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Obesity Medications Approved for Long-Term Use More Likely to Lead to Weight Loss
Results of a systematic literature review of the 7 current FDA-approved medications for the treatment of obesity in adults finds that 3 medications approved for long-term use, when used as an adjunct to lifestyle intervention, lead to a greater mean weight loss compared to placebo [JAMA 2013;doi:10.1001/jama.2013.281361].
“Obesity drugs approved for long-term use lead to weight loss beyond that of placebo ranging from about 3% of starting body weight for orlistat and lorcaserin to about 9% for phentermine plus topiramate-extended release (ER),” said lead author of the study, Susan A. Yanovski, MD, Office of Obesity Research, National Institute of Diabetes and digestive and Kidney Diseases, Bethesda, Maryland, during an interview with First Report Managed Care.
The study also found that the 3 medications approved for long-term use also led to greater improvements in cardiometabolic risk factors compared to placebo, including glycemic control. However, Dr. Yanovski emphasized that no weight loss medication has been shown to reduce cardiovascular disease morbidity or mortality.
The other 4 approved medications (ie, phentermine, diethylpropion, phendimetrazine, and benzphetamine) are only approved for short-term use (ie, ≤12 weeks), but the study found that these medications are frequently prescribed off-label for longer periods, according to Dr. Yanovski.
Included in the systematic review were 21 articles. All articles were published after September 15, 2013 and had to report randomized, placebo-controlled clinical trials lasting at least 1 year with body weight change as the primary or secondary outcome. Additionally, all studies included had to have at least 50 participants per group at baseline, report 50% retention of participants, and report results on an intention-to-treat basis.
Findings of this review showed that patients treated with long-term obesity medications were more likely to attain clinically meaningful weight loss (at least 5%) compared to those taking placebo, ranging from 37% to 47% for lorcaserin, 35% to 73% for orlistat, and 67% to 70% for phentermine plus topiramate ER (at top dose of 15/92 mg). For patients who failed to lose at least 5% of initial weight after 12 weeks of therapy, the authors found that these patients are more likely to be exposed to the risks and costs of obesity medications with little prospect of long-term benefit.
Based on this, Dr. Yanovski emphasized the need “for carefully selected patients who respond with clinically meaningful weight loss accompanied by improvements in feeling, functioning, cardiovascular disease risk factors, or other obesity-related comorbid conditions. Obesity drugs may be useful adjuncts to lifestyle treatment. Ongoing research will identify additional targets that should lead to the development of safer and more effective drugs and drug combinations for obesity treatment.”
Limitations of the study highlighted by Dr. Yanovski include only using currently approved medications with at least 1 year of data from studies with relatively large sample sizes, as well as not systematically reviewing drugs used off-label or drugs in development.
