94P Efficacy of first-line pembrolizumab in elderly patients with advanced non-small cell lung cancer with high PD-L1 expression

Pembrolizumab monotherapy is the standard of care for first-line treatment of advanced non-oncogene driven non-small cell lung cancer (NSCLC) patients with high programmed cell death ligand 1 expression (PD-L1 TPS ≥ 50%). Elderly patients have been omitted form clinical trials, therefore data regarding the efficacy of this treatment in elderly population is limited. The aim of this study was to compare treatment outcomes of elderly patients (≥ 70 years) with younger patients based on real-world data. This retrospective study was conducted at two centers (University Clinic Golnik, Slovenia, and the Pulmonology Clinic, University Clinical Centre of Serbia) and involved advanced NSCLC patients with PD-L1 TPS ≥ 50% and negative targetable mutations (ALK, EGFR, ROS1) who initiated first-line treatment with pembrolizumab between January 2017 and March 2023. Required data about patients, their treatment, response to therapy and survival was obtained from electronic patient records. We identified 445 advanced NSCLC patients, 91% current or ex-smokers, with median age of 65 years. There were 120 patients in the elderly group over 70 years old. No statistically significant differences were observed in mOS (18.3 vs. 27.1 months (m); p=0.299), mToT (11.9 vs. 11.9 m; p=0.078), ORR (42% vs. 41%; p=0.68), or DCR (76% vs. 72%; p=0.323) between older and younger age groups, respectively. Among elderly, Eastern Oncology Cooperative Group performance status (ECOG PS) of ≥ 2 was associated with worse mOS (4.9 vs. 27.8 m; HR 0.26; 95% CI 0.12-0.58; p<0.001) whereas smokers displayed maximum benefit with longer mOS (26.5 vs. 13.2 months; HR 0.48; 95% CI 0.23-0.99; p=0.047), respectively. Only 15 elderly patients (12.5%) received second-line therapy. First-line pembrolizumab monotherapy is effective across all age groups and provides similar treatment efficacy in advanced NSCLC patients with PD-L1 TPS ≥ 50%. Patients with smoking history and ECOG PS 0-1 derive the most benefit from this treatment modality. Adaptation of this treatment strategy for elderly patients is especially important, since only a few are capable of receiving second-line therapy.