Vaccinations are finding a new role in medicine. Traditionally, vaccines have been used as a preventive tool to protect us from disease like polio, tetanus, or small pox. These vaccines work by challenging one’s immune system with an inactive agent similar to the real pathogen. Thus, when faced with the real disease agent our body is able to effectively and efficiently mount an offensive to prevent illness.
More recently, strides have been made to harness the body’s defense system to better fight current illnesses, such as cancer, through the development of therapeutic vaccines.
Last week, the preliminary data on a vaccine to treat a type of brain tumor was presented at the American Association of Neurological Surgeon’s annual meeting.
Glioblastoma multiforme is the most common and aggressive type of brain cancer – this type of tumor claimed the lives of both Senator Ted Kennedy and the Met’s catcher Gary Carter.
The disease progresses very rapidly and even with aggressive treatment (surgery, radiation and chemotherapy), most patients survive only a few months following diagnosis. Novel therapies represent the only hope for prolonging survival.
Currently, a vaccination, HSPPC-96, against a tumor specific protein is being tested against Glioblastoma multiforme in a phase II clinical trial. At the meeting, the authors revealed that those treated with the vaccine experienced a 50 percent improvement in survival times compared to those treated with other therapies.
HSPPC-96 contains proteins purified from a patient’s own tumor tissue and is designed to activate the immune system, specifically target the cancer cells. The goal is that the immune system will attack the cancer cells while sparing the normal neural and glial cells, it is truly personalized medicine.
The goal of this type of immune therapy is not to eradicate the disease but to transform the cancer into a manageable chronic condition. The same philosophy has been applied to many other tumors, including lymphoma, melanoma, colon cancer and prostate cancer. For instance, experimental vaccines are currently being studied to treat non-Hodgkin’s lymphoma.
Small clinical trials have shown that vaccines directed at lymphoma specific surface proteins are associated with tumor shrinkage, prolonged treatment responses and improved survival. As the vaccine solely targets tumor cell, the hope is that patients will experience fewer side-effects, as compared with traditional therapies.
While promising, the majority of these vaccines are still in their infancy and require further testing before they are ready for widespread use. Sipuleucel-T (Provenge) is currently the only FDA approved cancer vaccine used to treat metastatic prostate cancer. For this vaccine, the patient’s immune cells are collected and exposed to a prostate cancer protein. The newly educated immune cells are infused back into the patient, where they mount an immune attack targeting prostate cancer cells anywhere in the body.
In clinical trials, patients receiving the therapeutic vaccine had a significantly decreased risk of death as compared to placebo, resulting in its FDA approval in 2010.
Current therapies, radiation, surgery, and chemotherapy, have been proven to provide effective treatment for many cancers. Unfortunately, treatment deficits still exist and we have yet to gain complete control of this disease.
Personalized medicine represents the future of cancer therapy. At this time, we don’t always know why some patients have full recovery while other relapse after the same treatment.
However, efforts are underway to refine current protocols to better pair ones specific disease characteristics with the optimal treatment, in order to maximize ones response. Further research is needed in this field to better understand the natural history of cancer and develop therapeutic solutions to current obstacles.
To learn more about ongoing clinical trials visit the National Cancer Institutes at www.cancer.gov.