Sanofi-Aventis’ antiobesity agent Acomplia (rimonabant) is facing a new challenge after the European Medicines Agency yesterday recommended strengthening its warning against using the drug in patients with major depression or those taking antidepressants because of the risk of psychiatric side effects.

Acomplia was first approved in the European Union in June last year for use alongside diet and exercise in treating obese or overweight adults. Doctors were cautioned at the time of approval about the drug’s risk of psychiatric side effects – particularly depression - but the EMEA’s scientific advisory committee, the Committee for Medicinal Products for Human Use, has now recommended this warning be upgraded.

The CHMP asked sanofi-aventis to submit all available information on the psychiatric side effects of Acomplia last month, as part of its normal monitoring process, including data from launch until 18 June and from five studies involving 781 patients taking Acomplia that had been completed since the medicine was granted marketing authorization.

And it concluded at a meeting this week that the treatment benefits of Acomplia continue to outweigh its risks, except in this cohort of patients. Specifically the panel said that “the risk of depression is approximately doubled in patients taking Acomplia…in a small minority of cases, this could lead to suicidal ideation or even suicide attempts.” It went on to say that “this doubling of the risk of depression occurs in all patients; however, this risk may be increased in patients with a past history of depression.”

On the back of this, it stressed that a warning should be added to the drug’s labelling that Acomplia treatment should be stopped if a patient develops depression, and that it should include additional information on the compound’s psychiatric safety. The committee also noted that too many patients are taking Acomplia at the same time as antidepressants even though the drug is contraindicated in this portion of the population.

Doctors will be sent a letter to inform them about the updated prescribing information and the EMEA says the recommendation will now be forwarded to the European Commission for adoption of a Decision.

More bad news following US filing withdrawal

It’s a double whammy of bad news for Sanofi-Aventis and what was once seen as a potential star in its pipeline. Earlier this month, the company pulled its regulatory package from the USA after the country’s Food and Drug Administration voted unanimously during a panel meeting not to recommend it for approval. The panel said that the benefits of the drug, which would have sold as Zimulti in the USA, do not outweigh the risk of psychiatric adverse effects seen in patients taking the drug, including suicide and seizures.

But despite this, Sanofi-Aventis is still keen to get its antiobesity offering onto the world’s biggest pharmaceutical stage, saying it is “committed to taking all steps necessary” to get the drug on the US market and will “undertake the necessary discussions with the FDA “to determine the required modifications to its filing”.