KANSAS CITY, Mo. — The vaccine that Larry Mathews is getting won't protect him from the flu. That's OK — the stakes are far higher than that.
He's hoping the shots will prime his immune system to fight the aggressive cancer that has invaded his brain. If it works as he wants it to, his body's own killer cells will mop up malignant cells that surgery, radiation and chemotherapy couldn't eliminate.
For decades, scientists have been trying to create vaccines like this to recruit the body's immune system to destroy cancer cells the way it wipes out foreign viruses and bacteria.
After many false starts and premature promises, it appears that their research is beginning to pay off.
In late April, the U.S. Food and Drug Administration approved the first cancer vaccine, Provenge, that can modestly extend the lives of men with advanced prostate cancer. Several major insurance plans and Medicare claims processors in some parts of the country, including Kansas and Missouri, already have agreed to pay for the costly treatment.
Mathews is taking part in a preliminary clinical study at St. Luke's Hospital on a brain cancer vaccine developed at the University of Kansas Medical Center. A larger two-year study aimed at gaining FDA approval is planned to start this fall.
Worldwide, scientists are working on dozens of vaccines against melanoma, breast cancer and cancers of the lung, colon and pancreas.
Researchers can cite anecdotes of cancer patients given months to live who have survived 15 years or longer after receiving vaccines. But so far, conclusive evidence from large clinical trials is scant.
Even so, experts anticipate that several cancer vaccines could prove effective enough to gain FDA approval in the next four or five years.
The goal for vaccines is to train the immune system to recognize ways that cancer cells differ from normal cells and motivate it to attack.
By trial and error scientists have identified targets on cancer cells, called antigens, that the immune system can identify as different from normal cells. They also better understand components of the immune system that recognize antigens and alert the immune system's killer cells.
Vaccines represent a major shift in thinking about how to treat cancer, said James Gulley, a researcher at the National Cancer Institute. Conventional cancer therapies aim toxic drugs and radiation at tumors, but can harm other tissues and cause nausea, fatigue, hair loss and other side effects.
Vaccines narrowly target the immune system. Side effects — fever, chills, soreness at the injection site — typically aren't much greater than what you may get from a flu shot. But getting vaccinated can take much longer than a flu shot.
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