PRN1371 is an irreversible covalent FGFR1-4 kinase inhibitor, with IC50s of 0.6, 1.3, 4.1, 19.3 and 8.1 nM for FGFR1, 2, 3, 4 and CSF1R, respectively.  

ARQ 531 is a reversible non-covalent inhibitor of Bruton’s Tyrosine Kinase (BTK), with IC50s of 0.85 nM and 0.39 nM for WT BTK and C481S BTK, respectively