Another recently-developed CD19/CD3 bsAb, designed in the single-chain Fv-Fc format (CD19/CD3-scFv-Fc), has shown to induce a particularly rapid killing of CLL cells isolated from ibrutinib-treated patients, including those with acquired ibrutinib-resistance (238). The gene discussed is CD19; the disease is B-cell chronic lymphocytic leukemia.