In an interview with Reuters Health ahead of the meeting, lead investigator Dr. Vidhu Bansal of GlaxoSmithKline Consumer Healthcare told Reuters Health, these studies show that orlistat 60 milligrams "is an excellent candidate for over-the-counter (OTC) use for weight loss."

Orlistat 60 milligrams, which will be marketed as Alli (pronounced AL-eye) is a low-dose version of GlaxoSmithKline's prescription drug Xenical (orlistat 120 mg capsules). It is currently under review at the U.S. Food and Drug Administration.

Orlistat blocks absorption of approximately 25 percent of fat consumed and would be indicated for use in people "18 years of age and older who are overweight and committed to losing weight and making the dietary changes that will be needed to be successful," Bansal told Reuters Health.

The three studies reported at the meeting involved a total of 1,729 overweight subjects who were placed on a reduced calorie diet (30 percent fat, 20 percent protein, 50 percent carbohydrate) alone (the control arm) or in combination with 60 milligrams orlistat.

At 6 months, almost 50 percent of orlistat-treated subjects had lost 5 percent or more of their baseline body weight, compared with 26 percent of subjects following a reduced calorie diet alone.

At 1 year, 45 percent of the orlistat group lost at least 5 percent of their body weight compared to 29 percent of the control arm.

Orlistat users also showed decreases in total cholesterol, "bad" LDL cholesterol and blood pressure.

"There was about a 6 percent reduction in LDL cholesterol with orlistat compared to a reduction of about 1.5 percent in the placebo group," Bansal said.

"There was about a 4 percent decrease for systolic and diastolic blood pressure with orlistat, whereas in the placebo group the systolic blood pressure was reduced by about 1.5 percent and diastolic blood pressure rose slightly," she added.

These data "provide the assurance" that low-dose orlistat does not increase cholesterol or blood pressure and "in fact provides an improvement in the lipid and blood pressure profile.

The data also show that patients tolerate 60 mg orlistat better than 120 mg. "Only 3 percent of people stopped taking 60 mg orlistat because of a gastrointestinal treatment-related side effects compared with 5.4 percent in prior studies of people taking the 120 mg dose," Bansal said. GI effects are mostly loose, oily stools, and urgency, which subside with time.