Sofosbuvir Plus Ribavirin Without Interferon for Treatment of Acute Hepatitis C Virus Infection in HIV-1-Infected Individuals: SWIFT-C.

Background: Historically, acute hepatitis C virus (HCV) infection was treated with shorter durations of interferon-containing therapies. In the era of direct-acting antivirals (DAAs), it is unclear whether the efficacy of treatment achieved in chronic infection can be maintained with abbreviated courses of therapy during the acute phase. Methods: The sofosbuvir-containing regimens without interferon for treatment of acute HCV in HIV-1 infected individuals (SWIFT-C) is an open-label, 2-cohort clinical trial in which the first cohort assessed for the safety and efficacy of 12 weeks of sofosbuvir plus ribavirin for the treatment of acute HCV infection in participants with chronic human immunodeficiency virus type 1 (HIV-1) infection. This is a preplanned analysis of the first cohort, which had a planned accrual of 17 participants. Results: Seventeen men (11 Hispanic, 6 white, median age 45 years) were enrolled. Most (88%) had HCV genotype-1 infection and few (24%) had the favorable IL28B CC genotype. Median baseline HCV RNA was 2 280 000 IU/mL (interquartile range, 272 000-4 230 000). Ten participants (59%) achieved the primary outcome of SVR12 (90% confidence interval, 36%-78%), failing to establish noninferiority. All treatment failures were due to viral relapse (41%). There were no premature treatment discontinuations. The only factor that differed between participants who achieved SVR vs those who relapsed was ribavirin concentration at the end of treatment. Conclusion: Sofosbuvir-ribavirin for 12 weeks for the treatment of acute HCV genotype-1 infection in HIV-1-infected persons results in a high relapse rate. Preliminary studies of DAA combination therapies suggest improved response rates, although the adequate duration of therapy remains unclear. Clinical Trials Registration: NCT02128217.

RG7128 alone or in combination with pegylated interferon-α2a and ribavirin prevents hepatitis C virus (HCV) Replication and selection of resistant variants in HCV-infected patients.

INTRODUCTION: RG7128 (prodrug of PSI-6130) shows potent antiviral efficacy in patients infected with hepatitis C virus (HCV) genotypes 1, 2, or 3, with mean viral load decreases of 2.7 and 5 log(10) IU/mL, respectively, associated with 1500-mg doses twice daily after monotherapy for 2 weeks and with 1000-mg and 1500-mg doses twice daily after treatment in combination with the standard of care (SOC) for 4 weeks. RESULTS: From 32 patients treated with RG7128 monotherapy for 2 weeks, marginal viral load rebound was observed in 3 HCV genotype 1-infected patients, whereas partial response was observed in 2 genotype 1-infected patients. From 85 patients receiving RG7128 in combination with SOC, 1 HCV genotype 1-infected patient experienced a viral rebound, and 2 genotype 3-infected patients experienced a transient rebound. Five genotype 1-infected patients had an HCV load of >1000 IU/mL at the end of 4-week treatment. No viral resistance was observed, per NS5B sequencing and phenotypic studies. PSI-6130 resistance substitution S282T needs to be present at levels of ≥90% within a patient's quasispecies to confer low-level resistance. No evidence of S282T was found by population or clonal sequence analyses. CONCLUSIONS: The requirement for a predominant S282T mutant quasispecies, its low replication capacity, and the low-level resistance it confers probably contribute to the lack of RG7128 resistance observed in HCV-infected patients.