PEDIATRIC ACUTE PROMYELOCYTIC LEUKEMIA HAS EXCELLENT RESULTS WITH AUTOLOGOUS AND ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT)

Abstract

Introduction: Acute Promyelocytic Leukemia (APL) has a high early morbidity and mortality, but a high cure rate. Primary refractory or relapsed disease are referred to HSCT. Patients with molecular remission undergo autologous, and allogeneic HSCT is reserved for those with molecular resistance/persistence or multiple relapses. It is the only pediatric leukemia for which autologous HSCT is indicated, as it is believed that there is no significant Graft-Versus-Leukemia (GVL) effect. There is scarce information on the outcome of HSCT for pediatric APL, and none to our knowledge in Brazil. Objective: To review the results of autologous and allogeneic HSCT performed for the treatment of pediatric APL. Method: retrospective analysis of the medical records of all patients with APL referred to HSCT. Results: A total of 121 HSCT were performed for AML between 2003 and 2023, 15 of them for APL. Three patients had Central Nervous System (CNS) disease prior to HSCT. The median age was 13.6 years (7.8‒21.7); 27% were female. Three patients were transplanted in 1st remission due to prior molecular persistent disease; 8 in second remission, and 4 in very advanced disease.Ten patients underwent autologous HSCT, 7 of them after arsenic (ATO)-based therapy; 9 had Busulfan-based conditioning and 1 TBI-based due to CNS relapse. With a median follow-up of 126 months, all patients were alive. Two patients received ATO post autologous HSCT, one due to molecular relapse and the second due to disease detected by PCR in the graft.Five patients underwent allogeneic HSCT due to very advanced disease. Donors were HLA-identical related (3), MUD (1) and haploidentical (1); ATO was used pre HSCT in two of them. All patients were in morphological remission, but one had persistent molecular disease. Three patients had Busulfan-based conditioning and 2 TBI. Three are alive with a median follow-up of 117 months. Conclusion: in this retrospective cohort, both autologous and allogeneic transplantation were effective therapies. All 10 patients are alive after autologous HSCT. Three of 5 patients with very advanced disease are alive and disease and GVHD-free.