Sanofi-Aventis has received some more bad news concerning Acomplia after researchers claimed that patients taking the obesity drug were at risk of suffering severe psychiatric side effects.

In a study published in The Lancet, scientists at the University of Copenhagen in Denmark carried out a meta-analysis of four double-blind randomised controlled trials featuring 4,105 patients, which compared treatment with 20mg per day of Acomplia (rimonabant) with placebo. They found that patients given Acomplia had a 4.7kg greater weight reduction after one year than did those given placebo but they had a 40% higher risk of suffering adverse events.

Specifically the patients given rimonabant were 2.5 times more likely to discontinue treatment because of depressive disorders than those given placebo, and were three times more likely to stop taking the tablets due to anxiety. However the researchers, led by Prof Arne Astrup, said that there were no follow-ups after discontinuation of active treatment with Acomplia, so any weight regain could not be assessed.

They authors noted that "as with other weight-loss drugs, relapse is expected to occur after treatment has ended, and to achieve weight maintenance and maintain the improvement of the cardiovascular and diabetes risk factors the drug needs to be taken for life”. They concluded that the findings suggest that 20mg per day of Acomplia increases the risk of psychiatric events “despite depressed mood being an exclusion criterion in these trials”.

The results seem to back the decision taken in June by a US Food and Drug Administration's advisory committee which voted 14-0 against approving Acomplia after saying that the benefits of the drug do not outweigh the risk of psychiatric adverse effects, including suicide and seizures.

Sanofi says that The Lancet study does not reveal any new data. Also it noted that the European Medicines Agency recently strengthened its warning against using the drug in patients with major depression or those taking antidepressants but still believes that the benefit of taking Acomplia outweighs the risk. Third-quarter sales of the treatment, which is still sold in 20 countries, reached just 21 million euros.