Exenatide once weekly plus dapagliflozin once daily versus exenatide or dapagliflozin alone in patients with type 2 diabetes inadequately controlled with metformin monotherapy (DURATION-8): a 28 week, multicentre, double-blind, phase 3, randomised controlled trial

Abstract

Background: Glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce glycaemia and weight, and improve cardiovascular risk factors via different mechanisms. We aimed to compare the efficacy and safety of co-initiation of the GLP-1 receptor agonist exenatide and the SGLT2 inhibitor dapagliflozin with exenatide or dapagliflozin alone in patients with type 2 diabetes inadequately controlled by metformin.

Methods: DURATION-8 was a 28 week, multicentre, double-blind, randomised, active-controlled phase 3 trial done at 109 sites in six countries. Adults (aged ≥18 years) with type 2 diabetes and inadequate glycaemic control (HbA_1c 8-12% [64-108 mmol/mol]) despite stable metformin monotherapy (≥1500 mg/day) were randomly assigned (1:1:1), via an interactive voice and web-response system, to receive once-weekly exenatide 2 mg by subcutaneous injection plus once-daily dapagliflozin 10 mg oral tablets, exenatide with dapagliflozin-matched oral placebo, or dapagliflozin with exenatide-matched placebo injections. Randomisation was stratified by baseline HbA_1c (<9·0% vs ≥9·0% [<75 mmol/mol vs ≥75 mmol/mol]). The primary endpoint was change in HbA_1c from baseline to week 28. Secondary endpoints were the change from baseline in fasting plasma glucose at week 2 and week 28, and 2 h postprandial glucose at week 28; the proportion of patients with an HbA_1c less than 7·0% (<53 mmol/mol) at week 28; change in weight at week 28; the proportion of patients with weight loss of 5% or more at week 28; and change in systolic blood pressure at week 28. Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02229396.

Findings: Between Sept 4, 2014, and Oct 15, 2015, we randomly assigned 695 patients to receive exenatide plus dapagliflozin (n=231), exenatide alone (n=231; n=1 untreated), or dapagliflozin alone (n=233). The intention-to-treat population comprised 685 participants (mean HbA_1c 9·3% [SD 1·1]; 78 mmol/mol [12]), of whom 611 (88%) completed the study. After 28 weeks, the change in baseline HbA_1c was -2·0% (95% CI -2·1 to -1·8) in the exenatide plus dapagliflozin group, -1·6% (-1·8 to -1·4) in the exenatide group, and -1·4% (-1·6 to -1·2) in the dapagliflozin group. Exenatide plus dapagliflozin significantly reduced HbA_1c from baseline to week 28 compared with exenatide alone (-0·4% [95% CI -0·6 to -0·1]; p=0·004) or dapagliflozin alone (-0·6% [-0·8 to -0·3]; p<0·001). Exenatide plus dapagliflozin was significantly superior to either drug alone for all secondary efficacy endpoints, with greater reductions in fasting plasma and postprandial glucose, more patients with an HbA_1c less than 7·0% (<53 mmol/mol), greater weight loss, a greater proportion of patients with weight loss of 5% or more, and greater reductions in systolic blood pressure (all p≤0·025). Adverse events were recorded in 131 (57%) of 231 patients in the exenatide plus dapagliflozin group, 124 (54%) of 230 patients in the exenatide group, and 121 (52%) of 233 patients in the dapagliflozin group. The most common adverse events (≥5% of patients in any group) were diarrhoea, injection-site nodules, nausea, and urinary tract infections. No episodes of major hypoglycaemia or minor hypoglycaemia were reported.

Interpretation: Co-initiation of exenatide and dapagliflozin improved various glycaemic measures and cardiovascular risk factors in patients with type 2 diabetes inadequately controlled by metformin monotherapy. The dual treatment regimen was well tolerated, with the expected safety profile for this combination. Additional data from an ongoing study (eg, AWARD-10; NCT02597049) will further inform the use of these drug classes in combination.

Funding: AstraZeneca.