OBJECTIVES: Radium-223 dichloride (Ra-223) is a novel alpha-radiopharmaceutical, which delayed time to first skeletal-related event (SRE) and improved overall survival versus best standard of care (BSoC) in patients with symptomatic castration-resistant prostate cancer (mCRPC) with bone metastases. This analysis evaluated economic benefits associated with Ra-223. METHODS: A Markov model was developed using patient-level data from a pivotal trial in which mCRPC patients receiving BSoC were randomized 2:1 to Ra-223 or placebo respectively. Patients entered the model progression-free, receiving active treatment until progression or completion of the therapy course. Health states reflected patients experiencing first or subsequent SRE.  In the trial, SRE was defined as treatment with external-beam radiation therapy (EBRT), surgical intervention, occurrence of pathological bone fracture, or spinal cord compression. A 5-year time horizon was considered. Costs were estimated from a US payer perspective. SRE costs were obtained by multiplying the number of patients experiencing SRE by its specific treatment cost (including hospitalization costs). RESULTS: Ra-223 increased mean life expectancy by 0.325 (95% CI: 0.324-0.326) years in the ITT population and 0.517 (95% CI: 0.516-0.518) years in the subgroup of patients who had not received first-line docetaxel. Ra-223 was projected to lead to 44% reduction in the cost of treatment of SREs versus BSC: 46% reduction in pathologic bone fracture costs; 48% for spinal cord compression; 16% for external beam radiation; and 11% for surgical interventions. A total of 32.9% of patients suffered a first SRE for Ra-223 versus 37.8% for placebo and 6.5% and 7.8%, respectively, suffered two or more SRE events. CONCLUSIONS: In patients treated with BSoC, Ra-223 reduced costs of SREs. Future studies will evaluate the total cost of care related to the benefit of Ra-223 versus placebo in patients treated with BSoC in mCRPC once the cost of therapy and the impact on quality adjusted survival are known.