It seems Fool readers were a little more optimistic about the timing of Arena Pharmaceuticals'
A little more than half of the readers figured the company could get the drug approved within a year when I polled them in October. Today, the company said it's shooting to resubmit the lorcaserin new-drug application by the end of 2011, which would put a potential approval in the middle of 2012, assuming a six-month review.
That could put Arena behind Orexigen's
No matter. An approval is most important; whether it's first or third doesn't matter all that much. But first, Arena has to address three nonclinical issues.
The first has to do with the diagnosis of rats with mammary tumors in its animal studies. Some of the readings -- benign versus malignant -- were changed from the initial to the final report. The FDA wants to know which one is the correct call, so a panel of five animal pathologists will reread the results. Unless you think Arena was trying to mislead the FDA with its original final report -- I don't -- this one should be the least worrisome for investors.
Of greater concern is how the rats got the tumors in the first place and whether that's relevant to humans. Arena thinks it has an easy answer: Lorcaserin increases prolactin levels in rats, which is known to cause mammary tumors. Proving that could be a little harder. First, it has to control for variable levels of prolactin, and then it'll have to show a persistent increase in prolactin level in rats taking lorcaserin.
Third, there's the issue of brain tumors in male rats. Since Arena doesn't have a mechanism of action for this one, Arena plans to compare the levels of lorcaserin in rats relative to humans. Figuring out the level of lorcaserin in rats' brains isn't that hard; just chop their heads off. Finding humans willing to undergo the corresponding experiment would be a little tougher. Instead, Arena is going to measure the drug level in spinal fluid. Whether it can show the level of drug is lower in humans than it is in rats that got brain tumors and whether the spinal fluid data will be good enough for the FDA, remains to be seen.
Keep in mind that lorcaserin doesn't really have stellar efficacy data. It helps patients lose more weight than placebo, but just barely. Because the drug doesn't treat a life-threatening disease, the FDA will require a stellar safety profile. The agency clearly doesn't want to see a repeat of Wyeth's fen-phen, Abbott Labs'
What say you now, Fools? Take the poll and tell us when, if ever, lorcaserin will be approved.