Slim Chances for Diet Pills?

New Medications Face Tough Scrutiny

By Tara Hulen

diet pillsPeople looking to lose a little extra padding now have help from two new Food and Drug Administration (FDA)-approved devices (see main story). But obese patients who need to lose serious amounts of weight for their health will not have the assistance of three much-anticipated diet drugs. In October 2010, the FDA rejected initial applications for Qnexa and lorcaserin in the same week, taking these treatment options off the table. In December 2010, a third drug, Contrave, received an endorsement from an FDA panel of experts, but the agency ultimately declined to approve Contrave on January 31, 2011.

These decisions do not necessarily represent the end of the road for any of the three drugs. The FDA asked Contrave’s manufacturer to complete a long-term study of heart attack risk. It requested more information on cardiac effects, risks of birth defects, and marketing issues for Qnexa, and rejected lorcaserin in its current form because it caused tumors in lab rats. Concern over side effects has been an ongoing issue for diet drugs, however. In early October 2010, the manufacturer of the weight-loss drug Meridia withdrew it from the market after 13 years over concerns of heart attack and stroke risk for certain patients.

High Standards

Such examples illustrate a clear need for caution, but the standards for weight-loss drugs are extraordinarily high, say UAB researchers. “The FDA has been very hard on drugs for metabolic diseases in the last year, and so it is very risk-adverse,” says W. Timothy Garvey, M.D., chair of the UAB Department of Nutrition Sciences and a principal investigator in clinical trials of Qnexa; UAB was one of a small group of test sites for the drug.

Garvey recognizes the necessity for caution because “there’s a lot of abuse potential with diet drugs.” He adds that “the FDA has to do its job carefully and assess risks, but consider benefit as well. These drugs, I think, offer a lot of promise for benefit, and there’s a huge clinical need.”

UAB weight-loss expert Jamy Ard, M.D., a member of the advisory board for the company that makes lorcaserin, Arena Pharmaceuticals, says that perceptions often come into play. The attitude that obesity is a lifestyle choice can lead to the misconception that diet pills are just for cosmetic use, akin to elective surgery, rather than life-saving options for people with real weight problems, he explains.

Devices such as cosmetic “fat-zapping” machines get approved with much less scrutiny, Ard says. “The number of studies required for these devices to be approved is a handful, but you have to devote millions and millions of dollars of research on medications to get them approved.”

Serious Need for Diet Drugs

Both Garvey and Ard say that people haven’t gotten used to the idea that obesity is a disease and a major public health issue. “It’s not just because people eat more than they should,” Garvey says. “It’s highly genetically determined, and we as clinicians need medications to treat this disease.”

Ard describes a serious need for diet drugs that are safe for long-term use so that obesity can be treated as a chronic disease, just like high blood pressure. When patients stop taking a helpful weight-control medication, they often gain the weight back despite other efforts, just as high blood pressure might return without drugs to lower it, he says.

Every time a drug is rejected, even temporarily, Garvey worries that it will have a chilling effect on research for obesity drugs—although there is a huge profit potential if they win approval and prove effective. And Garvey is optimistic that new treatments will eventually reach patients. Two of the three drugs now under scrutiny consist of drugs approved to treat other conditions, such as epilepsy and migraine headaches. Garvey says that might make it easier to satisfy FDA requests for more information by using existing data from similar patient populations.

Both researchers stress that responsible physicians will administer diet drugs only in combination with a comprehensive diet, exercise, and support plan. “All of the clinical trials were done with the patient taking the drug in combination with lifestyle intervention and regular physician follow-ups," Garvey says.

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