DPP4 and diabetes mellitus: Good glycemic control is a well-accepted outcome for diabetes management, and clinical practice guidelines recommend a step-wise approach.9 Treatment typically begins with metformin, and if the HbA1c target is not achieved after 3 months, a second agent is added, such as sulfonylurea, thiazolidinedione, DPP-4 inhibitor, SGLT2 inhibitor, GLP-1 receptor agonist, or basal insulin.