Comparison of test results of serogrouping and core region PCR-based genotyping in patients with chronic hepatitis C virus infection: Analysis of inderminate or discrepant cases and identification of a 2b/1b recombinant HCV

Successful treatment of Japanese hemophilia patient co-infected with HIV and HCV genotype 4a by glecaprevir/pibrentasvir therapy

Although direct-acting antiviral (DAA)-based anti-hepatitis C virus (HCV) therapies are very effective for patients with genotypes 1 and 2, evidence of the efficacy of DAA-based therapy for the special population of patients with genotypes 3-6 is insufficient due to the relatively small number of these subjects in Japan. Human immunodeficiency virus (HIV)/HCV-co-infected patients are recommended to be treated as HCV-mono-infected patients by the latest version of the Japan Society of Hepatology guidelines. However, evidence of efficacy in patients with HIV/HCV genotype 3-6 co-infection is insufficient. Currently, HCV genotypes 3-6 can be treated with two DAA-based therapies, including glecaprevir (GLE)/pibrentasvir (PIB) therapy in Japan. We experienced a relatively rare case of a Japanese hemophilia patient co-infected with HIV/HCV genotype 4a. We evaluated resistance-associated substitutions (RASs) against GLE and PIB before GLE/PIB therapy and found that he had no RASs. He was treated with 12 weeks of GLE/PIB therapy and achieved a sustained virologic response at post-treatment weeks 24. Although the treatment was well tolerated, the patient developed hyper-low-density lipoproteinemia that was probably associated with HCV elimination during the therapy. Additional studies are needed to confirm the efficacy and safety of GLE/PIB therapy for this special population in Japan.

Japanese Man with HCV Genotype 4 Infection and Cirrhosis Who Was Successfully Treated by the Combination of Glecaprevir and Pibrentasvir

A 74-year-old man with a history of transfusion at 35 years old in Egypt was referred to our hospital. He was infected with hepatitis C virus (HCV) genotype 4 (GT4), which is a rare HCV GT in Japan, and was also diagnosed with hepatic compensated cirrhosis. We safely treated the patient for 12 weeks with the combination of glecaprevir and pibrentasvir, and a sustained virologic response (SVR) was achieved. This is the first report of HCV GT4 infection in a treatment-naïve Japanese patient with cirrhosis in whom SVR was achieved with the combination treatment of glecaprevir and pibrentasvir.

Successful direct-acting antiviral treatment of three patients with genotype 2/1 recombinant hepatitis C virus

There have been a few reports on the treatment of patients infected with recombinant hepatitis C virus (HCV) genotype 2/1 strains with direct-acting antivirals (DAAs). We experienced three patients, with genotype 2/1 recombinant HCV, treated with DAAs successfully. The first, a 39-year-old man, was infected with recombinant HCV genotype 2a/1b, a rare variant. The sequence of the relapsed virus showed chimeric HCV 2a/1b with the recombinant breakpoint found at nucleotide +49 from the start of the NS3 region. Sofosbuvir plus ribavirin, a regimen recommended for HCV genotype 2, did not lead to a sustained viral response (SVR). Retreatment with grazoprevir plus elbasvir resulted in an SVR. The second case, a 70-year-old woman, was infected with recombinant HCV genotype 2b/1b. DAA therapy with sofosbuvir plus ledipasvir resulted in an SVR. The third case, a 48-year-old woman, was also infected with recombinant HCV genotype 2b/1b. DAA therapy with daclatasvir plus asunaprevir resulted in an SVR. The baseline sequences of the viruses from both the second and third cases showed chimeric HCV 2b/1b with the recombinant breakpoint found at nucleotide +10 from the NS3 start. We report three cases with 2/1 chimeras and discuss the prevalence and response to therapy.

Chronic hepatitis caused by hepatitis C virus showing a discrepancy between serogroup and genotype because of intergenotypic 2b/1b recombination: A pitfall in antiviral therapy with direct-acting antivirals

A 40-year-old male patient with virologic relapse after daclatasvir plus asunaprevir therapy for a serogroup 1 hepatitis C virus (HCV) infection visited our hospital for retreatment. Virologic examinations revealed that a genotype 2b HCV strain carrying both NS3-S122N / D168A and NA5A-R30Q / L31M / Q54H / Y93H mutations had relapsed. The patient received sofosbuvir plus ribavirin therapy, but virologic relapse occurred once again. Sequencing of the HCV genome clarified an intergenotypic recombination of 2b and 1b with an estimated crossover point between nucleotides 3114 and 3115, corresponding to the N-terminal end of the NS3 region (DDBJ/EMBL/GenBank databases accession no. LC273304). The NS5B-S282T mutation was not detected in the HCV strain, and resistance-association substitutions in the NS3 and NS5A regions were similar to those at baseline. Direct sequencing of the core and NS4A regions corresponding to the targeting sites of genotyping and serogrouping, respectively, is useful to determine the combination of direct-acting antivirals when a discrepancy is observed between the serogroup and genotype of HCV strains.

Identification of Genotype 2 HCV in Serotype-1 Hepatitis C Patients Unresponsive to Daclatasvir plus Asunaprevir Treatment

It is important to determine the genotypes or serotypes of hepatitis C virus (HCV) in patients before treatment with direct-acting antiviral agents (DAAs), because the effects of DAAs differ among genotypes. In Japan, two tests for HCV typing are available clinically, but only serotyping, not genotyping, is approved by the public health insurance. Although most serotype-1 Japanese patients are infected with genotype 1b HCV, it is known that a small proportion of patients show different results from two typing methods. This study focused on such patients and the effectiveness of treatment with daclatasvir plus asunaprevir (DCV/ASV) was evaluated. We analyzed 644 DCV/ASV-treated patients with serotype 1 or genotype 1b, and among them, 166 serotype-1 patients received a commercial-based direct sequencing (DS) test for resistant-associated variants of genotype 1b HCV. We found four patients (2.4%) with DS test failure, suggesting that the PCR primers targeting genotype 1b may not match. Importantly, none of the four patients achieved a sustained virological response. Our in-house DS test analyzing the 5'-untranslated region and coding regions for NS4 and NS5B of HCV showed that three of the four patients were infected with genotype 2 HCV, and one patient was infected with genotype 1a HCV. No recombinant virus of different genotypes was found. This study indicates that a subset of serotype-1 hepatitis C patients is infected with HCV of genotype 2 or 1a in Japan and that DCV/ASV is not effective for such patients. Thus, attention should be paid to DAA treatment without HCV genotyping.