When combined with a low-calorie diet, exercise and behavioral therapy, treatment with Xenical significantly improves weight management for obese teenagers, new research shows.

Used alone, behavioral modification seldom leads to sustained weight loss in obese adolescents, according to the report in this week’s Journal of the American Medical Association. So there is a need for other strategies to promote weight loss, the investigators say.

Xenical, known generically as orlistat, produces weight loss by markedly reducing fat absorption in the intestines. The drug has a good safety profile and it is currently approved for use in obese and overweight adults, Dr. Jean-Pierre Chanoine, from the British Columbia Children’s Hospital in Vancouver, and colleagues note.

Chanoine’s group assessed the weight-related outcomes of 539 obese teens who were randomly assigned to treatment with orlistat or an inactive placebo. All the participants also followed a low-calorie diet, exercised, and got behavioral therapy for 1 year.

One hundred seventeen subjects in the placebo group and 232 in the orlistat group completed the study, but 180 and 348 subjects in the two groups, respectively, were included in the analysis.

Both groups experienced a drop in body mass index (BMI, a measure of weight in relation to height) up to week 12.

After that point, the average BMI held steady in the orlistat group whereas the BMI of the control group increased to levels higher than at the start of the study.

At one year, BMI had dropped by 0.55 in the orlistat group, while it had increased by 0.31 in the control group.

The percentage of patients experiencing a reduction in BMI of at least 5 percent or 10 percent was significantly higher in the orlistat group, the researchers report.

Gastrointestinal side effects, such as passage of fatty or oily stool and abdominal pain, were more common in the orlistat group, but were typically mild in nature.

In a related editorial, Dr. Alain Joffe, from Johns Hopkins University in Baltimore, comments that the researchers “have made a valuable contribution” to the topic of adolescent obesity. “However, much more data are needed on the long-term benefits and risks of orlistat therapy (and other pharmacologic therapies) administered in a variety of treatment settings.”

SOURCE: Journal of the American Medical Association, June 15, 2005.