BackgroundGemigliptin is a potent, selective dipeptidyl peptidase (DPP)-4 inhibitor that does not require any dosage adjustment based on renal function. It is also known to have no apparent interaction with commonly used drugs. In the present study, we aimed to evaluate the glucose-lowering efficacy and safety of gemigliptin in post-transplant patients with type 2 diabetes mellitus (T2D). MethodsA total of 84 patients who were prescribed gemigliptin for more than 180 days after transplantation were analyzed retrospectively. Six-month changes in blood glucose and glycated hemoglobin (HbA1c) levels were checked to assess glycemic efficacy. Safety was evaluated by examining its influence on immunosuppressive treatment, as determined by the blood trough level and dosage of calcineurin inhibitors, as well as changes in parameters related to liver and renal function. ResultsSix months of gemigliptin treatment significantly lowered blood glucose level (HbA1c: 8.16 ± 1.69 to 7.44 ± 1.26%; P < .001). There were no significant changes in blood trough levels of immunosuppressants, including tacrolimus, cyclosporine, and sirolimus. The dosage of immunosuppressants was also stable. In addition, there were no significant changes in the levels of liver enzymes and renal function during 6 months of treatment. ConclusionGemigliptin robustly lowered blood glucose levels without exerting any significant effect on immunosuppressive treatment, renal function, and liver enzymes in post-transplant patients with T2D.