The anti–PD-1 humanized monoclonal antibody pembrolizumab has recently been approved in the United States to treat metastatic non–small cell lung cancer (NSCLC) in patients (pts) who are PD-L1 positive and have progressed on platinum therapy and an EGFR/ALK inhibitor if EGFR/ALK positive. Here, we report on the prevalence of PD-L1 expression in pts screened for enrollment in 3 global clinical trials that investigated the efficacy and safety of pembrolizumab in pts with advanced NSCLC: KEYNOTE-001 (NCT01295827), KEYNOTE-010 (NCT01905657), and KEYNOTE-024 (NCT02142738).
All 3 studies required provision of a tumor sample (archival or newly obtained) for PD-L1 testing as an entry criterion. PD-L1 expression was determined using the companion diagnostic PD-L1 IHC 22C3 pharmDx assay. PD-L1 expression was determined based on percentage of tumor cells with positive membranous staining and was reported as the tumor proportion score (TPS).
A total of 5879 pts were screened for eligibility in KEYNOTE-001 (n = 1242), KEYNOTE-010 (n = 2699), and KEYNOTE-024 (n = 1938). Of these, 4784 (81%) were evaluable for PD-L1; 1596 (33%) had TPS
This is one of the largest data sets of PD-L1 expression determined by an FDA-approved companion diagnostic in pts with advanced NSCLC screened for pembrolizumab therapy. 68% of pts with advanced NSCLC had PD-L1 TPS ≥1% and 28% had PD-L1 TPS ≥50%. The prevalence is similar across prior lines of therapy and different disease characteristics examined.
Clinical trial identification
KEYNOTE-001: ClinicalTrials.gov NCT01295827; KEYNOTE-010: ClinicalTrials.gov NCT01905657; KEYNOTE-024: ClinicalTials.gov NCT02142738
Legal entity responsible for the study
Merck & Co., Inc.
Merck & Co., Inc.
C. Aggarwal: Advisory Board member at Roche. E. Felip: Consulting for Lilly, Pfizer, Roche, Boehringer Ingelheim Speaker Bureau for BMS, Novartis, Astra Zeneca. M-J. Ahn: Consulting for Boehringer Ingelheim, Novartis, Astra Zeneca Research Funding for Astra Zeneca. M. Dolled-Filhart, Y. Shentu, R. Rangwala, B. Piperdi: Employee of Merck & Co. J. Zhang: Employee of Merck. P. Baas: Advisory board for BMS, MSD, Aduro. All other authors have declared no conflicts of interest.