DPP4 and diabetes mellitus: New classes of glucose-lowering agents including dipeptidyl peptidase 4 (DPP-4) inhibitors, glucagon-like peptide 1 receptor agonists (GLP-1RAs) and sodium-glucose transport protein 2 (SGLT2) inhibitors provide an opportune moment for DM therapies with a lower risk of side effects and higher therapeutic efficacy.