Immunotherapy is an FDA-approved treatment for cancer that has significantly improved outcomes for patients. Immunotherapy is actually an umbrella term for different kinds of treatment, according to oncologist Melissa Wilson, MD, PhD, of the NYU Langone Medical Center. Four commonly used types of immunotherapy include antibodies, vaccines, cytokines, and checkpoint inhibitors.
Antibodies are an active form of immunotherapy. They stimulate the natural immune system of the patient. Doctors introduce the antibodies through an IV, and the antibodies target a specific molecule on the surface of the cancer cell. The antibodies attach to this molecule, and then they signal to the immune system to attack this cell.
This helps the immune system—specifically the T cells that work to fight infections—attack the harmful cancer cells that it was previously not recognizing as a threat. (Learn more about the role of the T cells in fighting cancer with immunotherapy here.)
Vaccines are another type of immunotherapy that doctors use to keep cancer from recurring. After another form of treatment has successfully killed off cancer cells, doctors inject the immunotherapy vaccine with the intention of preventing future tumor growth. The vaccines work by helping the body develop antibodies to aid the T cells in recognizing and attacking future cancer cells. If the T cells can immediately kill off individual cancer cells, which are not necessarily a threat on their own, the cancer is less likely to spread and progress into a recurrence.
Cytokines are a signaling protein that the body already produces during any illness, even the common cold. Typically, the white blood cells produce these cytokines, but in immunotherapy, researchers can create cytokines in a laboratory and introduce them into the body of the cancer patient. Once in the body, the cytokines rev up the immune system and activate the T cells to attack foreign substances, such as the cancer cells.
Checkpoint inhibitors are the newest type of immunotherapy. This novel form of cancer treatment takes the brakes off the body’s immune system, according to Dr. Wilson. When the immune system experiences sustained activation, it begins to lose its effectiveness because the body wants to shut it off. (This is how many autoimmune disorders start.) As a result, the body triggers an “off switch” on the T cells, making them less likely to recognize and attack cancer cells.
However, checkpoint inhibitors can block these brakes, re-activating the T cells to continue fighting infections and foreign substances, such as cancer cells.
Although not technically a cure for cancer, different kinds of immunotherapy have proven to be more effective at treating certain kinds and stages of cancer than traditional methods. More research will continue to improve its effective and expand the types of cancers immunotherapy can treat.