Demartis A, Lahm A, Tomei L, Beghetto E, Di Biasio V, Orvieto F, Frattolillo F, Carrington PE, Mumick S, Hawes B, Bianchi E, Palani A, Pessi A. Polypharmacy through Phage Display: Selection of Glucagon and GLP-1 Receptor Co-agonists from a Phage-Displayed Peptide Library. Sci Rep. 2018 Jan 12;8(1):585. doi: 10.1038/s41598-017-18494-5. PMID: 29330364; PMCID: PMC5766609.

Combinatorial hormone therapy is an exciting and innovative approach to treating obesity and diabetes, involving the design of single-molecule peptides that combine the effects of multiple metabolically-related hormones. This study presents a proof-of-concept for developing unimolecular polypharmacy agents using phage-displayed peptide libraries (PDL). By applying selection methods on PDLs with glucagon (GCGR) and GLP-1 receptor (GLP1R)-overexpressing cells, researchers identified co-agonists targeting both receptors. After two to three rounds of selection, 7.5% of the clones were dual GLP1R/GCGR co-agonists, while 1.53% acted on a single receptor. Sequencing and synthesizing 35 peptides revealed 18 potent co-agonists, with eight demonstrating EC50 values ≤ 30 pM, matching or exceeding the efficacy of rationally designed co-agonists. Two peptides were further engineered for stability against dipeptidyl peptidase IV cleavage, achieving prolonged half-life without compromising potency. This study underscores the potential of phage-derived peptides as therapeutic agents and highlights a broadly applicable strategy for optimizing polypharmacology across multiple metabolically-relevant hormones.