Pembrolizumab for Previously Untreated Patients with Advanced Non-small-cell Lung Cancer and Preexisting Interstitial Lung Disease.

Objective Pembrolizumab has benefited patients with advanced non-small-cell lung cancer (NSCLC) with a programmed death-ligand (PD-L) 1 high expression, but little information is available regarding its safety for patients with interstitial lung disease (ILD). The aim of this study was to assess the efficacy and tolerability of pembrolizumab for patients with advanced NSCLC and preexisting ILD. Methods We retrospectively reviewed the medical records of five patients with advanced NSCLC and preexisting ILD who received pembrolizumab monotherapy in a first-line setting. Patients All patients had mild ILD and pulmonary emphysema with a forced vital capacity within the normal range. Pembrolizumab was administered at a dose of 200 mg/body on day 1 every 3 weeks. Results The overall response rate was 60%. Four patients developed pembrolizumab-induced lung injury, which was improved in all cases by corticosteroid therapy. One patient received pembrolizumab for two years, did not experience lung injury and achieved a complete response. Conclusion Pembrolizumab has a high risk of inducing lung injury in patients with preexisting ILD, although it may be very effective in NSCLC patients with a high PD-L1 expression, even concurrent with preexisting ILD. Further large-scale studies are needed to determine risk factors of pembrolizumab-induced lung injury in such patients.