Drug: Acomplia (rimonabant)
Year Approved: 2006 (UK)
The promise: Obesity. It's a virtually untapped, multi-billion market that draws drug developers like a moth to a flame. Incredible profits await the drug developer that finally cracks a the therapeutic area that has been plagued with safety issues and clinical failures for decades. Sanofi-Aventis thought it had a potential hit on its hands with Acomplia, a selective cannabinoid receptor CB1 antagonist that blocked hunger signals to the brain. It was the first to market with a drug in this class, and Acomplia was touted as the first major weight-loss drug since fen-phen was pulled a decade earlier. The European Union approved the drug in 2006, and it was eventually sold in 56 countries. U.S. regulators never approved Acomplia.
What went wrong: After Acomplia hit the market, reports began to surface that the drug's side effects were worse than clinical studies had indicated. Of particular concern were increased instances of depression and suicidal thoughts. In 2008, the EMA decided Acomplia's risks no longer outweighed its benefits and pulled the drug from the market. Approval was officially withdrawn in 2009. Merck, which was also developing a CB1 antagonist, abandon its work after subjects taking the drug became irritable and depressed.