Preliminary results of a randomized placebo-controlled double-blind trial of weekly docetaxel combined with imatinib in men with metastatic androgen-independent prostate cancer (AIPC) and bone metastases (BM)

4562 Background: To further examine preclinical (Uehara, JNCI 2003) and clinical (Mathew, JCO 2004) evidence that the platelet-derived growth factor receptor (PDGFR) inhibitor, Imatinib, may modulate taxane activity in AIPC with BM, a randomized trial was conducted. Methods: 144 men with progressive AIPC with BM, no prior taxane, ECOG Performance Score (PS) ≤ 2, stratified by PS, hemoglobin, alkaline phosphatase and number of prior regimens, were planned for equal randomization to i.v. Docetaxel 30mg/m2 D 1, 8, 15, 22 q42 + Imatinib 600 mg daily (DI) or placebo (DP) for an improvement in time-to-progression (TTP) from 4.5 to 7.0 months (two-sided α = 0.05,β = 0.20). Secondary endpoints included toxicity, tumor response and phospho-PDGFR expression. An IRB review of gastrointestinal adverse events led to a recommendation to halt accrual early. Results: 104 evaluable men (52/arm) accrued between April 2003 and July 2005 were followed for a median of 7 months (range 0.5–23.4). The median TTP was 4.4 months (...