R16(NSC29869, Nrf2-IN-3) is an inhibitor of NRF2 (nuclear factor erythroid 2-related factor 2) that selectively binds KEAP1 mutants and restores their NRF2-inhibitory function by repairing the disrupted KEAP1/NRF2 interactions. It significantly enhances the sensitivity of KEAP1-mutated tumor cells to cisplatin and gefitinib.