Skeletal Related Events (Sres) In Metastatic Androgen Independent Prostate Cancer (Aipc) Treated With Docetaxel-Based Chemotherapy: Results From Ascent.

4614 Background: Docetaxel prolongs survival in AIPC patients and zoledronic acid (ZA) reduces the incidence of SREs. The SRE incidence of patients treated with docetaxel-based chemotherapy has not previously been reported. Methods: ASCENT was a randomized clinical trial that compared weekly DN-101 (calcitriol, 45 μg p.o. on day 1) plus docetaxel (36 mg/m2 iv on day 2 for 3 weeks of a 4-week cycle) to placebo plus docetaxel in patients with chemotherapy-naïve metastatic AIPC. ZA use was not restricted. SRE-free survival was described for the entire group and then compared for patients randomly assigned to DN-101 or placebo and stratified by ZA use. Statistical comparisons were conducted using Cochran-Mantel-Haenszel for incidence and log-rank for SRE-free survival. Results: With a median follow-up of 18.3 months, 33% of subjects experienced at least one SRE and the overall median SRE-free survival was 13 (95% CI 10.5–14.3) months. The incidence of SRE by type was: radiation to bone (18.8%), fracture (10%), spinal cord compression (4%), surgery to bone (0.4%). Eighty-five (34%) patients received ZA. The study was not adequately powered to measure the impact of DN-101 or ZA on SRE endpoints. Exploratory analyses showed a trend for an increase in SRE-free survival (HR 0.78, p = 0.13) of DN-101-treated patients. SRE-free survival and incidence for subgroups were examined ( Table ). Conclusions: This is the first report of SRE incidence in a large, prospective study of docetaxel-based therapy. Improved therapies for reducing SREs in AIPC are needed because the risk of SREs remains high despite the use of modern chemotherapy and ZA. [Table: see text] [Table: see text]