The Year of the Diet Pill

New drug approvals sometimes come in class-specific clusters, as drug makers competing for the same indication race to get to market first. In the US, the year 2011 was notable for approvals of drugs to treat hepatitis C. Merck’s protease inhibitor, Victrelis (boceprevir), was the first in its class to be approved in May 2011, followed later that month by Incivek (telaprevir) from Vertex Pharmaceuticals. Both compounds promised substantially greater benefit than previously available therapies, and touched off a wave of acquisitions as companies such as Gilead and BMS sought to add hepatitis C treatments to their portfolio of products.

This year appears to be the year of the diet pill. In June, FDA approved a weight-loss pill for the first time in more than 10 years, with a second approval following in July. Belviq (lorcaserin hydrochloride), a serotonin 2C agonist developed by Arena Pharmaceuticals, was approved on Jun. 27, 2012 and Vivus’s Qsymia (phentermine and topiramate extended-release) was approved on Jul. 17, 2012. Both drugs are indicated for overweight or obese adults who also have at least one weight-related condition such as hypertension or diabetes.

Both drugs faced intense safety scrutiny on their way to approval, and both manufacturers are required to perform an extensive set of postmarketing safety studies to monitor, among other things, cardiovascular risk. With respect to weight-loss drugs, FDA’s risk-benefit analysis had to take into account not only the risks posed by these drugs, but also the prevalence of obesity and obesity-related diseases and the fact that few treatment options are available apart from diet and exercise and bariatric surgery. The danger, of course, is that the drugs will be irresponsibly prescribed and not used as intended, which is as an adjunct to diet and exercise. Weight-loss experts caution that there’s no such thing as a magic pill, but there are always those willing to believe in magic.