Some Vaccines Have Been Approved to Prevent Cancer-Causing Infections

Several cancervaccines are currently in use and many, many more are in the experimental stage in clinical trials. Cancer vaccines boost the body’s natural ability to protect itself through the immune system.

The U.S. Food and Drug Administration (FDA) has approved two types of preventive cancer vaccines. One vaccine was designed to prevent Hepatitis B (which can lead to liver cancer) and another to prevent human papillomavirus types 16 and 18 (HPV) infection and effectively prevents about 70 percent of cervical cancer.

And just recently (2010) the FDA approved a vaccine designed to treat (as opposed to prevent) metastatic prostate cancer in men. It has been used successfully to lengthen survival. Named sipuleucel-T (Provenge®), it is individualized to each patient by using immune cells from the patient’s body.

Cancer vaccines may lead to major improvements in cancer treatment in the future. Some studies to date have shown positive results and some have not.

If you are interested in clinical trials for cancer vaccines, check out the list offered on the NCI Factsheet on Cancer Vaccines.

More Cancer Vaccines on the Horizon

We already discussed the first FDA approved cancer vaccine, Provenge^©, an individualized treatment for metastatic (late stage) prostate cancer. The Journal of the National Cancer Institute recently published an article explaining the process of developing new cancer vaccines. According to the National Cancer Institute there are currently nine phase III clinical trials and 64 phase II clinical trials testing cancer vaccines. Cancer vaccines are developed to treat cancer—they’re not preventive.

The problem in developing vaccines has been to find a way to stimulate the body’s immune system to fight cancer. Cancer cells produce antigens which in turn trigger an immune response—often too weak to kill or weaken the cancer cells. NCI researchers are studying numerous ways to make it easier for your immune system to identify and mount a stronger response to destroy cancer cells. Cancer treatment vaccines have two goals. First, they must stimulate specific immune responses against the correct target. Second, the immune response must be strong enough to overcome the barriers that cancer cells use to protect themselves.

Vaccines were first tested on patients with late stage cancer who had suppressed (weakened) immune systems. Some current trials focus on patients with earlier stage cancers and stronger immune systems. Vaccines may work better when combined with standard treatments including chemotherapy and radiation.

Are you interested in a cancer clinical trial using a cancer vaccine? Go to the NCI clinical trials database and check out your type of cancer and see what clinical trials are available. Vaccines have the added benefit of minimal toxic side effects.

Want to know more about cancer vaccines? The NCI has an extensive Cancer Vaccine Fact Sheet online.

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How Will Cancer Vaccines Work?

When you are vaccinated for smallpox, measles, or shingles your body is flooded with antigens that trigger your immune system to produce antibodies and/or to activate immune “killer cells” to fight the perceived disease threat.

When the injected antigens are a weaker version of molecules in or on a cancer cell, the body creates ‘killer T cells’ to attack the cancer cells with that molecule. The body can also create B-cells that produce antibodies to the molecule, and by extension, the cancer cell.  The activated immune cells and/or antibodies are then able to attack cancer cells in the future that have the same molecule—this could create lifelong immunity to that specific type of cancer.

Vaccines must mimic parts of the cancer cells in the body in order to be effective. And the body must be healthy enough to produce an immune response.

In 2010 the U.S. FDA approved the first-ever tumor vaccine, called Provenge (also called Sipuleucel-T), to treat prostate cancer. Numerous vaccines are now being tested. There are many types of cancer and identifying the specific makeup of each individual’s cancer cells and creating or matching a vaccine specific to that type of cancer can be time consuming and expensive. 

Stopping Cancer—could the immune system hold the key?

Researchers hope new vaccines may be one of the answers.

Traditional cancer treatment often involves surgery, radiation, and chemotherapy. While these approaches often have success, cancer is still a leading cause of death. More than 150 types of cancer have been identified.

One of the newest treatment approaches uses vaccines to treat cancers. A unique feature of these vaccines is that they stimulate your own immune system to identify and kill cancer cells. This works much the same as the vaccines you have had for smallpox, measles, and other diseases, except it has been far more difficult with cancer. Unlike infections, which are caused by foreign organisms invading our bodies, cancer comes from within and therefore is much better at evading the immune system.

In recent clinical trials using vaccines, some participants have had their cancer growth stopped and a fortunate few have remained cancer-free since treatment. Why some patients respond to vaccines and others do not is still something of a mystery and the focus of intensive research.

Treatments like radiation and chemotherapy depress or weaken the immune system and can cause serious side effects. Cancer vaccines strengthen your immune system and are less likely to cause serious side effects.

Testing new vaccines will mean many clinical trials before they’re perfected and approved by the FDA (U.S. Food and Drug Administration).

Learn more about cancer vaccines from the American Cancer Society.