KEAP1 and STK11/LKB1 alterations enhance vulnerability to ATR inhibition in KRAS mutant NSCLC
KRAS mutations frequently co-occur with alterations in STK11/LKB1 and/or KEAP1, defining an aggressive subset of tumors associated with resistance to immuno- and chemotherapy. While LKB1 loss is associated with vulnerability to DNA-damage response (DDR)-based therapies, the impact of KEAP1 alterations remains unknown. Here we demonstrate that KEAP1/NRF2 pathway drives a compensatory modulation of ATR-CHK1 signaling, enhancing vulnerability to ATR inhibitors (ATRi) particularly in the setting of increased replication stress associated with LKB1 loss. ATRis show enhanced anti-tumor activity in LKB1 and/or KEAP1-deficient NSCLC models and synergy combined with gemcitabine. ATRi also enhances antitumor immunity and helps mitigate the immunosuppressed phenotype of LKB1 and/or KEAP1-deficient tumors. Finally, in the HUDSON trial, LKB1/KEAP1-deficient NSCLC patients demonstrate enhanced benefits to the ATRi ceralasertib plus durvalumab. These findings suggest that alterations in the KEAP1/NRF2 pathway and/or LKB1 are associated with enhanced sensitivity to ATRi and could serve as useful biomarkers for predicting response to ATRi combination regimens.