In Vitro: "A419259 is a second-generation pyrrolopyrimidine that blocks proliferation and induces apoptosis in CML cell lines. It induces apoptosis in K-562 cells and also inhibits Meg-01 proliferation (IC50=0.1 μM). In the absence of IL-3, A-419259 strongly inhibits DAGM/Bcr-Abl cell proliferation (IC50=0.1-0.3 μM). A-419259 also inhibits overall SFK activity in CML cell lines and blocks Src kinase activation (IC50=0.1-0.3 μM). A 419259 trihydrochloride (1 μM; 16 h) inhibits endogenous SFK (c-Src and Lck) activity, thereby inhibiting Src-driven differentiation of mES cells toward primitive ectoderm-like cells. A 419259 trihydrochloride (0.3, 1 μM; 5 days) has no effect on undifferentiated colony morphology of hES cells grown in mTeSR medium. "