Radium-223 dichloride for metastatic prostate cancer: long-term safety profile and future opportunities

Prostate cancer is the most common new cancer diagnosis and the second leading cause of cancer death in men in the United States. Worldwide, it is the second most common cancer in men (1). As a result of screening, the majority of new cases are diagnosed when the disease is localized and can be cured. For patients who develop metastatic disease, androgen deprivation therapy (ADT) has been the first line of treatment. Unfortunately, the disease eventually becomes castration-resistant [metastatic castration-resistant prostate cancer (mCRPC)], causing significant morbidity and mortality. There had been little progress in systemic therapy for mCRPC until 2004 when two randomized studies demonstrated that docetaxel improved the overall survival of these patients (2,3). In the last decade, five more new agents have been approved by the FDA for the treatment of mCRPC, the most recent one being radium-223 (²²³Ra) dichloride in 2013. In the ALSYMPCA study, patients with mCRPC were randomized to ²²³Ra or placebo (4). There was a significant improvement in median survival in patients receiving ²²³Ra for mCRPC as compared to placebo (14.9 vs. 11.3 months).