. Introduction
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder
characterized by hyperglycemia resulting from decreased insulin
secretion and increased insulin resistance. Although a number of
oral antihyperglycemic agents are available and glucose-lowering
therapy is effective to prevent and manage diabetes and its complications
(1), it is still difficult to maintain good glycemic control
with monotherapy over a long-term period because of their limited
efficacy (2). Patients with inadequate glycemic control often require
additional combination therapy with other oral agents or insulin to
achieve the desired glycemic target levels (3).
Glucagon-like peptide-1 (GLP-1), an incretin hormone released
from L cells, exerts multiple antidiabetic effects such as stimulating
insulin secretion, inhibiting gastric emptying and glucagon secretion,
and suppressing appetite (4). Dipeptidyl peptidase IV (DPP4)