Real-World Data Analysis of Pembrolizumab Monotherapy for NSCLC Using Japanese Postmarketing All-Case Surveillance Data

Introduction: Pembrolizumab is a programmed death-ligand 1 inhibitor that was initially indicated for monotherapy in patients with advanced lung cancer. The Japanese Lung Cancer Society conducted an observational study on pembrolizumab using confirmative data obtained through postmarketing all-case surveillance (PMACS), which was performed by a pharmaceutical company under the Japanese law in 2017. Methods: This multicenter observational study was conducted by the Japanese Lung Cancer Society using PMACS data with the newly created central registration system regarding patients with NSCLC who received pembrolizumab monotherapy between February 1, 2017 and June 30, 2017; a new database was created by adding the clinical information regarding prognosis for 3 years after therapy to the existing data collected by PMACS. Results: A total of 300 patients from 43 facilities were enrolled in this study. The median overall survival and progression-free survival after pembrolizumab initiation were 558 and 188 days, respectively. Moreover, the 1- and 3-year survival rates were 58.9% and 33.7%, respectively. Results of multivariate analysis revealed performance status (p < 0.0001), histology (p = 0.0118), previous chemotherapy (p = 0.0007), programmed death-ligand 1 expression status (p = 0.0195), and previous steroid use (p = 0.0460) as significant factors that affected overall survival. The toxicity profile was similar to that previously reported. Conclusions: In this first attempt to use PMACS data, we successfully collected clinical information and found the real-world efficacy and safety of pembrolizumab.