1. SOF + RBV GT2 Japanese SOF + RBV Open-label Japanese SOF + RBV Study: SOF + RBV in genotype 2  Design W12 Japanese patients ≥ 20 years Chronic HCV infection Genotype 2 HCV RNA ≥ 10,000 IU/ml Treatment naïve or pre-treated Compensated cirrhosis* (Child-Pugh A) allowed N = 153 SVR 12 * Metavir = 4 or Ishak ≥ 5 or Fibroscan > 12.5 kPa –SOF 400 mg : 1 pill qd –RBV (bid dosing) : 600 mg/day if 80 kg  Objective –Primary endpoint : SVR 12 (HCV RNA 18% of historical SVR (69%) in naïve patients without cirrhosis, significance level of 0.05, 80% power Omata M. J Viral Hepatitis 2015;21:762-8

2. Japanese SOF + RBV Study: SOF + RBV in genotype 2 Baseline characteristics and patient disposition SOF + RBV GT2 Japanese Naïve, N = 90Pre-treated, N = 63 Mean age, years5560 Female63%41% Genotype 2a / 2b58% / 42%63% / 37% Cirrhosis9%14% IL28B CC genotype81%76% HCV RNA log 10 IU/ml, mean6.26.5 Response to prior HCV Treatment Non response Relapse/breakthrough Interferon intolerant - 24% 71% 5% Discontinuation00 Omata M. J Viral Hepatitis 2015;21:762-8

3. SVR 12 (HCV RNA < 25 IU/ml), % (95% CI) 25 50 100 75 % N90 Naïve 97.6 (92-100)* 8263 100 (63-100) Pre- treated Naïve with cirrhosis Naïve No cirrhosis On-treatment failure, N 00 Relapse, N 23 98 (92-100) 95 (87-99) 96.3 (87-100) 54 89 (52-100) Pre-treated with cirrhosis Pre-treated No cirrhosis 98 * Superior to the adjusted historical control rate of 69% (p < 0.001) 4/5 relapses had RBV dose reduction SOF + RBV GT2 Japanese Japanese SOF + RBV Study: SOF + RBV in genotype 2 Omata M. J Viral Hepatitis 2015;21:762-8 0

4. Adverse events, n (%) Japanese SOF + RBV Study: SOF + RBV in genotype 2 SOF + RBV GT2 Japanese N = 153 Serious adverse event Anemia Anaphylactic reaction 211211 Adverse event leading to discontinuation0 Most common averse events Nasopharyngitis29% Anemia12% Headache10% Malaise7% Prurit6% Laboratory abnormalities Hemoglobin < 10 g/dl / < 8 g/dl19 (12%) / 1 (1%) Neutropenia1 (1%) Hyperglycemia3 (2%) Hyperbilirubinemia2 (1%) Omata M. J Viral Hepatitis 2015;21:762-8

5. SOF + RBV GT2 Japanese Omata M. J Viral Hepatitis 2015;21:762-8 Japanese SOF + RBV Study: SOF + RBV in genotype 2  Summary –12 weeks of treatment with SOF + RBV resulted in high rates of SVR 12 (> 95%) in treatment-naïve and previously treated Japanese patients with chronic genotype 2 HCV infection –In the present study, 22% of patients were aged 65 or older and 11% had cirrhosis Efficacy similar Increases in reported adverse events and laboratory abnormalities in patients ≥ 65 years, but these differences did not present a barrier to treatment as no premature discontinuation of study treatment occurred in any patient –Relapse rate was 3%, and none of the subjects who relapsed had S282T or other nucleoside inhibitor resistance-associated variants