In the phase @ , randomised , double-blind ALSYMPCA trial , patients with symptomatic castration-resistant prostate cancer , at least two symptomatic bone metastases , no known visceral metastases , and who were receiving best standard of care were randomly assigned ( @:@ ) via an interactive voice response system to receive six injections of radium-@ ( @ kBq/kg intravenously ) or matching placebo , with one injection given every @ weeks .