Immuncheckpointblockad

Immuncheckpointblockad, commonly referred to as immune checkpoint blockade, is a form of cancer immunotherapy that aims to boost the body's immune response against tumors. It achieves this by blocking inhibitory signals that restrain T cell activity, allowing T cells to recognize and attack cancer cells more effectively. The term may be encountered in various spellings, but refers to the same therapeutic concept.

The mechanism involves targeting immune checkpoints—regulatory pathways such as CTLA-4, PD-1, and PD-L1 that normally help maintain immune self-tolerance and prevent autoimmunity. Monoclonal antibodies directed against these checkpoints release the brakes on T cells, promote their proliferation and activity in the tumor microenvironment, and can lead to durable antitumor responses in some patients. Agents targeting CTLA-4 include ipilimumab; those targeting PD-1 include nivolumab and pembrolizumab; antibodies against PD-L1 include atezolizumab and others.

Indications span several cancers, including melanoma, non-small cell lung cancer, renal cell carcinoma, urothelial carcinoma, and certain mismatches repair–deficient tumors, with approvals expanding to additional indications and combinations. Biomarkers such as PD-L1 expression, tumor mutational burden, and mismatch repair deficiency can help guide use, though responses occur across biomarker groups.

Safety profiles feature immune-related adverse events affecting skin, gut, endocrine, liver, and other organs, ranging from mild to severe. Management may involve corticosteroids or other immunosuppressants and, in some cases, discontinuation of therapy. Limitations include nonresponse in many patients and mechanisms of resistance, as well as phenomena such as pseudoprogression. Immune checkpoint blockade emerged in the 2010s with conquering advances and has become a cornerstone of oncology in many settings.