Fat-Fighting Drug Delivers Results in First Human Trial

A closely watched new fat-fighting drug appears to help people lose weight, researchers announced Sunday.

In its first test on human subjects, leptin, a naturally occurring hormone discovered less than four years ago, helped patients lose an average of almost 16 pounds over six months.

Andrew S. Greenberg, an obesity specialist at Tufts University who led the study, cautioned that research on the drug is at a very early stage. The study involved 70 obese and 50 lean subjects, and only 47 obese patients completed the trial.

“There’s potential here, but efficacy has still got to be proved in larger populations,” said Greenberg, who presented the study Sunday at the American Diabetes Assn.’s annual convention in Chicago. Further clinical trials are underway with about 500 patients, he said.

“It’s very encouraging,” said Arthur Frank, head of the obesity management program at George Washington University. “Is it a miracle? No, it’s not a miracle. But it really changes the thinking about the management of obesity.”

Leptin appears promising in part because so far it appears to be safe, with minimal side effects. Subjects in the Greenberg study did have mild side effects. Fifty-six percent of the patients receiving daily injections of leptin reported irritation, hardening of the skin and similar complaints at the injection site.

Leptin was discovered and announced with great fanfare in 1994 by Jeffrey Friedman at Rockefeller University in New York, who identified an “obese gene” in mice and humans. The gene directs cells to make leptin, a protein produced by fat cells that is supposed to signal the brain to stop eating.

Shortly after Friedman’s discovery, Amgen Inc. of Thousand Oaks agreed to pay an estimated $20 million to Rockefeller University and the Hughes Institute for rights to make and sell a product based on leptin.