antiCD19

Anti-CD19 refers to therapies that target the CD19 antigen, a transmembrane protein broadly expressed on B-lineage cells, including many malignant B cells. CD19 is a common target in B-cell malignancies because its expression covers a wide range of disease and its loss is not essential for the function of non-B cells. By binding CD19, these therapies aim to deplete malignant B cells and, in some modalities, recruit immune effector mechanisms or deliver cytotoxic payloads.

Therapies fall into several categories. Monoclonal antibodies such as tafasitamab target CD19 and can be used in relapsed or refractory diffuse large B-cell lymphoma. Antibody-drug conjugates such as loncastuximab tesirine deliver a cytotoxic payload to CD19-positive cells. Bispecific T-cell engagers, like blinatumomab, connect CD19-positive B cells with CD3-positive T cells to trigger T-cell–mediated killing. CD19-directed chimeric antigen receptor T-cell therapies include tisagenlecleucel, axicabtagene ciloleucel, lisocabtagene maraleucel, and brexucabtagene autoleucel, which reprogram a patient’s T cells to recognize and destroy CD19-expressing B cells. These CAR-T products are approved for various B-ALL and non-Hodgkin lymphoma settings and are being explored in other B-cell malignancies.

Clinical considerations include risks such as cytokine release syndrome and neurotoxicity, particularly with CAR-T and bispecific constructs. B-cell aplasia and hypogammaglobulinemia may occur, increasing infection risk and sometimes requiring immunoglobulin replacement. Treatments are typically administered in specialized centers with close monitoring. Resistance can arise from loss or downregulation of CD19 expression or lineage switch, prompting ongoing research into combinations, sequencing, and toxicity mitigation.