Characteristics of patients withEGFR-mutant non-small-cell lung cancer who benefited from immune checkpoint inhibitors

Objectives Immune checkpoint inhibitors (ICIs) are less effective in non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations. However, a small percentage of patients withEGFR-mutant NSCLC do respond, and the characteristics of these patients are not known. Here, we identify the characteristics of patients who may respond to ICI therapy forEGFR-mutant NSCLC. Patients and methods The medical records of NSCLC patients withEGFRmutations who received PD-1/PD-L1 antibody monotherapy at nine institutions were reviewed. Results In total, 58 patients withEGFR-mutant NSCLC were analyzed. Various clinical factors such as smoking history andEGFRmutation type were not associated with progression-free survival (PFS) of ICIs, while the PFS of prior EGFR tyrosine kinase inhibitors (TKIs) was inversely associated with that of ICIs. Patients who responded to prior EGFR TKIs for > 10 months exhibited a significantly shorter response to ICIs compared to those who had responded for <= 10 months (PFS of ICI: 1.6 vs. 1.9 months; hazard ratio: 2.54; 95% confidence interval 1.26-5.12;p = 0.009). However, patients who responded to ICIs for > 6 months responded to prior EGFR TKIs for significantly shorter periods compared to those who responded to ICIs for <= 6 months (PFS of prior EGFR TKI: 5.3 vs. 12.1 months; log-rank test:p = 0.0025). Conclusion The duration of response to prior EGFR TKIs could be a predictive marker of ICI therapy inEGFR-mutant NSCLC patients.