Diet drug rimonabant (Acomplia / Zimulti), once regarded as a potential blockbuster weight-loss drug, should be withdrawn from the European Union market because of its link to mental disorders, regulators said on Oct. 23. The drug's developer, Sanofi-Aventis, immediately suspended sales of the diet pill.

While the diet drug failed to gain approval for use in the United States last year because of concern over depression and suicidal thoughts, Acomplia has been on sale in Europe since the summer of 2006.

But the European Medicines Agency said it had concluded "that the benefits of Acomplia no longer outweigh its risks." The EMEA said Acomplia proved to be less effective in actual use than clinical trials had suggested because patients only tend to take the diet drug for a short period.

Data from recent studies has revealed patients taking Acomplia have "an approximate doubling of the risk of" developing psychiatric disorders, and 5 patients among 36,000 on the drug committed suicide between June and August, compared to one suicide among those taking the placebo.

Sanofi-Aventis, developer of Acomplia, temporarily suspended sales of Acomplia following the announcement and said it would "immediately" start talks to have sales suspended in countries in Latin America, Asia and Africa where the drug also is available.

"More than 700,000 patients have been treated with Acomplia world-wide to date," Sanofi said in a statement. The company said it had been monitoring "real-life use of the product" and contended that the experience of patients to date was "consistent with the one observed during the clinical development."

The European Medicines Agency said doctors "should not issue any prescriptions for Acomplia and should review the treatment of patients currently taking the medicine. Patients who are currently taking Acomplia should consult their doctor or pharmacist at a convenient time to discuss their treatment."

Sanofi said it remained "committed to provide additional evidence for the re-evaluation of the benefit/risk profile of Acomplia," which it has been hoping to submit for approval both in Europe and the United States to treat patients with diabetes and cardiovascular disease.

Sanofi said it believes Acomplia will remain an important therapeutic answer to a highly prevalent and increasing unmet medical need, said it intended to continue the ongoing clinical trial program. But Sanofi said it would halt phase IV studies of the drug as an anti-obesity treatment.

Sanofi issued a statement by Dr. Robert Anthenelli, professor of psychiatry, psychology and neuroscience at the University of Cincinnati College of Medicine, which said:

“This first in its class medication continues to demonstrate great promise to reduce cardiometabolic risk and the pattern of side effects remains consistent across the randomized clinical trials conducted to date.

"As with any new drug category, more will be learned about optimizing benefit and minimizing risk through continuing controlled use of the medication in
different patient populations. While the pendulum has swung in the direction of extreme caution with today’s regulatory decision, at the end of the day, the medical community will allow the scientific process to unfold before rendering any final decisions about this medication’s ultimate therapeutic potential."

Acomplia several years ago seemed destined to be the newest blockbuster diet drug, with analysts forecasting sales of more than $5 billion by 2010. Last year, the diet drug's totaled a little over $100 million.