Radiation Medication (Radium-223 Dichloride) Versus Radium-223 Dichloride Plus Radiation Enhancing Medication (M3814) Versus Radium-223 Dichloride Plus M3814 Plus Avelumab (a Type of Immunotherapy) for Advanced Prostate Cancer Not Responsive to Hormonal Therapy

This phase I/II trial studies the best dose of M3814 when given together with radium-223 dichloride or with radium-223 dichloride and avelumab and to see how well they work in treating patients with castrate-resistant prostate cancer that had spread to other places in the body (metastatic). M3814 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Radioactive drugs, such as radium-223 dichloride, may carry radiation directly to tumor cells and not harm normal cells. Immunotherapy with monoclonal antibodies, such as avelumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. This study is being done to find out the better treatment between radium-223 dichloride alone, radium-223 dichloride in combination with M3814, or radium-223 dichloride in combination with both M3814 and avelumab, to lower the chance of prostate cancer growing or spreading in the bone, and if this approach is better or worse than the usual approach for advanced prostate cancer not responsive to hormonal therapy.