Valeant Pharmaceuticals presented 24-week data from Phase 2 clinical trials of Viramidine, a nucleoside (guanosine) analog, Valeant is developing in oral form for the treatment of chronic hepatitis C (HCV) in conjunction with a pegylated interferon. Valeant presented its data at the European Association for the Study of the Liver (EASL) Conference in Berlin, Germany.

The Viramidine Phase 2 study consists of 180 treatment-naïve subjects with chronic HCV. The on-going study was an open-label, randomized, active control trial, being conducted at multiple centers in the United States and with patients stratified by genotype. The study consists of four demographically comparable treatment groups: Viramidine 400 mg BID, Viramidine 600 mg BID, Viramidine 800 mg BID and ribavirin 1000/1200 mg daily all in combination with peginterferon alfa-2a. Treatment duration was based on genotype, with genotypes two and three receiving 24 weeks of treatment and genotype one receiving 48 weeks of treatment, each with a post-treatment follow-up period of 24 weeks.

The interim 24-week data shows that Viramidine demonstrates antiviral activity comparable to that of ribavirin, when used in combination with peginterferon alfa-2a in treatment naïve patients, but with a lower incidence of anemia.

The data demonstrates a sustained reduction in HCV RNA of approximately two-and-a-half log10 for all three doses of Viramidine, comparable to the ribavirin group in the same study. The proportion of patients with greater than or equal to 2 log10 reduction or non-detectable HCV RNA was 83 percent for both Viramidine (800-1600 mg/day) and ribavirin at 24 weeks. The results also show the percent of patients with non-detectable HCV RNA at 12 weeks and 24 weeks were similar between all treatment groups.

There were also fewer patients in the Viramidine groups with anemia (defined as hemoglobin < 10g/dL) when compared with the ribavirin arm (2 percent versus 24 percent; p < 0.001). In the Viramidine 400 mg BID and 600 mg BID dosage groups, defined anemia (hemoglobin < 10g/dL) did not occur, while there were only two occurrences of anemia in the 800 mg BID group. Other adverse events were similar among treatment groups.