Gilead Announces Phase 2 Data For Investigational All-Oral Regimen Of Sofosbuvir Plus GS-5816 For The Treatment Of Chronic Hepatitis C

Gilead Sciences, Inc.

today announced data from three Phase 2 open-label studies evaluating the safety and efficacy of an investigational all-oral pan-genotypic regimen containing the nucleotide analog polymerase inhibitor sofosbuvir (SOF), approved as Sovaldi® by the U.S. Food and Drug Administration in December 2013, and the investigational NS5A inhibitor GS-5816 for the treatment of chronic hepatitis C virus (HCV) infection. These data are being presented this week at the 65th Annual Meeting of the American Association for the Study of Liver Diseases (The Liver Meeting® 2014) in Boston. All three studies evaluated SOF 400 mg plus GS-5816 25 or 100 mg, with and without ribavirin (RBV), for eight or 12 weeks. Rates of sustained virologic response (SVR12) ranged from 88 percent to 100 percent among those receiving SOF plus GS-5816 100 mg for 12 weeks – the regimen selected for Phase 3 studies. Patients who achieve SVR12 are considered cured of HCV infection. “There continues to be a need for simple, interferon- and ribavirin-free treatment regimens that are effective for all hepatitis C patients, regardless of genotype,” said Norbert Bischofberger, PhD, Executive Vice President of Research and Development and Chief Scientific Officer, Gilead Sciences. “These data demonstrate the high efficacy and tolerability of sofosbuvir plus GS-5816 among patients with varying genotypes and disease progression and we look forward to providing Phase 3 data on the combination across all six genotypes.” The first study, GS-US-342-0109 (Oral #197), evaluated 12 weeks of SOF plus GS-5816 with and without RBV in treatment-experienced genotype 1 and 3 patients with and without cirrhosis. The genotype 1 patients had all failed a prior treatment course that included a protease inhibitor. The number and proportion of patients achieving SVR12 are summarized in the table below. SVR12 Rates Among Treatment-Experienced Patients in Study GS-US-342-0109 Regimen GT1 without cirrhosis GT1 with cirrhosis GT3 without cirrhosis GT3 with cirrhosis SOF+GS-5816 100 mg 100% (n=20/20) 100% (n=7/7) 100% (n=27/27) 88% (n=23/26) SOF+GS-5816 100 mg +RBV 100% (n=18/18) 90% (n=9/10) 100% (n=26/26) 96% (n=25/26) The second study, ELECTRON 2 (Oral #79), evaluated the same combination of SOF plus GS-5816, with and without RBV, for eight weeks in non-cirrhotic, treatment-naïve genotype 3 patients. Patients receiving SOF with GS-5816 100 mg achieved SVR12 rates of 100 percent (n=26/26) with RBV and 96 percent (n=26/27) without RBV. The third study, GS-US-342-0102, evaluated SOF plus GS-5816, with and without RBV, among non-cirrhotic treatment-naïve patients. The results of Part A of the study evaluating 12 weeks of therapy were presented at the 49th Annual Meeting of the European Association for the Study of the Liver (The International Liver Congress 2014) in April 2014. The results of Part B, presented at the Liver Meeting this week (Oral #80), evaluated eight weeks of SOF plus GS-5816, with and without RBV, in patients with genotype 1 or 2 HCV infection. Among genotype 1 patients receiving SOF plus GS-5816 100 mg, SVR12 rates were 81 percent (n=25/31) and 90 percent (n=26/29), with and without RBV, respectively. Genotype 2 patients achieved SVR12 rates of 88 percent (n=23/26) with RBV and 88 percent (n=23/26) without RBV. SOF plus GS-5816 was well tolerated in over 800 patients with HCV infection evaluated in these three studies. There was a low incidence of serious adverse effects and few discontinuations due to adverse events. The most frequently reported adverse events (>10%) were fatigue, headache, nausea and insomnia. The most frequently observed hematologic abnormality was hemoglobin decrease in the RBV-containing treatment groups. GS-5816 is an investigational product and its safety and efficacy have not been established. Additional information about these studies can be found at www.clinicaltrials.gov.