An orally available selective inhibitor of certain epidermal growth factor receptor (EGFR) activating mutations, including the resistance mutation T790M, with potential antineoplastic activity. Upon administration, the EGFR mutant-specific inhibitor ZN-e4 specifically binds to and inhibits selective EGFR mutations, which prevents EGFR mutant-mediated signaling and leads to cell death in EGFR mutant-expressing tumor cells. Compared to other EGFR inhibitors, ZN-e4 may offer therapeutic benefits in tumors with T790M-mediated drug resistance and may limit toxicities associated with non-selective EGFR inhibitors. EGFR, a receptor tyrosine kinase mutated in many tumor cell types, plays a key role in tumor cell proliferation and tumor vascularization.