Pharmasset initiates dosing in PSI-7977 exploratory study in HCV

Pharmasset, Inc. (Nasdaq: VRUS) announced today that dosing has begun in an exploratory study of PSI-7977, a nucleotide analog polymerase inhibitor, for the treatment of chronic hepatitis C (HCV). The trial will evaluate PSI-7977 400mg QD in combination with ribavirin (RBV), with 0, 4, 8, or 12 weeks of pegylated interferon alfa 2a (Peg-IFN) in treatment-naive patients infected with HCV genotype 2 or 3.

"Based on the encouraging efficacy, safety and resistance data from the Phase 2a trial with PSI-7977 in combination with pegylated interferon and ribavirin, we initiated a study to explore shorter durations of interferon, including an interferon-free regimen in treatment naïve patients with HCV genotype 2 or 3," stated Michelle Berrey, MD, MPH, Pharmasset's Chief Medical Officer. "An important limitation to the current treatment of HCV patients is the use of interferon with its associated side effect profile. We believe that PSI-7977's high barrier to resistance and the lack of a significant effect of IL28B genotype in the Phase 2a trial provide us an opportunity with PSI-7977 to explore shorter durations of interferon, and potentially even removing it from the treatment regimen altogether."

SOURCE Pharmasset, Inc.