This open-label international phase 3 trial aimed to determine whether six weeks of sofosbuvir/velpatasvir is non-inferior to twelve weeks of sofosbuvir/velpatasvir among people with recent hepatitis C (HCV) infection. People with HCV-HIV coinfection were eligible for inclusion, and participants with coinfection represented 69% of the final population analyzed. Recruitment was halted mid-2019 given interim DSMB concerns regarding six-week arm efficacy: the final population for primary analysis thus consisted of 188 participants (93 in the six-week [short] arm and 95 in the twelve-week [standard] arm). Overall, study adherence was good and noted to be higher in the short arm. Twenty-three percent of participants experienced a treatment-related adverse event (no difference by arm), with the vast majority as Grade 1-2 events. Intent-to-treat analysis demonstrated an end-of-treatment response of 91.4% in the short vs. 91.6% in the standard arm, and SVR12 of 81.7% in the short vs. 90.5% in the standard arm. Criteria for non-inferiority (selected threshold: 12%) was not met. Suboptimal efficacy in the short arm was driven primarily by higher post-treatment relapse, observed in 10% of participants in the short vs. 2% in the standard arm. Generation of resistance associated substitutions was limited and almost all participants with relapse were subsequently retreated successfully.