XMU-MP-3 is a potent, selective, noncovalent BTK inhibitor with IC50 of 10.7 nM and 17.0 nM for BTK WT and BTK C481S mutation.XMU-MP-3 inhibited BTK‐transformed Ba/F3 cell proliferation with an IC50 of 11.4 nM, with negligible anti‐proliferative effects on parental wild‐type Ba/F3 cells (IC50>10 uM).XMU‐MP‐3 inhibited both the autophosphorylation and trans‐phosphorylation of BTK at residues Y223 and Y551, in a dose‐dependent manner in BTK‐transformed Ba/F3 cells at concentrations as low as 100 nM and completely suppressed at 1,000 nM.XMU‐MP‐3 was considerably less potent (IC50, 2,815 nM) against proliferation of BTK(T474M)‐transformed Ba/F3 cells.XMU‐MP‐3 inhibits the growth of malignant B‐cells, inhibited phosphorylation of PLCγ2 at Y1217 and Y759, substantially suppresses tumour growth in mouse xenograft models.XMU‐MP‐3 maintained inhibitory potency with an IC50 of 182.3 nM against BTK(C481S)‐Ba/F3 cells and with an IC50 of 17.0 nM in biochemical assays, suppressed ibrutinib‐resistant BTKC481S mutation in vivo.
