A half-strength version of prescription diet drug Xenical (orlistat) -- when taken in combination with a reduced-calorie diet -- can provide meaningful weight loss and improve cholesterol and blood pressure levels in obese individuals, according to a study presented at the 2006 International Congress on Obesity.

The report was presented by Vidhu Bansal, Director of Medical Affairs for GlaxoSmithKline Consumer Healthcare, which currently is seeking U.S. Food and Drug Administration approval to market a 60 mg version of Xenical without a prescription under the trade name Alli (pronounced AL-eye).

If approved by the FDA, Alli would become the only FDA-approved weight loss medication available over-the-counter.

Bansai said three clinical studies involving 1,729 participants showed that in conjunction with a reduced-calorie diet, low-dose orlistat resulted in greater weight loss and reductions in BMI scores and waist-to-hip ratios when compared to diet alone.

At both 6 months and 12 months, significantly more low-dose users lost 5 percent or more of their baseline body weight compared to the diet alone group, he reported. He said low-dose orlistat users also showed decreases in total cholesterol, LDL (bad) cholesterol, and systolic and diastolic blood pressure levels.

"These findings provide further support that a lower dose of orlistat can not only effectively help individuals lose weight, but reduce risk factors associated with co-morbid diseases and improve health overall," Bansai added.

Orlistat prevents the absorption of approximately 25 percent of the fat consumed.

Since its introduction in 1999, Xenical has failed to achieve the sales originally expected, in large part because as undigested fat passes through the body, users often experience gastrointestinal effects such as oily spotting, gas with discharge, fecal urgency, fatty/oily stools and frequent bowel movements.

GlaxoSmithKline's hope is that users of low-dose orlistat will be less likely to experience these side effects.

In these studies, Bansai reported that only 3.2 percent of participants in the low-dose group dropped out of the studies as a result of gastrointestinal treatment effects compared to 5.4 percent in the prescription-strength group.