Type 2 diabetes mellitus (T2DM) and obesity are the major global health concerns. Glucagon-like peptide-1 (GLP-1) receptor agonists are effective incretin-based treatments for T2DM and obesity. The patient compliance of peptide-based GLP-1 receptor agonists is limited due to subcutaneous administration. This study aimed to develop small-molecule GLP-1 receptor agonists that can be administered orally. Pharmacological properties of YN1548 were evaluated using in vitro assays in Chinese hamster ovary (CHO) cells expressing GLP-1 receptor and diabetic monkey models. YN1548 demonstrated potent binding to human GLP-1 receptor and activation of the cyclic adenosine monophosphate (cAMP) signaling pathway at a half-maximal effective concentration of 4.59, 24.28, and 2.20 nM in CHO cells expressing various levels of human GLP-1 receptor. The maximal efficacy, ranging from 101.0 % to 103.9 %, was comparable to GLP-1 (7-36) amide. YN1548 exhibited biased agonism, preferentially activating cAMP response over β-arrestin recruitment, as well as selectivity for primate GLP-1 receptor. Pharmacokinetic evaluations indicated that YN1548 is suitable for oral administration. In diabetic monkeys, oral administration of YN1548 reduced blood glucose levels and enhanced insulin secretion in a concentration-dependent manner. YN1548 also reduced food intake and induced weight loss comparable to liraglutide, injectable GLP-1 receptor agonists. Toxicological studies in rats and monkeys revealed that YN1548 was well-tolerated up to 1000 and 500 mg/kg/day, respectively, with reversible and non-adverse changes in clinical pathology parameters. YN1548, a novel small-molecule GLP-1 receptor agonist, is a promising therapeutic candidate for the management of T2DM and obesity, addressing the unmet need for long-term and convenient oral treatments.
Keywords: Glucagon-like peptide-1 receptor agonist; Obesity; Small-molecule; Type 2 diabetes mellitus; YN1548.
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