A major class-action law firm has filed suit against Sanofi-Aventis alleging that the French pharmaceutical company misled U.S. investors about prospects for diet drug rimonabant (Acomplia / Zimulti).

Coughlin Stoia Geller Rudman & Robbins LLP said on November 13 it had commenced action on behalf of an institutional investor in the U.S. District Court for the Southern District of New York.

Acomplia had been touted by Sanofi as a potential $5 billion blockbuster drug, but while approved in Europe in mid-2006, an application to sell the drug in the U.S. was pulled by Sanofi after an FDA expert advisory committee raised concerns about depressive and suicidal side-effects.

With no prospect that the drug will make it to the U.S. market for several years, sales of Acomplia have been anemic, totalling only $30 million in the third-quarter of this year.

The complaint alleges that Sanofi's statements regarding Zimulti -- the name the drug was to have been sold under in the U.S. -- were materially false and misleading when made because the company concealed data concerning Zimulti’s propensity to cause depression.

The law firm said that any investor wishing to serve as lead plaintiff, or wanting to discuss the lawsuit, should contact Samuel H. Rudman or David A. Rosenfeld of Coughlin Stoia at 800/449-4900 or 619/231-1058.