Intensive Chemotherapy Along with Aggressive Supportive Care Can Spare Stem Cell Transplantation in a Subset of Patients without Compromising an Outcome in Infants with Acute Lymphoblastic Leukemia; A Report from the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) Trial MLL-10

▪ BACKGROUND: Outcome of infants with acute lymphoblastic leukemia (ALL), especially those with rearrangement of MLL (KMT2A) gene (MLL-r), is extremely poor. A strategy to perform allogeneic hematopoietic stem cell transplantation (HSCT) for all the infants with MLL-r ALL in first remission (1CR) have been tested in the previous Japanese trials MLL96/98/03, however, the improvement was modest. Given the recent evidence of a limited role of HSCT especially in infants lacking poor prognostic factors, efficacy and safety of an intensive chemotherapy and risk stratification to limit HSCT for only infants with high-risk of relapse were evaluated in the JPLSG MLL-10 trial (UMIN000004801). PATIENTS & METHODS: Infants age less than 365 days with ALL were registered in the MLL-10 study and were stratified by their MLL gene status, age at diagnosis, and presence of CNS disease; low-risk (LR), if the patients had germline MLL gene (MLL-g); intermediate-risk (IR), if the patients with MLL-r ALL were age 180 days or older and lack CNS disease; high-risk (HR), if the patients with MLL-r ALL were age