Weekly docetaxel and zoledronic acid every 4 weeks in hormone-refractory prostate cancer patients

Objectives: To investigate the safety and efficacy of docetaxel and zoledronic acid in patients with hormone-refractory prostate cancer (HRPC), based on preclinical evidence of synergism between taxanes and bisphosphonates. Methods: Twenty-five patients with advanced HRPC received weekly docetaxel 30 mg/m²: in 18 patients with symptomatic bone metastases and normal renal function, docetaxel was combined with zoledronic acid, 4 mg i.v. every 4 weeks. Premedication consisted of intravenous dexamethasone before docetaxel. No oral steroids were given. Results: Overall, 12 patients (48%) had a PSA response (reduction of 50% or more compared to baseline). A PSA response was achieved in 8/18 patients (44%) receiving concomitant docetaxel and zoledronic acid, and in 7/12 patients (58%) receiving docetaxel and zoledronic acid as first-line therapy. The weekly schedule of docetaxel resulted in a mean received dose intensity of 26 mg/m²/week, or 87% of the planned dose intensity. Toxicity was mild and as expected for docetaxel. The median time to progression was 7 months, and the median overall survival was 16 months. Conclusions: Concomitant treatment with docetaxel and zoledronic acid is safe and has encouraging activity in HRPC. The combination should be evaluated in randomised clinical trials.