Formulary management of 2 new agents: lorcaserin and phentermine/topiramate for weight loss

Abstract

Background: Obesity may lead to the development of multiple chronic disease states, including hypertension, dyslipidemia, and type 2 diabetes mellitus. Over a half billion adults worldwide are affected by obesity, and more than two-thirds of adults are either obese or overweight in the United States. Diet and exercise have been the mainstays of treatment in this population; however, once failed, noninvasive, long-term effective treatment modality is lacking, and medications may potentially fill the void. Lorcaserin and phentermine/topiramate were approved by the FDA in June 2012 and July 2012, respectively, as adjuncts to diet and exercise for chronic weight management of obese (body mass index [BMI] ≥ 30 kg/m2) or overweight (BMI ≥ 27 kg/m2) individuals with comorbidities.

Objective: To review the phase 3 trials of lorcaserin and phentermine/topiramate and provide managed care considerations that may be taken into account as a result.

Methods: A MEDLINE review was performed for articles published and available through September 17, 2012, using keywords "lorcaserin" or "phentermine/topiramate" with an emphasis on phase 3 trials. The literature search was limited to randomized controlled trials in humans published in the English language. Additional information on lorcaserin from its FDA review was obtained from the FDA website.

Results: 5 pivotal phase 3 trials were identified: 3 for lorcaserin and 2 for phentermine/topiramate. Both agents demonstrated a statistically significant higher proportion of individuals who lost ≥ 5% of body weight, as well as higher mean weight loss when compared with placebo. Safety concerns for lorcaserin include cardiac valvulopathy and increased risk of psychiatric, cognitive, and serotonergic adverse effects. Teratogenicity and increased heart rate are major safety concerns regarding phentermine/topiramate.

Conclusions: Health care decision makers have many factors to consider when developing strategies to fight obesity. Despite a great need for new therapies to treat obesity, medications used for weight loss have significant side-effect profiles and contraindications that may limit therapy. An appropriate utilization management strategy is needed.