M-808 is a potent and efficacious covalent inhibitor, targeting the interaction between Menin and MLL. It demonstrates a high binding affinity with an IC50 value of 2.6 nM.

MV-4-11 cells:1 nM (IC50), Menin-MLL (MV4):1 nM (IC50), Menin-MLL (MOLM-13 cells):4 nM (IC50)

M808 exhibits IC 50 values of 1 nM, 4 nM and 2.8 nM in MV4;11 cells, MOLM-13 cells and HL60 cells, respectively[1]. M808 forms a covalent bond between its acrylamide and the sulfur atom of Cys329 in menin[1].

M-808 (16) is well tolerated in severe combined immunodeficiency (SCID) mice with intravenous administration of 10 mg/kg (or 25 mg/kg) every other day dosing (three times a week) for one week. M-808 (25 mg/kg) achieves a maximum tumor growth inhibition (TGI) of 97% during treatment (day 35) and reduces the average tumor volume from 92 mm 3 at the beginning of the treatment to 59 mm 3 at day 35, with no significant toxicity[1].