FDA Approves Diet Drug for the Obese
The Food and Drug Administration on Monday approved a new diet drug for the seriously obese, the first of a new class of diet drugs that works by blocking the body’s absorption of fat, rather than by suppressing the appetite.
The drug, Xenical, developed by Hoffmann-LaRoche Inc., of Nutley, N.J., is part of a category of drugs known as lipase inhibitors because they prevent the body from producing lipase, an enzyme necessary for the breakdown of fat molecules. The drug--also known by its chemical name, orlistat--prevents about 30% of fat that is eaten from being absorbed in the gastrointestinal tract.
The agency approved Xenical only by prescription for the seriously obese--typically people 40 or more pounds overweight.
“The drug works in the gastrointestinal tract, not in the brain,” said John Foreyt, director of the nutrition research clinic at Baylor College of Medicine in Houston, who has studied the drug. “It really works. . . . But it’s not for the person who is trying to lose 10 pounds. It is for the obese--the person whose weight is interfering with his or her health.”
Federal health officials estimate that nearly 100 million Americans are overweight, and more than half of them are obese. Obesity is regarded as a serious health problem in this country, contributing to high blood pressure, high cholesterol and diabetes, among other things.
Xenical appears to work best in patients who already follow a low-fat diet because the drug only eliminates less than one-third of all the fat consumed.
In fact, patients taking the drug will be advised to stick to a reduced-calorie diet, containing no more than 30% of calories from fat. Clinical trials showed that most Xenical-treated patients experienced an average weight loss ranging from 5% to 10% of initial body weight over one year.
The FDA was poised months ago to license the drug, but had lingering concerns because clinical studies had found a higher-than-expected number of breast cancer cases among women who participated.
The FDA asked the company to test another group of women, and the data on breast cancer cases were encouraging. “We saw more cases in the placebo group than in those taking orlistat,” said Dr. Eric Coleman, the FDA medical officer who reviewed the data.
The drug’s only major side effect is gastrointestinal symptoms, such as loose stools--the result of undigested fat--which will probably discourage physicians from prescribing the drug to those only seeking to slim down a few pounds. Although the drug was approved only for the seriously overweight, once a drug is licensed, physicians can prescribe it to anyone they choose.
“It’s a good drug, but those who approach it with a sense of the trivial, or who see it as a magic pill, will be disappointed,” said Dr. Arthur Frank, medical director of the George Washington University weight management program. “They might see it as an easy way to lose weight, but it does not shift the responsibility. If you are not careful, you will have some awkward, unpleasant--even catastrophic--gastrointestinal symptoms.”
Xenical should reach the market in about three weeks. Once patients stop taking the drug, they must continue to eat a low-fat diet or they will regain the weight, experts said.
“We tested the drug for two years and people were able to lose weight and keep it off over the two years,” Foreyt said. “If they keep eating the way they were eating while they were on the drug, their weight will remain stable. But if they go back to their old ways of eating, they will put the weight right back on.”
The drug has been viewed as another strong successor to the once popular combination known as fen-phen, which all but ended when one of the two drugs and another, separate diet drug were pulled from the market last September after being linked to potentially life-threatening heart valve problems.
