Efficacy and safety of anti-programmed cell death protein 1 antibody combination therapy in patients with advanced experienced epidermal growth factor receptor-tyrosine kinase inhibitor-resistant lung adenocarcinoma: a retrospective cohort study.

Background: The effectiveness of combining anti-programmed cell death protein 1 (PD-1) and chemotherapy has been evaluated as superior to that of chemotherapy alone in the patients with advanced epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-resistant non-small cell lung cancer (NSCLC). In this study the efficacy and safety of anti-PD-1 combination therapy were evaluated retrospectively in patients who experienced EGFR-TKI-resistant with advanced lung adenocarcinoma (LUAD), with the goal of providing helpful guidance for clinical application. Methods: The clinical results of patients with incurable LUAD who received anti-PD-1 antibody combined with or without anti-angiogenic or chemotherapy after EGFR-TKI therapy failure were collected. The efficacy was calculated based on the objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). The efficacy of the regimes was compared according to treatment groups and programmed cell death ligand 1 (PD-L1) expression. Results: The final analysis included a total of 43 patients with advanced EGFR-mutant LUAD. The overall cohort had an ORR of 23.3%, median PFS (mPFS) of 6.5 months, and median OS (mOS) of 10.6 months. No notable distinction was observed in mPFS and mOS among patients receiving three types of anti-PD-1 antibody combination therapies. Patients with positive PD-L1 expression showed a longer mPFS compared to patients with negative PD-L1 expression. No statistical difference was detected in terms of mPFS between the use of immune combination chemotherapy and immune combination anti-angiogenic therapy in the PD-L1 positive subgroup, and PFS was prolonged regardless of the PD-L1 expression status being positive or negative in the population receiving immune combination chemotherapy. Treatment-related adverse events (TRAEs) of grade 3 or higher were observed in 16.3% of patients, including chemotherapy-containing immunotherapy. No deaths resulting from immune-related adverse events (irAEs) were reported, and only 1 patient receiving immunotherapy plus chemotherapy had to discontinue treatment due to irAEs. Conclusions: Combination immunotherapy is feasible in post-TKI resistant individuals with LUAD harboring EGFR mutations. Immune combination chemotherapy and immune combination anti-angiogenic therapy have equivalent efficacy in the PD-L1 positive population. PD-L1 expression can be used as a reference for screening candidates for combination immunotherapy.