.J., May 12 /PRNewswire-FirstCall/ -- Pharmasset, Inc. (Nasdaq: VRUS), a clinical stage pharmaceutical company committed to discovering, developing and commercializing novel drugs to treat viral infections, is pleased to announce that it has been selected to join the NASDAQ Biotechnology Index effective with the market open on May 19, 2008.

The NASDAQ Biotechnology Index is the basis for the iShares NASDAQ Biotechnology Index(sm) Fund (AMEX: IBB), which seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the NASDAQ Biotechnology Index. In addition, options based on the NASDAQ Biotechnology Index and the iShares NASDAQ Biotechnology Index Fund trade on various exchanges. For more information about the NASDAQ Biotechnology Index, including eligibility criteria, visit http://www.nasdaq.com.

About Pharmasset

Pharmasset is a clinical-stage pharmaceutical company committed to discovering, developing and commercializing novel drugs to treat viral infections. Pharmasset's primary focus is on the development of oral therapeutics for the treatment of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV).

Pharmasset is currently developing three product candidates. Clevudine, for the treatment of chronic HBV infection, is enrolling Phase 3 clinical trials for registration in North, Central and South America and Europe. Clevudine is already approved for HBV in South Korea and marketed by Bukwang Pharmaceuticals in South Korea under the brand name Levovir. R7128, an oral treatment for chronic HCV infection, is in a 4-week Phase 1 clinical trial in combination with Pegasys(R) plus Copegus(R) through a strategic collaboration with Roche. Racivir, which is being developed for the treatment of HIV in combination with other approved HIV drugs, has completed a Phase 2 clinical trial.

    Pegasys(R) and Copegus(R) are registered trademarks of Roche.

    Contact
    Alan Roemer, Vice President
    Investor Relations & Corporate Communications
    alan.roemer@pharmasset.com
    Office: (609) 613-4125

Forward-Looking Statements

Pharmasset 'Safe Harbor' Statement under the Private Securities Litigation Reform Act of 1995: Statements in this press release regarding our business that are not historical facts are 'forward-looking statements' that involve risks and uncertainties, including without limitation the risk that Pharmasset does not become a part of the Nasdaq Biotechnology Index, the risk that adverse events could cause the cessation or delay of any of the ongoing or planned clinical trials and/or our development of our product candidates, the risk that we cannot enroll enough patients for the Phase 3 registration clinical trial for clevudine, the risk that our collaboration with Roche will not continue or will not be successful and the risk that any one or more of our product candidates will not be successfully developed and commercialized. For a discussion of these risks and uncertainties, any of which could cause our actual results to differ from those contained in the forward-looking statements, see the section of our Annual Report on Form 10-K for the fiscal year ended September 30, 2007 filed with the Securities and Exchange Commission entitled 'Risk Factors' and discussions of potential risks and uncertainties in our subsequent filings with the Securities and Exchange Commission.

SOURCE Pharmasset, Inc.