Isis, Genzyme upbeat on PhIII mipomersen data

Isis (NASDAQ: ISIS) and Genzyme (NASDAQ: GENZ) have hit a slate of primary and secondary Phase III targets for their closely watched cholesterol drug mipomersen, putting them on track to file an NDA in the first half of 2011.  Despite the upbeat news, Isis shares slid about 8 percent this morning.

Investigators recruited more than 200 hard-to-treat patients for the late-stage trials. And they say that liver enzyme levels, a key safety biomarker, were comparable to earlier studies. In the smaller of the two trials, mipomersen reduced 'bad' LDL levels by 36 percent, compared with a 13 percent spike in the placebo group. In a separate study involving 158 patients running a high risk of heart disease, LDL levels plunged 37 percent among the drug group and 5 percent in the placebo arm.

Isis, though, has been plagued by persistent questions about the fluctuations of liver enzyme levels among patients taking mipomersen. CEO Stanley Crooke has insisted that the enzymes commonly spike with the adjustment of lipids. But those same safety issues may continue to worry analysts.

"We are pleased with the robust efficacy of mipomersen across all four Phase III trials. These data, along with the emerging safety profile, support our focused approach on patients at highest cardiovascular risk who are in the greatest need of new treatments," says Genzyme Senior Vice President John Butler.

Naturally, one of the first questions Isis had to field was what would happen in the event Sanofi buys Genzyme. In reply, the company said it could either go ahead with the new partner or get back the rights and sell them to someone else. At this stage, that would appear to be a relatively simple task, considering 2014 sales estimates pushing past the $350 million mark.

- here's the Genzyme/Isis release
- here's the Reuters story