4612 Background: Until recently the standard approved regimen for symptomatic HRPC has been mitoxantrone/prednisone (MP). The regimen has proven efficacy in pain reduction and improvement in quality of life but has not shown survival benefit. No standard chemotherapy has been approved in the second line setting. Prior to the reporting of the phase 3 results of Tax 327 and SWOG 9916, phase II data showing efficacy with docetaxel/prednisone (DP) led to considering DP in patients progressing after prior MP and was the rational for this study. Objectives: Determine the tolerabilty and response to docetaxel 75mg per square meter every 3 weeks and prednisone 5mg BID in the second line setting in patients with metastatic HRPC having progressed after first line MP. Methods: Thirty patients (30) from 4 centers have been entered in the study. All patients had had prior MP for symptomatic, metastatic HRPC. Baseline PSA, pain scores, analgesic scores, bone scan and CT of the abdomen and chest were obtained. Patients ...