HD-Idarubicin/Etoposide Intensified Conditioning Regimen Allo-HSCT for Adult ALL

Overview

Intensified conditioning regimen allo-HSCT is based on a hypothesis of that intensifying condition with less-used drugs could overcome resistance,reduce tumor burden, and most importantly, spare enough time for slow-growing GVL effect following immune reconstitution to finally get rid of MRD and control the disease. Our previous trial of HDE-ALL-2011 (NCT01457040) have confirmed the role of intensified conditioning allo-HSCT in adult ALL, resulting in significantly improved OS and EFS in comparison with previous standard TBI/CY2 conditioning regimen(data not yet published). But at the same time, FA-TBI/CY2-VP16 conditioning regimen was associated with high transplantation-related mortality (TRM), which might be attributed to excessive suppression on both bone marrow and immune. TT-ALL-HIE-2013, substituting FA with idarubicin, is aimed at maintaining anti-tumor effect with less cross-resistance and immune suppression and reducing TRM.

It's well-known that the long-term outcome of adult acute lymphoblastic leukemia (ALL) lags far behind that of pediatric ALL,associated with different molecular cytogenetics make-up and treatment strategies. In search of an optimal regimen for pediatric ALL, comprehensive series of clinical trials of intensive chemotherapies have been conducted and lead to 80%-90% long-term survival. At the same time, pediatric-inspired chemotherapy protocol aslo yielded a charming result of 50-60% 3-year EFS in adolescent and young adult. In comparison with the leading role of intensive chemotherapy in pediatric ALL, allogeneic hematopoietic stem cell transplantation (allo-HSCT) plays an important role in treatment strategy of adult ALL. According to the state-of-art understanding of ALL, total therapy of ALL should consist of molecular-cytogenetics classification at diagnosis, minimal residual disease (MRD) monitoring and redefining risk classification during treatment, pediatric-inspired chemotherapy with high-dose Methotrexate/L-asparaginase during consolidation therapy,furthermore,risk/MRD-adapted allo-HSCT for high-risk and refractory/relapsed ALL.In pre-pediatric-inspired protocol era, allo-HSCT still represents the major role for improving the outcome of adult ALL, especially for high-risk and refractory/relapsed ALL. It's established that graft-versus-leukemia (GVL) effect was weak in ALL and patient shows poor response for donor-lymphocyte infusion (DLI). Intensified conditioning regimen allo-HSCT is based on a hypothesis of that intensifying condition with less-used drugs could overcome resistance,reduce tumor burden, and most importantly, spare enough time for slow-growing GVL effect following immune reconstitution to finally get rid of MRD and control the disease. Our previous trial of HDE-ALL-2011 (NCT01457040) have confirmed the role of intensified conditioning allo-HSCT in adult ALL, resulting in significantly improved OS and EFS in comparison with previous standard TBI/CY2 conditioning regimen(data not yet published). But at the same time, FA-TBI/CY2-VP16 conditioning regimen was associated with high transplantation-related mortality (TRM), which might be attributed to excessive suppression on both bone marrow and immune. TT-ALL-HIE-2013, substituting FA with idarubicin, is aimed at maintaining anti-tumor effect with less cross-resistance and immune suppression and reducing TRM.