Ra-223 Delays Skeletal-Related Events in Advanced Prostate Cancer

The use of Radium-223 dichloride (Ra-223) significantly delays the time to skeletal-related events (SRE) in patients with prostate cancer that has spread to the bones. These results were recently presented at the 2013 annual genitourinary cancers symposium of the American Society of Clinical Oncology.

Besides skin cancer, prostate cancer is the most commonly diagnosed cancer among men in the United States. Fortunately, if prostate cancer is detected and managed early, survival rates are high. However, once the cancer has spread to the bones (bone metastases), cure rates fall dramatically.

Patients with bone metastases are at a significantly increased risk of experiencing a SRE. SREs can include bone fractures, spinal cord compression (an emergency situation), paralysis and extreme pain. Besides being associated with decreased survival, SREs can significantly reduce a patient’s quality of life, often necessitating surgery, immobility, external radiation and/or additional medication. Therefore, researchers continue to explore novel ways in which to delay the time a patient experiences their first SRE.

Ra-223 is a type of radioactive particle that has been designed for pharmaceutical use. It is given intravenously and travels to new areas of bone formation, such as bone metastases. Once bound, Ra-223 delivers radiation to nearby cells, such as cancer cells in the bone.

Researchers from the United States and Europe recently evaluated results from a large clinical trial (ALSYMPCA) evaluating Ra-223 among prostate cancer patients with bone metastases. These patients had stopped responding to standard therapies and their cancer was progressing. The trial included 921 patients: one group of patients received Ra-223 and the other group received placebo (inactive substitute).

The time to an initial SRE was delayed by nearly 6 months in the group of patients treated with Ra-223 compared to those who received placebo.
Patients treated with Ra-223 had a reduction in all types of SRE compared to the group treated with placebo
The researchers concluded that “ Ra-223 is an effectivetherapy with a highly favorable safety proļ¬le and may provide a new standard of care for treatment of CRPC pts with bone mets.”

Reference: Vogelzang N, Parker C, Nilsson S, et al. Updated analysis of radium-223 dichloride (Ra-223) impact on skeletal-related events (SRE) in patients with castration-resistant prostate cancer (CRPC) and bone metastases from the phase III randomized trial (ALSYMPCA). Proceedings from the 2013 annual genitourinary cancers symposium of the American Society of Clinical Oncology. Abstract #11.