Aim: Direct-acting antiviral (DAA) therapy for hepatitis C virus is associated with high sustained virologic response rates. However, patients for whom DAA therapy fails acquire resistance-associated substitutions (RASs). We therefore evaluated the efficacy of DAA retreatment and factors associated with retreatment failure.
Methods: Non-structural 5A RASs were investigated at the start of DAA therapy and at treatment failure in 64 patients with hepatitis C virus genotype 1b for whom DAA combination therapy had failed. A total of 59 patients were introduced to DAA retreatment. The factors associated with retreatment failure were investigated.
Results: A total of 20 of 43 (46.5%) daclatasvir + asunaprevir-treated patients with virologic failure had no RASs at baseline, and three (15%) acquired P32 deletion RASs. Four of seven sofosbuvir/ledipasvir-treated patients with virologic failure had more than two RASs of NS5A at baseline. The sustained virologic response rates on retreatment were as follows: sofosbuvir/ledipasvir, 81.8%; with elbasvir + grazoprevir, 0%; and glecaprevir/pibrentasvir, 87.5%. Patients for whom sofosbuvir/ledipasvir or elbasvir + grazoprevir failed achieved sustained virologic response with glecaprevir/pibrentasvir. Two of three patients for whom glecaprevir/pibrentasvir retreatment failed had Q24/L28/R30 and A92K RASs; the other had P32 deletion RAS at baseline. Interestingly, 10 of 11 patients with retreatment failure had the interleukin (IL)-28B single-nucleotide polymorphism (SNP) minor allele. A multivariate analysis showed that the IL28B SNP minor allele (P = 0.005, odds ratio 28.291) was an independent risk factor for retreatment failure.
Conclusions: In addition to viral factors (e.g. Q24, L28, R30, and A92 or P32 deletion RASs), host factors (e.g. IL28B SNP) are associated with DAA retreatment failure.
Keywords: IL28B SNP; direct-acting antiviral; resistance-associated substitutions; retreatment.
© 2019 The Japan Society of Hepatology.