The cliffhanger: FDA set to decide on Arena's lorcaserin

The biotech investment community is on high alert today, waiting for word of the FDA's formal decision on Arena Pharmaceuticals' application for its weight drug lorcaserin. 

A year-and-a-half ago you might recall that Arena ($ARNA) was forced to deal with a considerable backlash from investors and some prominent analysts after the agency exposed some serious safety issues on the drug dating back to its animal studies, forcing a CRL that spelled out some short-term remedies to repair the application.

But all of that was largely waved away after an FDA panel gave a solid endorsement to lorcaserin, bidding now to become the first new weight drug to gain an approval in more than a decade. Even a longtime critic like Adam Feuerstein at TheStreet--known for issuing a string of raspberries to management after the drug was initially rebuffed at the FDA--graciously gave the company props for a professional resubmission of the drug and a solid defense during its recent panel review. And growing expectations of an actual approval for Arena and its partner Eisai has driven up the biotech's share price fourfold this year--though shares dipped last Friday in an apparent round of profit taking.

The consumer advocacy group Public Citizen, though, still hates the drug. Yesterday Reuters reported that the group was urging the FDA to reject the drug based on evidence of potential heart valve damage--the kind of safety fear that has scuttled weight drugs in the past. But with the PDUFA date landing today, it's likely regulators have already made up their minds on that score--one way or the other.

Whichever way the FDA goes today, the next big weight drug decision comes July 17, when the FDA decides on Vivus's ($VVUS) Qnexa,which also won the backing of the same advisory panel which endorsed lorcaserin. A win for either company would set the stage for the next act in this drama, as analysts wait to see just how well a weight drug can perform in the marketplace.

- here's the Reuters story