Sofosbuvir (Gilead) success in genotype 2 and 3 Hepatitis C trial

Gilead Sciences has announced topline results from the Phase III POSITRON study examining a 12-week course of GS 7977 (sofosbuvir) plus ribavirin (RBV) in patients with genotype 2 or 3 chronic Hepatitis C 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). 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.

Additionally, the Phase II LONESTAR-2 study evaluated 12 weeks of sofosbuvir, RBV and pegylated interferon (peg-IFN) among patients who had previously failed treatment with peg-IFN/RBV, approximately half of whom had cirrhosis. In this study, 83 percent (n=20/24) of genotype 3 patients achieved SVR12. There were few discontinuations due to adverse events in VALENCE and LONESTAR-2. Sofosbuvir was well tolerated in VALENCE and adverse events in LONESTAR-2 were consistent with the safety profile of peg-IFN/RBV.