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Discovery And Clinical Proof-Of-Concept Of Rly-2608, A First-In-Class Mutant-Selective Allosteric Pi3kα Inhibitor That Decouples Antitumor Activity From Hyperinsulinemia, Andreas Varkaris, Ermira Pazolli, Hakan Gunaydin, Qi Wang, Levi Pierce, Alessandro A Boezio, Artemisa Bulku, Lucian Dipietro, Cary Fridrich, Adam Frost, Fabrizio Giordanetto, Erika P Hamilton, Katherine Harris, Michael Holliday, Tamieka L Hunter, Amanda Iskandar, Yongli Ji, Alexandre Larivée, Jonathan R Larochelle, André Lescarbeau, Fabien Llambi, Brenda Lormil, Mary M Mader, Brenton G Mar, Iain Martin, Thomas H Mclean, Klaus Michelsen, Yakov Pechersky, Erika Puente-Poushnejad, Kevin Raynor, Dipali Rogala, Ramin Samadani, Alison M Schram, Kelley Shortsleeves, Sweta Swaminathan, Shahein Tajmir, Gege Tan, Yong Tang, Roberto Valverde, Bryan Wehrenberg, Jeremy Wilbur, Bret R Williams, Hongtao Zeng, Hanmo Zhang, W Patrick Walters, Beni B Wolf, David E Shaw, Donald A Bergstrom, James Watters, James S Fraser, Pascal D Fortin, D Randal Kipp

Journal Articles

PIK3CA (PI3Kα) is a lipid kinase commonly mutated in cancer, including ∼40% of hormone receptor–positive breast cancer. The most frequently observed mutants occur in the kinase and helical domains. Orthosteric PI3Kα inhibitors suffer from poor selectivity leading to undesirable side effects, most prominently hyperglycemia due to inhibition of wild-type (WT) PI3Kα. Here, we used molecular dynamics simulations and cryo-electron microscopy to identify an allosteric network that provides an explanation for how mutations favor PI3Kα activation. A DNA-encoded library screen leveraging electron microscopy-optimized constructs, differential enrichment, and an orthosteric-blocking compound led to the identification of RLY-2608, a first-in-class allosteric mutant-selective inhibitor …