Sofosbuvir (SOF) in combination with ribavirin (RBV) for 12 or 24 weeks is the current standard of care for patients infected with hepatitis C virus (HCV) genotypes 2 and 3, respectively. patients without cirrhosis achieved SVR12, and for genotype 3, the SVR12 rate was 83% in patients both with and without cirrhosis. One patient discontinued study treatment because of an LY170053 adverse event and four patients experienced serious adverse events. The most common adverse events were influenza-like illness, fatigue, anemia, and neutropenia. genotype was determined by amplification and sequencing of the rs12979860 single-nucleotide polymorphism. Viral relapse was defined as HCV RNA >LLOQ at posttreatment weeks 4, 12, and 24, in patients who had HCV RNA LY170053 resulting sequences were compared to detect resistance-associated variants that emerged during treatment. We report variants that were present in more than 1% of the sequence reads. Safety Analysis Safety assessments included monitoring of patients for adverse events, review of concomitant medications, clinical laboratory analyses, vital signs, and physical examinations. Follow-up visits took place 4, 12, and 24 weeks after patients received their last dose of LY170053 study treatment. Statistical Analysis The primary LY170053 endpoint was to determine the proportion of patients with SVR12. No sample size calculations or formal hypothesis-testing were performed. Point estimates and two-sided 95% exact confidence intervals (CIs; based on the Clopper-Pearson method) were provided for SVR12 rates for subgroups. Exploratory multivariate LY170053 logistic-regression analyses characterizing the relationship between SVR12 and various prespecified demographic and baseline clinical characteristics were performed for each genotype. Data are presented for patients who received at least one dose of study treatment. Results Study Population Disposition and Demographics A total of 56 patients with chronic HCV were screened for the study; 47 were enrolled and 44 patients completed study treatment. Three patients discontinued the study treatment, one patient was lost to follow-up, one patient was not adherent to the protocol, and one patient withdrew due to an adverse event. Forty-five patients attended the week 4 and 12 posttreatment visits, and 43 returned for the week 24 posttreatment visit (Fig. 1). Twenty-three (49%) patients had HCV genotype 2 and 24 (51%) patients had HCV genotype 3 (Table?(Table1).1). Most patients were white (96%), male (68%), and had cirrhosis (55%). Of the 26 patients with cirrhosis, 25 had the presence of cirrhosis confirmed by biopsy. There were 36% patients with the CC IL28B genotype. At baseline, mean HCV RNA levels were 6.2 log10 IU/mL and mean alanine transaminase (ALT) was 109 U/L across genotypes 2 and 3. Overall, 85% of patients had experienced a relapse/breakthrough after previous treatment with an interferon-based regimen and 15% were nonresponders. Figure 1 CONSORT diagram of patient disposition. Table 1 Demographic and Clinical Characteristics of the Patients at Baseline On-treatment and SVR Treatment with SOF+Peg-IFN+RBV resulted in rapid suppression of HCV RNA. By week 4, 96% of patients had HCV RNA APAF-3 and 91% with genotype 3 HCV. By week 8, all 45 patients receiving treatment had HCV RNA