High Sustained Virologic Response Rates of Glecaprevir/Pibrentasvir in Patients With Dosing Interruption or Suboptimal Adherence

INTRODUCTION: Pangenotypic, all-oral direct-acting antivirals, such as glecaprevir/pibrentasvir (G/P), are recommended for treatment of hepatitis C virus (HCV) infection. Concerns exist about the impact on efficacy in patients with suboptimal adherence, particularly with shorter treatment durations. These post hoc analyses evaluated adherence (based on pill count) in patients prescribed 8- or 12-week G/P, the impact of nonadherence on sustained virologic response at post-treatment week 12 (SVR12), factors associated with nonadherence, and efficacy in patients interrupting G/P treatment. METHODS: Data were pooled from 10 phase 3 clinical trials of treatment-naive patients with HCV genotype 1-6 without cirrhosis/with compensated cirrhosis (treatment adherence analysis) and 13 phase 3 clinical trials of all patients with HCV (interruption analysis). RESULTS: Among 2,149 patients included, overall mean adherence was 99.4%. Over the treatment duration, adherence decreased (weeks 0-4: 100%; weeks 5-8: 98.3%; and weeks 9-12: 97.1%) and the percentage of patients with >= 80% or >= 90% adherence declined. SVR12 rate in the intention-to-treat (ITT) population was 97.7% (modified ITT SVR12 99.3%) and remained high in nonadherent patients in the modified ITT population (<90%: 94.4%-100%; <80%: 83.3%-100%). Psychiatric disorders were associated with <80% adherence, and shorter treatment duration was associated with >= 80% adherence. Among 2,902 patients in the interruption analysis, 33 (1.1%) had a G/P treatment interruption of >= 1 day, with an SVR12 rate of 93.9% (31/33). No virologic failures occurred. DISCUSSION: These findings support the impact of treatment duration on adherence rates and further reinforce the concept of "treatment forgiveness" with direct-acting antivirals.