GlaxoSmithKline has sold off the US rights to its irritable bowel syndrome drug Lotronex to Prometheus Laboratories, which will continue to distribute the treatment through a restricted use programme across the Atlantic.

Lotronex (alosetron) was withdrawn from the US market in 2000 after less than one year on the market following reports of ischaemic colitis and severe constipation, including three fatalities. GSK re-introduced the drug two years later, but under a specific “Prescribing Program”, which entails restricted use.

Under the terms of the deal, the financial details for which were not disclosed, Prometheus has acquired the exclusive rights to Lotronex, which is the only prescription drug approved by the US Food and Drug Administration for use in female patients with severe diarrhoea-predominant IBS who meet the conditions stated in the label. It will market and sell Lotronex under a distribution agreement until the acquisition is completed, which is expected in January.

The drug will still be sold exclusively through the Prescribing Program and scrips can only be written by doctors enrolled in the plan. Given the restrictions placed on it, Lotronex is unsurprisingly not a big earner for GSK and sales last year were $14 million.

Still Prometheus thinks it can add to that figure and chief executive Joseph Limber said that "Lotronex fits well with our long-term plans to grow through acquisitions of meaningful therapeutic products”. Stan Hull, senior vice president of US pharmaceuticals at GSK, added that Prometheus “is ideally positioned with their strong franchise and relationships with gastroenterologists to market Lotronex and to educate patients and physicians on its proper use”.

According to the American Gastroenterology Association, IBS affects more than 58 million people and 80% of them are sufferers. However controversy has surrounded the drugs that have been approved to treat the syndrome and recently Novartis’ withdrawn IBS drug Zelnorm (tegaserod) made a return to the US market but only as part of a restricted access programme for women under 55.