ABSTRACT
AIM: To improve the therapeutic efficacy of sofosbuvir/ledipasvir (SOF/LDV) for the retreatment of patients after daclatasvir/asunaprevir (DCV/ASV), a customized therapy with or without lead-in interferon (IFN)-ß injections was formulated according to the types of resistance-associated substitutions (RAS) in the non-structural protein (NS)5A region of genotype 1b hepatitis C virus (HCV). METHODS: Thirty-three patients failing prior DCV/ASV received SOF/LDV for 12 weeks. Patients with HCV carrying unfavorable NS5A-RAS and/or those previously treated with simeprevir were given lead-in IFN-ß injections twice a day for 2 weeks; sequential changes in the NS5A-RAS during the injection period were evaluated using deep sequencing. RESULTS: Lead-in injections were not undertaken in 27 patients; a sustained viral response (SVR) was achieved in 26 patients, while viral relapse occurred in 1 patient with HCV carrying NS5A-L28M/R30H/Y93H mutations. Among the 6 patients receiving lead-in injections, viral relapse occurred in 2 patients who had an unfavorable IFN-λ3-related gene single nucleotide polymorphism allele; both patients had been previously treated with simeprevir, and HCV carrying NS5A-L31V/Y93H mutations had emerged after DCV/ASV. Deep sequencing revealed no changes in the NS5A-RAS profiles during the lead-in injection period in either patient. In contrast, in a patient with a favorable allele who was infected with similar unfavorable HCV strains, NS5A-L31/Y93 wild-type strains appeared during the injection period, enabling an SVR. CONCLUSION: Using customized therapies based on the NS5A-RAS profiles, a high SVR rate was obtained after SOF/LDV in patients failing prior DCV/ASV. Lead-in IFN-ß injections did not improve the efficacy in patients with HCV carrying unfavorable NS5A-RAS except in those with a favorable IFN-λ3-related gene allele.
