Sanofi-Aventis' obesity drug Acomplia delayed by an FDA "approvable" letter

French drug major Sanofi-Aventis, the world's third largest pharmaceutical group, has been asked by the US Food and Drug Administration for fresh information to back up a New Drug Application for the anti-obesity drug Acomplia (rimonabant), via an "approvable" letter, before reaching a decision on clearing the product. The drug has, meanwhile, been rejected by the FDA as an anti-smoking agent.

Acomplia, the first in a new class of therapeutic agents known as CB1 blockers, acts by blocking certain cellular receptors which reduce the need to eat or smoke. The rejection of the drug for the smoking indication is seen as awkward for the company but not quite a catastrophe because the obesity indication is regarded as much more significant commercially.

Drug industry analysts at Merrill Lynch were earlier expecting annual sales of about 200.0 million euros ($238.1 million) for the smoking indication compared with 1.5 billion euros in sales for the treatment of obesity. Michel Joly, for Sanofi-Aventis, said that the anti-smoking market was much less medicalized than that for obesity and there were a number of products already on the market. The significance of the obesity indication for the USA is considerable given that over 30% of Americans are now regarded as obese with increased risk of heart attacks.