Immunotherapy is one of the most technologically advanced yet basic forms of cancer treatment. It uses the body’s own defense mechanism, the immune system, to fight cancer.
Immunotherapy is probably most familiar to you in the form of vaccinations for the flu, polio, chicken pox, and other contagious diseases. In those cases, people are injected with a dead or weakened form of the virus responsible for the disease. That prompts the immune system to produce antibodies and white blood cells that ward off infection from the live virus.
For cancer prevention, two immune system-stimulating vaccines are now in use: one to protect against infection by the hepatitis B virus, which can give rise to liver cancer; and one to prevent infection by the human papillomavirus (HPV), which is linked to cervical cancer, some cancers of the head and neck, as well as anal and penile cancers.
Immunotherapy has also become a key weapon in doctors’ arsenal for treating cancer. At many hospitals around the country, immune system-based approaches now account for nearly half of the treatments against the disease.
Such approaches can take a variety of forms, such as monoclonal antibodies, immune system proteins that zero in on diseased cells, and transplants of blood-forming stem cells, which can rebuild the immune system of patients with leukemia, multiple myeloma, and other blood-related cancers.
In 2010, a therapy called Provenge became the first therapeutic cancer vaccine to receive approval the U.S. Food and Drug Administration (FDA). It uses specially treated samples of patients’ own tumor cells to spark an immune system attack on cancer. The technique behind Provenge and therapeutic cancer vaccines now in clinical trials was pioneered by Dana-Farber scientists and their colleagues at other institutions.
One of the newest forms of immunotherapy for cancer uses antibodies to release a “brake” on the immune system’s response to tumors. Ipilimumab, an antibody that blocks a “stop!” signal on immune system cells, became the first agent to prolong the survival of melanoma patients in a clinical study and was approved for use by the FDA last year. A related approach, targeting a separate signal, has shown very encouraging effects in several types of tumors, including lung cancer, kidney cancer, colon cancer, melanoma, and lymphoma.
As we learn more about the fundamental operations of the immune system, scientists are honing vaccines to make them more specific – better able to target particular types of cancers while minimizing damage to healthy tissue – and longer lasting. In one promising approach, Dana-Farber investigators are using tiny polymer scaffolds to control the release of immune system-stimulating proteins, potentially prolonging the immune system’s attack on cancers.