Discovery of GSK2126458, a Highly Potent Inhibitor of PI3K and the Mammalian Target of Rapamycin

Phosphomositide 3-kinase alpha (PI3K alpha) is a critical regulator of cell growth and transformation, and its signaling pathway is the most commonly mutated pathway in human cancers The mammalian target of rapamycin (mTOR), a class IV PI3K protein kinase, is also a central regulator of cell growth, and mTOR inhibitors are believed to augment the antiproliferative efficacy of PI3K/AKT pathway inhibition 2,4-Difluoro-N-{2-(methyloxy)-5-[4-(4-pyridazinyl)-6-quinolinyl]-3-pyridinyl}benzenesulfonamide (GSK2126458, 1) has been identified as a highly potent, orally bioavailable inhibitor of PI3K alpha and mTOR with in vivo activity in both pharrnacodynamic and tumor growth efficacy models Compound 1 is currently being evaluated in human clinical trials for the treatment of cancer.