Perhaps the most advanced BsAb is Blinatumomab [39], an investigational Bispecific T cell engager (BiTE®) antibody construct designed to direct T-cells against target cells expressing CD19 expressing B-cell derived leukemias and lymphomas, which has received orphan drug designation from the FDA for a wide array of CD19 expressing hematological malignancies. This evidence concerns the gene CD19 and hematologic disorder.