Roche and Pharmasset Initiate Phase IIb Clinical Trial of R7128, Most Advanced Nucleoside Polymerase Inhibitor in Development for Chronic H...( Start of trial triggers $10 million m...),Health

Start of trial triggers $10 million milestone payment to Pharmasset

PRINCETON, N.J., April 24 /PRNewswire-FirstCall/ -- Pharmasset, Inc. (Nasdaq: VRUS) and Roche (Roche SWX: RO, ROG; Pink Sheets: RHHBY) today announced that the first patient has been dosed in a Phase IIb study of R7128, the nucleoside polymerase inhibitor most advanced in development for the treatment of chronic hepatitis C (HCV). The trial will evaluate the dose and duration of treatment of R7128 in combination with Roche's PEGASYS(R) (peginterferon alfa-2a) and COPEGUS(R) (ribavirin) - in HCV patients who have not been treated previously. The goal of adding R7128 to the existing standard therapy is to improve rates of sustained virological response (SVR) and to shorten the length of treatment for patients.

R7128 is being developed by Roche and Pharmasset under a partnership agreement entered into in 2004. The first patient dosed in this study triggered a $10 million payment to Pharmasset from Roche.

A Phase I/IIa trial demonstrated the ability of R7128 to generate high rapid virologic response rates (RVR) in combination with PEGASYS and COPEGUS. Unlike protease inhibitors in development, R7128 is active against multiple HCV genotypes and presents a high barrier to the development of resistance.

"We look for the Phase IIb study to further support the efficacy and safety of R7128, and nucleoside polymerase inhibitors as a class," said Michelle Berrey, MD, MPH, Pharmasset's Chief Medical Officer. "We believe nucleoside inhibitors have a number of advantages over other classes of HCV drugs, including a higher barrier to resistance and activity across multiple genotypes, as well as a high level of potency."

"The collaboration with Pharmasset underscores Roche's commitment to develop new therapies that will meet the n
'/>"/>