EXPEDITION-IV Study: glecaprevir/pibrentasvir in patients with renal impairment Design Single arm Open label W12 ≥ 18 years, HCV genotype 1 to 6 HCV RNA ≥ 1000 IU/mL eGFR (MDRD) < 30 mL/min Treatment-naïve or treatment-experienced with IFN/PEG-IFN ± RBV or SOF + RBV ± PEG-IFN Compensated cirrhosis allowed No HBV or HIV co-infection Acute renal failure excluded N = 104 GLE/PIB SVR12 GLE/PIB : 100/40 mg 3 tablets QD Objective SVR12 (HCV RNA < 15 IU/mL) EXPEDITION-IV Gane E. AASLD 2016, Abs. LB-11 1

EXPEDITION-IV Study: glecaprevir/pibrentasvir in patients with renal impairment Baseline characteristics and SVR12 GLE/PIB , N = 104 Median age, years 57 Female, % 24 Race : Black, % 25 Median BMI, kg/m2 26 Genotype 1a / 1b / 1 other / 2 / 3 / 4 / 5 / 6, % 22 / 28 / 2 / 16 / 11 / 19 / 1 / 1 Median HCV RNA, log10 IU/mL 5.9 Compensated cirrhosis, % 19 IL28B CC, % 23 Treatment-experienced, % IFN-based SOF-based 42 95 5 PPI use, % 41 Chronic kidney disease stage, % eGFR 15-29 ml/min/1.73 m2 eGFR < 15 ml/min/1.73 m2 (hemodialysis) 12 88 (82) SVR12, by ITT, n/N (%) 102/104 (98%) [1 discontinuation, 1 LTFU] EXPEDITION-IV Gane E. AASLD 2016, Abs. LB-11 2

Adverse events and laboratory abnormalities, % EXPEDITION-IV Study: glecaprevir/pibrentasvir in patients with renal impairment Adverse events and laboratory abnormalities, % GLE/PIB , N = 104 Any adverse event 71 Serious adverse event related to study drug 24 Adverse event leading to discontinuation 4 * Death 1 ** Adverse events in > 10% of patients, % Pruritus Fatigue Nausea 20 14 12 Laboratory abnormalities, % Hemoglobin grade ≥ 3 (6.5-8 g/dL) AST grade ≥ 2 (> 3 x ULN) ALT grade≥ 2 (> 3 x ULN) Total bilirubin grade ≥ 3 ( > 3 x ULN) 5 0 0 1 * 1) diarrhea, 2) pruritus, 3) pulmonary edema, hypertensive cardiomyopathy with congestive failure, and 4) hypertensive crisis ** Serious adverse event of cerebral hemorrhage, not related to study drug, at post-treatment W2 EXPEDITION-IV Gane E. AASLD 2016, Abs. LB-11 3

EXPEDITION-IV Study: glecaprevir/pibrentasvir in patients with renal impairment Summary GLE/PIB (300 mg/120 mg QD) achieved high efficacy in patients with stage 4 or 5 chronic kidney disease and HCV infection 98% ITT SVR12 rate across all major HCV genotypes No virologic failures GLE/PIB was well tolerated with a favorable safety profile in this difficult-to-treat population: No drug-related serious adverse event No grade ≥ 2 laboratory abnormalities in ALT or AST EXPEDITION-IV Gane E. AASLD 2016, Abs. LB-11 4