PD173955 is a potent Bcr-Abl inhibitor with IC50 of 1-2 nM, also inhibiting Src activity with IC50 of 22 nM.

PD173955 potently inhibits Bcr-Abl-dependent cell growth with IC50 of 2-35 nM in Bcr-Abl-positive cell lines, about 100- to 200-fold more sensitive than in Bcr-Abl-negative cell lines. PD173955 also inhibits kit ligand-dependent proliferation of M07e cells with IC50 of 40 nM, by inhibition of kit ligand-dependent c-kit autophosphorylation.In addition, PD173955, as a Src inhibitor, potently inhibits mitotic progression during early mitosis in cells of all types and induces varying degrees of apoptotic cell death.