Immunotherapy is a type of treatment that boosts the body's immune system to fight cancer.
Some types of immunotherapy are also called biological therapy.
Over the last decades, immunotherapy has become an important part of some types of cancer treatment. Currently, new types of immunotherapy are under development and they will affect the way we will be treating cancer in the future.
Key lines of immunotherapy include:
- Boosting the body’s immune system for more targeted and effective cancer treatment
- Administering additional components of the immune system
Just like other types of cancer treatment, immunotherapy targets some cancers with a higher intensity compared to others. It can be used as monotherapy or in combination with other types of treatment, like р chemotherapy.
Nowadays, healthcare uses several forms of immunotherapy:
Immune checkpoint inhibitors: this type of drugs prevents the “off” signal from being sent by checkpoints to immune cells, thus activating the immune cells to recognize and kill cancer cells. This group of drugs belongs to the category of monoclonal antibodies (see Target Therapy section for more information on monoclonal antibodies)
Vaccines: substances used to increase the body’s immune response against diseases. We often think about vaccines as a preventive method against infections in healthy people, but some vaccines play an important role in cancer treatment.
Nonspecific therapy: a set of actions aimed at increasing the efficiency of the immune system in general, which also improves its capacity to recognize and attack cancer cells.
CAR T-cell therapy: a form of cell therapy that helps modify the body’s immune cells, “teach” them to find cancer and actively fight it.
Allogeneic bone marrow transplantation: transplantation of bone marrow of a healthy person to the specially prepared body of a patient. Bone marrow of a healthy donor produces immune cells that actively seek and destroy cancer cells.
Immunotherapy can be used to fight the following diseases:
- colorectal cancer (bowel cancer)
- stomach cancer
- lung cancer
- bladder cancer
- kidney cancer
- head and neck cancer
- breast cancer
- Kaposi sarcoma
- Hodgkin lymphoma
- non-Hodgkin's lymphoma
- chronic myelogenous leukemia
- chronic lymphocytic leukemia
- acute lymphoblastic leukemia
- acute myeloblastic leukemia
Immune checkpoint inhibitors
An important part of the immune system is its ability to distinguish between normal and damaged, "abnormal" cells. This allows the immune system to selectively attack only harmful cells. To initiate an immune response, " checkpoints " - molecules on the immune cells necessary to "turn on (or off) the signal" - are used.
Tumor cells are sometimes capable of using these checkpoints to avoid being attacked by the immune system. Immuno-oncology drugs can "turn on" the immune response despite the blocking by tumor cells.
Today, there are 2 main types of drugs used in this form of immune therapy:
- drugs targeting PD-1 or PD-l1
- drugs targeting CTLA-4
PD-1 is the protein located on the surface of specific cells of the immune system - lymphocytes (T-cells).
Monoclonal antibodies (e.g., pembrolizumab and nivolumab) that target PD-1 or PD-L1, can stimulate an immune response against cancer cells.
CTLA-4 is another protein located on certain T-cells, which works on a similar principle. Binding this receptor (drug - ipilimumab) also allows for the activation of immune response.
Car T-cell therapy
Car T-cell therapy is a new promising way to obtain specialized immune cells, called T cells, by "tweaking" the patient's own cells in a laboratory.
On the surface of T-cells, used in this type of therapy, there is an artificially produced receptor, called CAR. This helps them find and destroy cancer cells.
Since different cancers have different cancer cells, each CAR is made for a particular type of cancer.
This type of therapy is currently used mostly for the treatment of patients with acute lymphoblastic leukemia and diffuse B-cell large cell lymphoma.
Anti-cancer vaccines can be divided into two main types:
The main type of preventive vaccine is a vaccine against human papillomavirus (certain types of it), that is the most common cause of cervical cancer.
Curative vaccines are a set of antigens, often derived from patient tumor cells, which are introduced into the body with the purpose to develop specific immune response, production of specific antibodies against tumor cells.
Non-specific immunotherapy stimulates the immune system in general, which leads to improved anti-cancer immune defense in particular.
A part of non-specific immunotherapy methods may be used as an independent type of therapy or in combination with other methods.
The main drugs used in non-specific immune therapy include:
- immunomodulating drugs (thalidomide, lenalidomide, pomalidomide).