Pharmasset, Inc. Enters Antiviral Research Collaboration with the University of Cincinnati's Genome Research Institute

PRINCETON, N.J., Oct. 31 /PRNewswire-FirstCall/ -- Pharmasset, Inc. entered into a research collaboration and license agreement with the University of Cincinnati (UC) on behalf of its Genome Research Institute (GRI). The purpose of the collaboration between Pharmasset and GRI's drug discovery professionals is to identify active and selective compounds against antiviral targets for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV).

According to the terms of the agreement, UC granted Pharmasset access to the GRI Lead Generation Library, which includes over 250,000 compounds. Pharmasset will also gain access to GRI's drug discovery capabilities, including high-throughput screening, computational chemistry and in silico docking expertise, which are led by Ruben Papoian, PhD. UC granted Pharmasset commercial rights for any lead compounds that are identified for HBV, HIV and HCV. Pharmasset will make an annual payment to UC in support of the research collaboration and shall be responsible for all development expenses of products that may result from the collaboration. If a lead compound progresses through clinical development activities and achieves regulatory approval, Pharmasset will make certain milestone payments and pay a royalty on any net sales of the product. The specific financial terms of the research collaboration and license agreement will not be disclosed.

"The University of Cincinnati's Genome Research Institute has resources and expertise that will expand our discovery efforts," stated Dr. Michael Otto, Executive Vice President, Pharmaceutical Research. "The GRI compound library, drug discovery platform and biology capabilities provide tremendous leverage for our internal efforts. We are very optimistic about the potential of this collaboration."

"The research collaboration and license agreement with Pharmasset marks an important step for UC's Genome Research Institute, as we strive not only to discover new drug treatments with the potential to improve health, but also to provide a meaningful fiscal return on our research investment," stated George Thomas, PhD, Professor of Genome Science and Interim Director of GRI. "We believe that Pharmasset will be an excellent collaboration partner, as their team is very experienced in the discovery and development of antiviral compounds."

About the Genome Research Institute

In 2001, the University of Cincinnati (UC) Academic Health Center received a gift of land and a 360,000 square foot facility in Reading, Ohio from Aventis Pharmaceuticals. The gift set in motion a two-year, $44 million renovation of the vacant building to create UC's Genome Research Institute (GRI). Nearly 40 principal investigators and 350 support staff and personnel work at the GRI to advance life science research by combining the talents, creativity and resources of academic and industrial scientists to develop treatments for cancer, metabolic disorders and other diseases. The interdisciplinary research program at GRI features core facilities for drug discovery, proteomics, structural biology, protein production and animal phenotype analysis.

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 the Americas 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 enrolling a 28-day Phase 1 clinical trial in combination with Pegasys(R) and 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.

alan.roemer@pharmasset.com

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 no compounds will be identified through the research collaboration, the risk that the on-going or anticipated clinical trials for any one or more of our product candidates will not be successful or 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 Quarterly Report on Form 10-Q for the quarter ended June 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.

CONTACT: Alan Roemer, Vice President, Investor Relations & Corporate
Communications, Pharmasset, Inc., +1-609-613-4125,
alan.roemer@pharmasset.com

Web site: http://www.pharmasset.com/