Incretin‐based drugs for type 2 diabetes: Focus on East Asian perspectives

Type 2 diabetes in East Asians is characterized primarily by β‐cell dysfunction, and with less adiposity and less insulin resistance compared with that in Caucasians. Such pathophysiological differences can determine the appropriate therapeutics for the disease. Incretins, glucose‐dependent insulinotropic polypeptide and glucagon‐like peptide‐1, are secreted in response to meal ingestion, and enhance insulin secretion glucose‐dependently. Incretin‐based drugs, dipeptidyl peptidase‐4 inhibitors (DPP‐4i) and glucagon‐like peptide‐1 receptor agonists, that ameliorate β‐cell dysfunction with limited hypoglycemia risk are now widely used in type 2 diabetes management. Recent meta‐analyses of clinical trials on DPP‐4i and glucagon‐like peptide‐1 receptor agonists found that the drugs were more effective in Asians, most likely because of amelioration of β‐cell dysfunction. In addition, we found increased glycated hemoglobin‐lowering effects of DPP‐4i to be associated with intake of fish in type 2 diabetes, which suggests that dietary customs of East Asians might also underlie the greater efficacy of DPP‐4i. Despite the limited risk, cases of severe hypoglycemia were reported for DPP‐4i/sulfonylureas combinations. Importantly, hypoglycemia was more frequent in patients also receiving glibenclamide or glimepiride, which activate exchange protein directly activated by cyclic adenosine monophosphate 2, a critical mediator of incretin signaling, and was less frequent in patients receiving gliclazide, which does not activate exchange protein directly activated by cyclic adenosine monophosphate 2. Prevention of insulin‐associated hypoglycemia by DPP‐4i has gained attention with regard to the enhancement of hypoglycemia‐induced glucagon secretion by insulinotropic polypeptide, but remains to be investigated in East Asians. Despite the safety issues, which are paramount and must be carefully monitored, the incretin‐based drugs could have potential as a first choice therapy in East Asian type 2 diabetes patients.