(Ivanhoe Newswire) -- A common respiratory virus, called a reovirus, may
provide a new, safe approach to treating prostate cancer.
The reovirus is a non-attenuated, environmental virus that has oncolytic
potential -- the ability to cause cancer cell death -- against many types of
cancer, specifically lymphoid, ovarian, breast, pancreatic and high grade glioma
cancer, according to a new study. This is the first time the virus has been
studied in the area of prostate cancer.
"The reovirus is a very common, ubiquitous virus that most people are exposed
to," Don Morris, M.D., Ph.D., medical oncologist in the Department of Oncology
at the Tom Baker Cancer Center in Alberta, Canada, was quoted as saying. "As far
as we know, it doesn't cause any significant illness in humans, even though when
someone is exposed to it, it manifests, at most, as a mild respiratory infection
or mild diarrhea. For the treatment of localized prostate cancer, we found that
the reovirus is safe and has evidence of specific tumor vs. normal prostate cell
efficacy."
Dr. Morris and colleagues examined the efficacy of the reovirus as an
experimental therapeutic for prostate cancer in vitro and in vivo. Among the six
patients who participated in the study, all had early-stage, organ-confined
prostate cancer. Each patient underwent a single intralesional virus injection
into a suitable prostate cancer nodule via transrectal ultrasound guidance.
Three weeks later, Dr. Morris and his team removed the prostate as part of the
patient's standard treatment for correlative science analysis.
Findings showed safety and efficacy with minimal toxicity and no viral
replication in the normal parts of the prostate, according to Dr. Morris. Cancer
cell death was evident in the prostate. Studies to date have suggested that the
virus' side effects are relatively modest, consisting of mild, self-limiting,
flu-like symptoms.
"Our results are a stepping stone into future prostate cancer clinical trials
with another category of cancer therapeutics," said Dr. Morris.
Robert Clarke, Ph.D., D.Sc., professor of oncology at Lombardi Comprehensive
Cancer Center at Georgetown University, agreed, stating that he believes this
study is worthy of subsequent clinical trials of the reovirus as a possible way
of treating some prostate cancers.
"People have known of this application of the reovirus in trials, but no one to
my knowledge has conducted studies in prostate cancer," Dr. Clarke was quoted as
saying. "I think this is an interesting approach. There is not a lot done in
oncolytics, but clearly it is an area that is getting increasing attention, and
we need everything we can get our hands on to make a difference in these
patients."
SOURCE: Cancer Research, March 9, 2010
