Gilead Announces Sustained Virologic Response Rate of 78% from Phase 3 Study of Sofosbuvir

Gilead Sciences GILD today announced topline results from the Phase 3 POSITRON study examining a 12-week course of once-daily sofosbuvir plus ribavirin (RBV) in patients with genotype 2 or 3 chronic hepatitis C virus (HCV) infection who are not candidates to take interferon (IFN). The study found that 78 percent of patients (n=161/207) remained HCV RNA undetectable 12 weeks after completing therapy (SVR12). The safety profile of sofosbuvir was similar to that observed in previous studies, and there were few treatment discontinuations due to adverse events. POSITRON is the first of three Phase 3 studies to be completed that are evaluating sofosbuvir therapy in HCV genotype 2 or 3 infected patient populations. In POSITRON, HCV genotype 2 or 3 patients who were interferon intolerant, interferon ineligible or unwilling to take interferon were randomized (3:1) to receive 12 weeks of either sofosbuvir 400 mg once daily plus weight-based RBV twice daily (n=207) or matching placebo (n=71). Of the 207 patients randomized to the sofosbuvir/RBV arm, 15 percent had compensated cirrhosis (more advanced liver disease) and 53 percent were infected with genotype 2. SVR12 rates were 93 percent in genotype 2 and 61 percent in genotype 3. In the small percentage of patients with cirrhosis at baseline who received sofosbuvir/RBV, 61 percent achieved SVR12. All patients receiving sofosbuvir/RBV became HCV RNA negative on treatment and relapse accounted for all virologic failures. No patient in the placebo group achieved an SVR12. The most common adverse events reported in greater than 10 percent of patients in the study were fatigue, nausea, headache, insomnia, pruritis and anemia. Full data from the study will be submitted for presentation at a future scientific conference.