Evolution and persistence of resistance‐associated substitutions of hepatitis C virus after direct‐acting antiviral treatment failures

摘要

Summary Daclatasvir plus asunaprevir ( DCV + ASV ) treatment is an all‐oral direct‐acting antiviral ( DAA ) therapy for the genotype 1b HCV ‐infected patients. In this study, we investigated how resistance‐associated substitutions ( RAS s) evolved after treatment failures and assessed the effect of those substitutions on viral fitness. Sequencing of NS 5A and NS 3 revealed typical RAS s after treatment failures. Interestingly, the RAS s of NS 3 reverted to the wild‐type amino acid within 1?year after treatment failures. However, the RAS s of NS 5A were stable and did not change. The effect of NS 5A and NS 3 RAS s on viral RNA replication was assessed after mutagenic substitution in the genotype 1b HCV RNA . Among single substitutions, the effect of D168V was more substantial than the others and the effect of the triple mutant combination (D168V+L31V+Y93H) was the most severe. The RAS at NS 5A Y93 affected both viral RNA replication and virus production. Finally, the effect of trans ‐complementation of NS 5A was demonstrated in our co‐transfection experiments and these results suggest that such a trans ‐complementation effect of NS 5A may help maintain the NS 5A RAS s for a long time even after cessation of the DAA treatment. In conclusion, the results from this investigation would help understand the emergence and persistence of RAS s.