- Patients must have current evidence of progressive castration-resistant disease that is asymptomatic. Progressive disease is defined by a) radiological evidence of progression: any increase of > 25% in the products of diameters or 30% in maximum diameter of any measurable lesion; or appearance of an unequivocally new lesion OR b) two consecutive rises in serum PSA of any magnitude measured at least 2 weeks apart, to a level above 2 ng/ml.