PHARMASSET, INC. (a Delaware corporation) 1,600,000 Shares of Common Stock UNDERWRITING AGREEMENTUnderwriting Agreement • January 28th, 2010 • Pharmasset Inc • Pharmaceutical preparations • New York
Pharmasset, Inc., a Delaware corporation (the “Company”), confirms its agreement with Leerink Swann LLC (“Leerink Swann”) and each of the other Underwriters named in Schedule A hereto (collectively, the “Underwriters,” which term shall also include any underwriter substituted as hereinafter provided in Section 10 hereof), for whom Leerink Swann is acting as representative (in such capacity, the “Representative”), with respect to (i) the issue and sale by the Company and the purchase by the Underwriters, acting severally and not jointly, of the respective numbers of shares of Common Stock, par value $0.001 per share, of the Company (“Common Stock”) set forth in said Schedule A, and (ii) the grant by the Company to the Underwriters, severally and not jointly, of the option described in Section 2(b) hereof to purchase all or any part of 230,400 additional shares of Common Stock. The aforesaid 1,600,000 shares of Common Stock (the “Initial Securities”) to be purchased by the Underwriters a
