Bone-targeting radiopharmaceuticals for the treatment of prostate cancer with bone metastases

Patients with castration-resistant prostate cancer (CRPC) frequently have metastases to the bone, which may cause pain and lead to a deterioration in quality-of-life. Bone-seeking radiopharmaceuticals are agents which, when administered systemically, localize to the site of bone metastases and deliver focal radiation there. In this review, we will summarize the current literature on bone-targeting radiopharmaceuticals for CRPC, focusing on strontium-89, samarium-153, rhenium-186 and radium-223. We will discuss their indications, clinical efficacy, and toxicities and highlight some of the challenges in optimizing treatment with these agents. Historically, clinical trials with these drugs have failed to demonstrate survival improvements, restricting their use for palliative purposes only. Radium-223 is the first agent in this class to show an overall survival advantage in CRPC patients with bone metastases. This landmark finding will likely have a considerable impact on the treatment paradigm of bone-metastatic CRPC, and will pave the way for further developments in the future.