[7] The principal use of radium-223, as a radiopharmaceutical to treat metastatic cancers in bone, takes advantage of its chemical similarity to calcium, and the short range of the alpha radiation it emits.
[17] Taking account of its preferential uptake by bone and the alpha particles' short range, radium-223 is estimated to give targeted osteogenic cells a radiation dose at least eight times higher than other non-targeted tissues.
[11] The phase II study of radium-223 in castration-resistant prostate cancer (CRPC) patients with bone metastases showed minimum myelotoxicity and good tolerance for the treatment.
223Ra received priority review as a treatment for an unmet medical need, based on its ability to extend overall survival as shown its Phase III trial.
Another single-arm, open-label Phase II trial reported possible efficacy of 223Ra combined with endocrine therapy in hormone-receptor-positive, bone-dominant breast cancer metastasis.
[26] The most common side effects reported during clinical trials in men receiving 223Ra were nausea, diarrhea, vomiting and swelling of the leg, ankle or foot.