The Southwest Oncology Group (SWOG) announced
the beginning of the first major phase III clinical trial comparing
the combination of docetaxel (Taxotere) and estramustine (Emcyt) to
the commonly used combination of mitoxantrone (Novantrone) and
prednisone in the treatment of advanced, hormone-refractory prostate
cancer. Patient enrollment is currently underway, with approximately
660 men being recruited. This trial is being conducted by SWOG and is
funded by the National Cancer Institute (NCI) in collaboration with
the Cancer and Leukemia Group B (CALGB) and North Central Cancer
Treatment Group (NCCTG).
Phase I/II studies have shown that the combination of docetaxel and
estramustine is very active and well tolerated in patients with
hormone-refractory prostate cancer. The encouraging response
rates seen thus far with the combination of docetaxel and
estramustine provide hope that using a tolerable, more effective
combination may prolong life in this group of difficult-to-treat
patients, said SWOG study chair Daniel P. Petrylak, md,
assistant professor of medicine at Columbia College of
Physicians and Surgeons, and director of the Genitourinary Oncology
Program at Columbia Presbyterian Center of New York.
The primary objectives of the study are to: (1) determine whether the
docetaxel-estramustine combination improves overall and
progression-free survival, as compared with the
mitoxantrone-prednisone; and (2) compare toxicities related to the
two treatments. Other objectives include assessments of the decline
of prostate-specific antigen (PSA) levels and of quality of life
among both treatment groups.
Although prior clinical trials using single-agent chemotherapy have
yielded objective response rates of 10% to 20% with subjective or
stable response rates in another 20% to 40% of patients, no single
agent or combination treatment has demonstrated a survival benefit in
patients with advanced, hormone-refractory prostate cancer in phase
III trials. The reported survival duration in these trials ranges
from 5 to 11 months.
Palliative benefit can be achieved by administering mitoxantrone with
corticosteroids; however, there is no evidence that survival is
prolonged with this therapy. There is an obvious need for new
therapies based on novel methods of inhibiting cancer growth,
said Dr. Petrylak.
For the present phase III study, participants will be randomized to
one of two treatment regimens: (1) oral estramustine taken three
times daily for 5 days combined with intravenous docetaxel
administered on the second day of treatment; or (2) intravenous
mitoxantrone administered every 3 weeks with twice-daily oral
prednisone taken for 3 consecutive weeks. A maximum of 12 cycles of
either treatment regimen will be administered.
For more information about this study (S9916), contact the National
Cancer Institutes toll-free Cancer Information Service (CIS) at 1-800-4-CANCER.