Prospects of an early FDA decision on Acomplia (rimonabant) dimmed March 9th with confirmation that the next meeting of the Endocrinologic and Metabolic Drugs Advisory Committee -- which had been set for August -- has been scrubbed, with no meeting even tentatively scheduled now until November.

Many observers believe the FDA, which three weeks ago gave Sanofi-Aventis an "approvable" letter for Acomplia setting out issues that need to be resolved prior to approval for weight management, will not act until the high-profile drug is thoroughly vetted by an advisory panel of independent outside experts.

That view was strengthened after researchers from the National Heart, Lung, and Blood Institute -- a highly respected arm of the National Institutes of Health -- declared in the Journal of the American Medical Association that adverse side effects which turned up in Acomplia clinical trials "must be considered."

Given that Acomplia is first in a new class of drugs that interferes with receptors in the brain that help regulate appetite, many 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.

But a March 9th update of the 2006 tentative meeting schedule for the FDA's Endocrinologic and Metabolic Drugs Advisory Committee deleted the meeting that had been posted for August 23-24. Since a May meeting had been cancelled earlier, the next meeting now is tentatively set for Nov. 8-9.

The decision not to hold an August meeting was confirmed by a spokesperson for the advisory committee.

That would appear to be bad news for Sanofi, which most recently said it was hopeful of getting Acomplia on the market in the U.S. in the second half of this year.

While Sanofi has long taken the position in briefing analysts that an advisory committee meeting should not be necessary prior to FDA approval, their ever-optimistic views on the how the U.S. regulators will proceed on this drug no longer have a great deal of credibility