Real-world evidence of pembrolizumab efficacy and safety in patients with NSCLC with high PD-L1 expression.

Abstract

e20620 Background: Immune check-point inhibitors improved survival in patients with NSCLC and no driver mutations. Pembrolizumab, PD-1 inhibitor, compared to standard chemotherapy resulted in higher response rate and significantly longer progression free survival and overall survival in patients with high PD-L1 expression. Methods: Study was conducted at the University Hospital Center Zagreb, Croatia and assessed the real-world efficacy of pembrolizumab in 246 patients with PD-L1-high (PD-L1 expression ≥ 50%) metastatic non-small cell lung cancer (NSCLC). Patients were treated between March 2018 and April 2020, with exclusion criteria of positive EGFR mutations, ALK rearangements and ROS1 fusions. Results: The mean age of patients was 65 years, 69.5% were male and most patients (92.9%) had a history of smoking (52.7% were current smokers, 40.2% were former smokers). The most common histology was adenocarcinoma (67.5%). Brain metastases were present at diagnosis in 21% patients. Efficacy was assesed with median progression-free survival (PFS) of 22 months and a median overall survival (OS) of 32 months. At 12 months, 60.6% of patients were alive without disease progression. The objective response rate (ORR) was 48.1%, with a disease control rate of 75.8%. There was no significant difference in PFS and OS based on tumor type, smoking status, or PD-L1 assessment method. The only statistical significance was observed in mOS between patients with CNS metastases and those without (p = 0.013; HR = 1.80 (1.04-3.15). In 44 patients (18.1%), adverse event led to treatment discontinuation, and in 7 patients (2.9%) led to death. Among these leading to discontinuation, 50% were grade 1 and 2. The most common treatment-related adverse events of any grade causing treatment discontinuation were pneumonitis in 21/44 patients (47.2%) and, dermatitis in 9/44 (20.4%). Among serious adverse events, grade 3-5, pneumonitis was the most common in 6/44 patients (13.6%). Conclusions: Our study showed that pembrolizumab is effective and safe in a real-world setting, with comparable outcomes from clinical trials.