Background: Clinical trials have opened the door to immunotherapy for NSCLC treatment. Reported patient outcomes outside of these highly selective studies are limited. This retrospective study aimed to evaluate the mortality risk and overall survival (OS) of metastatic NSCLC patients who received first-line pembrolizumab plus carboplatin doublet chemotherapy or pembrolizumab alone — aligned with KEYNOTE-189 and KEYNOTE-024 trials, in the real-world setting of oncology practice in Australia.
Methods: From the hospital records, metastatic NSCLC patients who received pembrolizumab were identified. Patient demographics, smoking history, EGFR/ALK/ROS1 mutation status, Eastern Cooperative Oncology Group (ECOG) performance status, programmed death-ligand 1 (PD-L1) tumour proportion score (TPS) were noted. Eligible patients were selected between 01/01/2019-31/07/2022 to allow for at least one year of follow-up. Kaplan-Meier method was used to estimate OS.
Results: Of the 42 patients with metastatic nonsquamous NSCLC, 6 (14.3%), 21 (50%), and 9 (21.4%) had PD-L1 TPS of ≥50%, 1-49% and ≤1% respectively. PD-L1 status was unknown for 6 patients (14.3%). Median age at diagnosis was 67 years and 52.4% were women. 36 patients (85.7%) were smokers. After a median follow-up period of 32.3 months, the median OS was 15.8 months (95% CI 17.0-24.9). The rate of OS at 12 months and 24 months were 59.4% and 50.3% respectively. Of the 21 patients with metastatic NSCLC who received first-line pembrolizumab, high PD-L1 was found in 16 patients (76.2%), low PD-L1 in 4(19%) and one undocumented. Estimated OS at 6 months and 12 months were 87.5% and 53.8% respectively.
Conclusions: The real-world survival outcomes for metastatic NSCLC patients was inferior in the pembrolizumab-chemotherapy group but pembrolizumab alone conveyed survival benefit comparable to trial results.