Radium-223 Chloride: New Hope for Prostate Cancer Patients

Alpha-pharmaceutical radium-223 chloride has been targeted as a potentially groundbreaking therapy for the treatment of castration-resistant prostate cancer patients with bone metastases.

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Results of an exciting new trial dealing with the benefits of radium-223 chloride (Alpharadin) for the treatment of certain prostate cancers were reported ahead of presentation schedule at a press briefing during the 2012 Genitourinary Cancers Symposium, which takes place February 2-4, 2012, in San Francisco, California.

The ALSYMPCA (Alpharadin in Symptomatic Prostate Cancer) trial, presented by lead author Oliver Sartor, MD, medical director at Tulane Cancer Center, examined the impact of novel agent Radium-223 and how it targets bone in the treatment of advanced prostate cancer patients with bone metastases. Bone metastases are a common problem for patients with castration-resistant prostate cancer (CRPC).

Researchers found that the “alpha-pharmaceutical” radium-223 emits targeted short-range radiation that focuses on areas of bone stroma damaged by a tumor. This particle was found to have a high antitumor effect on bone metastases, but does not hurt normal tissue because the short-range radiation only reaches cells directly to its target.

“As the radium deposits in this altered stroma, it ends up radiating the tumor and the surrounding areas, but it does so in an extremely localized fashion,” Dr. Sartor noted.
Results from the trial indicated  that radium-223 “halved the risk of bone fracture and spinal cord compression, and reduced the need for external beam radiation by a third in hormone-refractory prostate cancer metastatic to bone,” according to a report by Medpage Today.

The trials by Dr. Sartor and colleagues support previous research surrounding the radium-223 particle for the same indication, as reported at the 2010 ASCO Annual Meeting and appearing in the Journal of Clinical Oncology. In those trials, authors report that radium-223 was shown to have a promising survival benefit, a benign safety profile, and an improvement in pain in CRPC patients suffering from bone metastases.

Alpha-pharmaceuticals such as radium-223 have been studied as injectables, and would most likely be dispensed by a specialty pharmacist if they provide a significant enough benefit to patients to gain FDA approval in the future. The FDA assigned radium-223 a Fast Track designation in August 2011.