Vertex takes hit on data

Vertex Pharmaceuticals Inc. released data yesterday showing its experimental hepatitis C drug was more effective than current treatments, but results were not as strong as some expected and its shares fell 8.7 percent to $28.90.

Data from the Annual Meeting of the American Association of the Study of Liver Diseases in Boston showed the drug, telaprevir, in combination with standard treatment eradicated the hepatitis C virus in more than 60 percent of patients who took it as part of a 24-week treatment regime.

While that compares favorably with the 50 percent or less cure rate seen in patients who take standard therapies - which are typically taken for a year - some investors had hoped the results would be closer to 70 percent.

Shares of Cambridge-based Vertex have fallen 23 percent in 2007, amid concern the drug, which inhibits a hepatitis C protease essential for virus replication, might not live up to early expectations.

Investors also worry about competition, as rivals circle to take a bite out of the market for treating hepatitis C, a liver-borne disease that affects roughly 170 million people worldwide.

Telaprevir is Vertex's most important experimental product, accounting for the lion's share of its market capitalization of $4.2 billion.