Treatment of clozapine-associated obesity and diabetes with exenatide (CODEX) in adults with schizophrenia: study protocol for a pilot randomised controlled trial.

BACKGROUND: Clozapine causes significant metabolic disturbances including obesity and type 2 diabetes. Recent evidence that reduced glucagon-like-peptide-1 (GLP-1) may contribute to aetiology of clozapine-associated metabolic dysregulation suggests a potential therapeutic role for GLP-1 agonists. METHOD: This open-label, pilot randomised controlled trial evaluates the effect of exenatide in clozapine-treated obese adults who have schizophrenia, with or without poorly controlled diabetes. Sixty out-patients will be randomised to once weekly extended release exenatide or treatment as usual for 24 weeks. AIMS: To evaluate the feasibility of larger studies regarding methodology, acceptability, tolerability and estimate efficacy for glycaemic control or weight loss. Secondary outcomes are psychosis severity and metabolic parameters. CONCLUSIONS: This is the first trial investigating GLP-1 agonists for glycaemic control and weight loss in clozapine-treated patients with either diabetes or obesity. Clozapine-associated obesity and diabetes with exenatide (CODEX) will provide proof-of-concept empirical evidence addressing whether this novel treatment is practical and worthy of further investigation. DECLARATION OF INTEREST: A.W.R. has received speaker honoraria and travel grants from AstraZeneca, BoehringerIngelheim, Eli Lilly, MSD, Novo Nordisk and Sanofi and has participated on advisory panels for MSD and Novo Nordisk. COPYRIGHT AND USAGE: © The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.