Did the odds just get worse for Arena's new weight drug?

After the FDA panel vote against Vivus's obesity drug Qnexa, analysts tracking the wave of new weight drugs headed to the agency have been hyper-sensitive about anything that could highlight concerns about the safety of the experimental treatments. So when the agency scheduled an in-depth review of Abbott's Meridia right ahead of Arena's (ARNA) lorcaserin--just as it tackled Avandia risks right ahead of the Qnexa session--it didn't take long for fresh fright to take hold.

"The Meridia discussion is likely to create an unfavorable atmosphere for the discussion of Arena's application," wrote analysts at Concept Capital's Washington Research Group. But they also offered one important proviso in a Dow Jones overview: Arena's experts will come prepared to do everything possible to make the case that their drug can clear the panel's high bar on safety.

Meridia will be Topic A for the Endocrinologic and Metabolic Drugs Advisory Committee on September 15, which will have to address the same cardio safety issues that forced the drug from European markets. Arena had actually been benefiting from the panel's clear reluctance to green-flag Qnexa, which cost Vivus more than half the value of its shares. Lorcaserin is considered the cleanest of any of the new weight drugs when it comes to safety data.

But with the experts concentrating on heart attacks and strokes related to Meridia, some Street insiders say that they'll be in a poor frame of mind to balance risks and rewards when they're forced to evaluate another weight drug that could have hidden or unappreciated side effects--as so many weight drugs have had in the past. The panel's attitude to risk right now is that it's better to be safe than sorry--and that is changing the odds for drug developers in the space.

- here's the story from Dow Jones