Angiogenesis Inhibitors Therapy: Questions and Answers

Information courtesy National Cancer Institute Fact Sheet (NCI) (www.cancer.gov)
Reviewed: 12/06/2007
CancerNews

Angiogenesis Inhibitors Therapy: Questions and Answers

Key Points
Angiogenesis is the formation of new blood vessels and is controlled by chemicals in the body (see Question 1).
Tumors need blood vessels to grow and spread (see Question 2).
Angiogenesis inhibitors prevent the formation of new blood vessels so that the tumor cannot grow (see Question 3).
The U.S. Food and Drug Administration (FDA) has approved some angiogenesis inhibitors for the treatment of cancer (see Question 4).
Angiogenesis inhibitors have fewer side effects than many other cancer treatments, but they may only limit the growth of the cancer, not “cure” it (see Questions 5, 6, and 7).
Researchers continue to test new angiogenesis inhibitors and to investigate the way these drugs or chemicals work against different cancers (see Question 8).

What is angiogenesis?
Angiogenesis is the formation of new blood vessels. Angiogenesis is a process controlled by certain chemicals produced in the body. Some of these chemicals stimulate cells to repair damaged blood vessels or form new ones. Other chemicals, called angiogenesis inhibitors, signal the process to stop.

Why is angiogenesis important in cancer?
Angiogenesis plays an important role in the growth and spread of cancer. New blood vessels “feed” the cancer cells with oxygen and nutrients, allowing these cells to grow, invade nearby tissue, spread to other parts of the body, and form new colonies of cancer cells.

How can angiogenesis be stopped in tumors?
Because tumors cannot grow or spread without the formation of new blood vessels, scientists are trying to find ways to stop angiogenesis. They are studying natural and synthetic angiogenesis inhibitors, also called antiangiogenic agents, in the hope that these chemicals will prevent or slow down the growth of cancer by blocking the formation of new blood vessels.

Are any angiogenesis inhibitors currently being used to treat cancer in humans?
Yes. In 2004, the U.S. Food and Drug Administration (FDA) approved bevacizumab (Avastin®) for use with other drugs to treat colorectal cancer that has spread to other parts of the body and some non-small cell lung cancers. Bevacizumab was the first angiogenesis inhibitor proven to delay tumor growth and, more importantly, extend the lives of patients.

The FDA has also approved other drugs with antiangiogenic activity as cancer therapies for multiple myeloma, mantle cell lymphoma, gastrointestinal stromal tumors (GIST), and kidney cancer. Researchers are exploring the use of these drugs to treat other cancers too.

What are the advantages of angiogenesis inhibitors?
Angiogenesis inhibitors usually have only mild side effects and are not toxic to most healthy cells. Tumors do not seem to develop a resistance to angiogenesis inhibitors, even when given over a long period of time, unlike the resistance seen when chemotherapy drugs are used.

Angiogenesis inhibitors seem to help some chemotherapy drugs and radiation therapy work more effectively when given in combination.

What are the limitations of angiogenesis inhibitors?
Angiogenesis inhibitor therapy may not necessarily kill tumors, but instead may keep tumors stable. Therefore, this type of therapy may need to be administered over a long period. Because angiogenesis is important in wound healing and in reproduction, long-term treatment with antiangiogenic agents could cause problems with bleeding, blood clotting, heart function, the immune system, and the reproductive system (1).

Does angiogenesis inhibitor therapy have any complications or side effects?
A patient’s immune system may be compromised, making the patient more susceptible to infection and causing wounds to heal poorly, if at all. Patients may experience reproductive problems, and damage to the fetus is likely if a patient becomes pregnant while taking the antiangiogenic drug. Heart problems and high blood pressure could be made worse, and bleeding or blood clots could increase (1).

Since angiogenesis inhibitor therapy is still under investigation, all of the possible complications and side effects are still unknown.

What does the future hold for angiogenesis inhibitor therapy?
Other angiogenesis inhibitors are currently being evaluated in clinical trials (research studies) but have not yet been proven to be effective against cancer in humans. These studies include patients with cancers of the breast, prostate, brain, thyroid, pancreas, lung, stomach, ovary, and cervix; some leukemias and lymphomas; Kaposi sarcoma; and several other cancer types. If the results of clinical trials show that other angiogenesis inhibitors are both safe and effective in treating cancer in humans, these agents may be approved by the FDA and made available for widespread use. To learn more about clinical trials, call the National Cancer Institute’s (NCI) Cancer Information Service at the telephone number listed below or visit the clinical trials page of the NCI’s Web site at http://www.cancer.gov/clinicaltrials on the Internet. The NCI is a part of the National Institutes of Health.

Additional Authors:

Works Cited:

Selected References

Cohen MH, Gootenberg J, Keegan P, Pazdur R. FDA drug approval summary: Bevacizumab plus FOLFOX4 as second-line treatment of colorectal cancer. The Oncologist 2007; 12(3):356–361.

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Related NCI materials and Web pages:

National Cancer Institute Fact Sheet 2.11, Clinical Trials: Questions and Answers
(http://www.cancer.gov/cancertopics/factsheet/Information/clinical-trials)
National Cancer Institute Fact Sheet 6.7, Cancer: Questions and Answers
(http://www.cancer.gov/cancertopics/factsheet/Sites-Types/general)
National Cancer Institute Fact Sheet 7.2, Biological Therapies for Cancer: Questions and Answers
(http://www.cancer.gov/cancertopics/factsheet/Therapy/biological)
National Cancer Institute Fact Sheet 7.49, Targeted Cancer Therapies: Questions and Answers
(http://www.cancer.gov/cancertopics/factsheet/Therapy/targeted)
What You Need To Know About™ Cancer
(http://www.cancer.gov/cancertopics/wyntk/overview)

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