With a computer-generated randomisation sequence , patients were assigned in a 1:1 ratio to receive placebo matched in appearance to study drugs for 12 weeks followed by once daily combination fixed-dose tablets of 90 mg ledipasvir and 400 mg sofosbuvir plus weight-based ribavirin for 12 weeks , or ledipasvir-sofosbuvir plus placebo once daily for 24 weeks .