In October this year, the European Medicines Agency recommended suspending sales of Sanofi-Aventis's anti-obesity agent rimonabant (Acomplia)--which has been approved in Europe for 2 years but has not been approved in the US--concluding that the benefits of rimonabant no longer outweigh its risks. The agency considered that experience with rimonabant since approval has indicated that serious psychiatric disorders may be more common than in the clinical trials used in the initial assessment of the medicine. Sanofi-Aventis followed the recommendation, and in November announced that it had decided to discontinue all ongoing clinical trials of rimonabant, a first-in-class cannabinoid 1 receptor (CB1R) blocker.

Other companies' efforts to therapeutically target the endocannabinoid system have also been stopped recently. Merck announced in October that it was discontinuing development of its anti-obesity CB1R blocker taranabant, which had reached Phase III trials. In November, Pfizer did the same for another CB1R blocker CP-945,598, which had also been in Phase III trials for obesity.