Efficacy of Ra-223 in PSMA PET Optimally Selected Patients

Study Summary

This phase II trial studies how well prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans (in combination with bone scans) work in selecting patients for Ra-223 radiation therapy that have castration-resistant prostate cancer that has spread from where it first started (primary site) to the bones (bone metastasis). Ra-223 is a type of therapy that emits radiation. Radiation gives off energy which can kill tumor cells and other cells that may support the tumor cells. Ra-223 is given by infusion into the veins, where it is absorbed by the bones. PSMA PET is a type of scan used to detect prostate cancer tumors. PSMA is a radioactive tracer that binds to a specific protein that is found on prostate tumor cells. The PSMA tracer shows the areas on the PET scan where tumor cells are active. A PET scan uses a special camera to detect the energy given off from radioactive tracers (such as PSMA) to make detailed pictures of areas where the tracer accumulates in the body. The PET scan is often combined with a magnetic resonance imaging (MRI) or computed tomography (CT) scan, which helps to map the locations where PSMA has accumulated. PSMA PET scans may be able to select patients that will benefit the most from Ra-223 treatment.

Primary Outcome

The proportion of patients who achieve a greater than 50% decline from baseline prostate specific antigen (PSA) (PSA50) drawn prior to C1D1, at any point in the treatment course, will be descriptively reported along with 95% binomial confidence interval. It will be compared with the historical control by binomial test. A confirmation repeat PSA will be drawn after the initial PSA50 response to confirm the result. A PSA50 will only be counted if two PSA showing a 50% decline are measured.

Conditions Studied

Interventions

• DRUG Radium-223
• PROCEDURE PSMA Positron Emission Tomography (PET) Scan
• DRUG Technetium Tc 99M Medronate

Study Locations (1)