In February, the manufacturer of the weight-loss medication lorcaserin (Belviq, Belviq XR) voluntarily withdrew the drug from the US market at the request of the FDA. This was a result of emerging data showing that people who had taken the drug as part of a large clinical trial had an increased occurrence of cancer five years later.
What were the findings about Belviq, and why did this information come to light now?
Lorcaserin was approved by the FDA in 2012. As part of the approval process, the FDA reviewed a series of clinical trials that looked at its effects on weight and its safety profile, compared to a placebo.
Based on these studies, the drug was approved, but a larger study to assess its cardiovascular safety was mandated by the FDA. In that subsequent study, published in the New England Journal of Medicine, 12,000 people with overweight or obesity and cardiovascular disease (CVD) or risk factors for CVD took either lorcaserin or a placebo. During the three-year follow-up, as published in 2018, those who took lorcaserin had more weight loss and comparable rates of cardiovascular events compared to those who took a placebo. So from a cardiovascular safety perspective, the study was reassuring.
But the study subjects continued to be followed, and what recently came to light is that at five years, the group that took the drug has had a slight increase in the occurrence of cancers compared to those who took a placebo (7.7% of lorcaserin subjects developed cancer, compared to 7.1% in the placebo group). Increases in several different types of cancers were observed, including pancreatic, colorectal, and lung.
Where does the recall leave people who are currently taking Belviq?
Based on the evidence we have now, it is still uncertain whether lorcaserin truly increases the risk of cancer. And we don’t know anything about the mechanisms of how this drug could have such effects. It is also critical to reiterate that this possible increase in cancer occurrence is very small; 7.1% of people developed cancer if they were taking placebo, and 7.7% if they were taking lorcaserin.
That said, people taking lorcaserin are advised to stop taking it and contact the doctor who prescribed it for guidance on next steps. The FDA is not recommending any special cancer screening or other testing at this time.
Could my doctor prescribe a different weight-loss medication?
Loracaserin is one of several medications currently FDA-approved for weight loss in people who have overweight with weight-related medical issues, or w