Orlistat Helps Obese Patients Lose Weight

A two-year study of nearly 900 obese patients has shown that the drug orlistat (XenicalTM), in combination with a moderate-calorie diet, promotes weight loss, helps prevent weight regain, and produces other health benefits.

Results of the study conducted at Baylor College of Medicine and 17 other research centers nationwide, are published in the Jan. 20 issue of the Journal of the American Medical Association (JAMA).

"We are extremely encouraged by the outcome of this research, which was the largest and longest of any double-blind, placebo-controlled U.S. trials to test the effectiveness of a weight-loss medication in obese patients," says Dr. John Foreyt, principal investigator for the Baylor site.

Orlistat, which has not been approved by the Food and Drug Administration, is a "fat blocker." Unlike obesity drugs that manipulate the brain to decrease appetite, orlistat prevents about one-third of fat consumed during a meal from being digested so that the body will not absorb it.

Participants in the study had to be at least 30 pounds overweight. They were randomly assigned to receive orlistat or a placebo.

During the first year of the study, all participants were confined to a low-calorie diet. Those receiving orlistat lost 8.8 percent of body fat; the placebo group lost only 5.8 percent. At the end of the first year, 65.7 percent of the orlistat group lost more than 5 percent of their initial body weight, compared to 43.6 percent of the placebo group. Almost 39 percent of the participants who received orlistat lost more than 10 percent of their initial body weight, compared to nearly 25 percent of those who were given the placebo.

During the second year, participants were placed on a moderate calorie diet to see if they could maintain their weight loss. Participants given 120 milligrams of orlistat regained 32 percent of their lost weight; participants given 60 milligrams of orlistat regained 51.3 percent; and the placebo group regained 63.4 percent of their lost weight.

Patients who were treated with 120 milligrams of orlistat throughout the two years lost 7.6 percent of their initial body weight by the end of the study, while those given a placebo showed only a 4.2 percent loss throughout the two years.

In addition to weight loss, orlistat significantly reduced total cholesterol, low-density lipoprotein (LDL) cholesterol, the ratio of LDL to high-density lipoproteins, glucose, insulin, and blood-pressure levels.

Throughout the study, orlistat was well-tolerated by participants. The most common adverse reactions were intestinal, reported by 79 percent of the orlistat group and 59 percent of the patients given a placebo.

"This study is definitely good news for obese people who have difficulty regulating the amount of fat in their diet and whose weight is interfering with their health," says Dr. Foreyt, professor of medicine and director of the Behavioral Medicine Research Center at Baylor. "Study participants also had to exercise, which serves as a reminder that an effective weight-loss program cannot rely on medication and diet alone."

The research was funded by Hoffmann-La Roche, manufacturer of orlistat.

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©2006 Texas Medical Center

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