Sofosbuvir for previously untreated chronic hepatitis C infection.Lawitz E, Mangia A, Wyles D, Rodriguez-Torres M, Hassanein T, Gordon SC, Schultz M, Davis MN, Kayali Z, Reddy KR, Jacobson IM, Kowdley KV, Nyberg L, Subramanian GM, Hyland RH, Arterburn S, Jiang D, McNally J, Brainard D, Symonds WT, McHutchison JG, Sheikh AM, Younossi Z, Gane EJ. N Engl J Med. 2013 May 16;368(20):1878-87. BACKGROUND: In phase 2 trials, the nucleotide polymerase inhibitor sofosbuvir was effective in previously untreated patients with chronic hepatitis C virus (HCV) genotype 1, 2, or 3 infection. METHODS: We conducted two phase 3 studies in previously untreated patients with HCV infection. In a single-group, open-label study, we administered a 12-week regimen of sofosbuvir plus peginterferon alfa-2a and ribavirin in 327 patients with HCV genotype 1, 4, 5, or 6 (of whom 98% had genotype 1 or 4). In a noninferiority trial, 499 patients with HCV genotype 2 or 3 infection were randomly assigned to receive sofosbuvir plus ribavirin for 12 weeks or peginterferon alfa-2a plus ribavirin for 24 weeks. In the two studies, the primary end point was a sustained virologic response at 12 weeks after the end of therapy. RESULTS: In the single-group study, a sustained virologic response was reported in 90% of patients (95% confidence interval, 87 to 93). In the noninferiority trial, a sustained response was reported in 67% of patients in both the sofosbuvir-ribavirin group and the peginterferon-ribavirin group. Response rates in the sofosbuvir-ribavirin group were lower among patients with genotype 3 infection than among those with genotype 2 infection (56% vs. 97%). Adverse events (including fatigue, headache, nausea, and neutropenia) were less common with sofosbuvir than with peginterferon. CONCLUSIONS: In a single-group study of sofosbuvir combined with peginterferon-ribavirin, patients with predominantly genotype 1 or 4 HCV infection had a rate of sustained virologic response of 90% at 12 weeks. In a noninferiority trial, patients with genotype 2 or 3 infection who received either sofosbuvir or peginterferon with ribavirin had nearly identical rates of response (67%). Adverse events were less frequent with sofosbuvir than with peginterferon.