Idenix Pharmaceuticals (NASDAQ: IDIX) just can't catch a break. The company is down nearly 30% today after announcing that the Food and Drug Administration won't let Idenix start a clinical trial for its hepatitis C drug IDX20963 until the company turns in additional preclinical safety data.
This isn't the first time, or even the second or third time, that the FDA has delayed Idenix's clinical trials.
Last year, two of Idenix's hepatitis C drugs, IDX184 and IDX19368, were put on clinical hold by the FDA because they had a structure related to Bristol-Myers Squibb's (NYSE:BMY) BMS-986094, which produced severe cardiac side effects in its clinical trial. Like Bristol-Myers, Idenix eventually scrapped development of the drugs.
And back in 2010, IDX184 and another compound, IDX320, were put on a clinical hold, which Idenix eventually got lifted for IDX184 after concluding that IDX320 was the problem child.
Don't forget safety
Hepatitis C is a very interesting disease to follow in the clinic because efficacy in phase 1 trials usually translates into efficacy in phase 3 trials. If a drug does well in early trials, investors assume -- rightfully -- that it'll be able to pass future clinical trials.
But that confidence can cause investors to forget about the other reason the FDA requires clinical trials: safety. A severe adverse event that happens in 1% of patients might not show up in a small 30-patient trial.
What's the issue?
It isn't clear from Idenix's press release whether the FDA made the request for more information because Idenix just forgot to provide some routine preclinical data or if something in the data package Idenix turned in caused the FDA to want additional data before signing off on starting clinical trials. The latter is obvious more serious because it could mean IDX20963 will never get on the market.
Ultimately the delay itself, and not the reason for the delay, might be what derails IDX20963. Considering that Idenix felt the news was material enough to issue a press release, we're looking a delay of at least a few months if not more.
The most advanced second-generation hepatitis C drugs, Johnson & Johnson's (NYSE:JNJ) simeprevir and Gilead Sciences' (NASDAQ:GILD) sofosbuvir, are already being reviewed for approval by the FDA. They both should be approved by the end of the year.
And by the time IDX20963 gets approved, there will be perhaps a dozen drugs approved to treat hepatitis C. I can't imagine entering the market at that point is going to be easy, and any delays in development will only make it harder.
Idenix still has one more compound, IDX719, in phase 2 development, so the company isn't entirely dead. It might even get acquired by Johnson & Johnson, which is testing its hepatitis C drugs in combination with IDX719, if the combinations looks good.
Assuming, of course, that Idenix's string of bad luck doesn't extend to IDX719.