The Food and Drug Administration (FDA) today announced the approval of Zelnorm tablets (tegaserod maleate). This drug is the first to receive FDA-approval for short-term treatment of women with irritable bowel syndrome (IBS) whose primary bowel symptom is constipation. The safety and effectiveness of Zelnorm in men have not been established.
Zelnorm increases the movement of stools (fecal matter) through the bowels. Zelnorm does not cure IBS, nor does it treat diarrhea-predominant IBS. Zelnorm reduces pain and discomfort in the abdominal area, and reduces bloating and constipation.
FDA based its decision to approve Zelnorm on the results of three randomized, double-blind, placebo-controlled clinical studies each lasting 12 weeks.
During the studies, patients were asked each week to rate their overall well-being, symptoms of abdominal discomfort and pain, and altered bowel habits.
At the end of the third month of the studies, the proportion of patients responding favorably to Zelnorm was greater than the proportion of patients responding to placebo. The differences in response rates for Zelnorm vs. placebo were greater at month 1 than month 3 suggesting efficacy may decrease over time. The efficacy of Zelnorm beyond 12 weeks has not been studied.
The adverse event reported most often in association with Zelnorm compared to placebo was diarrhea (9% of patients receiving Zelnorm compared to 4% of patients receiving placebo). The majority of the patients treated with Zelnorm who reported diarrhea had a single episode. In most cases, diarrhea occurred within the first week of treatment. Typically, diarrhea resolved without patients having to discontinue Zelnorm therapy. The discontinuation rate from the studies due to diarrhea was 1.6%.
In addition, an increase in abdominal surgeries was observed in patients on Zelnorm (0.3%) compared to placebo (0.2%) in the clinical studies. The increase was primarily due to gall bladder removals reported in patients treated with Zelnorm (0.17%) compared to placebo (0.06%). A causal relationship between abdominal surgeries and Zelnorm has not been established.
Today's action follows the recommendation for approval made by FDA's Gastrointestinal Drugs Advisory Committee on June 26, 2000. FDA had required additional efficacy and safety information following that meeting because there were conflicting results in the efficacy studies and outstanding safety questions.
Novartis Pharmaceuticals Corporation of East Hanover, N.J., is the sponsor of the approved New Drug Application (NDA) for Zelnorm.