Filed at 7:48 p.m. ET
WASHINGTON (AP) -- Women who suffer constipation-causing irritable bowel syndrome won their first government-approved treatment Wednesday. But while its maker predicts Zelnorm will prove a blockbuster, a critic contends health authorities should not have let it be sold.
Zelnorm's approval comes just weeks after the Food and Drug Administration let another controversial bowel drug, Lotronex, back on the market, two years after serious side effects halted its sales.
The two drugs are for different types of irritable bowel syndrome, a mysterious disorder that gives millions of Americans, mostly women, abdominal pain and either severe diarrhea or constipation or both. Lotronex is for the diarrhea type, while Zelnorm on Wednesday became the only FDA-approved therapy for women with constipation-predominant IBS.
Until now, these women could try laxatives, but they did not relieve the cause of IBS. Zelnorm appears to go a step further, acting on nerve cells to speed the colon's movement of stools.
It is far from a cure. In studies, patients fared only a little better -- 5 percent to 11 percent better -- when taking Zelnorm than when taking dummy pills.
It has not been studied in men, and seems to work best the first month before its effects wane after three months of treatment, the FDA concluded.
Still, the government was on track to approve Zelnorm a year ago when instead it abruptly halted, citing concern about an increase in gall bladder and other abdominal operations among patients testing the drug. European regulators raised similar concerns.
On Wednesday, the FDA reversed course and approved Zelnorm's sale, saying the extra surgeries so far appear to be coincidence.
To be sure, the FDA ordered Zelnorm maker Novartis to study how patients fare as sales begin, and pledged to closely monitor any reports of side effects.
``We're all very interested in looking at this to make sure it doesn't turn out to be something unwanted,'' said Dr. Joyce Korvick, FDA's deputy director of gastrointestinal drugs.
A consumer advocacy group attacked the FDA's decision, saying officials were ignoring early signals of Zelnorm risks just as the agency two years ago downplayed a few bowel inflammations and other complaints that eventually derailed Lotronex.
``It's another serious, reckless mistake for the FDA,'' said Dr. Sidney Wolfe of the advocacy group Public Citizen. He contends there is no proof Zelnorm relieves constipation better than laxatives such as Metamucil.
Wolfe said potential Zelnorm users should know not only about the surgery issue -- nine operations among 2,965 Zelnorm users versus three among 1,740 women who got dummy pills -- but also that Zelnorm may cause or worsen ovarian cysts. Studies show Zelnorm can cause such cysts in animals, and a few Zelnorm users have them, too, he said.
The FDA's Korvick said most of those women had cysts when they started taking Zelnorm, but she acknowledged no one knows if the drug worsened them.
``I thought the drug got a clean bill of health,'' added Jeff Roberts of the IBS Self Help Group, a patient group that has pushed the FDA to approve treatments for the illness. He said some U.S. patients already are buying Zelnorm abroad, unwilling to await the FDA approval.
Novartis says its research accounted for Zelnorm users who also swallowed laxatives, and concluded that Zelnorm added benefit, particularly in relieving pain.
While that benefit appears small on paper, most patients do say they feel better, an important consideration, added gastroenterologist Dr. Susan Lucak of Columbia University, a Novartis consultant.
Novartis said sales should begin in early fall. Novartis has estimated Zelnorm will generate $1 billion in annual sales; it refused to release the actual price but suggested the tablets will be ``in the range'' of $3 to $4 each. Patients would generally take two a day.
Novartis is working with European regulators to determine what additional testing will be needed before Zelnorm can sell there, a spokeswoman said.