GDC-0941 is a potent inhibitor of p110α and p110δ (IC₅₀ = 3 nM). It selectively binds to PI3K isoforms in an ATP-competitive manner, inhibiting the production of the secondary messenger phosphatidylinositol-3,4,5-trisphosphate (PIP3) and activation of the PI3K/Akt signaling pathway.