EX is the first incretin-mimetic compound that has been approved by USA Food and Drug Administration (FDA) in April, 2005, as an adjunctive therapeutic agent to improve glycemic control in T2DM patients who have suboptimal glycemic control with either sulfonylurea or metformin monotherapy[3–5, 8] or with sulfonylurea and metformin combination[3]. Here, GCG is linked to type 2 diabetes mellitus.