Cancer immunotherapy is a type of biological treatment that helps the immune system fight cancer.
Immunotherapy is a form of therapy that harnesses the power of the body body's own immune system to prevent, control and eliminate cancer. Immunotherapy has the potential to revolutionize cancer care, alongside traditional cancer therapies including surgery, radiation therapy and chemotherapy. Cancer immunotherapy comes in a variety of forms including checkpoint inhibitors, targeted antibodies, cancer vaccines, adoptive cell transfer, and gene therapy. Certain modalities of immunotherapy, such as bispecific antibodies and chimeric antigen T cell receptor (CAR T) therapy, are considered complex because they elicit dramatic host immune reactions and require an advanced level of care.
Common forms of Immunotherapy
Bispecific antibodies engage T-cells and cancer cells simultaneously, triggering a potent immune response. By combining two antigen-recognizing elements into a single structure, they bring a T-cell and cancer cell into close proximity, allowing for the destruction of cancer cells.
CAR-T cell therapy involves extracting millions of T-cells from a patient with cancer. These cells are modified in the lab to express chimeric antigen receptors (CARs) on their surface. These CARs recognize a specific antigen found on the cancer cells. After modification, the T-cells are reintroduced into the patient's body, where they multiply and effectively attack and destroy the cancer cells. See CAR-T page for additional information and the LBMT website.
An immune checkpoint inhibitor works by blocking checkpoint proteins, such as PD-1, on T-cells from binding to their partner proteins on normal or cancer cells, like PD-L1. By doing this, the inhibitor prevents the "off signal" that would normally stop an immune response. This allows T-cells to effectively target and kill cancer cells.
Immunotherapy toxicities are different from those encountered with standard chemotherapy or targeted therapies. The immune system may become dysregulated during immunotherapy, leading to symptoms and findings which mimic autoimmune disorders. Adverse events can occur during or following treatment and can be life threatening. Any organ system in the body is at risk.
Management of toxicities needs prompt coordination with a medical oncologist with initiation of high dose corticosteroids, and may require referral to the appropriate subspecialty. If you suspect your patient is presenting with immune-related toxicity, please contact the patient’s medical oncologist directly or if after hours contact the on-call physician, or as per your local BC Cancer centre’s process outline in the patient letter below.
