New obesity agents: lorcaserin and phentermine/topiramate

To evaluate the evidence for lorcaserin and phentermine/topiramate in the treatment of obesity.

Literature was accessed through PubMed (June 1975-March 2013) using the search terms lorcaserin, phentermine, topiramate, or phenter mine/topiramate. Additionally, reference citations from publications identified were reviewed. Additional information was obtained from the Food and Drug Administration (FDA)-approved prescribing information and FDA briefing documents.

English-language articles focusing on Phase 3 clinical trials for obesity were critiqued. Data from preclinical and Phase 1 and/or 2 trials are reported when appropriate. Six prospective Phase 3 trials were reviewed.

Obesity has reached epidemic proportions, affecting more than one third of adults in the US. Two medication products, lorcaserin and phenter mine/topiramate, have recently received FDA approval as adjuncts to a reduced-calorie diet and increased physical activity among individuals with a body mass index greater than or equal to 30 kg/m(2) or greater than or equal to 27 kg/m(2) with an obesity-related comorbidity, such as hypertension, dyslipidemia, or diabetes. Lorcaserin is a selective serotonin 5-HT2C agonist that regulates food intake, while the combination of phentermine/topiramate causes appetite suppression and enhanced satiety. Three Phase 3 randomized, placebo-controlled trials reported approximately 75% and 45% of patients achieved greater than or equal to 5% weight loss with phentermine/topiramate and lorcaserin, respectively.

With lifestyle modification, phentermine/topiramate appears most effective in terms of weight loss. Lorcaserin demonstrates moderate efficacy. Long-term cardiovascular outcomes studies are needed to confirm the safety and benefit of these new obesity agents.