ENDURANCE-4 Study: glecaprevir/pibrentasvir in genotype 4, 5 or 6 Design Single arm Open label W12 ≥ 18 years HCV genotype 4, 5 or 6 BMI ≥ 18 kg/m2 Treatment-naïve or treatment-experienced with IFN or PEG-IFN + RBV or SOF + RBV + PEG-IFN No cirrhosis ** Creatinine clearance ≥ 50 mL/min No HBV or HIV co-infection N = 121 GLE/PIB SVR12 * Fibroscan® < 12.5 kPa or FibroTest® ≤ 0.48 + APRI < 1 GLE/PIB : 100/40 mg 3 tablets QD Objective SVR12 (HCV RNA < 15 IU/mL), by ITT ENDURANCE-4 Asselah T. Clin Gastroenterol Hepatol 2017; Sept 22 (Epub ahead of print) 1

ENDURANCE-4 Study: glecaprevir/pibrentasvir in genotype 4, 5 or 6 Baseline characteristics and SVR12 GLE/PIB , N = 121 Mean age, years 53 Female, % 36 Race : White / Black, % 71 / 8 Mean BMI, kg/m2 25.7 Genotype 4 / 5 / 6, % 63 / 21 / 16 Median HCV RNA, log10 IU/mL 6.3 Fibrosis stage (%) : F0-F1 / F2 / F3 86 / 7 / 7 IL28B CC, % 25 Treatment-experienced, % IFN-based SOF-based 32 100 PPI use, % 9 SVR12, by ITT, n/N (%) Genotype 4 Genotype 5 Genotype 6 120/121 (99% [95% CI : 97.6-100]) 75/76 (99%) * (1 discontinuation on D12) 26/26 (100%) 19/19 (100%) ENDURANCE-4 Asselah T. Clin Gastroenterol Hepatol 2017; Sept 22 (Epub ahead of print) 2

ENDURANCE-4 Study: glecaprevir/pibrentasvir in genotype 4, 5 or 6 Adverse events and laboratory abnormalities GLE/PIB, N = 121 Any adverse event, % 69% Serious adverse event, n (%) 1 (0.8%) * Adverse event leading to discontinuation, n (%) 3 (2.5%) ** Adverse events in > 10% of patients, % Headache Fatigue 21 17 Laboratory abnormalities AST grade ≥ 2 (> 3 x ULN) ALT grade ≥ 2 (> 3 x ULN) Total bilirubin grade ≥ 3 ( > 3 x ULN) * 1 patient with baseline risk factors discontinued treatment on D12 due to a transient ischemic attack (TIA); a second TIA occurred 24 days following discontinuation. This patient has not yet returned for SVR12 visit ** 3 patients presented with anxiety, heartburn, and transient ischemic attack, respectively. Two of the 3 patients achieved SVR12 ENDURANCE-4 Asselah T. AASLD 2016, Abs. 114 3

ENDURANCE-4 Study: glecaprevir/pibrentasvir in genotype 4, 5 or 6 Summary 99% of patients with genotype 4, 5 or 6 (120/121) without cirrhosis achieved SVR12 in ITT population following treatment with 12 weeks of GLE/PIB, with no virologic failures 100% SVR12 in mITT population GLE/PIB was well tolerated serious adverse events occurred in < 1% of patients there were no grade 3 or higher laboratory abnormalities discontinuation due to adverse events were rare 12-week treatment with the IFN- and RBV-free, once-daily GLE/PIB oral regimen can successfully treat patients with HCV genotype 4, 5, or 6, regardless of prior treatment experience or F0–F3 fibrosis status ENDURANCE-4 Asselah T. Clin Gastroenterol Hepatol 2017; Sept 22 (Epub ahead of print) 4