An inhibitor of the class I PI3K isoforms p110α (IC50 = 52 nM) and p110β (IC50 = 166 nM); selective for these isoforms over the class III PI3K Vps34 (IC50 = 2,410 nM), mTOR (IC50 = 2,866 nM), PI4Kβ (IC50 = >25,000 nM), and a variety of kinases (IC50s = >10,000 nM); inhibits proliferation of human tumor and glioma cell lines, with p53 wild-type glioma cells more sensitive than p53 mutant/deleted glioma cells (IC50s = 1.28 and 2.08 μM, respectively); crosses the blood brain barrier; increases survival in a U87 glioma mouse xenograft intracranial tumor model when orally administered at 20 and 40 mg/kg once per week