Gilead Sciences, Inc. (Nasdaq:GILD) today announced results from a Phase 3 study, PHOTON-1, evaluating the investigational once-daily nucleotide analogue sofosbuvir for the treatment of chronic hepatitis C virus (HCV) infection among patients co-infected with HIV. In the trial, 76 percent (n=87/114) of genotype 1 HCV treatment-naïve patients receiving 24 weeks of an all-oral, interferon-free regimen of sofosbuvir plus ribavirin (RBV) achieved a sustained virologic response 12 weeks after completing therapy (SVR12). Patients who achieve SVR12 are considered cured of HCV infection. These data will be presented this week during the 64 th Annual Meeting of the American Association for the Study of Liver Diseases (The Liver Meeting 2013) in Washington, D.C. Up to one-third of people living with HIV in the United States are co-infected with HCV. Current HCV medicines are associated with suboptimal cure rates among co-infected patients and can cause significant interactions with HIV drugs. “There is a clear need for HCV treatment regimens that are more effective and safer for patients who are co-infected with HIV,” said Douglas Dieterich, MD, Professor of Medicine in the Division of Liver Diseases and Director of Continuing Medical Education in the Department of Medicine at Mount Sinai School of Medicine. “In this study, sofosbuvir-based all-oral therapy achieved high SVR rates in a hard-to-treat patient population. This regimen may have the potential to help us overcome the clinical challenge of treating HCV/HIV co-infection.” PHOTON-1 also assessed 12 weeks of sofosbuvir plus RBV among genotype 2 and 3 HCV treatment-naïve patients with HIV. Among genotype 2 patients receiving this regimen, 88 percent (n=23/26) achieved SVR12, while 67 percent (n=28/42) of genotype 3 patients achieved SVR12. All patients in PHOTON-1 who did not achieve SVR12 had viral relapse after cessation of therapy, with the exception of two participants who were non-adherent to study drugs.