Atezolizumab for EGFR-mutated Non-small Cell Lung Cancer Patients: An Observation Study in Ibaraki Group (ATTENTION-IBARAKI)

Background/Aim: Atezolizumab, an anti-programed death-ligand 1 monoclonal antibody, targets programed death-ligand 1 expressed on cancer cells and antigen-presenting cells and is now commonly used in combination with chemotherapy. We conducted a study to clarify the efficacy of atezolizumab in epidermal growth factor receptor (EGFR)-mutated patients who are considered less responsive to immune checkpoint inhibitors. Patients and Methods: A retrospective review of patients with advanced non-small cell lung cancer (NSCLC) who received atezolizumab-containing therapy at 11 hospitals from April 2018 to March 2023 was performed. Results: Median progression-free survival and overall survival in 33 EGFR-mutated patients treated with atezolizumab monotherapy were 2.0 and 9.0 months, respectively, and those in 19 patients who received combined atezolizumab plus chemotherapy were 12.0 and 17.0 months, respectively. When comparing EGFR-mutated and EGFR-negative patients after propensity score matching, there were no significant differences in progression-free survival and overall survival between the two groups, whether atezolizumab monotherapy or combined atezolizumab plus chemotherapy. Among EGFR-mutated patients, being male was a significant favorable factor in both atezolizumab treatment groups. None of the EGFR-mutated patients had grade 5 immune-related adverse events. Conclusion: Efficacy of atezolizumab in EGFR-mutated NSCLC patients could be comparable to that for EGFR-negative patients. To prolong the survival of EGFR-mutated NSCLC patients, appropriate selection and sequencing of EGFR for tyrosine kinase inhibitors, as well as immune checkpoint inhibitors, anti-tumor agents, and anti-angiogenic agents are important.