RLY-5836

RLY-5836 is an orally bioavailable, small molecule inhibitor that selectively targets mutant forms of the phosphatidylinositol 3-kinase alpha (PI3Kα) enzyme. Developed by Relay Therapeutics, it is designed as a pan-mutant and isoform-selective PI3Kα inhibitor to overcome limitations of earlier PI3Kα inhibitors that lacked selectivity for mutant versus wild-type PI3Kα and had off-target effects on other isoforms. The drug aims to treat patients with advanced solid tumors and breast cancer harboring PIK3CA mutations. Its mechanism involves allosteric inhibition of the class I phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), which is frequently mutated in cancers[2][4][6]. Clinical development has included first-in-human Phase 1 trials in advanced breast cancer and other solid tumors[1][2][5].