Biological response modifiers (BRMs) are substances that help to fight infections. Many of these substances can be found naturally in small amounts in the body. BRMs are produced in the laboratory in larger amounts and then injected into the body to treat cancer. Sometimes the BRMs are combined with chemotherapy drugs. This helps to improve the effect of the chemotherapy. However, BRMs are not effective against most cancers.

The following are general types of BRMs:

Cytokines. This class of BRMs includes interferon and interleukin-2. These substances are normally produced by the body. These help to fight viral infections and to kill abnormal cells. Interferon gets into the cells that are affected by a virus or a cancer. It then stops the virus or cancer from multiplying. Interferon has been used to treat viral infections like hepatitis A, B, C and D. It has also been used to treat multiple sclerosis.

Interferon is used to treat some people with the following types of cancer:

Interleukin-2 has been used to treat certain types of kidney cancers.

A class of cytokines called colony-stimulating factors (CSFs) are used to stimulate the bone marrow to recover after chemotherapy. Each type of CSF causes the bone marrow to produce a different kind of blood cell: white cells, red cells, and platelets.

Monoclonal antibodies. These medications are made to cause the body to attack a cancerous tumor. The body acts the same way as when it responds to a viral infection. Sometimes the antibody is attached to a medication used in chemotherapy. The antibody is targeted against a specific cancer or tumor. As the antibody attacks the tumor, the chemotherapy medication is then delivered directly to the tumor. Many of these agents are still experimental.

Tumor vaccines. This is an experimental group of medications. Large studies of tumor vaccines are underway. These agents are made from bits of tumors. This is similar to how vaccines against other diseases are made. When the tumor vaccine is given to a person with that particular tumor, it is hoped that the body will attack the tumor and keep it from growing.

Other immunotherapy. A type of bacteria called bacillus Calmette-Guerin (BCG) can be injected into the body to treat certain types of cancer. BCG does this by causing the body to mount a general immune response. This causes the body to attack the cancer.

BCG has been injected directly into tumors caused by melanoma, a serious form of skin cancer. Injecting BCG into the bladder in the early stages of bladder cancer can destroy the cancer. This treatment will also help prevent the cancer from returning.

Who is a candidate for the procedure?

This form of therapy is offered to a person whose cancer may be sensitive to BRMs. Cancer in an early stage is more likely to respond to BRMs than later stages of the disease.

How is the procedure performed?

BRMs are most often given by injection into tissue or into a vein. This method gets the medications into the body quickly. Some BRMs are injected directly into a tumor or near a tumor.