FDA advisory panel rejects sanofi-aventisí weight loss pill

An FDA advisory panel has rejected the bid of French pharmaceutical company sanofi-aventis to market its weight loss treatment rimonabant in the US despite its approval in other countries.

The panel's conclusion, in a 14-0 vote makes it unlikely that regulators will approve the drug for US sales because the FDA usually follows such recommendations.

Rimonabant works by blocking the brain's cannabinoid receptors, the same receptors stimulated by marijuana, which accounts for the drug's weight loss effect by blocking the same receptors that cause the appetite-stimulating effect of marijuana.

FDA scientists produced an analysis of 13 studies showing that the drug nearly doubled suicidal thinking while also doubling cases of anxiety, depression, and other mood disorders. The data it obtained for 2004-2006 showed that 30 per cent of the 580,000 US patients prescribed diet pills each year also received a prescription for an antidepressant.

Dr Amy Egan, an FDA safety official, said the agency had become worried because the company had excluded patients being treated for depression from its analysis.

Sanofi-aventis had stressed that patients on antidepressants should not take its weight-loss drug Acomplia/ Zimulti (rimonabant) in the product labelling. The company added that it had excluded patients with a history of severe depression or severe psychiatric illness from its phase III clinical trials, and explained that antidepressant treatment was not allowed.

Sanofi-aventis had said: "There is limited data in patients taking antidepressant medication in combination with rimonabant; therefore, the use of rimonabant is not recommended in these patients."

The FDA's concern was that depressed, overweight people may succeed in getting hold of Zimulti (the US market name for rimonabant).

In order to quell the FDA's fears, sanofi-aventis had proposed a Risk Minimisation Action Plan (Risk MAP), which it said would reduce the possibility of rimonabant use inconsistent with the labelling in patients with diseases, conditions or concomitant therapy that raise identified or potential safety concerns.

Sanofi-aventis also stressed that in Europe, where Acomplia has been on sale for nearly a year, under five per cent of the 100,000 patients prescribed the drug received it in conflict with product labelling.

Other prescription weight loss drugs are already on sale on the US market, including Knoll Pharmaceutical's Meridia (sibutramine) and Roche's Xenical (orlistat). GlaxoSmithKline's over-the-counter version of Orlistat, known as Alli, will be sold in pharmacies and other outlets this week.

PMLive reported recently that two Indian pharmaceutical companies had already copied and marketed rimonabant, which has yet to gain patent protection in the country.

Torrent Pharmaceuticals and Zydus Cadila are already selling the molecule as Rimoslim and Slimona, respectively, in India for under USD 6 per month, compared with the EU market rate of over USD 100 a month. Both companies say that the Indian market for rimonabant is significant, as it has a growing urban, middle-class obesity problem which may turn out to be a bigger earner than S-A initially believed.

French newspaper, Les Echo, reported that a third Indian company, Sun Pharmaceutical, had developed its own generic version of rimonabant. India is not obliged under World Trade Organisation rules to respect patents on molecules developed prior to 1995: rimonabant was registered in 1994, according to the report.