In vivo efficacy studies showed that VRN110755 had superior or comparable efficacy to approved EGFR TKIs in osimertinib-resistant EGFR mutants (Del19/C797S and L858R/C797S) and uncommon EGFR mutants, and comparable efficacy to osimertinib even in common activating EGFR mutants (Del19 and L858R).