Treatment of clozapine‐associated obesity and diabetes with exenatide in adults with schizophrenia: <scp>A</scp> randomized controlled trial ( <scp>CODEX</scp> )

Clozapine causes obesity and type 2 diabetes (T2DM). Glucagon-like peptide-1 (GLP-1) receptor agonists (e.g. exenatide) can counter clozapine-associated GLP-1 dysregulation in animals, and may be beneficial in people on clozapine. This randomized, controlled, open-label, pilot trial evaluated weekly exenatide for weight loss among clozapine-treated obese adults with schizophrenia, with or without T2DM. A total of 28 outpatients were randomized to once-weekly extended-release subcutaneous exenatide or usual care for 24 weeks. The primary outcome was proportion of participants with >5% weight loss. All 28 participants completed the study; 3/14 in the exenatide group and 2/14 in the usual care group had T2DM. Six people on exenatide achieved >5% weight loss vs one receiving usual care (P = .029). Compared with usual care, participants on exenatide had greater mean weight loss (-5.29 vs -1.12 kg; P = .015) and body mass index reduction (-1.78 vs -0.39 kg/m² ; P = .019), and reduced fasting glucose (-0.34 vs 0.39 mmol/L; P = .036) and glycated haemoglobin levels (-0.21% vs 0.03%; P = .004). There were no significant differences in other metabolic syndrome components. Exenatide may be a promising therapeutic agent for glycaemic control and weight loss in clozapine-treated people with obesity, and could assist in reducing clozapine-associated cardio-metabolic morbidity and mortality.