or such Buyer’s failure to satisfy the conditions set forth in Sections 6 and 7 above (and the nonbreaching party’s failure to waive such unsatisfied condition(s)), the nonbreaching party shall have the option to terminate this Agreement with respect to such breaching party at the close of business on such date.

9. MISCELLANEOUS.

(a) Governing Law; Jurisdiction; Jury Trial. All questions concerning the construction, validity, enforcement and interpretation of this Agreement shall be governed by the internal laws of the State of New York, without giving effect to any choice of law or conflict of law provision or rule (whether of the State of New York or any other jurisdictions) that would cause the application of the laws of any jurisdictions other than the State of New York. Each party hereby irrevocably submits to the exclusive jurisdiction of the state and federal courts sitting in The City of New York, Borough of Manhattan, for the adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein, and hereby irrevocably waives, and agrees not to assert in any suit, action or proceeding, any claim that it is not personally subject to the jurisdiction of any such court, that such suit, action or proceeding is brought in an inconvenient forum or that the venue of such suit, action or proceeding is improper. Each party hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof to such party at the address for such notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. EACH PARTY HEREBY IRREVOCABLY WAIVES ANY RIGHT IT MAY HAVE, AND AGREES NOT TO REQUEST, A JURY TRIAL FOR THE ADJUDICATION OF ANY DISPUTE HEREUNDER OR IN CONNECTION WITH OR ARISING OUT OF THIS AGREEMENT OR ANY TRANSACTION CONTEMPLATED HEREBY.

(b) Counterparts. This Agreement may be executed in two or more identical counterparts, all of which shall be considered one and the same agreement and shall become effective when counterparts have been signed by each party and delivered to the other party; provided that a facsimile signature shall be considered due execution and shall be binding upon the signatory thereto with the same force and effect as if the signature were an original, not a facsimile signature.

(c) Headings. The headings of this Agreement are for convenience of reference and shall not form part of, or affect the interpretation of, this Agreement.

(d) Severability. If any provision of this Agreement shall be invalid or unenforceable in any jurisdiction, such invalidity or unenforceability shall not affect the validity or enforceability of the remainder of this Agreement in that jurisdiction or the validity or enforceability of any provision of this Agreement in any other jurisdiction.

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(e) Entire Agreement; Amendments. This Agreement and the other Transaction Documents supersede all other prior oral or written agreements between the Buyers, the Company, their affiliates and Persons acting on their behalf with respect to the matters discussed herein (other than any confidentiality agreement entered into with respect to the matters covered hereby), and this Agreement, the other Transaction Documents and the instruments referenced herein and therein contain the entire understanding of the parties with respect to the matters covered herein and therein and, except as specifically set forth herein or therein, neither the Company nor any Buyer makes any representation, warranty, covenant or undertaking with respect to such matters. No provision of this Agreement may be amended other than by an instrument in writing signed by the Company and the holders of at least a majority of the aggregate number of Registrable Securities issued and issuable hereunder and under the Notes, and any amendment to this Agreement made in conformity with the provisions of this Section 9(e) shall be binding on all Buyers and holders of Securities as applicable. No provision hereof may be waived other than by an instrument in writing signed by the party against whom enforcement is sought. No such amendment shall be effective to the extent that it applies to less than all of the holders of the applicable Securities then outstanding. No consideration shall be offered or paid to any Person to amend or consent to a waiver or modification of any provision of any of the Transaction Documents unless the same consideration also is offered to all of the parties to the Transaction Documents or holders of Notes, as the case may be. The Company has not, directly or indirectly, made any agreements with any Buyers relating to the terms or conditions of the transactions contemplated by the Transaction Documents except as set forth in the Transaction Documents. Without limiting the foregoing, the Company confirms that, except as set forth in this Agreement, no Buyer has made any commitment or promise or has any other obligation to provide any financing to the Company or otherwise.

(f) Notices. Any notices, consents, waivers or other communications required or permitted to be given under the terms of this Agreement must be in writing and will be deemed to have been delivered: (i) upon receipt, when delivered personally; (ii) upon receipt, when sent by facsimile (provided confirmation of transmission is mechanically or electronically generated and kept on file by the sending party); or (iii) one Business Day after deposit with an overnight courier service, in each case properly addressed to the party to receive the same. The addresses and facsimile numbers for such communications shall be:

If to the Company:

NPS Pharmaceuticals, Inc.

300 Interpace Parkway

Building B

Parsippany, New Jersey 07054

Facsimile: (973)  ###-###-####

Attention: Chief Financial Officer

with a copy to:

If to the Transfer Agent:

Computershare Trust Company, Inc.

350 Indiana Street

Golden, Colorado 80401

Facsimile: (303)  ###-###-####

Attention: Mr. Patrick Hayes

If to a Buyer, to its address and facsimile number set forth on the Schedule of Buyers, with copies to such Buyer’s representatives as set forth on the Schedule of Buyers, or to such other address and/or facsimile number and/or to the attention of such other Person as the recipient party has specified by written notice given to each other party five (5) days prior to the effectiveness of such change. Written confirmation of receipt (A) given by the recipient of such notice, consent, waiver or other communication, (B) mechanically or electronically generated by the sender’s facsimile machine containing the time, date, recipient facsimile number and an image of the first page of such transmission or (C) provided by an overnight courier service shall be rebuttable evidence of personal service, receipt by facsimile or receipt from an overnight courier service in accordance with clause (i), (ii) or (iii) above, respectively.

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(g) Successors and Assigns. This Agreement shall be binding upon and inure to the benefit of the parties and their respective successors and assigns, including any purchasers of the Notes. The Company shall not assign this Agreement or any rights or obligations hereunder without the prior written consent of the holders. A Buyer may assign some or all of its rights hereunder without the consent of the Company, in which event such assignee shall be deemed to be a Buyer hereunder with respect to such assigned rights. A Buyer shall give the Company prompt notice of any such assignment.

(h) No Third Party Beneficiaries. This Agreement is intended for the benefit of the parties hereto and their respective permitted successors and assigns, and is not for the benefit of, nor may any provision hereof be enforced by, any other Person.

(i) Survival. Unless this Agreement is terminated under Section 8, the representations and warranties of the Company and the Buyers contained in Sections 2 and 3, and the agreements and covenants set forth in Sections 4, 5 and 9 shall survive the Closing. Each Buyer shall be responsible only for its own representations, warranties, agreements and covenants hereunder.

(j) Further Assurances. Each party shall do and perform, or cause to be done and performed, all such further acts and things, and shall execute and deliver all such other agreements, certificates, instruments and documents, as any other party may reasonably request in order to carry out the intent and accomplish the purposes of this Agreement and the consummation of the transactions contemplated hereby.

(k) Indemnification. In consideration of each Buyer’s execution and delivery of the Transaction Documents and acquiring the Securities thereunder and in addition to all of the Company’s other obligations under the Transaction Documents, the Company shall defend, protect, indemnify and hold harmless each Buyer and each other holder of the Securities and all of their stockholders, partners, members, officers, directors, employees and direct or indirect investors and any of the foregoing Persons’ agents or other representatives (including, without limitation, those retained in connection with the transactions contemplated by this Agreement) (collectively, the “Indemnitees”) from and against any and all actions, causes of action, suits, claims, losses, costs, penalties, fees, liabilities and damages, and expenses in connection therewith (irrespective of whether any such Indemnitee is a party to the action for which indemnification hereunder is sought), and including reasonable attorneys’ fees and disbursements (the “Indemnified Liabilities”), incurred by any Indemnitee as a result of, or arising out of, or relating to (a) any misrepresentation or breach of any representation or warranty made by the Company in the Transaction Documents or any other certificate, instrument or document contemplated hereby or thereby, (b) any breach of any covenant, agreement or obligation of the Company contained in the Transaction Documents or any other certificate, instrument or document contemplated hereby or thereby or (c) any cause of action, suit or claim brought or made against such Indemnitee by a third party (including for these purposes a derivative action brought on behalf of the Company) and arising out of or resulting from (i) the execution, delivery or performance by the Company or enforcement by Buyers of the Transaction Documents or any other certificate, instrument or document contemplated hereby or thereby, (ii) any transaction financed or to be financed in whole or in part, directly or indirectly, with the proceeds of the issuance of the Securities, or (iii) the status of such Buyer or holder of the Securities as an investor in the Company pursuant to the transactions contemplated by the Transaction Documents. To the extent that the foregoing undertaking by the Company may be unenforceable for any reason, the Company shall make the maximum contribution to the payment and satisfaction of each of the Indemnified Liabilities that is permissible under applicable law. Except as otherwise set forth herein, the mechanics and procedures with respect to the rights and obligations under this Section 9(k) shall be the same as those set forth in Section 6 of the Registration Rights Agreement.

(l) No Strict Construction. The language used in this Agreement will be deemed to be the language chosen by the parties to express their mutual intent, and no rules of strict construction will be applied against any party.

(m) Remedies. Each Buyer and each holder of the Securities shall have all rights and remedies set forth in the Transaction Documents and all rights and remedies which such holders have been granted at any time under any other agreement or contract and

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all of the rights which such holders have under any law. Any Person having any rights under any provision of this Agreement shall be entitled to enforce such rights specifically (without posting a bond or other security), to recover damages by reason of any breach of any provision of this Agreement and to exercise all other rights granted by law. Furthermore, the Company recognizes that in the event that it fails to perform, observe, or discharge any or all of its obligations under the Transaction Documents, any remedy at law may prove to be inadequate relief to the Buyers. The Company therefore agrees that the Buyers shall be entitled to seek temporary and permanent injunctive relief in any such case without the necessity of proving actual damages and without posting a bond or other security.

(n) Rescission and Withdrawal Right. Notwithstanding anything to the contrary contained in (and without limiting any similar provisions of) the Transaction Documents, whenever any Buyer exercises a right, election, demand or option under a Transaction Document and the Company does not timely perform its related obligations within the periods therein provided, then such Buyer may rescind or withdraw, in its sole discretion from time to time upon written notice to the Company, any relevant notice, demand or election in whole or in part without prejudice to its future actions and rights.

(o) Payment Set Aside. To the extent that the Company makes a payment or payments to the Buyers hereunder or pursuant to any of the other Transaction Documents or the Buyers enforce or exercise their rights hereunder or thereunder, and such payment or payments or the proceeds of such enforcement or exercise or any part thereof are subsequently invalidated, declared to be fraudulent or preferential, set aside, recovered from, disgorged by or are required to be refunded, repaid or otherwise restored to the Company, a trustee, receiver or any other Person under any law (including, without limitation, any bankruptcy law, foreign, state or federal law, common law or equitable cause of action), then to the extent of any such restoration the obligation or part thereof originally intended to be satisfied shall be revived and continued in full force and effect as if such payment had not been made or such enforcement or setoff had not occurred.

(p) Independent Nature of Buyers’ Obligations and Rights. The obligations of each Buyer under any Transaction Document are several and not joint with the obligations of any other Buyer, and no Buyer shall be responsible in any way for the performance of the obligations of any other Buyer under any Transaction Document. Nothing contained herein or in any other Transaction Document, and no action taken by any Buyer pursuant hereto or thereto, shall be deemed to constitute the Buyers as a partnership, an association, a joint venture or any other kind of entity, or create a presumption that the Buyers are in any way acting in concert or as a group with respect to such obligations or the transactions contemplated by the Transaction Documents. Each Buyer confirms that it has independently participated in the negotiation of the transaction contemplated hereby with the advice of its own counsel and advisors. Each Buyer shall be entitled to independently protect and enforce its rights, including, without limitation, the rights arising out of this Agreement or out of any other Transaction Documents, and it shall not be necessary for any other Buyer to be joined as an additional party in any proceeding for such purpose.

[Signature Page Follows]

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IN WITNESS WHEREOF, each Buyer and the Company have caused their respective signature page to this Securities Purchase Agreement to be duly executed as of the date first written above.

[Signature Page to Securities Purchase Agreement]

IN WITNESS WHEREOF, each Buyer and the Company have caused their respective signature page to this Securities Purchase Agreement to be duly executed as of the date first written above.

[Signature Page to Securities Purchase Agreement]

SCHEDULE OF BUYERS

EXHIBITS

SCHEDULES

3(p) Indebtedness

Schedule 3(p)

On July 16, 2007, the Company’s wholly owned subsidiary, NPS Allelix Corp. (“NPS Allelix”), entered into an Agreement for the Sale and Assignment of Rights with Drug Royalty L.P.3 (“Drug Royalty”), pursuant to which NPS Allelix sold to Drug Royalty its right to receive future royalty payments arising from sales of PREOTACT under its license agreement with Nycomed Danmark ApS (the “Sale Transaction”). In light of certain provisions of the agreement, the Company will report the Sale Transaction as debt on its consolidated financial statements pursuant to United States’ generally accepted accounting principles. In connection with the Sale Transaction, NPS Allelix granted Drug Royalty a security interest in the Nycomed license agreement and certain of its patents and other intellectual property underlying the Nycomed license agreement.