Definition

The tartrate salt form of XZP-5809, an orally bioavailable third-generation inhibitor of certain epidermal growth factor receptor (EGFR) activating mutations, including the resistance mutation T790M, and the L858R and del 19 mutations, with potential antineoplastic activity. Upon oral administration, EGFR inhibitor XZP-5809 specifically and irreversibly binds to and inhibits selective EGFR mutations, which prevents EGFR mutant-mediated signaling and leads to cell death in EGFR mutant-expressing tumor cells. This agent shows higher activity against EGFR mutants compared with wild-type EGFR (WT EGFR). EGFR, a receptor tyrosine kinase mutated in many tumor cell types, plays a key role in tumor cell proliferation and tumor vascularization.