Phentermine and topiramate extended-release: a new treatment for obesity and its role in a complications-centric approach to obesity medical management

Abstract

Introduction: Weight-management options include lifestyle modifications, bariatric surgery and, until recently, limited pharmacotherapy. Phentermine and topiramate extended-release (phentermine/topiramate ER) has recently been approved in the USA for chronic weight management in obese adults and overweight adults with weight-related co-morbidities in conjunction with a reduced-calorie diet and increased physical activity.

Areas covered: This review describes the pharmacology and clinical trials data for phentermine/topiramate ER and its role in a complications-centric approach to medical care of the overweight and obese patient.

Expert opinion: Phentermine/topiramate ER is an effective and safe weight-loss medication that can produce and sustain approximately 10% loss of body weight. This is a landmark development in the pharmacotherapy of obesity. By offering an effective medical option to complement lifestyle and surgical approaches, phentermine/topiramate ER enables a comprehensive medical model for obesity care. The overall approach to the overweight and obese patient should be to identify individuals who will benefit most from therapy based on cardiometabolic or mechanical complications, establish therapeutic targets and goals for ameliorating these complications and selecting the treatment modality and intensity for weight loss to achieve these goals. This complications-centric model emphasizes weight loss as a tool to ameliorate obesity-related complications and optimizes benefit/risk for achieving the best outcomes in overweight/obese patients.

Figure 1.

Weight loss with phentermine/topiramate ER in (A) EQUIP, (B) CONQUER and (C) SEQUEL studies from baseline to study end . Least-squares mean change (95% CI). Weight-change curves are plotted for completers by visit. (A) EQUIP Study from baseline to week 56. Shown to the right of the graph are data derived from the analyses of the ITT-LOCF. p < 0.0001 vs placebo for all time points assessed (adapted from Allison et al. [26]); (B) CONQUER Study from baseline to week 56. Shown to the right of the graph are data derived from the analyses of the ITT-LOCF. p < 0.0001 vs placebo for all time points assessed (adapted from Gadde et al. [27]); (C) SEQUEL Study from baseline to week 108. p < 0.0001 vs placebo for all time points assessed.

Figure 2.

Achievement of categorical weight loss goals in (A) CONQUER and (B) SEQUEL . (A) CONQUER Study, subjects with ≥ 5% or ≥ 10% weight loss at week 56; (B) SEQUEL Study, percentage (95% CI) of subjects achieving ≥ 5, ≥ 10, ≥ 15 or ≥ 20% weight loss from baseline to week 108 (ITT-LOCF).

Figure 3.

Complications-centric medical model for treatment of the overweight or obese patient. Step 1 is to evaluate patients for the presence and severity of obesity-related complications. Step 2 is to select therapeutic targets for improvement in complications and to determine the appropriate treatment modality and intensity. Step 3 is to reassess complications, and if targets for improvements in complications are not met, intensify lifestyle and/or medical treatment modality for greater weight loss.