Biological Therapies for Cancer: Questions and Answers
9. What is gene therapy?
Gene therapy is an experimental treatment that involves introducing genetic material into a person's cells to fight disease. Researchers are studying gene therapy methods that can improve a patient's immune response to cancer. For example, a gene may be inserted into an immune cell to enhance its ability to recognize and attack cancer cells. In another approach, scientists inject cancer cells with genes that cause the cancer cells to produce cytokines and stimulate the immune system. A number of clinical trials are currently studying gene therapy and its potential application to the biological treatment of cancer. (More information about gene therapy is available in the NCI fact sheet Gene Therapy for Cancer: Questions and Answers, which can be found at http://www.cancer.gov/cancertopics/factsheet/Therapy/gene on the Internet.)
10. What are nonspecific immunomodulating agents?
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 and immunoglobulins. Two nonspecific immunomodulating agents used in cancer treatment are bacillus Calmette-Guerin(BCG) and levamisole.
BCG, which has been widely used as a tuberculosis vaccine, is used in the treatment of superficial bladder cancer following surgery. BCG may work by stimulating an inflammatory, and possibly an immune, response. A solution of BCG is instilled in the bladder and stays there for about 2 hours before the patient is allowed to empty the bladder by urinating. This treatment is usually performed once a week for 6 weeks.
Levamisole is sometimes 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.
11. Do biological therapies have any side effects?
Like other forms of cancer treatment, biological therapies can cause a number of side effects, which can vary widely from agent to agent and patient to patient. Rashes or swelling may develop at the site where the BRMs are injected. Several BRMs, including interferons and interleukins, may cause flu-like symptoms including fever, chills, nausea, vomiting, and appetite loss. Fatigue is another common side effect of some BRMs. Blood pressure may also be affected. The side effects of IL-2 can often be severe, depending on the dosage given. Patients need to be closely monitored during treatment with high doses of IL-2. Side effects of CSFs may include bone pain, fatigue, fever, and appetite loss. The side effects of MOABs vary, and serious allergic reactions may occur. Cancer vaccines can cause muscle aches and fever.
12. Where can a person get more information about clinical trials?
Information about ongoing clinical trials involving these and other biological therapies is available from the Cancer Information Service (see below) or the clinical trials page of the NCI's Web site at http://www.cancer.gov/clinicaltrials/ on the Internet.