FDA Issues Cancer Warning Over Weight-Loss Drug Belviq

The Food and Drug Administration (FDA) has warned the weight-loss drug Belviq, and its once-daily formulation Belviq XR, carry a possible increased risk of cancer.

Results from a clinical trial testing the safety of the drug, also known as lorcaserin, revealed "a possible increased risk of cancer," the FDA said in a statement on Tuesday.

The federal agency said: "At this time, the cause of the cancer is uncertain, and we cannot conclude that lorcaserin contributes to the cancer risk. However, we wanted to make the public aware of this potential risk." The FDA is currently reviewing the results of the clinical trial, and plans to publish its final conclusions and recommendations once this process is complete.

"Patients currently taking lorcaserin should talk to their health care professionals about the potential increased risk of cancer with use of lorcaserin," the FDA said. It advised healthcare professionals to consider whether the benefits of taking the medicine outweigh the potential risks when deciding whether to prescribe or keep patients on lorcaserin. Clinicians were also asked to report adverse events or side effects to the FDA's MedWatch Safety Information and Adverse Event Reporting Program.

The FDA asked the manufacturer, Eisai Inc., to carry out a clinical trial to check the drug didn't increase the risk of heart problems. The trial involved around 12,000 participants over a period of five years. At the end of the study, more patients taking the drug were diagnosed with cancer than those who took a placebo, the agency said.

"Our evaluation of this potential signal is ongoing, and at this time it is uncertain if lorcaserin increases the risk of cancer," said the FDA.

Eisai Inc. told Newsweek: "Patient safety is Eisai's priority and we will continue to work closely with the FDA to evaluate the clinical trial results. We recommend patients speak directly with their health care professional in order to make the best decision about their medical treatment. As indicated in the FDA's communication, at this time, the FDA and Eisai cannot conclude that BELVIQ increases the risk of cancer."

Approved in 2012, the weight loss and management medication is prescribed to overweight and obese patients who hare having weight-related medical problems. Patients are advised to stick to a calorie-controlled diet and increase their levels of exercise while using it.

Citing studies involving more than 6,600 patients, Eisai Inc. states on its website that patients who take BELVIQ are three to four times more likely to lose more or equal to 10 percent of their body weight versus a placebo.

In August 2018, the drug was hailed as the "holy grail" in the battle against obesity, after a study published in the New England Journal of Medicine had promising results. But the U.K.'s National Health Service Behind the Headlines service which fact-checks health stories said of the study at the time: "The results in terms of weight loss were modest. Most people taking the drug were still in the overweight or obese category by the end of the study."

"Although this drug may seem like an easy option for weight loss, the participants in this study were supposed to take the drug alongside a diet and exercise plan," it said.

This article has been updated with comment from Eisai Inc..

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