Secondary haematological dysplasia after CAR‐T‐cell therapy for acute lymphoblastic leukaemia in children.

Summary The use of CAR‐T is becoming more widespread in the treatment of haematological malignancies. In adults, secondary myelodysplastic syndromes (MDS) after CAR‐T have been described. However, there are currently no data on the risk of MDS following CAR‐T in children treated for acute lymphoblastic leukaemia (ALL). We studied all children treated with CAR‐T cells at Hospital Sant Joan de Déu in Barcelona and those with persistent cytopenias were evaluated at the cytological, cytogenetic, and molecular levels to look for MDS. A total of 106 patients received CAR‐T for ALL. Among 40 patients without early relapse or subsequent therapy after CAR‐T, four fulfilled the WHO criteria for myelodysplasia. These four patients had received a haematopoietic stem cell transplantation (HSCT) prior to CAR‐T and presented cytopenias with severe dysplastic changes in bone marrow after CAR‐T. One patient had clonal MDS with high‐risk cytogenetics arising from the host cells requiring a HSCT. Three patients had non‐progressive dysplasia arising from the donor cells. Two are alive in complete remission with stable cytopenias and one succumbed to ALL relapse. This is the first description of post‐CAR‐T MDS and haematological dysplasia in children and highlights the need to monitor children with persistent post‐CAR‐T cytopenias. [ABSTRACT FROM AUTHOR]