HD37-dgRTA

HD37-dgRTA is a murine-derived immunotoxin consisting of the anti-CD19 monoclonal antibody HD37 chemically conjugated to deglycosylated ricin A chain (dgRTA), a ribosome-inactivating protein toxin. This antibody-drug conjugate specifically targets the CD19 antigen on B-lineage cells, delivering the ricin toxin intracellularly to induce cell death by inhibiting protein synthesis. It has demonstrated potent cytotoxic activity in vitro and in vivo against pre-B acute lymphoblastic leukemia (ALL) and B-cell non-Hodgkin lymphoma (NHL) cells. Phase I clinical trials show anti-tumor efficacy, especially in combination with other agents, but immunogenicity (development of human anti-mouse and anti-toxin antibodies) limits repeat dosing. HD37-dgRTA served as a single agent as well as a component of the combination immunotoxin “Combotox,” which includes RFB4-dgRTA (an anti-CD22 immunotoxin)[1][2][4][5][6].