Ex-vivo expansion of bone marrow progenitor cells for hematopoietic reconstitution following high-dose chemotherapy for breast cancer

The use of hematopoietic growth factors, stromal monolayers, and frequent m edium exchange allows the expansion of hematopoietic progenitors ex-vivo. W e evaluated the use of ex-vivo expanded progenitor cells for hematopoietic reconstitution following high dose chemotherapy (HDC) in breast cancer pati ents. Patients with high-risk Stage II or metastatic breast carcinoma under went bone marrow aspirations using general anesthesia. A total of 675-1125 x 10(6) mononuclear cells (MNC) were seeded for ex-vivo expansion for 12 da ys in controlled perfusion bioreactors (Aastrom Biosciences, Inc.). The bon e marrow cultures, which included the stromal cells collected with the aspi rate,,were supplemented with erythropoietin, granulocyte-macrophage-colony stimulating factor (GMCSF)/IL-3 fusion protein (PIXY 321), and flt3 Ligand. Stem cell transplant was performed with expanded cells after HDC. A median bone marrow volume of 52.9 mt (range 42-187 mt) was needed to inoculate th e bioreactors. Median fold expansion of nucleated cells (NC) and colony for ming unit granulocyte-macrophage (CFU-GM) was 4.9 and 9.5, respectively. Th e median fold expansion of CD34(+)lin(-) and long-term culture-initiating c ulture (LTC-IC) was 0.42 and 0.32, respectively. Five patients mere transpl anted with ex-vivo expanded NC. Median days to an absolute neutrophil count > 500/mu L was 18 (range 15-22). Median days to a platelet count > 20,000/ mu l was 23 (range 19-39). All patients had sustained engraftment of both n eutrophils and platelets. Immune reconstitution was similar to that seen af ter HDC and conventional stem cell transplantation. We conclude that es-viv o expansion of progenitor cells from perfusion cultures of small volume bon e marrow aspirates, allows hematopoietic reconstitution after HDC. (C) 1999 International Society for Experimental Hematology. Published by Elsevier S cience Inc.