Pfizer and Sanofi discontinue CB1 obesity drugs

A once promising class of obesity drugs - the cannabinoid receptor-1 blockers - has been dealt a huge blow after both world drug giant Pfizer and French drug major Sanofi-Aventis decided to discontinue the development of their individual CB1 drugs. Pfizer is terminating the Phase III program for its investigational compound (CP-945,598) noting that, while it believes the drug could be a "safe and effective treatment for weight management," it has taken the decision based on the "changing regulatory perspectives on the risk/benefit profile of the CB1 class and likely new regulatory requirements for approval." The increased scrutiny on these drugs also prompted Sanofi to discontinue its drug Acomplia (rimonabant) in all indications. A few weeks ago (Marketletter November 3), the European Medicines Agency (EMEA) called for the market withdrawal of the agent over increased risk of psychiatric side effects such as suicidal behavior. Now Sanofi has also ended trials that were to assess the agent as a treatment for diabetes and heart disease.