This clinical trial is for men with advanced prostate cancer that has not responded to standard therapies. Prostate-specific membrane antigen (PSMA) is a protein that is on the surface of most prostate cancer cells. It is absent from most other normal places in the body, but is present to a lower degree in the kidney, small intestine, salivary glands, and brain. J591 is a monoclonal antibody (an engineered protein) which recognizes PSMA. Actinium-225 (225Ac) is a small radioactive particle that emits alpha-particles (damaging/ionizing radiation). 225Ac-J591 is the combination compound that has the radioactive particle linked to J591. It is designed so that J591 will recognize PSMA and drags the radioactive particle 225Ac with it wherever it goes. This drug is used not FDA approved and is considered experimental.
The purpose of this study is to find the highest dose level of the study drug, 225Ac-J591 that can be given without severe side effects. The research study is being done because the standard treatments for prostate cancer that has spread beyond the prostate gland are intended to minimize the adverse effects of the disease.
Patients who choose to participate in this study will have a screening visit to determine whether or not they are eligible to participate in the study. The treatment phase is comprised of 7 visits over approximately 8 weeks.
During the study visits, participants will undergo routine tests and procedures, such as physical examinations, and routine blood tests. Some blood tests will be done for research purposes only, and participants will also undergo a research PET/CT scan at screening and end of study. After completion of therapy, participants may be contacted on a periodic basis to see how they are doing.