Gilead Sciences, Inc. (Nasdaq: GILD) has announced results from two studies, the Phase 3 VALENCE study and the Phase 2 LONESTAR-2 study, evaluating the once-daily nucleotide analogue inhibitor sofosbuvir as part of combination therapy for the treatment of chronic hepatitis C virus (HCV) infection among patients infected with genotype 3 HCV. These data will be presented this week at the 64th Annual Meeting of the American Association for the Study of Liver Diseases (The Liver Meeting 2013) taking place in Washington, D.C.

In the Phase 3 VALENCE study, 85 percent (n=212/250) of treatment-naive or treatment-experienced patients with genotype 3 HCV who received a 24-week regimen of sofosbuvir plus ribavirin (RBV) achieved a sustained virologic response 12 weeks after treatment (SVR12). Patients who achieve SVR12 are considered cured of HCV infection.

"The VALENCE results demonstrate the high efficacy of a 24-week, sofosbuvir-based, interferon-free treatment regimen for genotype 3 HCV patients with and without cirrhosis," said Stefan Zeuzem, MD, Professor of Medicine and Chief of the Department of Medicine I, J.W. Goethe University Hospital, Frankfurt, Germany, and principal investigator for the VALENCE study. "Notably, the majority of these patients had failed prior therapy, and sofosbuvir was able to produce a sustained virologic response."

Additionally, the Phase 2 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.

About VALENCE

VALENCE is an ongoing, placebo-controlled, Phase 3 study in which patients with genotype 2 and 3 HCV infection were originally randomized (4:1) to receive sofosbuvir 400 mg once-daily plus weight-based RBV twice-daily (1,000 or 1,200 mg) for 12 weeks (n=334) or placebo (n=85). The study was subsequently amended to extend the treatment duration for genotype 3 patients (n=250) to 24 weeks. Patients randomized to receive placebo were offered treatment in an alternative protocol. Fifty-eight percent of trial participants were treatment-experienced and 21 percent had cirrhosis.

Among genotype 2 HCV patients receiving a 12-week all-oral course of sofosbuvir plus RBV, 93 percent (n=68/73) achieved SVR12.

Two patients receiving sofosbuvir and one patient receiving placebo discontinued treatment due to adverse events. The most common adverse events occurring in ≥10 percent of patients receiving sofosbuvir were headache, fatigue, pruritus, asthenia and nausea.

About LONESTAR-2

LONESTAR-2 is an ongoing open-label Phase 2 study evaluating the efficacy and safety of a 12-week regimen of sofosbuvir 400 mg once-daily, weight-based RBV twice-daily (1,000 or 1,200 mg) and peg-IFN (180 μg/week) among 47 patients with genotype 2 or 3 HCV infection. All patients in the study had previously failed treatment with peg-IFN/RBV and 55 percent had cirrhosis.

Ninety-six percent (n=22/23) of genotype 2 HCV patients achieved SVR12 in the study.

Two patients receiving sofosbuvir discontinued treatment due to adverse events. The most common adverse events occurring in ≥15 percent of the patients were consistent with the safety profiles of peg-IFN and RBV and included flu-like symptoms, fatigue and anemia.

Further information about these studies can also be found at www.clinicaltrials.gov.

Sofosbuvir is an investigational product and its safety and efficacy have not been established.