Nelarabine for T cell acute lymphoblastic leukemia relapsing after allogeneic hematopoietic stem cell transplantation: an opportunity to improve survival.

T-ALL relapsing after allogeneic stem cell transplantation is unusual but classically associated with poor outcome. Recently, encouraging results have been reported with Nelarabine in relapse or refractory cases. On behalf of the Group of Research in Adult ALL (GRAALL), we conducted a retrospective analysis of patients receiving Nelarabine following relapse after transplantation. Eleven patients received Nelarabine as salvage therapy in this situation. Most of them were transplanted in first Complete Remission (CR), and received a myeloablative conditioning regimen in 7 cases. Relapse occurred with a median time of 199 days. Nelarabine was given at 1.5 g/m(2)/day (Day 1, D3, D5) alone (N = 5) or in association (N = 6). The overall hematological response rate was 81%. Neurologic toxicity represents the main adverse event (N = 4), mainly grade I-II. Event free survival and overall survival at 1 year were 70 and 90% respectively. Nelarabine is a valuable option for salvage therapy in T-cell acute lymphoblastic leukemia relapsing after transplantation.