Background: The present study explored the treatment outcome of daclatasvir (DCV) and asunaprevir (ASV) therapy combining oral direct-acting antiviral agents (DAAs) for chronic hepatitis C (HCV) including liver cirrhosis according to resistance-associated variants (RAVs) in NS3/NS5A region.
Methods: Overall, 641 patients enrolled in Japan with HCV-1b received DCV and ASV for 24 weeks. Baseline drug-resistant mutations L31F/I/M/V, Q54H, P58S, A92K, and Y93H in the HCV NS5A region and V36A, T54A/S, Q80K/L/R, R155K/T/Q, A156S/V/T, and D168A/E/H/T/V in the HCV NS3/4A region were assessed by direct sequencing.
Results: Overall, 86.9 % (543/625) of patients had SVR12, which was significantly higher in NS5A 93Y (wild) (88.3 %) compared with NS5A 93H at baseline (48.0 %), indicating the SVR12 rate was significantly lower in patients with 93H mutations. Additionally, 66.7 % (18/27) of patients with prior triple therapy including simeprevir (SMV) failure had virological failure. The virological failure rate of DCV/ASV therapy after SMV failure was significantly higher in those with preexisting NS3/4A 168 substitutions compared with without substitutions at baseline [84.2 % (16/19) vs. 28.6 % (2/7), p = 0.014]. The number of patients with multiple RAVs or deletions in NS5A increased from 0 to 85 % in failed patients. Alanine aminotransferase elevation was a frequent adverse event causing discontinuation of DCV/ASV therapy, although 87.5 % (14/16) patients achieved SVR12, subsequently.
Conclusions: History of SMV therapy and pre-existing NS5A Y93H were associated with virological failure of DCV/ASV therapy, resulting in the emergence of multiple RAVs. Patients with RAVs at baseline should be assessed to optimize future DAA therapies.
Keywords: DCV/ASV; Direct acting antivirals; HCV; Resistance-associated variants; Simeprevir failure.