UPDATE 1-Novartis further curbs Zelnorm use in U.S.

(Recasts first paragraph; adds reaction, background, company comment, byline)

By Susan Heavey

WASHINGTON, April 2 (Reuters) - Novartis (NOVN.VX)(NVS.N) will further restrict access to its irritable bowel syndrome drug Zelnorm, reserving it for the sickest patients, the company and U.S. health regulators said on Wednesday.

Concerns about a possible link to heart attacks and strokes led the Swiss drugmaker to make a deal last year with the U.S. Food and Drug Administration to provide the drug for a limited number of patients under a special FDA-supervised program.

But the FDA now says Novartis will make Zelnorm available only to patients whose condition is life-threatening or who are so sick they require hospitalization.

The agency said the decision to further curb Zelnorm's use was a voluntary one by the drugmaker. Novartis spokeswoman Lauren Carhart said the drugmaker had "reassessed" the program but could not say why Novartis decided on further limits.

Zelnorm is the only FDA-approved drug to treat patients with irritable bowel syndrome whose main symptom is constipation.

Patient advocate Jeffrey Roberts said the move further burdens patients and doctors who are seeking relief.

He said most Zelnorm patients saw great improvement with the drug and were willing to accept what they saw as a small heart risk. "We believed they pulled the trigger far too quickly on this drug," said Roberts, president of the Irritable Bowel Syndrome Self Help and Support Group.

Irritable bowel syndrome affects the large intestine and causes a host of problems including bloating, abdominal cramping, diarrhea and constipation.

According to the National Institutes of Health, about 20 percent of U.S. adults have the disorder, which ranges in severity but can prevent people from leaving home.

Under the new Zelnorm restrictions, doctors who want the drug for their patients will have to ask the FDA for permission to authorize any shipment from the company.

"FDA may deny authorization, even in life-threatening situations, if available evidence fails to provide a reasonable basis for concluding that Zelnorm may be effective for the intended use, or if exposure to Zelnorm would pose an unreasonable or a significant additional risk to patients," the FDA said in a notice on its Web site.

The agency said it may deny the drug to those who have a history of heart problems, diabetes, obesity, depression or are older than 55, among other criteria.

Novartis pulled Zelnorm from U.S. shelves in early 2007 after clinical trial data suggested a possible heart risk. In July 2007, it began offering the drug under a special program at no cost to treat irritable bowel syndrome in some women younger than 55 who also experienced constipation.

Before the drugmaker halted mainstream use of the drug, Zelnorm brought in $488 million in U.S. sales in 2006. About 500,000 U.S. patients were taking Zelnorm, which had been the company's 12th-biggest selling drug.

Amitiza, a constipation drug marketed by Sucampo Pharmaceuticals Inc (SCMP.O) and Takeda Pharmaceutical Co Ltd (4502.T), is also being studied for irritable bowel syndrome with constipation.

Lotronex, by privately-held Prometheus Laboratories Inc, is approved for women with diarrhea and irritable bowel syndrome. (Reporting by Susan Heavey, editing by Tim Dobbyn)