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New Drug for Irritable Bowel Syndrome Raises Safety Concerns, May Not Be Effective

March 22, 2001

New Drug for Irritable Bowel Syndrome Raises Safety Concerns,
May Not Be Effective

Public Citizen Petitions FDA to Stop Drug From Reaching Market

WASHINGTON, D.C. ? A prescription drug that is on the verge of being approved by the Food and Drug Administration (FDA) should not be allowed on the market because it raises serious safety concerns and may not be effective, Public Citizen said today.

The drug, tegaserod (called Zelmac by its maker, Novartis Pharmaceuticals) is designed to treat constipation-predominant Irritable Bowel Syndrome (IBS). However, the drug was associated with a three-fold increase in the rate of ovarian cysts in women in clinical trials compared to a placebo. Five women were hospitalized and had surgery, Public Citizen noted in a petition to the director of FDA?s Center for Drug Evaluation and Research, Janet Woodcock. Studies in rats also showed that the drug unequivocally causes ovarian cysts.

Further, it is unclear if the drug is effective, the petition notes. None of the three pivotal trials demonstrated efficacy according to the original protocol. Even after Novartis altered the parameters of the trial, lowering the threshold for efficacy, just one of the two remaining trials showed some efficacy, and that was modest. And while tegaserod is to be marketed for constipation-predominant IBS, many of the patients in the trials were not constipated, the petition says.

“The FDA would be foolhardy to approve this drug,” said Dr. Peter Lurie, deputy director of Public Citizen?s Health Research Group. “Irritable bowel syndrome is not a life-threatening condition. The risks of letting this drug on the market are simply not worth the benefits, if any exist.”

Added Dr. Elizabeth Barbehenn, research analyst with Public Citizen, “If the FDA approves this drug, it may well have to be withdrawn because of the high probability of seeing more cases of ovarian cysts once the drug reaches the less-carefully monitored and less healthy population at large.”

The petition reminds the FDA of Lotronex, a drug that also was designed to treat IBS (diarrhea-predominant type) but had to be pulled from the market shortly after being approved because of serious adverse effects also known prior to approval.