Review: Biological Therapy

Edward Jenner, William Coley, Paul Ehrlich, and Steven Rosenberg are important names in the brief history of biological therapy research.

Our immune system is a very important line of defense against "foreign invaders" such as bacteria, viruses, or cancer cells. What makes it unique is that it can recognize "foreign invaders," and then develop the specific weapons to fight them. Biological therapy uses materials made by our own body or made in a laboratory to boost, direct, or restore our body's natural defenses against diseases such as cancer.

Two basic biological therapies exist: immunotherapy and cytotoxic therapy. Immunotherapy uses a variety of methods and drugs to manipulate the immune system to create a hostile environment for the cancer in the body, while cytotoxic therapy involves changing the cancer cells' biology so that they become weak and die.

In biological therapy, biologically derived agents are either used to modify the relationship between tumor and host. This is altering the host's biologic response to tumor cells with a resultant therapeutic effect or by activating the patient's immune system and inducing to attack cancer cells. Common biological agents include interferons, monoclonal antibodies, interleukins, growth factors, and tumor vaccines. Side effects do occur with biological therapy, but the type of effects and severity of effects depend on each individual patient and the drug(s) they are administered.

Bone marrow transplantation is often used to replace stem cells destroyed by high doses of chemotherapy and/or radiation therapy, or to directly attack the malignancy. Depending on the donor of the bone marrow, bone marrow transplant can be categorized as autologuous, syngeneic, or allogeneic.