Binding Kinetics, Bias, Receptor Internalization and Effects on Insulin Secretion in Vitro and in Vivo of a Novel GLP-1R/GIPR Dual Agonist, HISHS-2001

AIMS:The use of incretin analogues has emerged as an effective approach to achieve both enhanced insulin secretion and weight loss in Type 2 diabetes (T2D) patients. Agonists which bind and stimulate multiple receptors have shown particular promise. However, off-target effects remain a complication of using these agents, and modified versions with optimised pharmacological profiles and/or biased signalling are sought. MATERIALS AND METHODS:Ligand synthesis was achieved using standard solid-phase techniques. Assessments of GLP-1R-binding kinetics, G protein recruitment and receptor internalisation were performed using biochemical and imaging approaches. Insulin secretion was measured in purified mouse and human islets, and drug efficacy was assessed in hyperglycaemic db/db mice. RESULTS:We describe the synthesis and properties of a molecule which binds to both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors (GLP-1R and GIPR) to enhance insulin secretion. HISHS-2001 shows increased affinity at the GLP-1R, as well as a tendency towards reduced internalisation and recycling at this receptor versus FDA-approved dual GLP-1R/GIPR agonist tirzepatide. HISHS-2001 also displayed significantly greater bias towards cAMP generation versus β-arrestin 2 recruitment compared to tirzepatide. In contrast, Gαs recruitment was lower versus tirzepatide at the GLP-1R, but unchanged at the GIPR. Administered to obese hyperglycaemic db/db mice, HISHS-2001 increased circulating insulin whilst lowering body weight and HbA1c with similar efficacy to tirzepatide at substantially lower doses. CONCLUSION:HISHS-2001 represents a novel dual receptor agonist with a promising pharmacological profile and actions. Future clinical studies will be needed to assess the safety and efficacy of this molecule in humans.