If an FDA decision on diet drug Acomplia (rimonabant) is deferred until concerns over its side effects are aired by an FDA advisory panel, the bad news for Sanofi-Aventis is that the next meeting of the Endocrinologic and Metabolic Drugs Advisory Committee is tentatively scheduled for June 13th.

Sanofi-Aventis grudgingly conceded on Dec. 8th that the U.S. Food and Drug Administration has placed Acomplia on a slow track for review, and while the French pharmaceutical company said it hoped for an FDA decision on approval by April 26th, a spokesperson said: "Maybe it will take further time."

That possibility began to look a little more real when the FDA posted its tentative 2007 meeting schedule for advisory committees, and the calendar showed that the first meeting of the panel that would consider Acomplia has been tentatively set for June 13-14, 2007.

Obviously, a meeting of this panel could be convened well before next June. But the fact that no earlier meeting is even tentatively on the calendar is not an encouraging sign.

Interestingly, the same advisory panel voted last January to recommend that the FDA approve sale of a low-dose version of prescription diet drug Xenical (orlistat) as an over-the-counter pill called Alli (pronounced Al-EYE) -- but 10 months later, the FDA still has not acted on this recommendation.

Nearly all observers believe the FDA, which has held up action on Acomplia since the beginning of the year over issues that have never been made public by Sanofi, will not act until rimonabant is thoroughly vetted by its advisory panel of independent outside experts.

Given that Acomplia is first in a new class of drugs that interferes with receptors in the brain that help regulate appetite, most find it hard to imagine the FDA will move forward before outside experts weigh in -- particularly in light of trial side effects that included a 2.7-fold higher rate of psychiatric disorders.