Idenix plunges after FDA puts another hep C treatment on hold

Idenix already faces a partial clinical hold on its top hepatitis C program. Now the FDA has stepped in to add a clinical hold on its preclinical therapy IDX19368, another nucleotide polymerase inhibitor, or "nuc," in the pipeline. The biotech ($IDIX) also spelled out some added safety checks for its lead hep C treatment, which the company says can be completed in a matter of weeks. But its shares swiftly plunged on the fresh round of troubling news.

"Based on our discussions with the FDA, we understand the clinical hold is a precautionary decision made by the FDA in light of the adverse events seen with BMS-986094," said Idenix CEO Ron Renaud. "Both IDX184 and IDX19368 fall into the same broader class of NS5B inhibitors, and share the same active metabolite as BMS-986094. However, there are many attributes of our compounds, particularly the prodrug approach, that we believe favorably differentiate the toxicity profiles from that of BMS-986094."

Idenix's FDA woes were triggered by the abrupt failure of BMS-094, a once sizzling-hot hep C treatment which raised alarms after one patient died and 8 others in a study were hospitalized, just 8 months after Bristol-Myers Squibb paid $2.5 billion to acquire Inhibitex. Bristol ($BMY) announced on Thursday that it was writing off $1.8 billion and scrapping the drug entirely. Idenix added today that BMS is lending a hand in resolving the holds.  

Idenix also reported that it has lined up echocardiograms for 50 patients enrolled in its IDX184 study. A few done so far have not revealed any safety concerns and the developer says that it should be able to complete this process in a few weeks.

A lingering concern for Idenix, though, is whether the company can regain the glow that had enveloped it after some big deals in the hepatitis C space made the company a prime takeover target, with analysts speculating about the prospect for a big premium. The Cambridge, MA-based company has been among the leaders in the mad scramble to advance new "nucs" and NS5A inhibitors that can be combined with ribavirin into an all-oral regimen with megamarket potential.

Idenix shares plunged 40% on news of the partial hold 11 days ago. This morning the stock plunged another 16% in premarket trading. Both of these programs are unpartnered, which leaves Idenix holding the bag now for any long-term loss in value. 

 - here's the press release

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