Survival analysis for non-squamous NSCLC patients harbored STK11 or KEAP1 mutation receiving atezolizumab

Objective: To analyze the prognostic effect for patients with non-squamous non-small cell lung cancer (NSCLC) harbored STK11 or KEAP1 (STK11/KEAP1) mutations receiving atezolizumab and docetaxel.

Methods: Data from OAK and POPLAR clinical trials was firstly applied to analyze genomic alteration frequency and the correlation between STK11/KEAP1 mutations and blood-based tumor mutational burden (bTMB)/PD-L1 expression. Univariate and multivariate Cox regression hazard models were preformed to analyze the influence of prognostic factors on survival. Survival difference was compared by Kaplan-Meier and log-rank test.

Results: Most STK11/KEAP1 mutations (7.33 %/10.76 %) were found in non-squamous NSCLC compared with squamous lung cancer. Interestingly, only 1.56 % STK11 mutation or 3.13 % KEAP1 mutation occurred in EGFR mutant non-squamous NSCLC. Compared with wild type, patients with STK11/KEAP1 mutations had higher bTMB (both, P < 0.001). Moreover, compared with wild type, patients harbored KEAP1 mutation had higher PD-L1 expression (TC3/IC3: 25.00 % vs. 14.54 %), while patients harbored STK11 mutation had lower PD-L1 expression (TC3/IC3: 7.89 % vs. 15.90 %). Univariate and multivariate analyses revealed that STK11/KEAP1 mutations were independent and significant prognostic factors on overall survival (OS) (both, P < 0.05) and progression-free survival (PFS) (both, P < 0.05). Importantly, patients harbored STK11/KEAP1 mutations had a relatively worse OS than wild type both in those receiving atezolizumab and docetaxel (all, P < 0.05). In addition, for STK11 mutant subset, atezolizumab did not improve OS compared with docetaxel (HR = 0.669; 95 %CI: 0.380-1.179; P = 0.669); while cox-regression analysis showed the improved survival of patients with KEAP1 mutation who receiving atezolizumab compared with docetaxel (HR = 0.610; 95 %CI: 0.384-0.969; P = 0.036).

Conclusion: Compared with wild type, non-squamous NSCLC patients with STK11/KEAP1 mutations may not benefit more from both atezolizumab and docetaxel. However, patients with mere KEAP1 mutations and without STK11 mutations may have a better response to atezolizumab than docetaxel.