Hemopoietic reconstitution after repeated autologous transplantation with mafosfamide-purged marrow

Twenty-nine children (median age: 41 months) with advanced solid tumors received, as consolidation therapy, two consecutive courses of high-dose chemotherapy (HDC) followed by mafosfamide-purged autologous marrow transplantation (ABMT) with a 3- to 4-month interval between each course. The malignancies were neuroblastoma (n = 22), Ewing's sarcoma (n = 5) and rhabdomyosarcoma (n = 2). Patients received a preparatory regimen consisting of combined high-dose melphalan before each ABMT, with the exception of five patients who received busulfan and cyclophosphamide before the second ABMT. Prior to HDC, bone marrow sufficient for two transplantations was harvested in remission, treated with mafosfamide (50 micrograms/ml) and cryopreserved. Following incubation with the drug, a consistent inhibition (greater than 99%) of granulocyte and macrophage colony-forming units was observed. Despite the elimination of measurable hematopoietic progenitors, all patients underwent engraftment within a similar period of time after the first and the second ABMT. However, peripheral leukocyte and granulocyte recovery was delayed (median 26 and 28 days, respectively, after the first graft; median 27 and 28 days after the second graft). No difference was observed in the bacterial infections following the first and second ABMT. One patient died after the second transplant with diffuse aspergillosis. Recovery to 50 x 10(9) platelets/l occurred after a median 42 days (range 19-71) after the first ABMT and 43 days (range 14-110) after the second. Two patients died of recurrent disease before attaining a normal platelet level. One patient remained thrombocytopenic and died from visceral failure at day 200. These results demonstrate the feasibility of repeated ABMT with mafosfamide-treated marrow.(ABSTRACT TRUNCATED AT 250 WORDS)