Autologous bone marrow transplantation for acute lymphoblastic leukemia: the high dose vincristine study of AIEOP BMT group.

This study was performed in 5 pediatric centers. It considered a group of children affected by acute lymphoblastic leukemia (ALL) treated with ABMT. 56 patients were considered, 35 males and 21 females, with a median age of 11 years. The children were transplanted in 2nd (36) or subsequent (20) complete remission. The mean of 1st remission duration was 32 months. Analysis of the sites of relapse before transplantation showed that 39 patients had bone marrow relapses, 17 patients had CNS and/or testicular isolated relapses only. 32 harvests were purged in vitro by 1 mcgr/ml Vincristine and 30 mcgr/ml Prednisone, 16 by 100 mcgr/ml Mafosfamide, 8 were not cleaned. 29 patients received high dose Vincristine (4 mg/m2), TBI (1200 cGy), Cyclophosphamide (3600 mg/m2) as standard conditioning regimen before transplant. 27 patients received other conditioning treatments with (14) or without (13) TBI. Of the 56 children 25 relapsed from 1 to 42 months after ABMT, 7 toxicity related deaths were registered and 1 death for second tumor was observed. 23 children remained in continuous complete remission from 1 to 49 months after transplantation. The probability of EFS at 4 years was 21%. High dose Vincristine did not statistically improve the EFS, but a trend was observed (44% versus 0%). Vincristine, Asta-Z or none purging did not show any significant effect on EFS (37% vs 32% vs 0%). On the contrary when the EFS was related to the site of relapse, isolated or sistemic, the difference was almost statistically significant (46% vs 18%). The analysis of our results indicates the isolated relapse as good prognostic factor in ABMT for ALL and high dose Vincristine associated to conditioning regimen as worthy of further investigations.