An orally bioavailable mammalian target of rapamycin (mTOR) kinase inhibitor with potential antineoplastic activity. mTOR kinase inhibitor OSI-027 binds to and inhibits both the raptor-mTOR (TOR complex 1 or TORC1) and the rictor-mTOR (TOR complex 2 or TORC2) complexes of mTOR, which may result in tumor cell apoptosis and a decrease in tumor cell proliferation. mTOR is a serine/threonine kinase that is upregulated in some tumors and plays an important role downstream in the PI3K/Akt/mTOR signaling pathway.