Association of PD-L1 Expression on Tumor and Immune Cells with Survival in Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma and Assay Validation.

Programmed cell death ligand-1 (PD-L1), expressed on both tumor cells (TC) and tumor-associated immune cells (IC), has been shown to be a useful biomarker and predictive of response to anti-PD-L1 agents in certain tumor types. In recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC), there is a growing interest in the role of PD-L1 expression on ICs, as well as TCs, for predicting response to immune checkpoint inhibitors. Using pooled data from the phase II HAWK and CONDOR studies, we investigated the association of baseline PD-L1 expression with durvalumab efficacy in patients with R/M HNSCC. To determine an optimal PD-L1 cut-off point for predicting survival, we assessed PD-L1 expression levels at different TC and IC cut-off points in patients treated with durvalumab. Longer survival was associated with higher TC membrane PD-L1 expression and IC staining. When the combined TC/IC algorithm was applied, a cut-off point for PD-L1 expression of ≥50% on TCs or ≥25% on ICs (TC ≥ 50%/IC ≥ 25%) showed a higher objective response rate (17.2% vs. 8.8%), longer median progression-free survival (2.8 vs. 1.9 months), and longer median overall survival (8.4 vs. 5.4 months) in the PD-L1-high versus PD-L1-low/negative patient populations, respectively. A scoring algorithm combining PD-L1 expression on TCs and ICs using the cut-off point TC ≥ 50%/IC ≥ 25% was optimal for identifying patients with HNSCC most likely to benefit from durvalumab treatment. The new algorithm is robust and can be reproducibly scored by trained pathologists. A novel algorithm for PD-L1 expression using the cut-off point TC ≥ 50%/IC ≥ 25% is robust for identifying patients with HNSCC most likely to benefit from durvalumab treatment and can be reproducibly scored by trained pathologists.

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© 2022 The Authors; Published by the American Association for Cancer Research.

Déclaration de conflit d'intérêts

S. Wildsmith, A. Franks, G. Melillo, J. Armstrong, J. Whiteley, and J. Walker are current employees and stockholders of AstraZeneca. J. Ye was an employee and stockholder of AstraZeneca during the initial conceptual design of the study through the final draft of the manuscript and is now an employee of Merck Research Laboratories. B. Roland reports other from AstraZeneca during the conduct of the study; personal fees from Roche outside the submitted work. C. Sabalos reports a patent to 10620211B2 issued; and C. Sabalos is an employee of Roche. P. Ahmadi reports other from AstraZeneca during the conduct of the study. J. Fayette reports personal fees from BMS, MSD, AstraZeneca, Merck, and Roche outside the submitted work. C. Even reports personal fees from BMS, MSD, Innate Pharma, and Merck Serono outside the submitted work. R. Mesía reports personal fees from Merck, MSD, BMS, Bayer, Nanobiotics, and Seagen during the conduct of the study. L.L. Siu reports personal fees from AstraZeneca and grants from AstraZeneca during the conduct of the study; personal fees from Arvinas, Celgene, GeneSeeq, GlaxoSmithKline, Loxo Oncology, Merck, Morphosys, Navire Pharma, Oncorus, Pfizer, Relay, Roche, Rubius Therapeutics, Seattle Genetics, Symphogen, Tessa, Treadwell Therapeutics, Voronoi, Agios, and Treadwell Therapeutics; grants from Abbvie, Amgen, Astellas, Avid, Bayer, Boehringer-Ingelheim, BMS, Celgene, GlaxoSmithKline, Intensity Therapeutics, Karyopharm, Merck, Mirati Therapeutics, Novartis, Pfizer, Roche/Genentech, Shattucks Lab, Symphogen outside the submitted work. D.P. Zandberg reports other from Merck, BMS, Aduro, Checkmate Pharmaceuticals, GSK, AstraZeneca, BICARA, Aethlon, Macrogenics, and Blueprint Medicines during the conduct of the study. No other disclosures were reported.