Evaluation of Programmed Death Ligand 1 (<i>PD-L1</i>) Gene Amplification and Response to Nivolumab Monotherapy in Non–small Cell Lung Cancer
Authors: Yusuke Inoue, Katsuhiro Yoshimura, Koji Nishimoto, Naoki Inui, Masato Karayama, Hideki Yasui, Hironao Hozumi, Yuzo Suzuki, Kazuki Furuhashi, Tomoyuki Fujisawa, Noriyuki Enomoto, Yutaro Nakamura, Kazuhiro Asada, Tomohiro Uto, Masato Fujii, Takashi Matsui, Shun Matsuura, Dai Hashimoto, Mikio Toyoshima, Hideki Kusagaya, Hiroyuki Matsuda, Nao Inami, Yusuke Kaida, Mitsuru Niwa, Yasuhiro Ito, Haruhiko Sugimura, Takafumi Suda
Journal: JAMA Network Open (2020)

<h3>Importance</h3> Robust predictors for response to anti–programmed death 1 and its ligand (PD-1/PD-L1) immunotherapy in non–small cell lung cancer (NSCLC) are not fully characterized. <h3>Objective</h3> To evaluate whether<i>PD-L1</i>(<i>CD274</i>) copy number gains (CNGs), comprising amplification and polysomy, in pretreatment specimens assessed by fluorescence in situ hybridization are associated with response to nivolumab monotherapy in NSCLC. <h3>Design, Setting, and Participants</h3> This multicenter cohort study enrolled 200 patients, of whom 194 had assessable tumors, with advanced or recurrent NSCLC who were treated with nivolumab after progression following prior treatment at 14 institutions in Japan between July 2016 and December 2018. Median (interquartile range) duration of follow-up was 12.6 (5.6-20.4) months. Data were analyzed from December 2019 to February 2020. <h3>Exposures</h3> Sequential nivolumab was given on day 1 of a 14-day cycle. Response was assessed every 4 cycles using Response Evaluation Criteria in Solid Tumors version 1.1. <h3>Main Outcomes and Measures</h3> Overall response rate (ORR) according to the<i>PD-L1</i>copy number status. Additional end points were progression-free survival, overall survival, and PD-L1 tumor proportion score (TPS) assessed by immunohistochemistry based on<i>PD-L1</i>copy number status. <h3>Results</h3> A total of 6 of the 200 patients were excluded because of poor-quality tumor specimens for the biomarker study, resulting in 194 assessable patients. Of these, 155 (79.9%) were men, with a median (range) age of 69 (43-83) years.<i>PD-L1</i>CNGs were identified in 32 patients (16.5%), including 5 (2.6%) with amplification and 27 (13.9%) with polysomy. The ORR among patients with and without<i>PD-L1</i>CNGs was 28.1% (95% CI, 13.7%-46.7%) and 17.9% (95% CI, 12.3%-24.7%), respectively. Although patients with<i>PD-L1</i>polysomy did not demonstrate improved ORR (18.5% [95% CI, 6.3%-38.1%]) compared with those without<i>PD-L1</i>CNGs, 4 of 5 patients (80.0% [95% CI, 28.4%-99.5%]) with<i>PD-L1</i>amplification showed response, among whom median duration of response was not reached. Patients with<i>PD-L1 </i>amplification showed excellent survival outcomes for progression-free and overall survival. Overall, 3<i>PD-L1</i>-amplified tumors (60.0%) showed PD-L1 TPS of at least 80%, but 2 (40.0%) had PD-L1 TPS of 15% or less. <h3>Conclusions and Relevance</h3> In this study, tumor<i>PD-L1</i>amplification but not polysomy was associated with response to nivolumab monotherapy among patients with NSCLC. External validation with a larger sample size is warranted.