Hematopoietic stem cell transplantation with conditioning regimens containing melphalan in pediatric patients with acute lymphoblastic leukemia

A multicenter comparative study was carried out to investigate the efficacy and safety of hematopoietic stem cell transplantation with conditioning regimens containing melphalan in pediatric patients with acute lymphoblastic leukemia. One hundred twenty three patients at a variety of remission stages were eligible for study participation. Eighty-nine were transplanted with allogeneic grafts and 34 patients with autologous grafts (23 cases with bone marrow and 11 cases with peripheral blood stem cells). Conditioning regimens used were as follows: (A) melphalan and busulfan for 40 patients, (B) melphalan, busulfan and TBI for 44 patients, (C) other regimens for 39 patients. To accelerate engraftment G-CSF (lenograstim) was administered as a 1-hour or 24-hour drip infusion daily at 5 micrograms/kg from day 5 until hematological recovery. The five year disease free survival (DFS) was 63% for 42 patients at CR 1, 41% for 41 patients at CR 2 and 33% for 40 patients at other stages. There was no significant difference in the DFS between allogeneic-transplantation and autologous-transplantation in all disease stages. In patients at remission stage for CR 1 and CR 2, the 5-year DFS by conditioning regimen was 63% for regimen (A), 54% for regimen (B) and 54% for regimens with melphalan and TBI. There was no significant difference in the DFS between the groups. Serious complications such as renal failure were observed in 11%, veno-occlusive disease in 9%, and interstitial pneumonia in 9%. The most dominating cause of death was relapse in the disease (48% of deaths) which was most commonly observed in autologous transplantation. Contrary to that, treatment related toxic death was the most frequent cause of deaths in allogeneic-transplantation.