Shares in US firm Valeant Pharmaceuticals rose slightly on the Nasdaq stock exchange yesterday, despite announcing that its hepatitis C drug Viramidine (taribavirin) was no better than a standard therapy in a second Phase III trial in 960 treatment naïve patients.

Results showed patients in the Viramidine group saw a 40% viral response rate versus 55% for those taking the conventional treatment ribavirin. While, overall, Viramidine receivers underperformed the ribavirin group, the researchers pointed out that participants given a high-dose of Viramidine had higher response rates with no increase in anaemia and a general improvement in safety. In fact, just 6% of those given Viramidine developed anaemia compared to 22% of ribavirin patients.

It’s been a bad week for the firm, which on Monday revealed it is the subject of a US Securities and Exchange Commission probe into share trading and data disclosure ahead of the unveiling of its first Viramidine trial.

But, on the plus side, Valeant says it has a high-dose Viramidine Phase IIb study in the pipeline, involving 240 patients over a 48-week period, and plans to start looking for a development partner to help take it into another Phase III study should this throw up positive results. “Our retrospective analyses of 750 patient plasma samples indicate that Viramidine could be as effective as ribavirin at higher doses," said Timothy Tyson, Valeant’s President and Chief Executive. “These analyses, coupled with feedback from the medical community that there will continue to be a strong need for ribavirin or ribavirin analogues in the treatment of hepatitis C, indicate that further clinical testing is prudent.”

Meanwhile, SEC investigators are also looking into stock option grants and the company’s court bid to get bonuses paid to former chief executive Milan Panic returned. Mr Panic left Valeant in 2002.