Radium-223 Dichloride, otherwise known as Xofigo, is the first alpha-emitting radiopharmaceutical used to treat prostate-cancer-related bone metastasis. The FDA approved Xofigo in May of 2013. The clinical trial that led to the FDA approval was called the ALSYMPCA trial. Eligible patients were randomized in a 2:1 fashion to either receive six monthly intravenous injections of radium-223 or best standard of care, such as antiandrogen hormonal therapy, local external beam radiation, corticosteroids, estramustine, or ketoconazole. The men who received radium-223 had improvement in bone pain and also experienced an increased survival.

Radium-223 is used to treat bone metastases, a common problem for men living with metastatic hormone resistant prostate cancer (MHRPC), affecting up to 90% of these patients. The development of a drug called radium-223 (brand name: Xofigo) is a substantial innovation, not only because it causes less toxicity compared to its predecessors, but also because it prolongs life.

Given enzalutamide’s unique and multi-targeted mechanism of action, its once a day oral administration, avoidance of accompanying requirement of a steroid, and its established safety and efficacy data, it appears to be a very promising therapy. Future studies should investigate both combination strategies with other approved prostate cancer drugs, as well as the potential role of enzalutamide in earlier stages of both CRPC and androgen-sensitive prostate cancer.