Efficacy of Ra-223 in PSMA PET Optimally Selected Patients

Inclusion Criteria: Male participants >= 18 years of age on the day of signing informed consent Castrate level of serum testosterone at study entry (< 50 ng/dL), checked within three months of enrollment Patient is a candidate for standard of care Ra-223 therapy Bone only disease on PSMA PET using a Food and Drug Administration (FDA) approved PSMA targeted PET radiopharmaceutical Note: Nodal disease on PSMA PET that is less than 1 cm in short axis and without evidence of change in size over the past six months on conventional imaging is allowed Positivity on PSMA PET is defined as uptake greater than the liver that is not attributable to physiologic activity Histologically confirmed prostate adenocarcinoma that is progressive by Prostate Cancer Working Group 3 (PCWG3) criteria at the time of study entry Prior progression on at least one second generation androgen signaling inhibitor including abiraterone, apalutamide, darolutamide, and/or enzalutamide Platelets > 100,000/microliter (mcL) Hemoglobin (Hgb) > 9.0 g/dL White blood cells (WBC) > 2.5 Albumin > 3.0 g/dL Adverse events related to prior anti-cancer treatment must have recovered to =< Grade 2 Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 For patients who have partners of childbearing potential: Partner and/or patient must use a method of birth control with adequate barrier protection, deemed acceptable by the principal investigator during the study and for 3 months after last study drug administration Individuals with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial Ability to understand and the willingness to sign a written informed consent document Exclusion Criteria: Prior treatment with Lutetium-177 (177Lu)-PSMA-617, Radium-223, Strontium-89, Samarium-153, Rhenium-186, Rhenium-188 Prior exposure to taxane-based chemotherapy. * Note: Exposure is defined as two or more cycles of taxane-based agents Any systemic anti-cancer therapy (e.g., chemotherapy, immunotherapy or biological therapy, including monoclonal antibodies) within 21 days prior to the first day of treatment Greater than 75% bone involvement, based on PSMA PET Presence of visceral metastases, untreated central nervous system metastases, or untreated epidural or spinal cord involvement Prior treatment with radioligand therapy Blood transfusion within past 45 days Any condition that, in the opinion of the Principal Investigator, would impair the patient's ability to comply with study procedures