Rimonabant Ruling Too Cautious?

On Wednesday an advisory panel to the U.S. Food and Drug Administration reached the conclusion that Sanofi-Aventis, the maker of rimonabant, a much hyped and long-awaited weight loss drug, had failed to prove that the drug, sold under the name Acomplia, is safe.

The panel raised concerns about the psychiatric side effects -- such as depression -- of the drug, which works by blocking receptors in the brain that trigger a reward response to activities ranging from eating, to smoking, to using marijuana.

I think rimonabant should win FDA approval, and I think the panel today may have exaggerated the dangers of the drug.

But I should put my opinion in context. First, I don't have a vested interest in the success of this drug. Second, I am generally unenthusiastic about the use of medications to manage weight control. I think the real action is with a healthy diet and regular physical activity. The solution to the urgent problem of epidemic obesity will not come out of a pill bottle.

FDA Too Cautious?

It is in that skeptical context that I still think the panel today may have thrown more cold water on rimonabant than they should have.

Results of a large, international trial called RIO (rimonabant in obesity), published in the most prestigious medical journals, indicate that the drug is effective both for weight loss, and for improving cardiac risk factors. It shows more promise than any drug studied to date, and certainly more than the very few drugs now FDA-approved for weight control. Rimonabant is already on the market in Europe and South America.

I suspect recent high-profile blunders by the FDA have everyone proceeding with more than customary caution. The arthritis drug Vioxx should perhaps never have received FDA approval -- and similar questions have recently been raised about the diabetes drug Avandia. It may be that rimonabant's day in court has come at a time of heightened scrutiny.

I don't expect this drug to work wonders, and I don't challenge its potential to increase the risk of depression, anxiety and sleep disturbances. But the panel today acknowledged that, at worst, the drug may double the risk of these disorders.

That's not trivial, but how great is two times your current risk of depression if you're not depressed? And how much does uncontrolled obesity increase the risk of depression, anxiety and sleep disturbances in comparison?

Balancing Risk and Benefit

All drugs that can do some good can do some harm. Medical decision-making, and FDA decisions, too, should be based on the ratio of likely benefit to potential harm. Based on my review of the scientific studies of rimonabant, that ratio appears favorable.

That doesn't mean the drug is perfect, or perfectly safe. It may be that strict monitoring for depression should be a routine component of rimonabant use. But obesity is not a theoretical danger; it is a clear and present danger for millions of Americans. If rimonabant can help even a small percentage of them, it could do far more good than harm.

In my opinion, medication will make at best a very modest contribution to our ultimate success in turning the tide of epidemic obesity. But for a given individual, an effective drug might make a vitally important difference. Rimonabant could be that drug, and the FDA should give patients the opportunity to find out.

Dr. David Katz is director of the Prevention Research Center at the Yale University School of Medicine and medical contributor to ABC News. Visit his Web site at www.davidkatzmd.com.