Radium-223 Combined With Dexamethasone as First-line Therapy in Patients With Metastatic Castrate Resistant Prostate Cancer

More than 90% of patients with metastatic castration-resistant prostate cancer (mCRPC) no longer responding to androgen deprivation hormonal therapy have evidence of bone metastases. This is a major cause of death, disability, and decreased quality of life.

Radium-223 is radiopharmaceutical meaning that the drug is a radioactive compound used for therapeutic purposes. It is given intravenously (through a vein) every 4 weeks for 6 cycles. Research has demonstrated safety and efficacy in mCRPC patients resulting in radium-223 becoming a standard of care option for such patients in addition to chemotherapy and new oral hormonal drugs enzalutamide or abiraterone.

Prior research studies using radium-223 have shown improved survival in about 30% of patients. The same studies in combination with data collected from clinical use have also shown that between 20 and 50% of men do not complete the full 6 cycle course of treatment due to side effects or a rise in prostate specific antigen (PSA) requiring the stoppage of radium-223 therapy to start one of the other drug therapies.

The purpose of this study is to determine whether an oral drug called dexamethasone (a corticosteroid) given together with radium-223 may control PSA levels and reduce side effects during radium-223 treatment. Corticosteroids are anti-inflammatory medicines prescribed for a broad range of conditions and are widely used in conjunction with chemotherapy treatments for cancer. Prior research studies have shown that dexamethasone reduces PSA levels by lowering the production of androgens (i.e. male hormones) and improves overall tolerance for cancer-fighting drugs and therapies.

Up to 24 men being treated with radium-223 at University Health Network will be enrolled into this study. If the study is positive, it might offer an improved quality of life and extended survival.