['Exenatide has been demonstrated to improve glycaemic control in patients with type 2 diabetes, with no effect on heart rate corrected QT (QTc ) at therapeutic concentrations. This randomized, placebo- and positive-controlled, crossover, thorough QT study evaluated the effects of therapeutic and supratherapeutic exenatide concentrations on QTc .', 'Intravenous infusion was employed to achieve steady-state supratherapeutic concentrations in healthy subjects within a reasonable duration (i.e. days). Subjects received exenatide, placebo and moxifloxacin, with ECGs recorded pre-therapy and during treatment. Intravenous exenatide was expected to increase heart rate to a greater extent than subcutaneous twice daily or once weekly formulations. To assure proper heart rate correction, a wide range of baseline heart rates was assessed and prospectively defined methodology was applied to determine the optimal QT correction.', 'Targeted steady-state plasma exenatide concentrations were exceeded (geometric mean ± SEM 253 ± 8.5\u2009pg\u2009ml(-1) , 399 ± 11.9\u2009pg\u2009ml(-1) and 627 ± 21.2\u2009pg\u2009ml(-1) ). QTc P, a population-based method, was identified as the most appropriate heart rate correction and was prespecified for primary analysis. The upper bound of the two-sided 90% confidence interval for placebo-corrected, baseline-adjusted QTc P (ΔΔQTc P) was <10\u2009ms at all time points and exenatide concentrations. The mean of three measures assessed at the highest steady-state plasma exenatide concentration of ∼500\u2009pg\u2009ml(-1) (ΔΔQTc P(avg) ) was -1.13 [-2.11, -0.15). No correlation was observed between ΔΔQTc P and exenatide concentration. Assay sensitivity was confirmed with moxifloxacin.'] Does exenatide at therapeutic and supratherapeutic concentrations prolong the QTc interval in healthy subjects?