Sanofi-Aventis, the French pharmaceutical group, suffered a crippling blow to the prospects for its weight-loss drug Acomplia yesterday when regulators ordered the product to be withdrawn across the Europe Union.

The European Medicines Authority concluded that the benefits no longer outweighed the risks for the drug - known generically as rimonabant - after reviewing data suggesting that obese and overweight patients had twice the risk of psychiatric disorders as those on a placebo.