Autologous transplantation for CML using marrow treated ex vivo with recombinant human interferon gamma

Six chronic and four advanced patients with Ph1 positive chronic myelogenous leukemia (CML) received autologous bone marrow transplantation (ABMT) using bone marrow treated ex vivo with recombinant human interferon gamma (rIFN gamma). In three cases 100% Ph1 negative bone marrow hematopoiesis was demonstrated 4 to 8 weeks after ABMT. In three additional cases, a maximum of 40-45% bone marrow metaphases were Ph1 negative 2 to 12 weeks following ABMT. In four cases, no or minimal evidence of Ph1 negative hematopoiesis could be demonstrated posttransplant. Seven patients survive in chronic phase at a median of 375 days (range 100-495 days). Five patients have not required therapy, while two patients receive low doses of rIFN alpha to control peripheral blood counts. Ex vivo treatment of CML bone marrow with rIFN gamma followed by ABMT in patients dependent upon or refractory to therapy prior to transplantation is associated with transient complete or partial Ph1 negative bone marrow hematopoiesis in the majority of patients post-transplant and with return of a chronic phase characterized by no need for therapy or by response to low doses of rIFN alpha. Modification of the ABMT procedure and efforts to maintain cytogenetic and hematologic remission following ABMT may lead to prolonged survival or cure.