Groundbreaking immunotherapy: More tailored, less toxic treatments
Inside your body, standing at attention in your blood, tissues, and organs, there are millions of tiny troopers mobilized against invaders. They are the cells of your immune system, a powerful battalion divided into regiments: some attacking on the front lines, some sneaking into enemy territory to gather information, some running messages to the generals who will map the battle plan. They do a good job — a great job, even — but they are not invincible.
Occasionally, your body meets a foe too strong or too devious to overpower on its own. Cancer is one such opponent. This disease is almost impossible to defeat without enlisting foreign aid; traditionally, surgery, chemotherapy and radiation. These therapies are powerful, but they have limitations.
"If you apply these conventional therapies correctly all the time, you’re only going to cure about half the people who develop cancer," says Walter J. Urba
, M.D., Ph.D., director of cancer research, Robert W. Franz Cancer Research Center in the Earle A. Chiles Research Institute at Providence Cancer Center. "And because these therapies aren’t always able to distinguish between normal and abnormal cells, they can damage healthy cells and cause serious side effects. We need cancer treatments that work differently."
Dr. Urba leads a team of researchers who are focused on developing new therapies that do just that. The treatments they are investigating are designed to boost the immune system’s ability to identify and mount an informed attack against abnormal cells, leaving healthy cells alone. This approach, called immunotherapy, offers the potential for treatments more tailored and less toxic than traditional therapies.
Using the immune system to fight cancer
Immunotherapy rsearch underway at the Franz Cancer Center is focused on the development of therapeutic agents to fight cancer using the immune system.
"A cancer cell is different in every patient," Dr. Urba says. "If you take five women with breast cancer, the cancers in those five women are not the same. The genetic changes that caused the malignancy probably have something in common, but they are not identical in each patient."
Immunotherapy research is currently focused on understanding the differences between individual cancers, and refining the immune system’s responses to cancer. Knowledge gained will help determine answers to the most important questions in cancer vaccine research, according to Dr. Urba: "Can we consistently induce a strong immune response to tumor antigens in patients with cancer, and if we do, will the tumor go away?"
Current immunotherapy research, combined with ongoing study of genetic mutations that increase a person’s risk of cancer, may someday make preventive cancer vaccines possible. But as a first step, it is hoped that immunotherapy will offer effective new treatment options for existing disease.
Cancers being studied
Franz Cancer Center scientists are focused on researching immunotherapies for many cancer types: melanoma, breast cancer, prostate cancer, lung cancer, renal cell (kidney) cancer, colon cancer and others.
Kidney cancer and melanoma have shown the most susceptibility to immunotherapeutic approaches. These cancers have little in common except a unique record of spontaneous remissions. "In both types of cancer, there are extremely rare cases in which the tumors have just gone away," Dr. Urba says. "Our hypothesis is that the patients’ immune system came into effect, but we don’t know why it happens in these patients and not in others."
In addition, when early immunotherapy agents were tested on a variety of cancers, melanoma and kidney cancers proved unusually susceptible to the therapies. Because of these characteristics, most cancer immunotherapy researchers are studying these two cancers.
Efforts to find effective immunotherapies for breast, prostate, lung cancer and colon cancer are underway primarily because the diseases are major public health problems. "When we find something that works for these types of cancer, it will help a lot of people," Dr. Urba says.
The future of immunotherapy
Two immunotherapy agents have been recently approved by the Food and Drug Administration for use in patients with advanced cancer. Both new agents are monoclonal antibodies. Rituxan® (rituximab) is used to treat patients with non-Hodgkins lymphoma, and Herceptin® (Trastuzumab) is used to treat women with breast cancer. Neither Rituxan nor Herceptin are curative, but they are extending survival in people with advanced disease.
Dr. Urba expects that within the next decade, immunotherapy will begin to play a prominent role — alongside surgery, radiation and chemotherapy — in the treatment of more cancers.
Is an immunotherapy trial right for you?
Cancer immunotherapy research is still in its early stages. While it may eventually become an important therapeutic tool, it is not approved as standard treatment for people with cancer.
For people who have been diagnosed with cancer and are choosing a treatment approach, Dr. Urba recommends the following steps:
- Select a good doctor in whom you have confidence
- Have a frank conversation with him or her about what the standard treatments are, and take the time to research your options
- Participate in all conventional therapies that are available to you
"If standard treatments don’t work or an effective treatment is not available for your type of tumor," Dr. Urba says, "You should discuss experimental options with your physician. Bear in mind that not all experimental therapy is immunotherapy. I encourage you to consider all kinds of experimental therapy to find what’s right for you."
Definitions used in this article
: A protein or carbohydrate substance (as a toxin or enzyme) capable of stimulating an immune response
: A relatively permanent change in hereditary material Remission : A state or period during which evidence of a disease can no longer be detected.
: An antibody is a specialized protein produced by white blood cells after stimulation by an antigen. It acts specifically against the antigen in an immune response. Monoclonal antibodies are identical antibodies produced in the laboratory from a single, cloned cell.