Pfizer Inc., the world's largest drug maker, said on Nov. 30th that two of its experimental obesity drugs appeared to be as effective for weight loss as the Sanofi-Aventis diet drug Acomplia (rimonabant).

Officials of Pfizer told analysts that patients taking a 15mg and a 25 mg dose of a medicine called CP-945,598, a CB-1 antagonist like Sanofi's Acomplia, lost in total between 7 and 8 percent of their body weight in mid-stage clinical trials that lasted 168 days.

The officials said that adjusted for the weight loss by the group taking the placebo, patients on the 15 mg dosage of CP-945,598 lost 4.8 percent more of their body weight, compared to 4.5 percent for patients on Acomplia in the RIO-Europe study, and 4.4 percent for patients on the 25 mg dose of CP-945,598.

Pfizer said it has now begun the Phase III clinical trials needed before it can submit CP-945,598 to regulators for marketing approval.

While the trials are expected to take two years, Sanofi's Acomplia remains stalled at the U.S. Food and Drug Administration, with approval not expected at best until mid-2007.

Pfizer said another obesity drug that it has in Phase II trials, called MTPi which limits fat absorption in the gut, produced an average weight loss of 6 percent, which it said was comparable to Acomplia.