Triple Antiviral Regimen Shows Promise Against Hepatitis C in Phase III Trial
96% of subjects achieve consistent virologic response (December 10)
Positive phase III results have been reported for an investigational three direct-acting-antiviral (3D) regimen (AbbVie) plus ribavirin in patients with chronic genotype-1 (GT1) hepatitis C virus (HCV) infection.
In the 394-patient SAPPHIRE-II study, 96% of patients who had failed to respond to treatment with pegylated interferon (peg-IFN) and ribavirin achieved a sustained virologic response at 12 weeks (SVR12) with the 3D regimen plus ribavirin.
Most of the patients had subtype GT1a, which is considered to be difficult to treat. The SVR12 rates for GT1a and GT1b were 96% and 97%, respectively.
Virologic relapse or breakthrough was noted in 2% of patients receiving the 3D regimen plus ribavirin. In addition, the discontinuation rate attributed to adverse events was 1%.
SAPPHIRE-II was a global, randomized, double-blind, placebo-controlled phase III study evaluating the efficacy and safety of 12 weeks of treatment with ABT-333 (250 mg), ribavirin (weight-based), both dosed twice daily, and the fixed-dose combination of ABT-450 and ritonavir (150/100 mg) co-formulated with ABT-267 (25 mg) and dosed once daily in non-cirrhotic, GT1a and GT1b HCV-infected, treatment-experienced adult patients who had no responded to treatment with peg-IFN and ribavirin.
The study population consisted of 394 GT1 treatment-experienced patients with no evidence of liver cirrhosis. Of these patients, 297 were randomly assigned to the 3D regimen plus ribavirin for 12 weeks; the remaining 97 patients received placebo for the initial 12 weeks. The placebo-treated patients then received open-label treatment with the 3D regimen plus ribavirin for an additional 12 weeks. In the study, 49% of patients were prior null responders to peg-IFN and ribavirin, generally considered among the most difficult patients to treat successfully.
After 12 weeks of treatment with the 3D regimen plus ribavirin, 96% (286/297) of the patients achieved SVR12, based on an intent-to-treat analysis in which patients with missing values for any reason were considered to be treatment failures.
Source: AbbVie; December 10, 2013.