Improvement in overall survival seen in subset of patients
refractory to docetaxel
GPC Biotech AG (Frankfurt Stock Exchange: GPC, NASDAQ: GPCB) today
announced that data from the double-blind, randomized satraplatin Phase
3 trial, the SPARC trial (Satraplatin and Prednisone Against Refractory
Cancer) are being presented at the 2009 American Society for Clinical
Oncology (ASCO) Genitourinary Cancers Symposium in Orlando, Florida. The
SPARC trial evaluated satraplatin plus prednisone versus placebo plus
prednisone in 950 patients with androgen-independent or
castrate-refractory prostate cancer (CRPC) who had progressed after
initial chemotherapy. The data being presented today are the result of
pre-specified exploratory analyses of the SPARC trial, and they show an
improvement in overall survival in a subset of patients refractory to
docetaxel.
Of the 950 patients in the SPARC trial, 488 received first-line
docetaxel. As there is no universally accepted definition of
docetaxel-refractory CRPC patients, two definitions were adopted based
on the literature: R1) disease progression while on docetaxel or within
100 days of the last docetaxel dose; and R2) disease progression while
on docetaxel or within 50 days of the last docetaxel dose. Both R1 and
R2 patients were randomized to the SPARC trial within 100 days of
receiving their last docetaxel dose.
When stratified and adjusted for the three pre-specified prognostic
factors which showed statistically significant imbalances between the
two treatment arms (lactate dehydrogenase, hemoglobin and alkaline
phosphatase), there was a positive trend toward better overall survival
for the patients treated with satraplatin observed in the following
three groups: 1) in those patients who had progressed after receiving
docetaxel - hazard ratio 0.78 (95% CI: 0.61, 0.99); 2) in the R1 group -
hazard ratio 0.65 (95% CI: 0.47, 0.90) and 3) in the R2 group - hazard
ratio 0.69 (95% CI: 0.49, 0.96).
“There are currently no approved treatment options for advanced prostate
cancer patients once they become refractory to docetaxel. Thus, there is
an urgent need for new therapies for these patients,” said Daniel
Petrylak, M.D., Associate Professor of Medicine at Columbia University
College of Physicians & Surgeons, Director of the Genitourinary Oncology
Program at New York-Presbyterian Hospital/Columbia, and one of the
principal investigators of the SPARC trial. “I am encouraged by the
positive trends in overall survival observed in patients refractory to
docetaxel when adjusted for significant prognostic factors, along with
the treatment’s safety profile.
