Acute Lymphoblastic Leukaemia in Children and Adolescents

Acute lymphoblastic leukaemia (ALL) is the most common cancer in children; approximately 60% of ALL cases occur in children and adolescents under the age of 20. Allogeneic haematopoietic cell transplantation (HCT) has become the most commonly used cellular immunotherapy and the standard of care for children with ALL who are either at high risk of relapse or have previously relapsed. HCT is a successful therapeutic option and a significant proportion of patients achieve long-term survival. The most common cause of treatment failure is relapse after allogeneic HCT. The risk of relapse after transplantation is influenced by several factors, including remission status at transplantation, conditioning regimen and donor type. Strategies to reduce the risk of relapse include reduction of pretransplant minimal residual disease (MRD), replacement of toxic pretransplant chemotherapy with bispecific antibodies, replacement of HCT with chimeric antigen receptor (CAR) T-cell therapy, improved transplantation strategies for specific groups, including infants, adolescents and young adults (AYA), and innovative prophylaxis and treatments for acute and chronic graft-versus-host disease. In addition, therapeutic drug monitoring with dose adjustment of some drugs, including busulfan, and novel radiation techniques may allow a more personalised approach.