CART4-34 therapy

CART4-34 therapy is an experimental chimeric antigen receptor T cell treatment that targets the IGHV4-34 B cell receptor, developed to treat certain B-cell lymphomas and autoimmune diseases such as systemic lupus erythematosus. A patient's own T cells are modified to express a chimeric antigen receptor based on the 9G4 antibody, which binds IGHV4-34 on malignant or disease-causing B cells; because IGHV4-34 appears on only about five percent of normal B cells, CART4-34 is designed to spare most healthy B cells, unlike CD19-targeted CAR T therapies, which eliminate a much broader population of B cells and suppress the immune system more broadly. As of 2026, CART4-34 remains in preclinical development, with cell-line and mouse-model studies reporting cancer-killing effects similar to CD19 CAR T therapy but with reduced off-target damage, and plans for phase 1 trials in lymphoma and lupus.