To address C797S resistance, a promising therapeutic avenue is combination therapy that targets both total EGFR and acquired mutations to increase drug efficacy. We showed that combining vorinostat, a histone deacetylase inhibitor (HDACi), with brigatinib, a TKI, enhanced antitumor effects in primary culture and cell lines of lung adenocarcinomas harboring EGFR L858R/T790M/C797S mutations (EGFR-3M).