Vitamin D Aids Chemotherapy For Advanced Prostate Cancer.
Orlando
FL, 20 May 2002
Calcitriol
May Safely Double Effectiveness of Taxotere® Treatment
The
addition of high-dose calcitriol to weekly treatment with the chemotherapy
agent docetaxel (Taxotere®) appears to improve the therapeutic
response in men with hormone-refractory prostate cancer without
compromising safety, according to results reported at the 38th Annual
Meeting of the American Society of Clinical Oncology (ASCO). Calcitriol
is the active form of vitamin D.
Data
from a phase II clinical trial suggest as much as twice the efficacy
with the docetaxel/calcitriol combination than docetaxel alone,
as measured by prostate-specific antigen (PSA) response rate. The
study showed that 81 percent of patients treated with the combination
regimen cut their PSA levels by more than half. Studies of docetaxel
without calcitriol have reported a 42 percent PSA response rate
overall. PSA is a substance produced within the prostate gland,
and a high PSA level may indicate the presence of cancer. In patients
with advanced prostate cancer, PSA correlates with the amount of
cancer in the body.
"Because
there is no standard treatment for hormone-refractory prostate cancer,
new therapeutic strategies are clearly needed," said Tomasz Beer,
MD, an oncologist at the Oregon Health & Science University (OHSU)
Cancer Institute in Portland, Oregon, and lead investigator of the
study. "Docetaxel used alone has shown promise in treating prostate
cancer, and our new data strongly indicate that the favorable results
can be enhanced with the addition of high-dose vitamin D."
The
study included 37 men with hormone-refractory prostate cancer, or
disease that was progressive despite standard hormonal therapy,
including anti-androgen withdrawal. In addition to PSA response,
eight of 15 men with measurable disease responded with significant
reductions of their tumors.
Patients
in the study received oral calcitriol, 0.5 mcg/kg, (micrograms)
on the first day of the treatment cycle, followed by an infusion
of docetaxel, 36 mg/m2, on the following day. The treatment was
repeated weekly for six weeks of an eight-week cycle until there
was evidence of disease progression or unacceptable toxicity, or
until the patient requested to be withdrawn from the study.
The
results of this phase II study are now the basis for a future phase
III study to be conducted at OHSU and other institutions. That randomized
study will evaluate the use of weekly docetaxel versus weekly docetaxel
plus calcitriol in hormone-refractory prostate cancer.
Prostate
cancer is the most common malignancy among men and the second leading
cause of cancer death in men in the United States. The American
Cancer Society estimates that in 2002, approximately 189,000 men
will be diagnosed with the disease, and about 32,200 will die of
it. Overall, roughly one in six American men will develop prostate
cancer during his lifetime. If detected early, however, treatment
can be highly effective.
Oregon
Health & Science University is a health and research university
focused on improving the well-being of people in Oregon and beyond.
OHSU educates health practitioners, bioscientists, high-technology
professionals, and environmental scientists and engineers, and it
undertakes the indispensable functions of patient care, community
service and biomedical research.
Source
Oregon
Health & Science University, via PR Newswire.
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