Table 1.

Mechanisms of action and clinical indications of approved classes of immunotherapy drugs.

Immune checkpoint inhibitors (ICI)	Monoclonal antibodies target specific receptor–ligand pathways on T cells	Ipilumamb (Yervoy®)—metastatic melanoma
Chimeric antigen receptor T cell (CAR-T) therapy	T cells are removed from the patient and genetically modified to express specific chimeric antigen receptors (receptors developed in the laboratory to bind specific proteins on tumour cells). T cells are then cloned and returned to the patient to trigger an immune response.	CAR-T cells—acute lymphoblastic leukaemia and lymphoma
Non-specific immunotherapies	No specific targets. Use of cytokines (e.g. interleukin [IL]-2, interferon α & β) to boost immune system or slow angiogenesis.	IL-2 therapy (Proleukin®)—kidney cancer BCG (intravesivular immunotherapy)—bladder cancer
Cancer vaccines	Exposure to tumour antigens activates a tumour-specific humoral response.	Sipuleucel-T (Provenge®)—prostate cancer