Weight-loss drug withdrawal latest blow to obesity fight
Saturday, October 9, 2010; 12:11 AM
The withdrawal of the diet drug Meridia on Friday marks the latest setback in the long, frustrating quest for a pharmaceutical solution to the nation's obesity epidemic.
Despite millions of dollars in research by scientists and drug companies, only a handful of government-approved weight-loss drugs remain on the market. Only one can be used long term, and none is considered very effective.
"It's been very frustrating," said Jennifer Lovejoy, incoming president of the Obesity Society, a research and advocacy group. "We desperately need safe new drugs so we can begin to have something effective against this public health epidemic."
The search for a weight loss cure, once dismissed as a cosmetic luxury, has intensified as more than two-thirds of Americans have become overweight, including one-third who are obese, boosting their risk for a host of health problems.
Experts stress that the best way to be healthy is to eat well and exercise regularly and to avoid gaining weight in the first place - and the failure to produce a pharmaceutical magic bullet makes the importance of that ever clearer. Doctors recommend that people always try to improve their eating habits and increase their physical activity to lose weight. But diets and exercise regimens often fail, and many people are unable to shed significant numbers of pounds or keep them off, so they resort to drugs or even surgery.
The effort to develop safe and effective weight-loss drugs, however, has suffered one setback after another. Part of the problem has been scientific, experts say. The body's hunger, fat storage and energy-burning system has turned out to be far more complex than originally thought.
"It's got lots of fail-safes and mechanisms in it," said Donna H. Ryan of the Pennington Biomedical Research Center in Baton Rouge. "Our biology is really designed to promote food intake and prevent weight loss. Our genes evolved to defend against starvation."
But some experts argue that obesity drugs are held to too high a standard and should be treated like medications for other chronic diseases, such as diabetes, and approved and allowed to remain on the market even if they have some risks.
"The criteria seem to be more strenuous to get a drug approved for obesity than it does for other chronic conditions," said George Blackburn, director of the division of nutrition at Harvard Medical School. "It's a real hardship for millions of Americans who are asked to live in an environment which is very difficult for them to restrain their eating."
Part of that, some experts argue, is because of a bias against obese people.
"The attitude is all people have to do is eat less and exercise more and that's going to be the solution to the problem," Ryan said. "That's a failure to understand the complex nature of what is essentially a complex disease."
The most stunning disappointment came 13 years ago, when the widely popular "fen-phen" two-drug combination was pulled off the market after being linked to heart-valve damage and to a rare but potentially deadly lung disease. Since then, a parade of major drug companies has abandoned once-promising diet drugs, most notably Sanofi-Aventis, which finally gave up on Acomplia after it was linked to depression.
In recent weeks, a panel of Food and Drug Administration advisers recommended against approval of two experimental weight-loss drugs, lorcaserin made by Arena Pharmaceuticals Inc. and Qnexa from Vivus Inc.
The last diet drug to win FDA approval was Orlistat in 1999, which was authorized for over-the-counter use in 2007 at a lower dose. But it is not very effective and can cause unpleasant side effects, most notably diarrhea.
Meridia, or sibutramine, was approved in November 1997 based on studies that showed the drug could help people lose at least 5 percent of their weight compared with people who took a placebo and relied on diet and exercise alone. But safety advocates have long called for the drug's withdrawal, citing concerns that it raised blood pressure.
Those concerns spiked earlier this year with the results of a European study that found Meridia increased by 16 percent the risk of serious heart problems, including heart attacks, strokes and death. The drug led only to a small weight loss, the study found.
Abbott Laboratories withdrew Meridia for sale in the United States at the request of the FDA, which concluded that the drug's power to help people lose a small amount of weight was far outweighed by new data showing it carried significant risks. Canadian drug officials announced a similar withdrawal.
About 100,000 Americans take Meridia, the FDA estimated. All should immediately stop and doctors should cease prescribing it, the agency said. Patients who have taken the drug in the past should no longer face increased risk after they discontinue the medication, officials said.
Drug safety advocates welcomed Meridia's withdrawal, arguing that it should have come far sooner and that the lag illustrated the FDA's lax enforcement of drug safety, especially compared with European regulators. Meridia was taken off the market in Europe in January.
Sidney Wolfe of Public Citizen's Health Research Group, which had petitioned the FDA to remove Meridia, noted that while European regulators recently pulled two other drugs - the pain pill Darvon and the long-controversial diabetes drug Avandia - both remain available in the United States.
"Both of these unacceptably dangerous drugs remain on the market in this country, predictably injuring or killing many people, who, unlike their European counterparts, do not have the government protecting them from drugs with no unique benefits but significant, unique risks," Wolfe said.
Meanwhile, in yet more bad news for people trying to lose weight, the FDA also warned Friday against using "Slimming Beauty Bitter Orange Slimming Capsules," an herbal product sold over the Internet, because tests found it contains sibutramine.
Several experts said that the solution will probably come from developing a cocktail of drugs, similar to how cancer and AIDS are treated.
"The solution to the problem is going to be multiple drugs that produce some weight loss, which would enable us to combine them together," Ryan said.