Prognostic impact of metastatic sites for pembrolizumab efficacy as first-line therapy in patients with PD-L1 tumour proportion score (TPS) ≥ 50% advanced non-small cell lung cancer: A retrospective multicenter study

Abstract Background Little is known about the associations between treatment outcome for immune checkpoint inhibitors and metastatic sites in patients with advanced non-small cell lung cancer (NSCLC). Furthermore, these previous studies included patients irrespective of their PD-L1 status and treatment lines. Therefore, we conducted a multicentered retrospective study to investigate the predictive factors of metastatic sites as first-line pembrolizumab efficacy in patients with PD-L1 tumor proportion score (TPS) ≥50% advanced NSCLC. Methods We retrospectively analyzed patients with advanced NSCLC and PD-L1 TPS ≥ 50% who received pembrolizumab as the first-line therapy at 11 institutions between February 2017 and April 2018. Clinical data including metastatic sites at the time of administering pembrolizumab treatment were collected. Treatment outcome of pembrolizumab was assessed according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Results In total, 213 patients were included in the study. The median age was 71 years (range 39-91). Of the 213 patients, 176 (83%) were men, 172 (81%) had Eastern Cooperative Oncology Group performance status (ECOG PS) 0-1. The major metastatic sites were thoracic lymph nodes metastasis (77%), intrapulmonary metastasis (31%), bone metastasis (28%), and malignant pleural effusion (26%). In multivariate analysis, poor PS (hazard ratio: 1.82, 95.0% confidence interval: 1.15–2.30; P = 0.046) and malignant pleural effusion (hazard ratio: 1.52, 95.0% confidence interval: 1.01–2.30; P = 0.046) was identified as an independent predictor of shorter progression free survival in patients treated with pembrolizumab. Conclusions In patients with advanced NSCLC and PD-L1 TPS ≥50% who received first-line pembrolizumab, poor PS and malignant pleural effusion are independent predictors of pembrolizumab efficacy. Clinical trial identification UMIN000032470. Legal entity responsible for the study Hanshin Oncology clinical Problem Evaluation group (HOPE). Funding Has not received any funding. Disclosure H. Kawachi: Honoraria (self): Taiho Pharmaceutical Co., Ltd.; Honoraria (self): Merck Sharp & Dohme, Corp. M. Tamiya: Honoraria (self): Taiho Pharmaceutical Co., Ltd.; Honoraria (self): Merck Sharp & Dohme, Corp. A. Tamiya: Honoraria (self): Taiho Pharmaceutical Co., Ltd.; Honoraria (self): Merck Sharp & Dohme, Corp. K. Hirano: Honoraria (self): Taiho Pharmaceutical Co., Ltd.; Honoraria (self): Merck Sharp & Dohme, Corp. T. Yokoyama: Honoraria (self): Taiho Pharmaceutical Co., Ltd. T. Ishida: Honoraria (self): Merck Sharp & Dohme, Corp. D. Fujimoto: Honoraria (self): Taiho Pharmaceutical Co., Ltd.; Honoraria (self): Merck Sharp & Dohme, Corp. T. Hirashima: Honoraria (self): Taiho Pharmaceutical Co., Ltd. M. Kanazu: Honoraria (self): Merck Sharp & Dohme, Corp. T. Kumagai: Honoraria (self): Taiho Pharmaceutical Co., Ltd.; Honoraria (self): Merck Sharp & Dohme, Corp. All other authors have declared no conflicts of interest.