Novartis Yanks Zelnorm

"The number of patients who suffered a heart attack, stroke or severe heart chest pain that can turn into a heart attack was small," the FDA said. "However, patients treated with Zelnorm had a higher chance of having any of these serious and life-threatening side effects than did those who were treated with a sugar pill."

The key issue is the concept of relative risk. The FDA said the analysis shows that 13 Zelnorm patients, or 0.1%, had "serious and life-threatening cardiovascular side effects." One of them died. Among the placebo patients, only one, or 0.01%, "had symptoms suggesting the beginning of a stroke that went away without complication."

Those results were enough to prompt the agency to issue a public health advisory. The FDA has told Novartis it would be willing to consider "limited re-introduction" of Zelnorm "if a population of patients can be identified in whom the benefits of the drug outweigh the risks."

However, any revival of Zelnorm would require review by a panel of outside experts convened by the FDA.