Drugmakers stop studies on two diet pills

Armen Hareyan's picture

The possibility of psychiatric side effects may be to blame for the demise of two diet drugs designed for obesity treatment. French drugmaker Sanofi-Aventis said it’s stopping all research on Accomplia - a diet drug sold in Europe. Just a few hours later, Pfizer Inc. announced it’s ending research on an experimental weight-loss drug in the same class.

"Given that obesity and related complications are arguably the world's biggest public health problem, the demise of both drugs will be a big disappointment for patients and doctors, and possibly for investors. The decisions leave New York-based Pfizer, the world's top drugmaker by sales, and Paris-based Sanofi-Aventis, ranked No. 4, suddenly without drugs in a category all but guaranteed as a blockbuster.

"This will significantly affect the perception of their (future) revenues," but the companies could overcome that with replacement drugs down the road, said analyst Steve Brozak of WBB Securities.


Just four years ago, scientists were touting obesity treatment drug Acomplia as a Holy Grail of medical research, saying it showed promise in helping people lose weight, control blood sugar and other aspects of diabetes, lower cholesterol, quit smoking and stop abusing alcohol, marijuana and cocaine.

Some researchers predicted that once Acomplia got approval for weight loss or smoking cessation, research would ramp up in those other areas. But that early promise didn't materialize, it didn't win approval for smoking cessation and problems began piling up as psychiatric side effects - now a huge red flag for regulators - emerged in various studies of Acomplia as a diet drug.

Sanofi-Aventis said in a brief statement it was stopping ongoing human testing of Acomplia, known chemically as rimonabant, for all uses, "in light of recent demands by certain national health authorities."

Two weeks ago, Sanofi-Aventis temporarily stopped sales of Accomplia in Europe after reports that the drug’s risks - depression, anxiety and stress disorders - outweighed its benefits.

Pfizer and Sanofi-Aventis are not the only pharma companies that has recently canceled the same class of obesity drugs. Merck & Co. (NYSE: MRK) stopped development of a similar drug candidate called Taranabant a few weeks ago. Those companies all had high hopes the drug could be used for smoking, diabetes and high cholesterol along with obesity. According to Bloomberg, only Bristol-Myers Squibb Co. (NYSE: BMY) is still developing a similar medicine.