July 2015, Special ASCO Edition
Docetaxel Boosts Survival in Hormone-Naive Metastatic Prostate Cancer
Adding docetaxel to standard hormone therapy extends overall survival (OS) by a median of 10 months versus hormone therapy alone in men with newly diagnosed, advanced hormone therapy–naive prostate cancer according to results from the STAMPEDE trial. The survival benefits were more pronounced in metastatic disease and were less certain in nonmetastatic disease. Another finding of this analysis of STAMPEDE is that zoledronic acid had no benefit in this setting.
“Docetaxel should be routinely used in patients with metastatic hormone-naive prostate cancer as part of up-front treatment. In nonmetastatic disease, docetaxel should be offered to men about to start hormones for the first time, because it prolongs failure-free survival. There is some uncertainty regarding its effect on overall survival in men with nonmetastatic disease, and longer follow-up is needed,” said lead author Nicholas David James, MD, PhD, University of Warwick in Coventry, UK.
STAMPEDE, the largest randomized clinical trial to date in prostate cancer, has a multiarm, adaptive design. The standard-of-care (SOC) arm continues to enroll patients on an ongoing basis, as ineffective treatments are discarded and more effective treatments are added to the SOC arm according to trial results.
James presented OS results for 2962 hormone-naive men with advanced prostate cancer randomized to 1 of 4 treatment arms of 9 ongoing treatment arms. Men were randomized between October 2005 and March 2013 in a 2:1:1:1 ratio to SOC, SOC with docetaxel for 6 cycles, SOC with zoledronic acid for 2 years, and SOC with both docetaxel and zoledronic acid.
In this comparison in hormone-naive men, SOC treatment was at least 3 years of androgen-deprivation therapy with local radiation for suitable patients. At a median follow-up of 42 months, 948 deaths were reported.
OS was a median of 77 months in the SOC plus docetaxel arm versus 67 months for SOC alone, for a 24% relative improvement in survival. OS was longer in the subset of men with metastatic disease when docetaxel was added to hormone therapy, a difference of 22 months favoring docetaxel.
Patients with metastatic disease had a clinically and statistically significant 37% improvement in survival, whereas the study was not fully powered to detect a significant survival benefit in the nonmetastatic group.
The addition of docetaxel to hormone therapy does lead to some increased toxicity, James said.
STAMPEDE adds further support to results from the CHAARTED trial presented at ASCO 2014, which showed a significant survival advantage when docetaxel was added to hormone therapy in hormone-sensitive advanced prostate cancer. At present, the SOC for men with newly diagnosed hormone-sensitive metastatic prostate cancer should be up-front docetaxel plus hormone therapy.
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