GlaxoWellcome's IBS drug Lotronex (alosetron hydrochloride) has been withdrawn from the US market after just nine months, following reports of five deaths among patients. In all, the Food and Drug Administration, the US's drug regulator, received 70 cases of serious adverse reactions.
Its withdrawal is all the more remarkable as Lotronex was chosen as the first drug to come with a full treatment guide under "patient power" regulation. The guide warned that the principal side effect discovered in trials was constipation.
Hailed as "a promising aid for irritable bowel syndrome" (Drug Infoline, December, 1999), a 12 week trial among 370 IBS sufferers found that the drug was effective among women compared with a placebo.
As well as being a drug intended only for women, it was also only supposed to treat the diarrhoea form of IBS.
Strangely, the trial did not pick up the serious adverse reactions which were soon being reported to the FDA. The reports centred around cases of intestinal damage resulting from reduced blood flow to the intestine, and severely obstructed or ruptured bowels, a complication of severe constipation.
Within four months of its release, six women needed hospital treatment, and three of those underwent surgery, after being on the drug.
By the time GlaxoWellcome agreed to withdraw Lotronex at the end of last November, 34 patients had been treated in hospital, 10 others had undergone surgery, and three had died. Two other deaths were not conclusively linked to the drug.
Dr Sidney Wolfe, of the consumer watchdog group Public Citizen, said that in clinical trials, there had been little difference in effectiveness between Lotronex and placebo.
More worrying, why did the clinical trials not discover the possibly fatal reactions, and what benefit, therefore, are "patient power" leaflets?