Valeant Pharmaceuticals (Valeant) has provided additional results from the week-72 analysis of its phase IIb dose-finding clinical trial for taribavirin, a prodrug of ribavirin which is in development for the treatment of chronic hepatitis C in conjunction with a pegylated interferon.
According to the company, taribavirin (TBV) may present an alternative therapy to ribavirin (RBV) for the treatment of hepatitis C by delivering similar efficacy to ribavirin but with significantly less anemia, which is the main treatment-limiting toxicity associated with ribavirin.
Reportedly, the phase IIb trial was a US multi-center, randomised, parallel, open-label study in 278 treatment-naive, genotype 1 patients evaluating taribavirin at weight-based doses of 20mg/kg, 25mg/kg, and 30 mg/kg per day in combination with pegylated interferon alfa-2b. The control group was administered weight-based dose ribavirin (800/1000/1200/1400mg daily) and pegylated interferon alfa-2b. Overall treatment duration was 48 weeks with a post-treatment follow-up period of 24 weeks.
Additionally, the company said that consistent with previous reports, the viral response data continued to show comparable reductions in viral load for weight-based doses of taribavirin and ribavirin in a difficult-to-treat population of subjects infected with hepatitis C genotype 1 and end-of-study sustained virologic response rates were again comparable across the treatment groups. Relapse rates were identical for taribavirin 25mg/kg and weight-based doses of ribavirin.
The company said that the significant lower anemia rate for patients receiving taribavirin in the 20mg/kg and 25mg/kg arms versus the ribavirin control arm has been maintained at a rate similar to the end-of- treatment (week 48) throughout.