PD-1 inhibitor + CTLA-4 inhibitor

**PD-1 inhibitor + CTLA-4 inhibitor** refers to the combination therapy of monoclonal antibodies blocking programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), two key immune checkpoints that inhibit T-cell activation and antitumor responses. This dual blockade enhances efficacy over monotherapy by inducing distinct cellular responses, such as expansion of activated effector CD8 T cells and Th1-like CD4 effector T cells while reducing phenotypically exhausted T cells and certain regulatory T cells (Tregs), leading to improved proinflammatory cytokine production and effector-to-suppressor ratios in the tumor microenvironment. Primarily indicated for advanced cancers like metastatic melanoma, renal cell carcinoma, and MSI-H colorectal cancer, the combination (e.g., nivolumab + ipilimumab) is FDA-approved in these settings, offering superior overall survival in multi-organ metastatic disease but with higher toxicity including grade 3-4 immune-related adverse events.[1][2][5]

Other names

anti-PD-1 + anti-CTLA-4PD-1/CTLA-4 blockadedual checkpoint blockadeipilimumab + nivolumab