Hormone-refractoriness: Defined by a rise in PSA and/or RECIST-based progression of evaluable lesions, and/or increased number of hotspots on a bone scan, while the patient has a castrated level of testosterone. This castrated level may have been obtained by orchiectomy, or LH-RH analog ± antiandrogen. Antiandrogen must be discontinued for at least 4 weeks before study entry to exclude a withdrawal effect.