Abstract:  Background and purpose: With the increasing application of immune checkpoint inhibitors in lung cancer, immune-related adverse event (irAE) has attracted more and more attention. This study aimed to analyze the occurrence of irAE in patients receiving single-drug immunotherapy and the correlation between irAE and immunotherapy efficacy. Methods: Data of patients with advanced non-small cell lung cancer (NSCLC) treated with anti-programmed death-1 (PD-1) monotherapy in Shanghai Pulmonary Hospital, Tongji University from June 2015 to Janurary 2019 were collected. Patients’ baseline clinical data, irAE types, occurrence time, severity, management of irAE, the objective response rate (ORR), disease control rate (DCR) and progression-free survival (PFS) were retrospectively analyzed. And then, we used the SPSS 23.0 software to explore the correlation between irAE and PFS. Results: One hundred and nine advanced NSCLC patients were treated in our hospital. The median age of the patients was 64 years (range 32-82 years). The ratio of male to female was 89∶20. The ECOG performance status scores of 0, 1 and 2 were 4, 103 and 2 cases respectively. The number of patients who received the first-line, second-line and third-line and above treatment were 15, 65 and 29 respectively. At the data cutoff, irAE occurred in 63 patients (57.8%). Among them, 43 cases had complex irAE. The most common irAE were skin adverse events (n=28, 25.7%). Other irAE were liver dysfunction (n=18, 16.6%), fatigue (n=16, 14.7%), endocrine toxicity (n=15, 13.8%), immune-related pneumonitis (n=12, 11.0%) and gastrointestinal toxicity (n=10, 9.2%). Most irAE occurred between 6 and 27 weeks. Ten patients (9.2%) had grade 3-4 irAE, mainly immune-related pneumonitis. Among the overall population, ORR was 24.7%, DCR was 77.9%, and median PFS was 4.6 months (95% CI: 3.9-5.2). Patients with irAE had significantly higher ORR compared with patients who did not have irAE (36.5% vs 8.7%, P=0.001). Similarly, the median PFS among patients with irAE was longer than patients without irAE (8.7 months vs 3.5 months, HR=0.294, 95% CI: 0.184-0.469, P<0.001). Among them, skin adverse events were most correlated with prognosis (median PFS: 12.7 months vs 4.3 months, HR=2.332, 95% CI: 1.184-4.595, P=0.014). Conclusion: Most cases of irAE in immunotherapy of lung cancer occurred in 6-27 weeks of treatment, and most of them were grade 1-2. Grade 3-4 irAE were mostly immune-related pneumonitis. Development of irAE was associated with survival outcome.

Key words: Non-small cell lung cancer, Programmed death-1, Immune-related adverse events, Efficacy