Experimental Weight-Loss Pill Passes Early Test

The result was lorcaserin, which targets the 5-HT2C serotonin receptor only.

For the phase 2 trial, 469 men and women with a body mass index ranging from 30 to 45 were randomly assigned to one of four groups: 10 milligrams (mg) of lorcaserin once a day, 15 mg once a day, 10 mg twice a day, or a placebo.

Participants taking lorcaserin at 10 mg, 15 mg and 20 mg a day lost 4 pounds, 5.7 pounds and 7.9 pounds, respectively, over the 12-week period. Those in the placebo group lost less than a pound.

In the 10 mg, 15 mg and 20 mg groups, respectively, 12.8 percent, 19.5 percent and 31.2 percent of participants lost 5 percent or more of their starting body weight, versus only 2.3 percent of patients on the placebo.

Participants taking the two higher doses of lorcaserin also shaved inches off their waist and dropped their cholesterol levels.

Also, their echocardiograms -- ultrasound images of the heart -- were normal.

"It [lorcaserin] certainly looks a bit better [than other weight-loss medications]," Weiss said. "We don't have much out there. They're really just modest medications and they don't do much at all."

More information

Visit the U.S. Centers for Disease Control and Prevention for more on overweight and obesity.

SOURCES: Dominic P. Behan, Ph.D., co-founder, director, senior vice president and chief scientific officer, Arena Pharmaceuticals, San Diego; Stuart Weiss, M.D., clinical assistant professor of medicine, New York University Langone Medical Center; Dec. 4, 2008, Obesity