Thomas Weisel Analyst Rates Idenix 'Overweight'

Hepatitis C is caused by a blood-borne virus that can lead to liver scarring or liver cancer. Current treatments on the market include combinations of the drugs peginterferon and ribavirin, but less than half on it are cured. There is currently a large push by several companies to develop treatments that directly target the virus, making the outlook for the hepatitis C market very competitive.

Vertex Pharmaceuticals Inc., Schering-Plough Corp. and InterMune Inc. are all developing Hepatitis C treatments.

Willey said the underlying technology in IDX184 has become the cornerstone of combination therapies for HIV because of a high barrier to genetic resistance. That propensity for viral resistance will likely drive a push to more combination treatments for hepatitis C, benefiting Idenix.

"This high resistance barrier and broad genotypic coverage will translate into a similar outcome for this class of drugs in hepatitis C," he said.

Idenix currently only has one marketed product, the hepatitis B drug Tyzeka, sold overseas as Sebivo. That drug was licensed to Swiss drugmaker Novartis AG, and Idenix receives royalty payments on sales.

Shares of Idenix rose 4 cents to $3.41 in afternoon trading.