PKI-179 is an orally bioavailable dual inhibitor of PI3K and mTOR, demonstrating potent inhibition of PI3K isoforms (IC50s ranging from 8 to 74 nM) and common PI3Kα mutants (IC50s of 14 and 11 nM), as well as mTOR (IC50 of 0.42 nM) in an in vitro enzymatic assay. It exhibits selectivity for PI3K and mTOR over 361 other kinases, hERG, and CYP isoforms, with the exception of CYP2C8 (IC50 of 3 μM). PKI-179 inhibits cell proliferation via the Akt/mTOR pathway in MDA-361 breast and PC3MM2 prostate cancer cell lines (IC50s of 22 and 29 nM, respectively) and suppresses tumor growth in an MDA-361 mouse xenograft model at a dose of 50 mg/kg.