While full strength prescription Xenical has been the subject of more than 100 clinical studies including a four-year study, the longest ever of a weight-loss drug, only a single four-month trial has been reported of the low-dose version now seeking approval as an over-the-counter medication.

Glaxo said on February 8, 2007 following FDA approval of alli (pronounced Al-eye) that it intends to conduct further studies of the drug, but said it was not prepared to provide further information at this time.

According to data presented at the 2005 annual meeting of NAASO, The Obesity Society in October 2005, a 60 mg low-dose version of Xenical (orlistat) was found to be safe, effective and tolerable in overweight individuals.

The study, which compared low-dose Xenical plus diet to placebo plus diet in patients with a body mass index (BMI) of 25 to 28, demonstrated a statistically significant difference in weight loss, according to researchers.

Low-dose Xenical patients who completed the four-month treatment period lost 5 percent of their baseline weight and while those who received the placebo plus diet lost 3.3 percent.

The randomized, placebo-controlled, 16-week study was conducted in a primary care setting, offered minimal intervention and was largely self-instructional.

Approximately 36 percent of the low-dose Xenical users and 28 percent of the placebo group (who used diet modifications alone) lost more than five percent of their initial body weight, the researchers reported.

Approximately 57 percent of the low-dose Xenical users, compared to 42 percent of the placebo group, lost more than three percent of their initial body weight, the researchers added.

Low-dose Xenical patients also demonstrated significant decreases in total cholesterol, LDL cholesterol, systolic and diastolic blood pressure, the researchers said. Safety and tolerability of 60 mg orlistat in this population was similar to that observed in previous studies in a more overweight population.