title: [Direct-acting antiviral-resistant variant].
abstract: Recently, IFN-free NS5A inhibitor daclatasvir and protease inhibitor asunaprevir combination treatment was approved for genotype 1b HCV-infected patients who were ineligible or who failed to respond to previous therapies. NS5A inhibitor-resistant variants occasionally exist in HCV-infected patients who have never been exposed to direct-acting antivirals. In Japanese HCV genotype 1b-infected patients, the frequency of NS5A inhibitor-resistant variants is approximately 11-23 %. The phase 3 study of daclatasvir and asunaprevir combination therapy showed that more patients with NS5A 31 and/or 93 resistance-associated variants experienced virological failure. Preexisting NS5A inhibitor-resistant variants should be evaluated carefully before choosing the drugs.
authors.forename: Michio
authors.initials: M
authors.lastname: Imamura
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology; D002219:Carbamates; D024882:Drug Resistance, Viral / Q000235:genetics*; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics*; D019698:Hepatitis C, Chronic / Q000188:drug therapy*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011759:Pyrrolidines; D014633:Valine / Q000031:analogs & derivatives
chemical_list: D000998:Antiviral Agents; D002219:Carbamates; D007093:Imidazoles; D011480:Protease Inhibitors; D011759:Pyrrolidines; D014633:Valine; C549273:daclatasvir