Pharmasset Commences Dosing in 28-Day Combination Study of R7128 with Pegasys(R) plus Copegus(R) for H...( PRINCETON N.J. Oct. 3 /- Pharmass...),Health

PRINCETON, N.J., Oct. 3 /PRNewswire-FirstCall/ -- Pharmasset, Inc. (Nasdaq: VRUS) has commenced dosing in a Phase 1 study of R7128 in combination with Pegasys (pegylated interferon) plus Copegus (ribavirin) in up to 75 treatment-naive patients chronically infected with hepatitis C virus (HCV) genotype 1. R7128 is a prodrug of PSI-6130, an oral cytidine nucleoside analog polymerase inhibitor of HCV that is being developed through Pharmasset's collaboration with Roche. The purpose of this study is a preliminary evaluation of safety, tolerability, pharmacokinetics and antiviral activity of R7128 in the clinically-relevant setting of combination therapy with the current standard of care for chronic HCV infection.

The study will include two to three oral doses of R7128 (500 mg to 1500 mg) that will be administered twice-daily with Pegasys plus Copegus for 28 days. There will be 25 patients in each dose cohort with 20 patients randomized to receive R7128 and 5 patients randomized to receive placebo, all administered in combination with the standard of care. After completing 28 days of the triple combination regimen and a follow-up period of 4 weeks of Pegasys plus Copegus, all patients will then receive 40 weeks of open-label standard of care dosing under a separate protocol. Please see http://www.clinicaltrials.gov or e-mail clinicaltrials@pharmasset.com for more information.

"We are excited about the rapid pace of development of R7128, and the opportunity to evaluate its safety and potency in combination with the standard of care," stated Dr. Michelle Berrey, Pharmasset's Vice President, Clinical Develo
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