Tumor PD-L1 Expression and Clinical Outcomes in Advanced-stage Non-Small Cell Lung Cancer Patients Treated with Nivolumab or Pembrolizumab: Real-World Data in Taiwan

Background: Immunotherapy that targets programmed death protein-1 (PD-1) provides improved treatment efficacy and survival in patients with metastatic non-small cell lung cancer (NSCLC), especially those with high tumor expression of PD-L1.However, data on this treatment are mostly from clinical trials enrolling highly selected patients.The real-world experience of anti-PD-1 treatment and the usefulness of tumor PD-L1 expression in prediction of treatment response are largely unknown.Methods: We retrospectively reviewed patients with stage IIIB/ IV NSCLC who received monotherapy with nivolumab or pembrolizumab, and evaluated response using RECIST 1.1 criteria.Factors associated with treatment response, progression free survival (PFS), and overall survival (OS) were determined.Results: Seventy-four NSCLC patients out of 116 examined patients were included, most of whom had adenocarcinoma (48/74, 64.9%) and received immunotherapy as a third-line or subsequent treatment (51/74, 68.9%).The median PFS and OS were 1.8 and 7.9 months, respectively.The objective response rate was 32%, but only 47 of 74 patients were evaluable.Through multivariate analysis, epidermal growth factor receptor (EGFR) mutation was independently associated with a poor treatment response.Good performance status (ECOG≤1) and smoking were independently associated with better PFS and OS.Data on tumor PD-L1 expression were available in 43 patients (58%); higher PD-L1 expression correlated with better treatment response and longer PFS.Severe treatment-related adverse events were uncommon.Conclusion: The efficacy and safety of anti-PD-1 medications for advanced NSCLC were comparable in real-world and clinical settings, except in those with poor ECOG scores.Prediction of treatment response from tumor PD-L1 expression seemed practical.