GLP-1 receptor agonists and immune checkpoint inhibitor therapy: a narrative review on mechanistic and clinical evidence

Obesity paradoxically increases sensitivity to immune checkpoint inhibitors (ICIs) despite elevating cancer risk, creating a clinical opportunity where metabolic dysfunction may generate a target-rich immune microenvironment. However, immunosuppressive mechanisms, including regulatory T-cells, myeloid-derived suppressor cells, and pro-inflammatory macrophages, can limit durable anti-tumor responses. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) extend beyond metabolic comorbidity management, functioning as metabolic-immunologic adjuvants capable of reprogramming the tumor microenvironment in obese patients receiving ICIs. A literature search was conducted in PubMed/MEDLINE through December 2025 using MeSH headings related to glucagon-like peptide-1 receptor agonists and immune checkpoint inhibitors. Mechanistically, GLP-1R signaling activates cAMP-PKA-AMPK pathways that suppress NF-κB-driven inflammation and promote macrophage repolarization, improving CD8 T-cell metabolic fitness, enhancing central memory formation, and reducing lipid-induced T-cell exhaustion. Real-world observational data across renal cell carcinoma, non-small cell lung cancer, colorectal cancer, and neuroendocrine neoplasms suggest improved overall survival, fewer immune-related adverse events, and lower cardiometabolic complications with concurrent GLP-1RA and ICI therapy. Pharmacovigilance concerns regarding pancreatitis, ICI-induced diabetes, and immune-related toxicities remain incompletely characterized. This review critically appraises mechanistic insights, real-world evidence, and safety considerations, proposing a translational-clinical research agenda to prospectively validate GLP-1RAs as rational adjuncts to checkpoint blockade.