Chemotherapy with the Use of TKIs Based on MRD Has the Potential to Avoid Hematopoietic Stem Cell Transplantation in Treatment for Children with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph+ALL). Results of the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) Study ALL-Ph13

Aims: Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) patients generally have a poor prognosis when treated with chemotherapy alone. In adults, allogeneic hematopoietic stem cell transplantation (HSCT) in first complete remission is still the standard strategy for Ph+ALL. However, in children, HSCT should be avoided as much as possible to eliminate late complications. There are some reports showing that the combination of tyrosine kinase inhibitors (TKIs) with chemotherapy may avoid HSCT in childhood Ph+ALL. Thus, we planned this clinical trial (JPLSG ALL-Ph13) with the aim of improving outcomes with as few HSCT by chemotherapy with TKIs based on Ig/TCR minimal residual disease (MRD).