Idenix shares crash after tox scare forces hold on hep C drugs

Idenix--one of the biotech industry's star stock performers this year--saw its share price crash and burn this morning after it announced that the FDA had put its two lead hepatitis C programs on clinical hold. The hold was issued after researchers tracked signs of liver toxicity in three patients taking the therapies--a classic red flag on drug safety. Its shares (IDIX) slid 55 percent in premarket trading.

"We have not yet received a formal letter from the FDA, nor has the Agency had an opportunity to review the safety and efficacy data from recently completed clinical trials with IDX184 and IDX320. Based upon our discussions with the Agency, we are primarily focused on three cases of elevated liver function tests observed during our drug-drug interaction study of the combination of IDX184 and IDX320 in healthy volunteers," says Jean-Pierre Sommadossi, Idenix chairman and CEO. "Based upon the safety and antiviral activity we observed in the IDX184 14-day study and the IDX320 3-day proof-of-concept study, both in HCV-infected patients, we remain committed to the future potential of these drug candidates."

As TheStreet's Adam Feuerstein notes in a story out this morning, Idenix's shares have been one of the top 5 performers in the industry, up 176 percent through the end of last week. That changed for the worse in a matter of minutes, however, with its share price melting from $5.99 to under the $3 mark. Idenix, a 2004 Fierce 15 company, has had plenty of ups and downs as it pursues new therapies for hepatitis C--one of the toughest targets in the industry. Novartis passed on its option to partner on IDX184 last October.

- check out the Idenix release
- here's the story from TheStreet