R7128, a prodrug of PSI-6130, is a nucleoside analogue polymerase inhibitor of HCV that is being developed through Pharmasset’s collaboration with Roche. In this study, R7128 demonstrated potent short-term antiviral activity and was generally safe and well tolerated. Approximately 85% of patients receiving R7128 1500mg twice-daily (BID) with Pegasys plus Copegus for four weeks achieved undetectable hepatitis C virus (HCV) RNA levels with safety and tolerability comparable to placebo with Pegasys plus Copegus.
John McHutchison, clinical investigator for this study, said: “R7128, in combination with Pegasys plus Copegus, has demonstrated Rapid Virologic Response (RVR) percentages in a four-week study that are similar to HCV protease inhibitors and has an encouraging short-term clinical safety profile. Longer-term studies of R7128 with Pegasys plus Copegus are needed to provide additional information about its potential to improve sustained virologic response rates for HCV patients.”