Sustained efficacy of dapagliflozin when added to metformin in type 2 diabetes inadequately controlled by metformin monotherapy

Background and aims: The selective SGLT2 inhibitor dapagliflozin (DAPA) reduces hyperglycaemia independently of insulin secretion or action by inhibiting renal glucose reabsorption. This study (MB102014) is a randomised double-blind, placebo (PBO)-controlled trial of DAPA added to metformin (MET) in T2DM (n=546) inadequately controlled with MET alone. Previously reported short-term data at week 24 showed significant mean reductions in the primary [HbA1c] and secondary [fasting plasma glucose (FPG) and weight] endpoints with DAPA compared to PBO. Here we report efficacy and safety results at week 102 of the long-term extension. Materials and methods: Patients aged 18-77 years with HbA1c 7-10% received DAPA 2.5 mg, 5 mg, 10 mg or PBO, plus open-label MET (≥1500mg/d). Exploratory endpoints at week 102 included changes from baseline in HbA1c, FPG and weight, and were analyzed by longitudinal repeated measures analysis. Results: Overall 71.2% of patients completed 102 weeks of the study; fewer on PBO (63.5%) than on DAPA 2.5 mg, 5 mg, and 10 mg (68.3%, 73.0%, 79.8%), due mainly to more patients on PBO discontinuing for lack of efficacy. At week 102, all DAPA groups showed greater mean reductions from baseline in HbA1c, FPG and weight compared to PBO (table), effects that were similar to those observed at week 24 and maintained throughout the trial. More patients at week 102 also achieved a therapeutic response of HbA1c<7% with DAPA 2.5 mg, 5 mg, and 10 mg (20.7%, 26.4%, 31.5%) than with PBO (15.4%). Adverse events (AEs), serious AEs and AEs leading to discontinuation were balanced across all groups. Signs and symptoms suggestive of genital infection (GenInf) were reported in 11.7%, 14.6%, 12.6% (DAPA 2.5 mg, 5 mg, 10 mg) and 5.1% (PBO) of patients, with 1 discontinuation due to GenInf. Signs and symptoms suggestive of urinary tract infection (UTI) were reported in 8.0%, 8.8%, 13.3% (DAPA 2.5 mg, 5 mg, 10 mg) and 8.0% (PBO), with 1 discontinuation due to UTI. No event of pyelonephritis was reported. Conclusion: In comparison to PBO, DAPA added to MET over 102 weeks demonstrated greater and sustained improvements in glycaemic control, clinically meaningful reduction in weight, and no increased risk of hypoglycaemia in patients with T2DM inadequately controlled with MET alone.