Idenix falls on partial clinical hold

Idenix Pharmaceuticals Inc. (NASDAQ:IDIX) fell $2.47 (30%) to $5.84 on Thursday after FDA placed a partial clinical hold on Idenix's most advanced HCV product -- IDX184 -- following cardiac safety concerns with a similar nucleotide NS5B polymerase inhibitor from Bristol-Myers Squibb Co. (NYSE:BMY). FDA asked for additional cardiac data from patients in an ongoing Phase IIb trial, which Idenix plans to submit in the "coming weeks." Idenix said there has been no evidence of cardiotoxicity associated with IDX184 during clinical development, including in 67 patients who received the product for at least 12 weeks. Under the hold, Idenix cannot enroll new IDX184 patients or start additional trials. No patients are receiving IDX184.

In a conference call, Idenix said it believes there are "significant differences" between IDX184 and Bristol-Myers' compound, BMS-986094. Idenix said the compounds use different pro-drug technologies, and that IDX184 more specifically targets the liver. Earlier this month, Bristol-Myers suspended dosing in a Phase II trial of BMS-986094 after one patient suffered heart failure after receiving a 200 mg dose of the compound in combination with the company's daclatasvir, an HCV NS5A inhibitor (see BioCentury, Aug. 6). ...