Belviq (lorcaserin) was a prescription medication for chronic weight management. It was approved for adults with obesity (BMI of 30 kg/m² or greater) or those overweight (BMI of 27 kg/m² or greater) with at least one weight-related health condition, such as high blood pressure, elevated cholesterol, or type 2 diabetes.
How the Medication Worked
Belviq targeted specific brain receptors to influence appetite. It acted as a selective agonist of the serotonin 2C (5-HT2C) receptor, primarily in the hypothalamus, which regulates hunger and fullness. Activating these receptors promoted satiety, helping reduce food consumption and aiding weight loss. The drug’s selectivity aimed to minimize off-target effects seen with older serotonergic weight-loss drugs.
Effectiveness for Weight Management
Clinical trials evaluated Belviq’s effectiveness when used alongside a reduced-calorie diet and increased physical activity. Patients who took Belviq achieved modest but meaningful weight loss compared to those on a placebo. Studies showed 38% to 47.5% of non-diabetic patients lost 5% or more of their body weight over a year, compared to 16% to 25% in the placebo groups. A smaller percentage, 16% to 22.6%, achieved a 10% or greater weight reduction.
Belviq was intended as part of a comprehensive weight management program that included dietary changes and regular exercise. Prescribing guidelines indicated that if a patient did not achieve at least a 5% reduction in body weight by week 12, the medication should be discontinued, as further significant benefit was unlikely.
Reported Side Effects
Belviq had various side effects. Common ones included headache, dizziness, fatigue, nausea, dry mouth, and constipation. For individuals with diabetes, low blood sugar (hypoglycemia) was more frequently observed, along with headache, back pain, cough, and fatigue.
More serious, though less common, concerns included serotonin syndrome, a condition caused by excessive serotonin activity, particularly when taken with other serotonin-affecting medications like antidepressants or migraine drugs. Other serious issues included heart valve problems, psychiatric disturbances (e.g., depression or thoughts of self-harm), and priapism (prolonged, painful erections).
Reasons for Market Withdrawal
Belviq was voluntarily withdrawn from the U.S. market in February 2020 by its manufacturer, Eisai Inc., at the FDA’s request. This action stemmed from concerns about an increased cancer risk identified in a long-term clinical trial.
The FDA had required this trial, CAMELLIA-TIMI 61, as a condition for Belviq’s 2012 approval. The trial involved 12,000 participants over five years, primarily to assess cardiovascular safety. While initial results showed no increased cardiovascular risks, further analysis revealed a higher cancer incidence in the Belviq group (7.7%) compared to placebo (7.1%). Observed cancers included colorectal, lung, and pancreatic.
The FDA concluded that lorcaserin’s potential risks, particularly the increased cancer risk, outweighed its weight loss benefits. The agency determined the medication was no longer safe and effective. Individuals taking Belviq were advised to discontinue use and consult their healthcare provider for alternative weight management strategies. The FDA did not recommend special cancer screening for former users, emphasizing adherence to standard cancer screening guidelines.