Post-marketing study data on the weight management drug lorcaserin (Belviq, Belviq XR) .
The drug safety communication warned that the mechanism isn't clear and it's not certain that the link is causal. Moreover, the announcement didn't quantify the increased risk. The agency's review is still underway as it continues to evaluate clinical trial results.
Meanwhile, FDA didn't call for patients to stop taking lorcaserin. Rather it suggested shared decision making. "Health care professionals should consider if the benefits of taking lorcaserin are likely to exceed the potential risks when deciding whether to prescribe or continue patients on lorcaserin."
Lorcaserin was approved in 2012 -- as an adjunct to diet and exercise for those with a BMI of 30 or more, or a BMI of 27 with obesity-related comorbidities -- after a rocky start with the FDA. Its first application was rejected by the FDA over a need for more safety data. The second time around, the FDA advisory panel was concerned about lack of data to rule out heart valve issues.
However, the CAMELLIA-TIMI-61 post-marketing trial specifically powered to look at cardiovascular outcomes with 5 years of lorcaserin use turned up no excess major adverse cardiovascular event risk and even a reduced risk of new-onset type 2 diabetes among those with prediabetes at baseline.
While cancer risk was not initially noted as an issue in that approximately 12,000-patient trial, FDA said that is where it noted the compared with the placebo group.
Some rat studies had suggested "mammary gland tumors in both sexes at clinically relevant exposures" and other tumor types in male rats at higher doses, according to an from 2012. But "[o]verall, malignancies were seen infrequently in the Phase 3 program. No formal cancer screening was conducted," it said, and the advisory committee "in general agreed that there is a sufficient safety margin for the drug when it is used at the concentrations intended for patients."