Treatment outcomes of childhood PICALM::MLLT10 acute leukaemias

Summary The prognostic impact of PICALM::MLLT10 status in childhood leukaemia is not well described. Ten International Berlin Frankfurt Münster‐affiliated study groups and the Children's Oncology Group collaborated in this multicentre retrospective study. The presence of the PICALM::MLLT10 fusion gene was confirmed by fluorescence in situ hybridization and/or RNA sequencing at participating sites. Ninety‐eight children met the study criteria. T‐cell acute lymphoblastic leukaemia (T‐ALL) and acute myeloid leukaemia (AML) predominated 55 (56%) and 39 (40%) patients, respectively. Most patients received a chemotherapy regimen per their disease phenotype: 58% received an ALL regimen, 40% an AML regimen and 1% a hybrid regimen. Outcomes for children with PICALM::MLLT10 ALL were reasonable: 5‐year event‐free survival (EFS) 67% and 5‐year overall survival (OS) 76%, but children with PICALM::MLLT10 AML had poor outcomes: 5‐year EFS 22% and 5‐year OS 26%. Haematopoietic stem cell transplant (HSCT) did not result in a significant improvement in outcomes for PICALM::MLLT10 AML: 5‐year EFS 20% for those who received HSCT versus 23% for those who did not ( p = 0.6) and 5‐year OS 37% versus 36% ( p = 0.7). In summary, this study confirms that PICALM::MLLT10 AML is associated with a dismal prognosis and patients cannot be salvaged with HSCT; exploration of novel therapeutic options is warranted.