Official Title Efficacy and Safety of 12 Weeks versus 18 Weeks of Treatment with Grazoprevir (MK-5172) and Elbasvir (MK-8742) with or without Ribavirin for Hepatitis C Virus Genotype 1 Infection in Previously Untreated Patients with Cirrhosis and Patients with Previous Null Response with or without Cirrhosis (C-WORTHY): a Randomised, Open-Label Phase 2 Trial.