 Patients will have PSA level and symptoms assessment checked every cycle. Every 3 cycles patients will have repeat boneCT scans to evaluate treatment response status. On CT scan, radiographic progression will be defined by RECIST criteria i.e. 20 increase in the sum of target lesions. On bone scan, radiographic progression will be defined by PCWG2 criteria as 2 new bone lesions. However, for the first reassessment scan only, patients should remain on study and have a confirmatory scan performed 12 weeks 3 cycles later. If this confirmatory scan shows 2 or more additional new lesions, this defines progression. The date of progression is the date of the first reassessment bone scan. If the confirmatory scan does not show any additional new lesions, patient remains on study. If progression is observed on subsequent bone scans, a confirmatory scan is not required; the date of this bone scan is the date of progression. 