Phase III trial of GS 7977 plus RBV (Gilead Sciences) shows positive results in patients with Hepatitis C

Gilead Sciences has announced topline results from the Phase III POSITRON study 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. The most common adverse events reported in greater than 10 percent of patients in the study were fatigue, nausea, headache, insomnia, pruritis and anemia. The safety profile of sofosbuvir was similar to that observed in previous studies, and there were few treatment discontinuations due to adverse events.

The Phase III program for sofosbuvir includes two additional studies evaluating 12 and 16 weeks of therapy with sofosbuvir plus RBV in HCV genotype 2 and 3 infected patients. A fourth Phase III clinical trial is evaluating sofosbuvir combined with RBV and peg-IFN among patients with HCV genotypes 1, 4, 5 and 6. Pending the results, these studies will support initial regulatory filings in mid-2013 for an all-oral therapy with sofosbuvir plus RBV among genotype 2/3 treatment-na�ve, treatment-experienced and interferon-intolerant patients, and for sofosbuvir in combination with RBV and peg-IFN among treatment-na�ve patients with HCV genotypes 1, 4, 5 and 6.