Researchers from Scorpion Therapeutics Inc. presented the discovery and preclinical evaluation of a novel mutant-selective, allosteric phosphoinositide 3-kinase α (PI3Kα) inhibitor, STX-478. In vitro, STX-478 showed mutant selectivity, as it selectively inhibited the viability of cell lines with mutations in the PIK3CA kinase domain and helical domain.