A new weight loss drug recently approved by an Food and Drug Administration panel has received a mixed response from two Yale professors.
A panel of medical experts voted 20 to 2 last February to approve the diet drug Qnexa, which opens the door for the FDA to approve the drug later this year. But David Katz, an obesity expert and director of the Yale Prevention Research Center, and Silvio Inzucchi, a professor of endocrinology, expressed reservations about the ruling, citing weight loss drugs’ notoriously poor history.
Katz said he generally agreed with the panel, noting the drug helped patients lose a modest amount of weight — roughly 10 percent — more than a placebo. But he questioned the ultimate value of drugs in solving the problem of obesity, particularly because of their side effects.
“It’s not that they don’t work,” he said, “but when they do work, there’s hell to pay.” He cited the drug rimonabant, which decreased appetite but also resulted in increased risk for depression and suicide.
Izzuchi also said that drugs like simbutramine and fen-phen were pulled from the market because of their association with cardiovascular problems.
In 2010, the same FDA panel rejected Qnexa over concerns about the drug’s potential cardiovascular risks.
But the drug came up for approval again this year after a new study assessed the risk. In the trial, patients experienced improvements in blood pressure, but also saw a mild increase in heart rate, which is linked with a risk for heart attack or stroke.
Katz said the drug might be worth the risk of cardiovascular issues for patients with extreme weight problems.
“Everything in medicine is about risk benefit pay-offs,” he said. “About the only thing that works for serious obesity is anatomy-altering surgery.”
Inzucchi also said that there is a shortage of obesity treatments for severe cases, explaining that a weight loss drug would help fill the large gap between traditional diet and exercise routines and expensive, complicated bariatric surgery.
But both men agreed that no weight loss drug is a magic bullet. Katz said that the very idea of a diet pill goes against the grain of our metabolic systems, which are designed to help us survive when calories are scarce.
Elaine Morrato, who sat on the panel in both 2010 and 2012 when it examined Qnexa, defended her decision to vote for approval.
“It had a better characterization of the risk, and it had a better risk management program,” she said. She also emphasized that the drug’s proponents had a fuller plan for education about its appropriate use, all of which explains why the panel ultimately approved Qnexa, among other drugs being considered.
She said the drug would be limited to seriously obese individuals, for whom the benefits outweigh the risks and other options short of surgery, such as dieting and exercise, would not suffice.
The FDA is not required to follow the advice of its expert panels, though it typically does. A final decision on Qnexa is expected by April 17.