Vertex down on hepatitis C drug results

Shares of drug maker Vertex Pharmaceuticals Inc. fell in premarket electronic trading today after trial results for its hepatitis C drug telepravir disappointed investors.

Cambridge-based Vertex presented results from a clinical trial of telaprevir Saturday at a Meeting of the European Association for the Study of the Liver. A total of 250 hepatitis patients were treated with telaprevir for 24 weeks.

A group of 17 was eligible to stop treatment after only 12 weeks, but eight of those patients did not complete the trial. Six of the 17 did not sustain the same level of virus response.

The most common side effect was rash, although gastrointestinal problems and anemia were also reported.

"The fact that some patients have remained persistently viral negative 20 weeks after stopping the 12 weeks of telaprevir-based therapy, suggest that we may be able to shorten the treatment duration in genotype 1 HCV patients," said Dr. John McHutchison, Principal Investigator for the PROVE 1 study and Director of Gastroenterology and Hepatology Research at Duke Clinical Research Institute.

CIBC World Markets analyst Brian Abrahams said the results were "impressive," but predicted the stock will lose ground due to the 12-week group results.

"We believe these are solid but not spectacular results," he said. "We would caution against over-interpreting this data due to the potential for statistical variability from the very small sample size."

JPMorgan analyst Richard Smith said the results were positive, and may reduce safety concerns.

"We believe the numbers are small, but suggest that some patients may be able to achieve a sustained viral response on a much shorter, more potent treatment regimen," he said. (AP)