An inhibitor of PI3Kγ (IC50s = 16, 3,200, 3,500, and >8,400 nM for PI3Kγ, PI3Kα, PI3Kβ, and PI3Kδ, respectively); selective for PI3Kγ over a panel of 468 mutant and nonmutant protein and lipid kinases and a panel of G protein-coupled receptors, ion channels, and transporters at 10 μM; inhibits migration of BMDMs (IC50 = 85 nM); sensitizes doxorubicin-resistant SW620/Ad300 cells to P-gp substrates, such as paclitaxel (IC50s = 710 and 6.7 nM for paclitaxel alone and in combination with IPI-549, respectively); enhances the tumor growth reduction of paclitaxel in an SW620/Ad300 mouse xenograft model at 3 mg/kg in combination with paclitaxel