STX-478, a Mutant-Selective, Allosteric PI3Kα Inhibitor Spares Metabolic Dysfunction and Improves Therapeutic Response in PI3Kα-Mutant Xenografts

The contribution of the X-ray crystallography team from our WuXi AppTec site in Germany was acknowledged in a recent study published in the journal Cancer Discovery. In this study, the authors show that compound STX-478, an allosteric PI3Kα inhibitor, selectively targets prevalent PI3Kα helical- and kinase-domain mutant tumors. STX-478 demonstrated robust efficacy in human tumor xenografts without causing the metabolic dysfunction previously observed with non-selective inhibitors. Combining STX-478 with fulvestrant and/or cyclin-dependent kinase 4/6 inhibitors was well tolerated and provided robust and durable tumor regression in ER+HER2− xenograft tumor models.