Modular PEG Scaffold Enables Rapid Assembly of Potent GLP-1/Amylin Dual Agonists

Multi-receptor peptide agonists are a highly effective strategy for treating obesity and Type 2 Diabetes Mellitus (T2DM), building on the success of incretin-based therapies like GLP-1 agonists. However, developing these multi-agonists is synthetically challenging, often requiring de novo preparation of complex fusion peptides for each receptor combination. This labor-intensive process hinders the systematic exploration of different receptor targets, valencies, and functionalities, limiting the pace of innovation in this promising therapeutic area. A more efficient, modular assembly method is needed to accelerate the discovery of next-generation multi-agonists.

Researchers developed a modular polyethylene glycol (PEG)-based scaffold designed for orthogonal attachment of up to three functional components, including therapeutic peptides and half-life-extending units. The scaffold was assembled on solid phase without intermediate purification. This platform utilizes sequential strain-promoted azide-alkyne cycloaddition (SPAAC) and copper-catalysed azide-alkyne cycloaddition (CuAAC) for precise component integration. As a proof-of-concept, glucagon-like peptide-1 (GLP-1) and amylin receptor agonists were used to generate dual-agonist constructs with tuneable valency and functionality. The activity of these conjugates was then assessed in cyclic adenosine monophosphate (cAMP) assays and through selective receptor-mediated internalization studies in GLP-1R-expressing cells.

The modular PEG-based platform successfully enabled the rapid generation of GLP-1 and amylin dual-agonist constructs. Lead conjugates demonstrated highly potent and balanced activity at both target receptors. Specifically, these constructs exhibited low-picomolar potency in cAMP assays, indicating strong agonism. This balanced activity across both GLP-1R and amylin receptor is crucial for achieving synergistic therapeutic effects. Furthermore, the conjugates showed selective receptor-mediated internalization in GLP-1 receptor-expressing cells, confirming their specific engagement with the intended targets. This selective internalization is a key indicator of functional receptor activation and potential therapeutic efficacy. The orthogonal click-based platform proved highly versatile, allowing for systematic exploration of various receptor combinations and valency.

Lead conjugates displayed balanced, low-picomolar potency at both GLP-1R and amylin receptor in cAMP assays, confirming robust and specific agonism.