Efficacy and Toxicity of Inotuzumab Ozogamicin for Treatment of Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia in Pediatric and Young Adult Patients After CD19-Chimeric Antigen Receptor T-Cell Therapy

We retrospectively analyzed outcomes for nine children and young adults who were treated with inotuzumab ozogamicin (InO) for relapsed/refractory (R/R) B-acute lymphoblastic leukemia (ALL) after CD19-chimeric antigen receptor T-cell therapy (CART). After InO cycle 1, overall response rate was 77.8%; 66.7% achieved measurable residual disease (MRD)-negative remission. One-year event-free survival (EFS) was 37.5%; 1-year overall survival (OS) was 50%; 2-year EFS was 37.5%; 2-year OS was 37.5%. Median survivor follow-up is 2.9 years (0.5–4.7). Significant adverse events included prolonged cytopenias, hepatotoxicity, and post-transplant sinusoidal obstructive sydrome. InO showed promising efficacy as treatment for children and young adults with R/R B-ALL after CD19-CART. Extramedullary disease prior to InO and positive MRD after InO cycle 1 were associated with poor outcomes.