Firm Says Obesity Pill Shows Promise

Arena Pharmaceuticals Inc., a small San Diego biotechnology company, plans to announce today that overweight patients lost an average of 2.9 pounds after taking the company’s experimental obesity pill for 28 days in a clinical trial.

Chief Executive Jack Lief said the loss was comparable to what was seen with Abbott Laboratories’ weight-loss drug Meridia in a month.

A three-month study of Arena’s drug, ADP356, is planned, Lief said. The company must conduct two yearlong studies to receive Food and Drug Administration approval.

Lief said the effect of Meridia plateaued over time. “We hope that our [pill] will work much better,” he said.

Arena said that the 28-day study included men and women and that their average weight was 223 pounds. Half of the patients were white, and a total of 352 participated.

The pill appeared to work only at the highest dose of 15 milligrams, the company said. Patients on a placebo pill lost less than a pound during the trial. Lief said patients lost weight gradually and were not asked to exercise or diet during the trial.

Twenty percent of patients in the high-dose group reported having a headache, the most common side effect, compared with 14% of patients taking a placebo.

Arena said that patients received echocardiograms after 29 days and that the drug appeared to have no effect on the heart. ADP356 targets the same site in the brain as “fen-phen,” the diet drug combination withdrawn from the market in 1997 because it damaged patients’ heart valves. The site in the brain is believed to control appetite.

Arena believes that its pill is safer because ADP356 does not target a site on the heart as fen-phen did.