Total-body irradiation and melphalan is a safe and effective conditioning regimen for autologous bone marrow transplantation in children with acute myeloid leukemia in first remission

Purpose: To evaluate the safety and efficacy of a preparative regimen consisting of fractionated total-body radiation (9.9 to 12 Gy) and melphalan (140 mg/m2 in a single dose) in children with acute myeloid leukemia in first complete remission (CR) given autologous bone marrow transplantation (ABMT). Patients and Methods: Fifty-three children (30 males and 23 females; age range, 1.5 to 18 years) were enrolled onto the study. The median time from first CR to ABMT was 3.5 months (range, 1.4 to 13 months), with 45 patients (85%) undergoing transplantation within 6 months from the diagnosis. Forty-five patients received in vitro marrow purging with standard-dose mafosfamide (100 μg/mL), seven patients were treated with interleukin-2 before marrow collection, and in the remaining child, the marrow was unmanipulated. The median infused cell dose was 1.8 x 108/kg (range, 0.4 to 5.8 x 108/kg). Results: All patients but one achieved hematopoietic engraftment, with a median time to neutrophil recovery of 24 days (range, 11 to 66 days). Treatment-related toxicity was moderate and consisted mainly of mucositis. One patient died from cytomegalovirus interstitial pneumonia, and one died from pulmonary hemorrhage. Fourteen patients (26%) relapsed at a median time of 6 months after ABMT (range, 2 to 17 months), with a cumulative relapse probability of 29% (95% confidence interval, 16% to 42%). The 5-year Kaplan-Meier estimate of survival for all 53 patients was 78% (range, 65% to 90%), whereas the overall 5-year disease-free survival was 68% (range, 55% to 81%), with a median follow-up duration of 40 months (range, 7 to 130 months). Conclusions: These data suggest that, in our cohort of patients, the combination of total-body irradiation and melphalan is safe and associated with good antileukemia activity, making ABMT an appealing alternative for postremission therapy in children with acute myeloid leukemia in first CR