Real-life effectiveness and safety of the daclatasvir/asunaprevir combination therapy for genotype 1b chronic hepatitis C patients: An emphasis on the pretreatment NS5A resistance-associated substitution test

This study aimed to investigate the real-life effectiveness and safety of daclatasvir (DCV) and asunaprevir (ASV) combination therapy in Korean patients. We consecutively enrolled patients with genotype 1b hepatitis C virus (HCV) infection treated with at least one dose of DCV/ASV combination therapy in seven tertiary hospitals of South Korea. The sustained virologic response (SVR) rates and safety according to intention-to-treat (ITT) and per-protocol (PP) analyses were evaluated. Among the 526 enrolled patients, 91% showed negative (87%) or "undetermined" (4%) resistance-associated substitution (RAS); 9% did not undergo RAS testing. The SVR rates for ITT and PP were 89.3% and 95.0% in treatment-naive patients and 93.2% and 95.6% in treatment-experienced patients, respectively. In PP analysis, negative RAS was associated with higher SVR (96.3%) than with "undetermined RAS" (85.7%) or "not tested for RAS" (84.4%). Adverse events were reported in 185 (35.4%) patients, and events leading to discontinuation were observed in 4.3% of the study population. Forty-two (8.0%) patients developed transaminase elevation (≥2 × upper normal limit), resulting in treatment discontinuation in six (1.1%) patients. DCV/ASV combination therapy showed acceptable efficacy in genotype 1b compensated HCV-infected patients with negative pretreatment RAS. Although most adverse events were tolerable to continue antiviral treatment, adequate monitoring for transaminase elevation is warranted.