Biological Therapies for Cancer: Questions and Answers
3. What are biological response modifiers, and how can they be used to treat cancer?
Some antibodies, cytokines, and other immune system substances can be produced in the laboratory for use in cancer treatment. These substances are often called biological response modifiers (BRMs). They alter the interaction between the body's immune defenses and cancer cells to boost, direct, or restore the body's ability to fight the disease. BRMs include interferons, interleukins, colony-stimulating factors, monoclonal antibodies, vaccines, gene therapy, and nonspecific immunomodulating agents. Each of these BRMs is described in Questions 4 to 10.
Researchers continue to discover new BRMs, to learn more about how they function, and to develop ways to use them in cancer therapy. Biological therapies may be used to:
- Stop, control, or suppress processes that permit cancer growth.
- Make cancer cells more recognizable and, therefore, more susceptible to destruction by the immune system.
- Boost the killing power of immune system cells, such as T cells, NK cells, and macrophages.
- Alter the growth patterns of cancer cells to promote behavior like that of healthy cells.
- Block or reverse the process that changes a normal cell or a precancerous cell into a cancerous cell.
- Enhance the body's ability to repair or replace normal cells damaged or destroyed by other forms of cancer treatment, such as chemotherapy or radiation.
- Prevent cancer cells from spreading to other parts of the body.
Some BRMs are a standard part of treatment for certain types of cancer, while others are being studied in clinical trials (research studies). BRMs are being used alone or in combination with each other. They are also being used with other treatments, such as radiation therapy and chemotherapy.
4. What are interferons?
Interferons (IFNs) are types of cytokines that occur naturally in the body. They were the first cytokines produced in the laboratory for use as BRMs. There are three major types of interferons-interferon alpha, interferon beta, and interferon gamma; interferon alpha is the type most widely used in cancer treatment.
Researchers have found that interferons can improve the way a cancer patient's immune system acts against cancer cells. In addition, interferons may act directly on cancer cells by slowing their growth or promoting their development into cells with more normal behavior. Researchers believe that some interferons may also stimulate NK cells, T cells, and macrophages, boosting the immune system's anticancer function.
The U.S. Food and Drug Administration (FDA) has approved the use of interferon alpha for the treatment of certain types of cancer, including hairy cell leukemia, melanoma, chronic myeloid leukemia, and AIDS-related Kaposi's sarcoma. Studies have shown that interferon alpha may also be effective in treating other cancers such as kidney cancer and non-Hodgkin lymphoma. Researchers are exploring combinations of interferon alpha and other BRMs or chemotherapy in clinical trials to treat a number of cancers.