ALL Maintenance Treatment for Early Loss of B-Cell Aplasia after Tisagenlecleucel Therapy

Chimeric antigen receptor (CAR) T-cell therapy is a new, effective treatment for patients with relapsed/refractory (r/r) B-cell acute lymphoblastic leukaemia (ALL). Tisagenlecleucel achieved a complete remission (CR) rate and minimal residual disease (MRD) negativity of 81% at 3 months in the pivotal study; overall survival (OS) was 76% at 12 months (Maude et al, 2018). Real world data confirmed similar outcomes, with 1-year OS of 77% and event free survival (EFS) of 52% (Pasquini et al, 2020). Relapse can occur in the form of CD19 negative or CD19 positive ALL. The latter is associated with lack of persistence of the CAR T product. B-cell aplasia (BCA) is an indirect measure of CAR T presence. Early (