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Prostate Cancer Study Results Far Exceed
Expectations
Reported June 23, 2009
(Ivanhoe Newswire) -- Two Mayo Clinic patients whose aggressive
prostate cancer tumors had grown well beyond the prostate into the abdominal
areas and had been considered inoperable are now cancer free thanks in part
to an experimental drug therapy.
The men were participating in a clinical trial of an immunotherapeutic agent
called MDX-010 or ipilimumab. In these two cases, physicians say the
ipilimumab initiated the death of a majority of cancer cells, causing the
tumors to shrink sufficiently to allow surgery. "The goal of the study was
to see if we could modestly improve upon current treatments for advanced
prostate cancer," Eugene Kwon, M.D., Mayo Clinic urologist and leader of the
clinical trial is quoted as saying. "The candidates for this study were
people who didn't have a lot of other options. However, we were startled to
see responses that far exceeded any of our expectations."
The patients first received a type of hormone therapy called androgen
ablation, which removes testosterone and usually causes some initial
reduction in tumor size. Researchers then introduced a single dose of
ipilimumab, an antibody which builds on the anti-tumor action of the hormone
and causes a much greater immune response, resulting in massive death of the
tumor cells. Both men experienced consistent drops in their prostate
specific antigen (PSA) counts over the following weeks until both were
deemed eligible for surgery.
The greatest surprise came during surgery. "The tumors had shrunk
dramatically," Michael Blute, M.D., Mayo urologist, co-investigator and
surgeon, who operated on both men, is quoted as saying. "I had never seen
anything like this before. I had a hard time finding the cancer. At one
point the pathologist (who was working during surgery) asked if we were
sending him samples from the same patient."
One patient underwent radiation therapy after surgery; both have resumed
their regular lives. Further research is being planned to understand more
about the mechanisms of the antibody and how best to use the approach in
practice.
The researchers note the significance of their findings.
"This is one of the holy grails of prostate cancer research," says Dr. Kwon.
"We've been looking for this for years."
SOURCE: Discovery's Edge, Mayo Clinic research publication, June 20, 2009 |
