PD-L1 assessment in cytology samples predicts treatment response to checkpoint inhibitors in NSCLC. (September 2022)

• Record Type: Journal Article
• Authors: Lau, Sally C.M.; Rabindranath, Madhumitha; Weiss, Jessica; Li, Janice J.N.; Fung, Andrea S.; Mullen, Dorinda; Alshamlan, Najd; Ruff, Heather M.; Tong, Leung Chu B.; Pal, Prodipto; Cabanero, Michael R.; Hsu, Ying-Han R.; Sacher, Adrian G.; Shepherd, Frances A.; Liu, Geoffrey; Bradbury, Penelope A.; Yasufuku, Kazuhiro; Czarnecka-Kujawa, Katarzyna; Mi Ko, Hyang; Tsao, Ming-Sound; Leighl, Natasha B.; Schwock, Joerg
• Is Part Of: Lung cancer. Volume 171(2022)
• Page Start: 42
• Page End: 46
• Publication Date: 2022-09
• Subjects: PD-L1 testing -- Immunohistochemistry -- Cytology -- Non-small cell lung cancer -- Immune checkpoint inhibitors; Lungs -- Cancer -- Periodicals; Lung Neoplasms -- Abstracts; Lung Neoplasms -- Periodicals; Poumons -- Cancer -- Périodiques; Lungs -- Cancer; Periodicals; Electronic journals; Electronic journals; 616.99424
• DOI: 10.1016/j.lungcan.2022.07.018
• Languages: English
• ISSNs: 0169-5002

Abstract

Highlights: In a large population, cytology and histology samples had similar PD-L1 TPS distribution. Despite different sites of sampling, overall PD-L1 TPS proportions remained similar. PD-L1 TPS determined by the 22C3 assay on cytology was predictive of treatment response. PFS to PD1 inhibitors were similar according to PD-L1 TPS on cytology vs histology samples. PFS of patients with PD-L1 ≥ 50 % on cytology was comparable to clinical trials. Abstract: Background: Testing for tumor programmed death ligand-1 (PD-L1) expression was initially developed with histology specimens in non-small cell lung cancer (NSCLC). However, cytology specimens are widely used for primary diagnosis and biomarker studies in clinical practice. Limited clinical data exist on the predictiveness of cytology-derived PD-L1 scores for response to immune checkpoint inhibitor (ICI) therapy. Methods: We reviewed all NSCLC specimens clinically tested at the University Health Network (UHN) for PD-L1 with 22C3 pharmDx, from 01/2013 to 04/2021. Treatment outcomes in patients treated with single agent ICI therapy were reviewed and compared according to cytology- and histology-derived PD-L1 scores. Results: We identified 494 and 1942 unique patients with cytology- and histology-derived tumor proportion scores, respectively, during the study period. Informative testing rates were 95 % vs 98 % for cytology and histology, respectively. Clinical data were available for 152 patients treated with single agent ICI: 61 cytology and 91 histology. Overall response rates (ORR) were similar for cytology and histology (36 % vs 34 %; p = 0.23), as well as median progression free survival (PFS) (4.9 vs 4.2 months; p = 0.99) and overall survival (23.4 vs 19.7 months; p = 0.99). The results remained similar even after adjusting for PD-L1 expression levels and line of ICI treatment (PFS HR 1.15; 95 %CI 0.78–1.70; p = 0.47). Conclusions: Treatment outcomes to single agent ICI based on cytology-derived PD-L1 scores were comparable to histology controls. Our results support PD-L1 biomarker testing on both cytology and histology specimens.