Terauchi Y, et al. - This trial examined the long-term safety and efficacy of tofogliflozin as an add-on treatment to insulin over 52 weeks. The eligible candidates included Japanese patients with type 2 diabetes mellitus, aged 20 to 75 years, with suboptimal glycaemic control (7.5%-10.5%) receiving insulin monotherapy (basal-bolus, bolus, premix [low and high] and basal) or receiving combination therapy with basal insulin and dipeptidyl peptidase-4 inhibitor. Mean HbA1c and body weight at baseline in the those who received tofogliflozin throughout the study (52 weeks) (tofo-tofo) and placebo and tofogliflozin (pla-tofo) groups were discovered to be 8.53% and 8.40%; 68.84 kg and 72.24 kg, respectively. Therefore, the safety and efficacy of tofogliflozin were demonstrated as an add-on to insulin therapy in type 2 diabetes mellitus patients, thereby yielding a new therapeutic solution to diabetes management.