Pilot Study of Mobilization and Treatment of Disseminated Tumor Cells in Men With Metastatic Prostate Cancer

This is an open label, multiple site, pilot study. Hypothesis: Treatment with Burixafor hydrobromide will effectively mobilize metastatic prostate cancer (PCa) cells (i.e. disseminated tumor cells; DTCs) into the blood from the bone marrow. In preclinical models, these bone marrow niche engaged cells are more resistant to therapy as compared to soft tissue sites. It has been demonstrated that prostate cancer cells have been mobilized out of the bone marrow of mice utilizing an anti-CXCR4 strategy; making them more susceptible to chemotherapy. Currently, the anti-CXCR4 agent plerixafor is FDA approved to be given for up to 4 consecutive days in order to mobilize hematopoietic stem cells (HSCs). Burixafor hydrobromide is a potent anti-CXCR4 agent that is in clinical trials. Burixafor hydrobromide, alone or in combination with G-CSF, is currently in Phase II testing for use as a hematopoetic stem cell (HSC) mobilization agent. When Burixafor hydrobromide is given intravenously (IV) alone at a dose of 3.14 mg/kg it has been shown to result in a 7.8 fold mean increase in peripheral blood CD34+ (a HSC marker) cells 6-hours post-infusion.