To determine whether IDH-mutant NSCLC patients could benefit from the combination of IDH inhibitors and EGFR TKIs, we overexpressed wild-type or mutant (IDH1-R132H) IDH1 in HCC827 cells carrying an EGFR mutation in vitro....we treated these cells with erlotinib, the IDH1 inhibitor AGI-5198, and a combination of Erlotinib and AGI-5198...the combination of an EGFR TKI and IDH inhibitor suppressed its growth to a lower level, indicating that the combination of an IDH inhibitor and EGFR TKI is more efficient in inhibiting tumor cell growth than the single treatment. Thus, these in vitro results revealed that EGFR-mutant NSCLC patients who carry an IDH mutation may benefit from combined therapy of EGFR TKIs and IDH inhibitors.