High-dose melphalan with autologous hematopoietic stem cell transplantation for acute myeloid leukemia: results of a retrospective analysis of the Italian Pediatric Group for Bone Marrow Transplantation

This retrospective study from the Italian Association of Pediatric Hematology Oncology-Bone Marrow Transplant Group (AIEOP-TMO) reports the results of consolidation with high-dose melphalan and autologous hematopoietic stem cell transplantation (auto-HSCT) in patients with acute myeloid leukemia (AML) in first complete remission (CR1). From October 1994 to July 1999, 20 patients (median age 9.9 years, range 0.11-16.2) were treated in six centers. Eighteen had de novo AML and two had secondary AML. According to BFM criteria, 10 were classified as standard- and 10 as highrisk patients, respectively. The median time from diagnosis to CRI and from diagnosis to Auto-HSCT were 1.1 months (range 0.8-1.6) and 4.3 months (range 3.1-6.2), respectively. Purging with either mafosfamide (three) or in vivo interleukin-2 (four) was performed in seven of 20 patients. Melphalan was administered at a dosage of 150-220 mg/m(2) (median 180). Median total number of nucleated cells infused was 2.5 x 10(8)/kg (range 1.1-8.9). The myeloablative regimen was well tolerated with no toxic death, veno-occlusive disease or life-threatening complications. All patients had hematopoietic recovery in a median time of 27 days for neutrophils and 44 days for platelets. Eight of 20 patients relapsed after a median time of 7.2 months from transplant (range 5.7-15.9). Six of them died (five of progression of disease and one of sepsis) while the remaining two patients are alive in CR2. The 3-year cumulative probability of survival and event-free-survival (EFS) is 62% and 56%, respectively. This study showed that in pediatric patients with AML consolidation of CRI with high-dose melphalan allows survival and EFS to be obtained comparable to other auto-HSCT or chemotherapy published series with a potential sparing effect both on duration of treatment (with respect to chemotherapy) and on long-term side-effects (with respect to auto-HSCT with TBI or busulfan containing regimens).