Ahead of its results presentation today, GlaxoSmithKline’s consumer health arm was feeling cheery after the US Food and Drug Administration gave it a big thumbs up to sell its anti-obesity agent orlistat as an over-the-counter treatment – the first prescription product to be given a green light for OTC use.

The drug, which will be sold OTC as Alli, is a lower dose version of the prescription product Xenical, which has been marketed in the USA by Roche since 1999 and works by preventing fat absorption in the intestine. Initially sales of Xenical failed to take off to the extent Roche had hoped with patients complaining of oily stools and faecal urgency but the Swiss giant – and now its OTC and US prescription partner GSK – are stressing the need to combine orlistat treatment with a low-fat diet to prevent such unpleasant reactions. “Alli is not for everyone, it’s for the committed consumer who can follow a reduced calorie low fat diet,” GSK explained in a statement.

A launch is scheduled for the summer with a major pre-market awareness programme being put into place. A staggering 65% of US adults are either overweight or obese, according to National Institutes of Health data, a condition that’s associated with long-term health complications such as cardiovascular disease and type 2 diabetes – as well as being a major financial burden on national health systems.

"We know that being overweight has many adverse consequences, including an increase in the risk of heart disease and type 2 diabetes," said Dr Douglas Throckmorton, Deputy Director for FDA's Center for Drug Evaluation and Research. "OTC orlistat, along with diet and exercise, may aid overweight adults who seek to lose excess weight to improve their health."

Major market opportunity

GSK secured an approvable letter from the drug agency in April last year and had originally hoped for a market introduction before the end of 2006 after certain questions put forward by the FDA had been answered. Clearly, these timelines have dragged on slightly, but GSK will likely be cheered at the thought of the immense market potential for the product: 2004 estimates put the weight control market at over $39 billion.

Backed with clinical trial data that shows it can lead to weight loss of 5 to 6 pounds over six months, Alli could quickly become a leading brand with sales of more than $1 billion, according to analysts.

GSK has previously said it plans to make Alli available at a cost of around $12 to $15 a week, and expects could be used by 5 to 6 million consumers, which would bring in sales of $1.5 billion or more.