Serum alkaline phosphatase changes predict survival independent of PSA changes in men with castration-resistant prostate cancer and bone metastasis receiving chemotherapy

Abstract Objectives The association of a change in serum alkaline phosphatase (ALP) with overall survival OS in men with metastatic castration-resistant prostate cancer (CRPC) receiving chemotherapy is unknown. We evaluated the association of changes in ALP within 90 days with OS in men with CRPC and bone metastases treated with docetaxel or mitoxantrone in the TAX327 trial. Materials and methods Eligible patients included those with bony metastatic disease, baseline ALP ≥ 120 u/L (upper limit of normal) and ≥2 post-therapy measurements of ALP available. Survival was estimated using the Kaplan-Meier method and prognostic potential of change in ALP was evaluated using Cox proportional hazards regression. Surrogacy was calculated by the Likelihood Reduction Factor. Results 601 patients met the eligibility criteria. By day 90, 159 patients had ALP normalization (