Japan subset of Phase III study KEYNOTE-024: Pembrolizumab for PD-L1 TPS > =50%, treatment-naïve NSCLC

Abstract

Background: Prognosis of NSCLC patients who do not have targetable gene alterations such as EGFR or ALK remains poor. The previous phase 1 study (KEYNOTE-001) demonstrated the improved efficacy of pembrolizumab for PD-L1 TPS>=50%, treatment-naïve NSCLC. Methods: This is an international randomized phase 3 trial for PD-L1 TPS>=50%, treatment-naïve NSCLC. The primary endpoint was PFS by blinded independent central review based on RECIST 1.1. Results: Between Sep 2014 and Oct 2015, 305 (40 Japanese) patients were enrolled: 154 (21 Japanese) allocated to pembrolizumab 200 mg Q3W, 151 (19 Japanese) allocated to standard of care (SOC). At the median follow-up of 11.2 months, 44% (53% of Japanese) of patients in the SOC arm crossed over to pembrolizumab. Hazard ratios for PFS were 0.50 (95%CI 0.37-0.68) in the overall population and 0.35 (95%CI 0.14-0.91) in Japanese patients. Hazard ratios for OS were 0.60 (95%CI 0.41-0.89) in the overall population and 0.40 (95%CI 0.10-1.61) in Japanese patients. Grade 3-5 treatmentrelated adverse events that occurred in the overall population and in Japanese patients were 27% and 33% for the pembrolizumab 200 mg Q3W arm, and 53% and 47% for the SOC arm, respectively. Conclusion: Similar to the overall population, the subset analysis of Japanese patients of KEYNOTE-024 indicated superior efficacy and safety of pembrolizumab for PD-L1 TPS>=50%, treatment-naïve NSCLC.