Study design A phase 4, monocenter, randomized, double-blind, comparator-controlled, parallel-group, mechanistic intervention trial to assess the effect of 12-week treatment with the sodium-glucose linked transporters (SGLT)-2 inhibitor dapagliflozin versus the sulfonylurea (SU) derivative gliclazide on renal physiology and biomarkers in metformin-treated patients with type 2 diabetes mellitus (T2DM)