Belviq: First New Obesity Drug in More than a Decade

Belviq® (lorcaserin) this week becomes the first new drug for obesity on pharmacy shelves in more than a decade. Expectations for Belviq are all over the place, ranging from blockbuster hype to a cautious yawn. We can only hope for some middle ground.

With Belviq, we have the first totally new drug in more than a decade to treat obesity. The active ingredient, lorcaserin, has a mechanism of action that is completely different from anything available before. It selectively activates receptors in the brain — 5HT2C receptors — that control hunger.

The closest thing to lorcaserin’s mechanism of action was dexfenfluramine (brand name Redux), which activated 5HT receptors in a less selective way. The problem with this, of course, was that the less selective mechanism of action meant that dexfenfluramine also activated 5HT2B receptors and caused heart valve problems. It was these problems that led to the drug being withdrawn from the market.

Safety data for Belviq suggest that the more selective mechanism of lorcaserin sidesteps this problem.

Even so, Belviq faces a number of challenges before it can become a solid success. It doesn’t offer miraculous weight loss efficacy, just a solid 5-10% reduction in weight that can significantly improve the health of someone with obesity. Every patient responds differently. Some will see little efficacy and should stop taking it. Some will see a much better effect and really value the benefit it offers.

The other major challenge Belviq faces is one of cost. Bringing a new drug for obesity to market is an expensive proposition and the price of Belviq — $200 per month — reflects that fact. The real problem with cost, though, is the stupid approach that health plan take to covering the cost of obesity treatment, often forcing patients to pay out of pocket for treating obesity and then paying huge bills for the myriad chronic diseases that result from untreated obesity.

The other new product for obesity, Qsymia, combines two drugs — topiramate and phentermine — that have been available separately for some time. And it’s faced these same challenges with sales growing more slowly than people looking for an instant blockbuster would like.

Let’s hope that both extremes of expectations for Belviq — hype and gloom — are wrong. What we need is a solid hit that will add a good tool to the obesity treatment toolbox. Plus, we need wiser health plans that will pay for treating obesity. We can’t afford to keep paying for the chronic diseases that result when you don’t treat it.

Click here to read more in the LA Times, here to read more from Seeking Alpha, and here to read more from USA Today.

Drugs, photograph © Professor Bop / flickr

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