VALEANT'S VIRAMIDINE STUDY FAILS TO MEET EFFICACY ENDPOINT

Valeant Pharmaceuticals International has reported summary results of VISER2, the second of two Phase III trials of Viramidine. The company is developing Viramidine (taribavirin hydrochloride), a nucleoside analog prodrug of ribavirin, for oral administration in combination with a pegylated interferon for the treatment of chronic hepatitis C in treatment-naive patients. The trial included two primary endpoints: one for safety (superiority to ribavirin in the incidence of anemia) and one for efficacy (non-inferiority to ribavirin in sustained viral response).

The study did not meet the non-inferiority efficacy endpoint on an intent-to-treat basis, with overall response rates of 40 percent and 55 percent for the Viramidine and ribavirin arms, respectively. However, consistent with the results seen in VISER1, sustained viral response rates in VISER2 trended higher among patients receiving increased exposure on a mg/kg basis in the Viramidine arm without a substantial increase in the anemia rate.

As a result of the combined study data, the company also announced that it is initiating a Phase IIb program to evaluate the efficacy of Viramidine at higher doses. The Phase IIb program is a multicenter, randomized, parallel, open-label study in 240 treatment-naive, genotype-one patients that will evaluate Viramidine at 20 mg/kg, 25 mg/kg and 30 mg/kg per day in combination with pegylated interferon alpha-2b. Based on a 12-week interim analysis of this study, the company will decide whether to begin a third Phase III study at the appropriate higher dose.