Biologic Therapy: The Basics
What is biologic therapy and how does it work?
Biologic therapies use substances that occur naturally in your body, are man-made versions of these substances, or living organisms to help the body fight cancer. The therapy may stimulate your body to make more of a substance that can attack cancer cells, the therapy may be a man-made version of that natural substance itself or the therapy may target something found on the cancer cells. Biological therapies may use cells from the patient's body, which have been altered in a laboratory, and given back to the patient. Other names for biologic therapies include: biologic agents, biologics, biological response modifiers (BRMs), or immunotherapy.
Biologic therapy differs from chemotherapy. Biologic therapy works with the immune system to fight cancer, whereas chemotherapy affects cancer cells directly. The body's immune system helps to prevent disease, but it also plays a role in preventing cancer from developing or spreading. The goal of biologic therapy is to enhance the body’s natural defenses and its ability to fight cancer. Biologic treatments work to strengthen or restore the body’s natural immune function to make it easier for the immune system to destroy the cancer cells and to prevent cancer from spreading to other parts of the body.
Types of biologic therapy
Some biologics are used to help deal with the side effects of other treatments. For example, colony stimulating factors (G-CSF or Neupogen) can help the body increase the production of white blood cells after chemotherapy and thereby decrease the risk of neutropenia, and in turn, infection. Epogen is an injectable biologic that stimulates red blood cell production. Just as there are many different ways of stimulating the immune system, there are different types of biologic therapies. Some of the biologic therapies include: Cytokines (interferon, interleukin, colony stimulating factors), monoclonal antibodies (Rituxan, Herceptin), vaccines, live organisms (BCG) and gene therapy.
How are biologic therapies given?
Biologic therapies may be given by mouth (pill), into a vein (intravenously), or by injection, either under the skin (subcutaneous) or into a muscle (intramuscular). Therapies may also be given directly into a body cavity to treat a specific site. For example, bladder cancer can be treated with a biologic therapy administered into the bladder. Some of these therapies are approved by the U.S. Food and Drug Administration, but many are still being tested in clinical trials. Depending on the type of cancer and how far it has spread, some patients may only need biologic therapy, while others may receive this in conjunction with other therapies (i.e. chemotherapy, surgery, or radiation therapy).
What are the side effects of biologic therapies?
Although many biologic therapies use substances that occur naturally in the body, side effects can occur as a result of the increased production or the higher-than-normal levels of these substances. The most common side effects with biologic therapies are the result of the "revving up" and stimulation of the immune system. They include fever, chills, body aches (flu-like symptoms), nausea/vomiting, loss of appetite, and fatigue. Depending on the doses and how the therapy is administered, patients may experience an allergic type reaction that may cause a decrease in blood pressure, difficulty breathing, rash or swelling at the injection site. Each therapy may have side effects specific to the cells that are being affected by the therapy. Your healthcare team will review potential side effects of the therapy you are receiving. Biologic therapies are relatively new, and we are still learning what long-term side effects they may lead to years later. Visit OncoLink Rx to learn more about a specific therapy.
How do I know if biologic therapy is working?
Patients may have radiology studies (CT scans, MRIs, PET scans) periodically to see if the tumor has responded (either shrunk or stayed the same versus grown). Some types of tumors can be measured in the blood with a "tumor marker." This is a substance that is either produced by the tumor or by the body in response to the tumor, and can be measured by a blood test. If the chemotherapy is working, one would expect the tumor marker to decrease. In some cases, a decrease in a patient's symptoms may signal whether or not the medications are shrinking the tumor. Talk with your healthcare team about how your response will be measured.
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