Pembrolizumab vs chemotherapy in patients with advanced/metastatic adenocarcinoma (AC) or squamous cell carcinoma (SCC) of the esophagus as second-line therapy: Analysis of the Chinese subgroup in KEYNOTE-181

Abstract

Background: KEYNOTE-181 (NCT02564263) is an open-label, randomized, phase 3 trial of pembrolizumab (P) vs investigator's choice of single-agent paclitaxel, docetaxel, or irinotecan (standard of care [SOC]) in advanced/metastatic AC or SCC of the esophagus. In the global cohort, P was superior to SOC for OS in pts with PD-L1 combined positive score (CPS) >=10, with a more favorable safety profile. We present results of the China cohort. Method(s): Eligible pts were randomly assigned 1:1 to receive P 200 mg Q3W for up to 2 y or investigator's choice of SOC. Randomization was stratified by histology (SCC vs AC) and region (Asia vs rest of world). Primary end points were OS in the intention-to-treat (ITT), SCC, and PD-L1 CPS >=10 populations. Result(s): Of the 123 Chinese pts enrolled, 119 had SCC and 54 had CPS >=10. Pts were randomly assigned to receive P (62 pts; 60 had SCC; 25 had CPS >=10) or SOC (61 pts; 59 had SCC; 29 had CPS >=10). As of Feb 13, 2019, the median follow-up (from randomization, regardless of death) was 15.1 mo (P) vs 14.7 mo (SOC). Median OS was longer with P vs SOC overall (8.4 vs 5.6 mo; HR 0.55; 95% CI 0.36-0.82) and in the SCC (8.4 vs 5.6 mo; HR 0.55; 95% CI 0.37-0.83), and CPS >=10 groups (12.0 vs 5.3 mo; HR 0.34; 95% CI 0.17-0.69). Median OS for P vs SOC in the CPS <10 group was 6.4 vs 6.1 mo (HR 0.72; 95% 0.43-1.21). OS rates at 12 mo for the P vs SOC groups were 36.3% vs 16.7% overall, 35.7% vs 15.3% in the SCC, and 53.1% vs 16.1% in the CPS >=10 groups. PFS rates at 6 mo were similar for P vs SOC (26.4% vs 24.1% in the ITT group), but ORR was substantially higher (16.1% vs 3.3% in the ITT group). Median DOR was not reached for P (4.4+ to 14.6+ mo) and was 3.2 mo (2.6-3.9) for the SOC group. Fewer pts receiving P vs SOC had any-grade (76% vs 83%) or grade 3-5 (21% vs 42%) drug-related AEs or drug-related AEs that resulted in discontinuation (6.4% vs 11.9%). Conclusion(s): P showed favorable OS, compared with SOC, as second-line therapy for AC/SCC in Chinese pts, with a more favorable safety profile. In China, more patients had SCC than AC and P showed clinically meaningful OS improvement regardless of PD-L1 status. This finding was consistent with that of the Asia group from the full global cohort. Clinical trial identification: NCT02564263, September 30, 2015. Editorial acknowledgement: Amy McQuay, PhD, of the ApotheCom pembrolizumab team (Yardley, PA, USA), funded by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Legal entity responsible for the study: Merck Sharp & Dohme Corp, a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Funding(s): Merck Sharp & Dohme Corp, a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Disclosure: J. Zhang: Advisory / Consultancy: Bayer; Advisory / Consultancy: BMS; Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert testimony: Sanofi; Speaker Bureau / Expert testimony: Merck-Serono; Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: Taiho; Speaker Bureau / Expert testimony: HengRui; Speaker Bureau / Expert testimony: Novartis. Y. Cui: Full / Part-time employment: MSD, China. P. Bhagia: Full / Part-time employment: Merck & Co., Inc. S.P. Kang: Full / Part-time employment: Merck & Co., Inc.; Shareholder / Stockholder / Stock options: Celgene; Shareholder / Stockholder / Stock options: Macrogenics; Shareholder / Stockholder / Stock options: Celldex; Shareholder / Stockholder / Stock options: Agenus; Shareholder / Stockholder / Stock options: Pharmacyclics; Shareholder / Stockholder / Stock options: Endocyte. W. Lu: Full / Part-time employment: MSD, China. Y. Zhou: Full / Part-time employment: MSD China. All other authors have declared no conflicts of interest.Copyright © 2019 European Society for Medical Oncology