Stromagen and Autologous CD34+ Cells for Metastatic Breast Cancer After High-Dose Chemotherapy

OBJECTIVES: I. Determine the safety of expanded mesenchymal stem cells (Stromagen) infusion and autologous CD34+ peripheral blood stem cells transplantation after high dose chemotherapy in women with metastatic breast cancer. II. Compare the time to neutrophil and platelet engraftment in patients receiving different doses of Stromagen. III. Evaluate the immune reconstitution of these patients after this therapy. OUTLINE: This is a randomized, placebo controlled, blinded study. Patients are randomly assigned to one of three treatment arms. All patients undergo mobilization of peripheral blood stem cells (PBSC) using cyclophosphamide IV over 1 hour and paclitaxel IV over 3 hours on day 1, and filgrastim (G-CSF) subcutaneously beginning on day 4 and continuing until completion of leukapheresis. PBSC and bone marrow cells are collected and CD34 positive cells are then selected. About 4 weeks later, patients receive high dose chemotherapy. Cyclophosphamide IV over 24 hours, carboplatin IV over 24 hours, and thiotepa IV over 24 hours are administered on days -7 to -4. Patients then receive placebo or one of two doses of expanded mesenchymal stem cells (Stromagen) IV on day -1 and CD34+ selected PBSC IV over 2 hours on day 0. Patients are followed at 6 weeks and 12 weeks, than at 1 year. PROJECTED ACCRUAL: A total of 30 patients will be accrued for this study.