Biologic therapies (biotherapy) focus on the body's biological response to the tumor. Most of these therapies take advantage of the body's immune system, either directly or indirectly, to fight cancer or to lessen the side effects that may be caused by some cancer treatments.
In order for cancer to succeed, it must contend with the immune system. The immune system consists of a complex network of cells and organs that work together to defend the body against invaders, like bacteria and viruses.
The key cells involved in the immune system include:
Lymphocytes—This type of white blood cells are concentrated in areas of the body that commonly encounter hostile invaders (eg, gastrointestinal system, respiratory system, lyphatic system). Types of lymphocytes include:
- B cells—lead to the production of antibodies
- Cytotoxic T cells—directly attack infected or cancer cells
- Helper T cells—regulate the immune system's response by signaling other immune system cells
- Natural killer (NK) cells—produce powerful chemical substances that bind to and kill invaders
- Macrophages—a type of white blood
Cytokines—chemicals produced by both lymphocytes and monocytes; examples include:
- Colony-stimulating factors
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Biologic therapies repair, stimulate, or enhance the body’s response to cancer. According to the Leukemia and Lymphoma Society, biologic therapies:
- Eliminate, regulate, or suppress conditions that allow uncontrolled cell growth
- Enhance the immune system to fight the uncontrolled growth of cancer cells
- Make cancer cells more vulnerable to destruction by the immune system
- Change the growth patterns of cancer cells so that they are more like normal cells, and are less likely to metastasize (spread)
- Block or reverse the process that changes a normal or precancerous cell into a cancerous cell
Enhance the body's ability to repair normal cells that get damaged by other forms of treatment for cancer (eg,
- Prevent a cancer cell from spreading to other parts of the body
Biologic therapies are most commonly used either to treat cancer that does not or has not responded to other forms of treatment or to try to treat tumors that may respond to the body’s own immune defenses.
The most common biologic therapies include:
- Interferons (IFN)
- Interleukins (IL)
- Colony-stimulating factors (CSF)
- Monoclonal antibodies (MOAB)
Interferon (IFN) occurs naturally in the body. IFN is produced by virally infected cells and is capable of protecting other cells from infection. There are three major types:
Researchers have found that interferons enhance the immune system’s ability to fight cancer cells and act directly on these cells by slowing growth and encouraging normal cell behavior.
Like interferons, interleukins (IL) occur naturally in the body and can be synthesized in a lab. Interleukins are named numerically: IL-1, IL-2, IL-3, up to IL-18.
IL-2 has been the most widely studied in cancer treatment. This type of interleukin stimulates the growth and activity of many cancer-killing immune cells, including NK cells and cytotoxic T cells. In addition, IL-2 enhances antibody responses.
(Proleukin) is an IL-2 that is used to treat
Colony-stimulating factors (CSFs) do not affect cancer cells directly. Instead, CSFs help stimulate the production of new red blood cells, white blood cells, and platelets. This is important because many cancer treatments can decrease the levels of blood cells, which increases the risk of infection,
anemia, and bleeding problems. Stimulating blood cell production can help stimulate the immune system.
Some examples of CSFs include:
G-CSF (Neupogen) and GM-CSF (Leukine, Prokine)—increase the number of white blood cells, which reduces the risk of infection; also used to stimulate the production of stem cells in preparation for stem cell or
bone marrow transplants
Erythropoietin (Epogen, Procrit)—increase the number of red blood cells and reduce the need for
red blood cell transfusion
- Oprelvekin (Neumega)—increase the number of platelets and reduce the need for platelet transfusions
Monoclonal antibodies (MOABs) are substances that are produced in a lab. The process involves injecting a mouse with cells for a certain type of human cancer. Once injected with the cancer cells, the mouse produces antibodies to fight against the cancer. These mouse antibodies are then combined with other lab cells to create hybrid cells to fight caner.
MOABs can be used in cancer treatment in a number of ways, for example:
- React with certain types of cancer, which may enhance the immune response
- Be programmed to act against specific cell growth factors to interfere with the growth of cancer cells
- Be linked to anticancer drugs, radioactive substances, other biologic therapies, or other toxins
- Possibly help destroy cancer cells in bone marrow (during the process of bone marrow transplant)
There are a number of MOABs available, such as:
Rituximab (Rituxan)—used to treat
Trastuzumab (Herceptin)—used to treat
when the tumor expresses excess amounts of a protein called HER-2
Cetuximab (Erbitux)—used to treat cancers of the
rectum, as well as head and neck cancer
- Panitumumab (Vectibix)—used to treat colorectal cancer
Bevacizumab (Avastin)—used to treat a certain type of
kidney cancer, colon cancer, rectum cancer,
lung cancer, and breast cancer
Alemtuzumab (Campath)—used to treat
chronic lymphocytic leukemia
- Ipilimumab (Yervoy)—used to treat melanoma
The side effects depend on the type of biologic therapy that is used.
At the beginning of therapy, you will most likely experience flu-like symptoms. Examples include chills, headaches, muscle pain, joint pain, and discomfort.
Chronic side effects tend to increase in intensity after you have been on IFN therapy for several weeks. Loss of appetite with weight loss and fatigue can be severe enough to limit the dose. Other side effects include:
- Lack of energy
- Lack of concentration
- Decreased blood counts
- Protein in your urine
- Low blood pressure
Less common side effects:
- Nausea and vomiting
- Altered taste
- Mood swings
- Decreased sex drive
- Memory problems
More common side effects include:
- Flu-like symptoms (eg, chills, fever, fatigue, headache, muscle pain, joint pain)
- Gastrointestinal effects (eg, nausea, vomiting,
diarrhea, decreased appetite)
Other side effects include:
- Skin—redness, rash, dry skin, itchiness
Heart and lungs—low blood pressure, rapid heart rate,
arrhythmia, edema (fluid retention), weight gain
Nervous system—confusion, disorientation, drowsiness, lethargy,
anxiety, depression, irritability
Decreased blood counts—anemia, thrombocytopenia,
- Problems with kidney function
Severe toxicities are associated with high doses of IL-2.
CSF therapy is generally well tolerated. The side effects are minimal. Bone pain is one of the most commonly reported side effect.
With MOABs, allergic reaction to mouse protein is a major concern. The acute reaction can result in
anaphylaxis, a severe, sometimes life-threatening, allergic reaction. This is rare, though.
More common side effects include:
- Nausea and vomiting
- Difficulty breathing
- Low blood pressure
A delayed toxicity that can occur is called serum sickness. Symptoms of serum sickness include:
- Joint pain
- Swollen glands
- Flu-like symptoms
Biologic therapies: using the immune system to treat cancer. National Cancer Institute webite. Available at:
http://www.cancer.gov/cancertopics/factsheet/Therapy/biological. Accessed September 4, 2012.
Biological therapy for lung cancer. CancerHelp UK website. Available at:
http://cancerhelp.cancerresearchuk.org/type/lung-cancer/treatment/biological-therapy-for-lung-cancer. Accessed September 4, 2012.
Vachani C. Biologic therapy: the basics. OncoLink website. Available at:
http://www.oncolink.org/TREATMENT/article.cfm?c=16&s=117&id=335. Updated November 22, 2010. Accessed September 4, 2012.
Last reviewed September 2012 by Igor Puzanov, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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