JAMA Publishes Analysis of Weight Loss Agents

The Food and Drug Administration (FDA) has approved five weight loss medications in the United States indicated for patients with a BMI measurement over 30 kg/m² or over 27 kg/m² and at least one weight-associated comorbidity.

Scarce data exists comparing these agents to one another.

The Journal of the American Medical Association included a study in its June 2016 issue showing Orlistat (Xenical® and Alli®), lorcaserin (Belviq®), naltrexone-bupropion (Contrave®), phentermine-topiramate (Qsymia®), and liraglutide (Saxenda®) produce at least a 5% weight loss in 52 weeks.

The authors produced a meta-analysis of studies enrolling patients according to the FDA indication and reporting patients achieving at least 5% weight loss or the differences in mean weight loss between different study groups.

The researchers excluded studies enrolling special populations (e.g. patients with nonalcoholic fatty liver disease or polycystic ovary syndrome), observational studies, and studies using non-approved medications.

All five medications produced at least 5% weight loss in a greater proportion of patients than placebo.

Phentermine-topiramate patients were most likely to lose at least 5% and 10% of the baseline weight. Liraglutide patients were the second-most likely to lose more than 5% and 10% of their weight, but had greater drop-out due to adverse effects.

Phentermine-topiramate and naltrexone-bupropion had similar rates of discontinuation related to adverse effects.

Lorcaserin and orlistat were the least effective (although orlistat-treated patients were likely to lose 5% of their baseline weight by 52 weeks) and had the lowest rate of adverse effects.

Experts suggested that providers should match weight loss agents to comorbidities when possible (e.g. liraglutide in diabetics and naltrexone-bupropion in alcohol- and opiate-dependent patients).

However, the FDA approved four of these agents (except orlistat) in the last 3 years, so long-term safety is uncertain.