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Head and neck cancers

2031 - A comparative study of PD-L1 diagnostic assays in squamous cell carcinoma of the head and neck (SCCHN)


08 Oct 2016


Head and neck cancers


Marianne Ratcliffe


Annals of Oncology (2016) 27 (6): 328-350. 10.1093/annonc/mdw376


M.J. Ratcliffe1, A. Sharpe2, M. Rebelatto3, M. Scott1, C. Barker2, P. Scorer2, J. Walker2

Author affiliations

  • 1 Personalised Healthcare And Biomarkers, AstraZeneca, CB4 0WGT - Alderley Park, Macclesfield/GB
  • 2 Personalised Healthcare And Biomarkers, AstraZeneca, Cambridge/GB
  • 3 Translational Medicine, MedImmune, Gaithersburg/US


Abstract 2031


PD-1/PD-L1 directed antibodies are emerging as effective therapeutics in multiple oncology settings. In the SCCHN Checkmate 141 study, improved efficacy with nivolumab, a PD-1 targeted therapy, was observed in pts with tumour PD-L1 expression ≥1% vs pts with PD-L1 expression below this cut off. Multiple diagnostic PD-L1 tests are available using different antibody clones, different staining protocols and different cut offs. A better understanding of the technical performance of these assays will allow appropriate interpretation of clinical outcomes with different drugs.


108 tumour biopsy samples from stage I–IV SCCHN pts, obtained from a commercial source and including HPV positive and HPV negative, were assessed using 3 PD-L1 diagnostic assays: the Ventana SP263 assay currently being used in durvalumab (anti-PD-L1) clinical trials, the Dako 28-8 and Dako 22C3 assays, commonly used in nivolumab (Opdivo®) and pembrolizumab (Keytruda®) trials, respectively. Assays were performed in an accredited laboratory, following the device protocol. Concordance between tumour membrane staining was assessed across a range of clinically relevant cut offs, including ≥1%, ≥10% and ≥25%. Lower 95% CI were calculated using the Clopper-Pearson method.


Data indicated strong association, with a Spearman correlation coefficient of ≥0.9 for each pairwise comparison. Overall percent agreement (OPA) of >90% was seen between the three assays across multiple clinically relevant cut points. Assessment of a further 392 samples is ongoing to complement the current data set with a larger dynamic range of PD-L1 expression.

Ventana SP263 vs Dako 28-8 Dako 22C3 vs Dako 28-8
Assay cut off OPA (%) Lower 95% CI OPA (%) Lower 95% CI
≥1% 91.7 85.9 96.3 91.7
≥10% 92.6 87.0 95.4 90.5
≥25% 94.4 89.3 97.2 93.0


This study indicates that the SCCHN patient population defined by Ventana SP263, Dako 28-8 and Dako 22C3 assays is similar where an identical cut point is used. The findings align with those of a similar study in NSCLC, and build optimism that it may be possible to compare studies using different PD-L1 tests and deliver harmonization of PD-L1 diagnostic testing.

Clinical trial identification


Legal entity responsible for the study

AstraZeneca PLC




M.J. Ratcliffe, A. Sharpe, M. Scott, C. Barker, P. Scorer, J. Walker: AstraZeneca employee and holds stocks/shares. M. Rebelatto: Employee of MedImmune LLC and hold stocks or shares in AstraZeneca.

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