Aim: The aim of this study was to examine the efficacy and safety of topiramate as an adjunct to diet and exercise in drug-naive, obese subjects with type 2 diabetes.
Methods: Drug-naive individuals with type 2 diabetes, body mass index (BMI) of ≥27 and <50 kg/m2 and haemoglobin A1c (HbA1c) of <10.5% were enrolled into the study. All the individuals participated in a non-pharmacologic weight loss program (Pathways to Change®; Johnson & Johnson Healthcare Systems, Piscataway, NJ, USA) throughout the trial. After a 6-week placebo run-in, the subjects were randomized to placebo, topiramate 96 mg/day or topiramate 192 mg/day. Subjects were scheduled for 8-week titration and 52-week maintenance phases. The study was ended early; efficacy data were reported for a predefined modified intent-to-treat (MITT) population (n = 229), with 40 weeks of treatment. All the subjects who provided any safety data were included in the safety population (n = 535).
Results: Baseline mean weight was 103.7 kg, BMI 36 kg/m2 and HbA1c 6.7% across all treatment groups. By the end of week 40, the placebo, the topiramate 96 mg/day and topiramate 192 mg/day groups lost 2.5, 6.6 and 9.1% of their baseline body weight respectively (p < 0.001 vs. placebo, MITT population using last observation carried forward). The decrease in HbA1c was 0.2, 0.6 and 0.7% respectively (p < 0.001 vs. placebo, MITT). Topiramate significantly reduced blood pressure and urinary albumin excretion; a weight-loss-independent HbA1c improving effect of topiramate was demonstrated. Adverse events were predominantly related to central nervous system (CNS).
Conclusions: Topiramate as an add-on treatment to lifestyle improvements produced significant weight loss and improved glucose homeostasis in obese, drug-naive subjects with type 2 diabetes. These treatment advantages should be balanced against the occurrence of adverse events in the CNS.