Incretin-Based Polypharmacology and the Redefinition of Cardiometabolic Medicine

Abstract

Within little more than a decade, agonists of the glucagon-like peptide-1 (GLP-1) receptor have moved from incremental glucose-lowering agents to the most consequential drug class in cardiometabolic medicine. The defining advance has been less a single molecule than a design strategy—rational polypharmacology—in which one peptide, or a fixed co-formulation, engages two or three nutrient-sensing receptors. In this narrative review, built from a documented search of the primary literature and graded by level of evidence, we trace the resulting efficacy ladder from single GLP-1 agonism (≈15% mean weight loss with semaglutide) through dual GLP-1/GIP agonism (tirzepatide, ≈21%) to triple GLP-1/GIP/glucagon agonism (retatrutide, 24% in phase 2, with provisional phase 3 topline results in the high-20% range). We argue that the class’s significance lies less in weight than in convergent benefits across cardiovascular, renal, respiratory and hepatic disease; synthesize the pivotal outcome trials (SELECT, FLOW, SURPASS-CVOT, SURMOUNT-OSA, SUMMIT, ESSENCE); quantify the principal safety signals in absolute terms; and confront the unresolved problems of durability, tolerability, lean-mass loss, special populations, cost and equitable access. Negative results—most notably the failure of oral semaglutide to slow early Alzheimer’s disease in EVOKE and EVOKE+—are given equal weight.