A Baker's Dozen Classes of Drugs for Diabetes

Lorcaserin, brand name Belviq, is a selective 5-HT2C receptor agonist. It affects receptors that influence feeding behaviors. The drug was approved by the FDA in 2012 as a "prescription weight-loss medication that, when used with diet and exercise, can help some overweight adults with a weight-related medical problem, or obese adults, lose weight and keep it off."

It has some worrisome side effects: in combination with other drugs, it can cause something called "Serotonin Syndrome or Neuroleptic Malignant Syndrome (NMS)-like reactions." And it's been associated with valvular heart disease, changes in attention and memory, "mental problems" including hallucinations, depression or suicidal thoughts, hypoglycemia in people with type 2 diabetes on insulin or sulfonylureas, painful erections, slow heartbeat, decreased red and white blood cell counts, increase of a hormone called prolactin, and other effects.

One of the studies the manufacturer has done was a one-year study in overweight/obese people with T2D (body mass index of 27 to 45 kg/m2) who were taking one or more oral anti-hyperglycemic drugs. PWD who were on insulin in any form, exenatide (Byetta) or pramlintide (Symlin) within 3 months prior to screening were excluded from the study. The study's name, as usual, was a cute acronym: "BLOOM-DM" (Behavioral Modification and Lorcaserin for Overweight and Obesity Management in Diabetes Mellitus).

604 patients with T2D and A1C levels between 7 and 10 were enrolled. All were on a program of diet and exercise; some were randomized to lorcaserin in two different doses, and others to placebo. As expected for a weight-loss drug, more patients lost =5% body weight with lorcaserin compared to those taking placebo. Of note, A1C decreased more with lorcaserin than with placebo; fasting glucose also decreased more. Symptomatic hypoglycemia occurred in about 10% on lorcaserin, compared to about 6% on placebo. The authors concluded that "Lorcaserin was associated with significant weight loss and improvement in glycemic control in patients with type 2 diabetes."

No big surprise, assuming that those who lost weight were the same folks who had lowered A1C and glucose levels -- losing weight is a good idea for overweight people with T2D. But it also was nice to see in a post-hoc analysis that those patients who used lorcaserin and were considered "responders" also needed fewer of the same number of diabetes medications at week 52 compared with baseline, when compared to the placebo group. And the authors added that “glycemic control was substantially improved despite minimal weight loss in lorcaserin non-responders.”

Sounds like the manufacturer is going for an indication for use in type 2 diabetes. Currently, it's approved as a weight loss drug only. But adding an indication to use it in overweight and obese people with T2D would certainly add to the company's bottom line, as well as adding yet another class of diabetes drugs. (As of now, there are a dozen classes of diabetes drugs: See Eleven classes of diabetes drugs and Another class of diabetes drugs for a review of what's available already.) And there's nothing to stop the practicing physician or NP or PA from writing a prescription for it now for diabetes control, as it's already on the market -- although technically it would be "off-label" to prescribe it simply for diabetes.