LY900009

LY900009 is an orally available small molecule inhibitor developed by Eli Lilly that selectively targets the γ-secretase enzyme, thereby inhibiting Notch signaling. Notch signaling regulates stem cell development and survival and is implicated in various cancers. By blocking γ-secretase, LY900009 prevents the proteolytic cleavage of Notch receptors required for activation of oncogenic pathways, disrupting tumor cell proliferation, survival, and maintenance of cancer stemness. The drug also reduces plasma amyloid-β levels in a dose-dependent manner. In phase I clinical trials for advanced cancers (including ovarian cancer), the maximum tolerated dose was established at 30 mg thrice weekly; common adverse events included diarrhea, vomiting, anorexia, nausea, and fatigue. No objective responses were observed but some patients achieved stable disease. Development was discontinued after phase I due to limited efficacy and tolerability concerns[1][3][4][6].