The U.S. Food and Drug Administration has declined to put consideration of the new Sanofi-Aventis obesity drug Acomplia (rimonabant) on an accelerated track, meaning the agency will not rule on whether the drug can be sold in the United States until well into 2006.

"The FDA has not granted a priority review for rimonabant," a company spokeswoman said in a terse statement on June 23rd.

Sanofi had been expressing hope it would receive approval to bring the drug to market before the end of 2005, but many analysts thought it unlikely the FDA would grant "priority review" because of the drug's novel mode of action in targeting the same brain signal that makes people hungry when they smoke marijuana.

While Sanofi has described Acomplia as "a new approach for the comprehensive management of cardiovascular risk factors," the priority designation generally has been reserved for breakthrough drugs -- many of them cancer drugs -- that "address unmet medical needs," according to the FDA.

In four major clinical trials, Acomplia has been shown to help obese people lose weight, improve diabetic control, reduce cardiovascular risk factors, and stop smoking. Sanofi has not said for which of these indications it is seeking approval.

According to the FDA, the 'standard' review process for a New Drug Application (NDA) sets the target date for reaching a decision on an application at 10 months after a filing, while the 'priority' designation sets the target date for FDA action on a drug at six months.

Sanofi's only comment on the FDA decision to proceed with a standard review was: "'We fully understand that the FDA requires a standard review process to assess the NDA for rimonabant."

The company also has applied for approval of the drug with the European Medicines Agency.