The weight-loss drug lorcaserin is safe and not associated with an increased rate of cardiovascular events, according to data presented at the 2018 ESC Congress. Lorcaserin is a selective agonist of the 5-hydroxytryptamine receptor 2C, which is involved in the regulation of appetite. The drug was shown in previous trials to be effective for promoting weight loss and was consequently approved by the FDA in 2012 as an adjunct to a reduced-calorie diet and increased physical activity for long-term weight management. However, other weight-loss drugs have had an adverse cardiovascular risk profile, so the CAMELLIA-TIMI 61 trial was initiated to test the cardiovascular safety and efficacy of lorcaserin.

A total of 12,000 patients who were overweight or obese (BMI ≥27) with established atherosclerotic cardiovascular disease or multiple cardiovascular risk factors were randomly assigned to receive either lorcaserin (10 mg twice daily) or placebo. At 1 year, weight loss of ≥5% had occurred in 38.7% of patients in the lorcaserin group and in 17.4% of patients in the placebo group (OR 3.01, 95% CI 2.74–3.30, P < 0.001).

During follow-up (median 3.3 years), the rate of the primary safety outcome (a composite of cardiovascular death, myocardial infarction, or stroke) was 2.0% and 2.1% per year in each group, respectively (HR 0.99, 95% CI 0.85–1.14, P < 0.001 for noninferiority). The rate of the primary cardiovascular efficacy end point (extended major cardiovascular events) was not significantly different between the two groups (4.1% versus 4.2% per year).

The rates of adverse events were generally similar in both groups; however, more patients in the lorcaserin group than in the placebo group developed serious hypoglycaemia (13 versus 4; P = 0.04). “Liraglutide [a GLP1 receptor agonist] would provide a similar degree of weight loss but a lower risk of diabetes [mellitus],” comment Julie Ingelfinger and Clifford Rosen in an accompanying editorial. Accordingly, they advise that lorcaserin “may be best used on a cautious basis according to the needs of individual patients”.