Matched pair analysis comparing intravenous busulfan and oral busulfan as part of conditioning regimen in autologous stem cell transplantation in high risk neuroblastoma

Abstract

18003 Background: This case control multicenter study was designed to compare iv Busulfan (Bu) versus oral Bu as part of conditioning regimen in autologous stem cell transplantation (ASCT) in terms of toxicity, 100 days TRM, engraftment kinetics, relapse rate (RR), survival (SUR) and event free survival (EFS), in the treatment of high risk neuroblastoma (HRNB). Methods: Between 2004 and 2007, 12 paediatric patients (Group 1) with HRNB underwent ASCT and received iv Bu every 6 h for a total of 16 doses, + Melphalan (L-PAM). Iv Bu doses were based on accrual patients weight: <9 kg 0.95 mg/kg/dose; 9–16 kg, 1,2 mg/kg/dose; 16–23 kg, 1.1 mg/kg/dose; 24–34 kg, 0,95 mg/kg/; >34 kg, 0,8 mg/kg/dose. 24 paediatric patients (Group 2), underwent ASCT between 1993 and 2007 conditioned with oral Bu, 1 mg/kg/dose every 6 h for a total of 16 doses, + L-PAM ± other were available for selection as appropriate control for matched pairs analysis. Matching criteria were sex, centre, age, disease status, stem cell source, conditioning regimen, days of PMN and PLT engraftment, number of CD34+ infused and grade of toxicity according to Bearman scale. Results: Between the two groups of patients PMN (p = 0.490) and PLT (p = 0.230) engraftment were comparable. 100 days TRMp was 0.00 in Group 1 and 0.04 in Group 2 where 1 patient died for transplant related complications. Two year SURp, EFSp and RRp in Group 1 were 0.77, 0.64 and 0.23 respectively. Two year SURp, EFSp and RRp in Group 2 were 0.69, 0.51 and 0.35 respectively, without significant statistical differences in front of Group 1. After a median follow up of 21 months (range, 3–36), 9/12 patients in Group 1 are alive and well. Conclusions: i.v. Bu in children grafted because affected by HRNB, administered on accrual pt weight, is safe and feasible and in comparison with oral Bu seems less toxic. On the observation of a better outcome in terms of SUR, EFS and RR it is possible to suppose a more efficiency in disease control. No significant financial relationships to disclose.