ON 146040 is a potent PI3Kα and PI3Kδ ( IC 50 ≈14 and 20 nM, respectively) inhibitor. ON 146040 also inhibits Abl1 ( IC 50 In Vitro In biochemical testing, ON 146040 inhibits PI3Kα/ PI3Kδ isoforms (IC 50 ≈14 and 20 nM, respectively) without having a major effect on PI3Kβ/ PI3Kγ isoforms (IC 50 ≈3 and 1 μM, respectively). ON 146040 is also found to inhibit Abl1 and several mutant versions of this kinase (IC 50 Form:Solid IC50& Target:PI3Kα 14 nM (IC 50 ) PI3Kδ 20 nM (IC 50 ) PI3Kγ 1 μM (IC 50 ) PI3Kβ 3 μM (IC 50 )