This page discusses the use of biologic therapy for the treatment of colorectal cancer. For a thorough review of biologic therapy for cancer treatment, please see the biologic therapy treatment monograph .

Biologic therapy, also called immunotherapy, is a treatment that uses drugs to improve the way your body’s immune system fights disease. Your immune system is your body’s natural defense against disease. A healthy and strong immune system can detect the difference between healthy cells and cancer cells. Biologic therapy attempts to repair, stimulate, or enhance the immune system so that it can fight the cancer more effectively. These therapies can be used to fight cancer or to lessen the side effects that may be caused by some cancer treatments.

The most common types of biologic therapy used for the treatment of colorectal cancer are:

  • Nonspecific immunomodulating agents
  • Interleukins

Nonspecific Immunomodulating Agents (Levamisole)

Nonspecific immunomodulating agents are substances that stimulate or indirectly augment the immune system. Often, these agents target key immune system cells and cause secondary responses such as increased production of cytokines (substances produced by cells of the immune system that affect immune response) and immunoglobulins (proteins that act as an antibody).

One type of nonspecific immunomodulator that is used in the treatment of colon cancer is levamisole. Levamisole is used along with fluorouracil (5–FU) chemotherapy in the treatment of Stage III (Dukes' C) colon cancer following surgery . Levamisole may act to restore depressed immune function. Levamisole is not as commonly used today because of its toxicity to the kidneys.

Side Effects

Side effects of levamisole include the following:

  • Possible allergic reaction, resulting in constriction of the nose and throat, swelling of the lips or tongue, and hives
  • Decreased bone marrow function, resulting in fatigue or signs of infection
  • Problems related to the nervous system, such as confusion, loss of consciousness, or speech disturbances

Special Considerations

  • Levamisole should not be taken if you have any of the following:
    • Liver disease
    • Seizure disorder
    • Bleeding or blood clotting disorder
  • Levamisole should not be used by women who may be pregnant.
  • Levamisole may lower your immune function, so you should avoid contact with people who have contagious illnesses.
  • Levamisole should not be taken in conjunction with the following medications:
    • Phenytoin (Dilantin)
    • Warfarin (Coumadin)
    • “Live” virus vaccine of any kind

Interleukins (IL)

Interleukins are cytokines that occur naturally in the body and can be made in the laboratory. Many interleukins have been identified; interleukin–2 (IL–2 or aldesleukin) has been the most widely studied in cancer treatment. IL–2 stimulates the growth and activity of many immune cells, such as lymphocytes, that can destroy cancer cells. Researchers continue to study the effects of interleukins for the treatment of various cancers, including colorectal cancer.

Side Effects

Side effects of interleukin-2 include the following:

  • Flu-like symptoms (chills, fever, fatigue)
  • Loss of appetite
  • Skin problems such as a rash, itchiness, scaling
  • Cardiac arrhythmias
  • Gastrointestinal disturbance, such as nausea and vomiting
  • Neurologic effects, such as depression and poor concentration

Effectiveness of Biologic Therapies for Colorectal Cancer

Research continues on the effectiveness of immunotherapy in general, and nonspecific immunomodulating agents and interleukins specifically for treatment of colorectal cancer. At this time, these therapies are generally used in conjunction with other forms of treatment such as surgery, chemotherapy, and radiation.

For more information on biologic therapies including how to manage side effects, see the biologic therapy treatment monograph.