Purpose: To determine if peripheral-blood stem cells (PBSC) collected during the recovery of standard induction and consolidation chemotherapy in acute myeloblastic leukemia (AML) can be used as a safe tool for autologous transplantation, and to study aspects of the autologous blood stem-cell transplantation (ABSCT) procedure and their results in AML patients in first remission.
Patients and methods: Twenty-four AML patients in first remission received busulfan (BU; 16 mg/kg) and cyclophosphamide (CY; 200 mg/kg) followed by ABSCT. PBSC were collected by continuous-flow leukaphereses after induction and consolidation courses.
Results: The median numbers of mononuclear cells (MNCs) and colony-forming unit granulocyte-macrophage (CFU-GM) administered were 6 x 10(8)/kg and 11 x 10(4)/kg, respectively. ABSCT induced engraftment in 22 patients and there were two graft failures. The median times to reach a polymorphonuclear (PMN) leukocyte count of 0.5 x 10(9)/L and a platelet count of 50 x 10(9)/L were 13 and 19 days, respectively. Fatal hepatic veno-occlusive disease (VOD) was observed in two cases. Other toxicities were mild and uncommon. Twelve patients relapsed between 1 and 9 months posttreatment. Actuarial disease-free survival (DFS) and actuarial risk of relapse at 30 months were 35% (95% confidence interval [CI], 25% to 45%) and 60% (95% CI, 50% to 72%), respectively.
Conclusion: These preliminary results show the fast hematopoietic recovery and the low infectious and hemorrhagic morbidity associated with the procedure and strongly suggest that ABSCT may be as effective as autologous bone marrow transplantation (ABMT) in AML. However, further strategies for reducing leukemic relapse must still be investigated.