DPP4 and type 2 diabetes mellitus: Saxagliptin [(S)-3-hydroxyadamantylglycine-L-cis-4,5-methanoprolinenitrile], approved by the U.S. Food and Drug Administration (FDA) is a dipeptidyl peptidase-4 (DPP-4) inhibitor used in the therapy of T2DM in adults [7].