Cancer vaccines represent another approach to marshaling the immune system's disease-fighting forces against cancer. Some of these vaccines consist of cancer cells, parts of cells, or immune-stimulating proteins called antigens. Others involve removing some of a patient's white blood cells and exposing them to a protein from the cancer, along with a stimulatory molecule. The process primes the white cells to attack cancer when they're reinjected into the body.
One type of cell-based vaccine involves removing certain immune system cells from a patient's blood and sending them to a lab. The cells display cancer-related proteins called tumor antigens to T cells, which use the information to identify and attack cancer cells. For the vaccine, dendritic cells are combined with a stimulatory protein and infused back into the patient through a vein. The process may be repeated several times, a few weeks apart, so patients receive multiple doses of the cells. The side effects are usually mild and can include fever, chills, fatigue, back and joint pain, nausea, and headache. Provenge®, a prostate cancer therapy that is the only vaccine approved to treat cancer in the U.S., is an example of a dendritic cell vaccine. This approach is under investigation in other cancers as well.
Another approach is to construct a vaccine out of cancer cells that have been removed from the patient during surgery. The killed tumor cells are processed in a lab to make them more "visible" to the immune system, then re-injected into the patient along with an immune-stimulating compound. The patient's immune system launches a vigorous attack not only on the newly-injected cancer cells but also on similar cells throughout the body. An example of this type of vaccine is GVAX, which is used to treat pancreatic cancer and is the subject of a recently completed clinical trial in patients with acute myelogenous leukemia. A recently opened trial is testing it in pediatric patients with neuroblastoma.
Protein-based vaccines represent still another way to "teach" the immune system to confront cancer cells in the body. This approach is based on increasing immune system's ability to detect tumor antigens, proteins on the surface of tumor cells that advertise the cells' cancerous identity. Patients first undergo surgery to have the bulk of their tumor removed. Cells from the tumor are sent to a lab where they are engineered to display new antigens indicative of cancer. Reinjected into the patient, the cells are primed to draw a strong, focused immune system attack on other cancer cells in the body.
At Dana-Farber Brigham Cancer Center, investigators are leading clinical trials of this type of vaccine, known as NeoVax, in patients with melanoma or glioblastoma brain cancer.
Cellular therapies are being expanded for the treatment of many different types of cancer and non-cancerous diseases. Patients should check with their care team about the availability of such therapies for their particular condition.