What is Immunotherapy?

Immunotherapy refers to treatments that use the body's own immune system to combat diseases; immuno-oncology specifically involves immunotherapy directed at cancer.

Immunotherapy includes a variety of treatments that work in different ways: some are intended to boost the immune system defenses in a general way; others help train the immune system to recognize and attack cancer cells specifically. So far it appears that this type of treatment works better for some types of cancer than others. The immune system, which is a collection of organs, specialized cells and substances that protect against infectious organisms, can help protect against cancer. Often, however, cancer cells make themselves "invisible" to the immune system by masquerading as harmless body cells.

How is Immunotherapy Used to Fight Cancer?

If you take the brakes off the immune system, you can unleash an attack on cancer cells. That's the theory behind PD-1/PD-L1, a vitally important immunotherapy discovery illustrated in this video.

Types of Immunotherapy

Cancer vaccines are substances given to people to prevent cancer from developing, or to treat existing cancers by strengthening and optimizing the body's immune response against the tumors. Examples of preventive cancer vaccines are those that protect against infection with the human papilloma virus (HPV), which causes cervical cancer and some other cancers, including cancers of the mouth and throat.

The first cancer treatment vaccine was approved by the Food and Drug Administration in 2010. Called Provenge, it is designed to stimulate an immune response against metastatic prostate cancer. Provenge is customized to each individual patient.

Researchers are testing experimental treatment vaccines in a variety of cancers, including melanoma, brain tumors, breast cancer, kidney cancer, leukemia, and others.

Cancer vaccines can be combined with other types of therapies.

Monoclonal antibodies are synthetic copies of antibody proteins that exist in the immune system and whose job is to identify foreign invaders by binding to specific proteins called antigens on the surface of cells. After they bind, antibodies recruit other cells and substances of the immune system to attack the foreign cells.

Researchers can make large numbers of identical (monoclonal) synthetic antibodies in the laboratory and give them to cancer patients. Monoclonal antibodies can be used to block so-called "checkpoint molecules," such as CTLA-4, PD-1, and PD-L1 and thereby "release the brake" from immune cells in order for these cells to kill tumor cells more effectively. Other monoclonal antibodies attach to and block antigens that cancer cells use to grow and spread. Still other monoclonal antibodies carry a radioactive substance, drug, or toxin that kills cancer cells that are recognized by the antibody.

Read our Insight blog for information and inspiration about Dana-Farber and immunotherapy.