The researchers perform the treatment by first taking a certain amount of a particular type of the patients own immune cells, called dendritic cells. These cells are messengers of sorts, telling other cells in the immune system what they should be mounting an attack against.
In a New Jersey lab, these cells are fused with a substance called prostatic acid phosphatase -- normally present only on prostate tumor cells.
The result is a treatment that offers a kind of "target practice" for the T-cells, the immune cells responsible for getting rid of threats within the body.
"Essentially, this shows the T-cells where to aim," says Provenge investigator Dr. David Penson, associate professor of urology and preventive medicine at the Keck School of Medicine at the University of Southern California in Los Angeles.
With the new treatment showing some promise in its first three studies, many may now wonder whether this treatment strategy may be applied to other cancers as well.
Part of the appeal of this therapy is that it is specifically targeted to prostate cancer cells -- and only those cells. Other cells remain untouched, which means that the worst side effects experienced by those in the trials so far have been a few fevers and chills, which are easily treated with Tylenol.
"This drug is very, very non-toxic," Vieweg says.
Penson agrees. "This is not like classic chemo; there is no loss of hair, no sickness associated with it."
Though initial trials were performed only on men whose prostate cancer was at an advanced stage, the hope is that it will eventually show promise in patients with earlier phases of prostate cancer.
And cancer experts say the need for a new treatment option is growing. But for now, only a few patients with the worst prognoses are considered for participation in trials.
"This is not for every prostate cancer patient -- it is for a select group only, the most desperate patients."
However, researchers also hope the treatment will eventually be used as a front-line therapy, as it may be able to help those experiencing the first stages of prostate cancer as well.