Immunoglobulin Depletion and Recovery Following Blinatumomab in Infants With KMT2A‐Rearranged ALL

Adding blinatumomab to standard chemotherapy for infants with KMT2A-rearranged acute B-cell lymphoblastic leukemia (KMT2A-r B-ALL) improves outcomes. Although blinatumomab impairs immunoglobulin G (lgG) production, increasing infection susceptibility, IgG recovery remains poorly understood. Thirty infants received Interfant-06 protocol chemotherapy with one course of blinatumomab added post-induction. We screened 169 IgG levels post-blinatumomab and IVIg supplementation timepoints. An increase in IgG was subsequently noted until maintenance, where practically all available values returned to normal (>4 g/L). Blinatumomab leads to an IgG reduction, with near-complete recovery occurring before end of treatment. Future trials should monitor immunoglobulin recovery post-blinatumomab to guide infection-preventing strategies. Trial Registration: EudraCT no: 2016-004674-17.