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The alpha radiation emitting radiopharmaceutical radium-223 was approved as a treatment for patients with castration-resistant prostate cancer who have symptomatic bone metastases on May 15, 2013. The decision was based on the phase III ALSYMPCA trial, which demonstrated a median OS of 14.0 months with radium-223 compared with 11.2 months with placebo (HR = 0.70; P = .00185).
Alpha radiation has a short range, causing less damage to the healthy tissue surrounding the tumor. Moreover, a similarity between the chemical structure of radium-223 and calcium results in the treatment being preferentially taken up by the bones, specifically those with metastatic lesions, explains Raoul S. Concepcion, MD.
Various regulations exist on a state-by-state basis regarding the use of radium-223, which is administered by a radiation oncologist or nuclear medicine specialist, notes Richard Harris, MD. The recommended dose for the medication is 50 kBq/kg (1.35 microcuries/kg) by a slow intravenous injection over the course of 1 minute every 4 weeks for 6 cycles.
The approval of radium-223 for patients with prostate cancer emphasizes the importance of clinical trials, the panelist notes. Various tools exist for connecting patients with clinical trial programs, notes Sanford J. Siegel, MD. One such item provides a pop-up within the electronic medical record with applicable clinical trials. Clinical trials allow patients access to emerging therapies years before they are approved or available, adds Harris.