Testing Technologies



Available PD-L1 immunohistochemistry assays


PD-L1 immunohistochemistry

There are five immunohistochemistry (IHC) assays, either commercially available or in development, to determine programmed cell death ligand-1 (PD-L1) expression in cancer tumours.

*Based on the FDA and CE-IVD diagnostic regulatory approval
BMS, Bristol-Myers Squibb; CE-IVD, Conformité Européenne-in vitro diagnostic; Dx, diagnostic; FDA, Food and Drug Administration; IHC, immunohistochemistry; MSD, Merck Sharp & Dohme; NA, not applicable; PD-L1, programmed cell death ligand-1

Laboratory-developed tests

A laboratory-developed test (LDT) is an alternative approach for those with limited or no access to commercially developed PD-L1 assays. In this regard, LDTs are PD-L1 IHC assays that contain components from a variety of sources and apply custom procedures (de novo LDT); or, are based on the components from a regulatory-approved assay, but either apply a custom procedure to detect PD-L1 or for a different purpose (kit-derived LDT).11

The use of LDTs is associated with less reliable capture of PD-L1
positivity in non-small cell lung cancer (NSCLC) samples, when
compared with approved PD-L1 assays.12, 13

It is important that LDTs are adequately validated before their use on patient samples.11

The validation of PD-L1 LDTs

Video runtime: 0.31 secs

Professor Keith Kerr (University of Aberdeen, Aberdeen, UK) discusses the need to properly validate LDTs for PD-L1 assessment.

PD-L1 assay concordance

The availability of different PD-L1 IHC assays, each with their own antibody clone, IHC detection system and staining characteristics, raises challenges. Due to the lack of standardisation between assays, it is important to determine their concordance for staining PD-L1 in cancer specimens.

The potential interchangeability of validated PD-L1 assays

Video runtime: 0.31 secs

Professor Keith Kerr (University of Aberdeen, Aberdeen, UK) discusses the potential interchangeability of the four commercially available PD-L1 IHC assays.

Non-small cell lung cancer

Various research groups and initiatives have explored the concordance of PD-L1 IHC assays in NSCLC.13-20

Collectively, concordance studies are in agreement that tumour cell (TC) staining for PD-L1 is analytically equivalent when comparing the VENTANA SP263, PD-L1 IHC 22C3 and 28-8 pharmDx assays.13-17, 19-21 The VENTANA SP142 showed less consistent TC staining than the VENTANA SP263, PD-L1 IHC 22C3 and 28-8 pharmDx assays.15-17, 19

When looking at PD-L1 staining on tumour infiltrating immune cells (ICs), PD-L1 scoring was more variable, compared with PD-L1 scoring on TCs.16, 17

While the aforementioned studies demonstrated analytical concordance among PD-L1 IHC assays, further studies using real-world clinical pathology data are needed to determine the interlaboratory variation in NSCLC PD-L1 testing and to determine the potential of assay interchangability.21

The concordance of PD-L1 assays in NSCLC

Video runtime: 0.31 secs

This short animation describes the different concordance studies comparing the performance of PD-L1 IHC assays in NSCLC.

Bladder cancer

A recent AstraZeneca-funded comparative study of the four commercially available PD-L1 assays (VENTANA SP263, VENTANA SP142, PD-L1 IHC 22C3 pharmDx and PD-L1 IHC 28-8 pharmDx) was undertaken to establish the extent of concordance between assays used in staining urothelial carcinoma (UC) samples.22 It was concluded that VENTANA SP263, PD-L1 IHC 22C3 and 28-8 pharmDx assays were concordant for TC and IC staining; the VENTANA SP142 assay showed similar staining to the other three assays for ICs, but was less sensitive for PD-L1 staining on TCs.22 These results are in agreement with earlier findings by others.23, 24

TC PD-L1 staining correlations between four IHC assays in UC22

Figure adapted from Zajac et al. Diagn Pathol 2019.22 TC, tumour cell

Further prospective analyses are warranted to determine the degree of clinical harmonisation among PD-L1 diagnostic tests in UC.22

External quality assurance schemes

Laboratories carrying out clinical PD-L1 IHC testing must continuously participate in an external quality assurance (EQA) scheme.25 Additionally, PD-L1 IHC assays must be validated and their analytical performance verified before testing patients samples, especially when using LDTs.11

The overall aims of EQA schemes are to provide useful information on methods and reagents and to ensure best practice across testing laboratories.26 EQA schemes analyse PD-L1 test samples and report potential issues that may result in false-positive or false-negative results.25

Examples of PD-L1 EQA schemes include the:

ESP, European Society of Pathology; IHC, immunohistochemistry; NordiQC, Nordic immunohistochemical Quality Control; NSCLC, non-small cell lung cancer; PD-L1, programmed cell death ligand-1; UK NEQAS ICC & ISH, UK National External Quality Assessment Service for Immunocytochemistry and In-Situ Hybridisation

  1. Roche. VENTANA PD-L1 (SP263) Assay (CE IVD). 2020. Available from: https://diagnostics.roche.com/global/en/products/tests/ventana-pd-l1-_sp263-assay2.html. Accessed: 15 May 2020
  2. Roche. VENTANA PD-L1 (SP263) Assay (US FDA Approved). 2020. Available from: https://diagnostics.roche.com/global/en/products/tests/ventana-pd-l1-_sp263-assay1.html. Accessed: 15 May 2020
  3. Roche. VENTANA PD-L1 (SP142) Assay (CE IVD). 2020. Available from: https://diagnostics.roche.com/global/en/products/tests/ventana-pd-l1-_sp142-assay2.html. Accessed: 15 May 2020
  4. Roche. VENTANA PD-L1 (SP142) Assay (US FDA Approved). 2020. Available from: https://diagnostics.roche.com/global/en/products/tests/ventana-pd-l1-_sp142-assay1.html. Accessed: 15 May 2020
  5. Agilent. PD-L1 IHC 22C3 pharmDx Overview (EU). 2020. Available from: https://www.agilent.com/en/product/pharmdx/pd-l1-ihc-22c3-pharmdx-overview. Accessed: 15 May 2020
  6. Agilent. PD-L1 IHC 22C3 pharmDx Overview (US). 2020. Available from: https://www.agilent.com/en-us/product/pharmdx/pd-l1-ihc-22c3-pharmdx-overview. Accessed: 15 May 2020
  7. Agilent. PD-L1 IHC 28-8 pharmDx Overview (EU). 2020. Available from: https://www.agilent.com/en/product/pharmdx/pd-l1-ihc-28-8-overview. Accessed: 15 May 2020
  8. Agilent. PD-L1 IHC 28-8 pharmDx Overview (US). 2020. Available from: https://www.agilent.com/en-us/pd-l1-ihc-28-8-overview. Accessed: 15 May 2020
  9. OncLive. FDA approves PD-L1 IHC 28-8 pharmDx as companion diagnostic for nivolumab plus ipilimumab in NSCLC. 2020. Available from: https://www.onclive.com/web-exclusives/fda-approves-pdl1-ihc-288-pharmdx-as-companion-diagnostic-for-nivolumabipilimumab-in-nsclc. Accessed: 19 May 2020
  10. Patel MR, Ellerton J, Infante JR, et al. Avelumab in metastatic urothelial carcinoma after platinum failure (JAVELIN Solid Tumor): pooled results from two expansion cohorts of an open-label, phase 1 trial. Lancet Oncol 2018;19:51–64
  11. Cheung CC, Barnes P, Bigras G, et al. Fit-for-purpose PD-L1 biomarker testing for patient selection in immuno-oncology: guidelines for clinical laboratories from the Canadian Association of Pathologists-Association Canadienne Des Pathologistes (CAP-ACP). Appl Immunohistochem Mol Morphol 2019;27:699–714
  12. Velcheti V, Patwardhan PD, Liu FX, et al. Real-world PD-L1 testing and distribution of PD-L1 tumor expression by immunohistochemistry assay type among patients with metastatic non-small cell lung cancer in the United States. PLoS One 2018;13:e0206370
  13. Adam J, Le Stang N, Rouquette I, et al. Multicenter harmonization study for PD-L1 IHC testing in non-small-cell lung cancer. Ann Oncol 2018;29:953–958
  14. Ratcliffe MJ, Sharpe A, Midha A, et al. Agreement between programmed cell death ligand-1 diagnostic assays across multiple protein expression cutoffs in non-small cell lung cancer. Clin Cancer Res 2017;23:3585–3591
  1. Scott M, Ratcliffe MJ, Sharpe A, et al. Concordance of tumor and immune cell staining with Ventana SP142, Ventana SP263, Dako 28-8 and Dako 22C3 PD-L1 tests in NSCLC patient samples. J Clin Oncol 2017;35:7
  2. Hirsch FR, McElhinny A, Stanforth D, et al. PD-L1 immunohistochemistry assays for lung cancer: results from phase 1 of the blueprint PD-L1 IHC assay comparison project. J Thorac Oncol 2017;12:208–222
  3. Tsao MS, Kerr KM, Kockx M, et al. PD-L1 immunohistochemistry comparability study in real-life clinical samples: results of blueprint phase 2 project. J Thorac Oncol 2018;13:1302–1311
  4. Rimm DL, Han G, Taube JM, et al. A prospective, multi-institutional, pathologist-based assessment of 4 immunohistochemistry assays for PD-L1 expression in non-small cell lung cancer. JAMA Oncol 2017;3:1051–1058
  5. Scheel AH, Baenfer G, Baretton G, et al. Interlaboratory concordance of PD-L1 immunohistochemistry for non-small-cell lung cancer. Histopathology 2018;72:449–459
  6. Brunnström H, Johansson A, Westbom-Fremer S, et al. PD-L1 immunohistochemistry in clinical diagnostics of lung cancer: inter-pathologist variability is higher than assay variability. Mod Pathol 2017;30:1411–1421
  7. Koomen BM, Badrising SK, van den Heuvel MM, et al. Comparability of PD-L1 immunohistochemistry assays for non-small-cell lung cancer: a systematic review. Histopathology 2020;76:793–802
  8. Zajac M, Scott M, Ratcliffe M, et al. Concordance among four commercially available, validated programmed cell death ligand-1 assays in urothelial carcinoma. Diagn Pathol 2019;14:99
  9. Eckstein M, Erben P, Kriegmair MC, et al. Performance of the Food and Drug Administration/EMA-approved programmed cell death ligand-1 assays in urothelial carcinoma with emphasis on therapy stratification for first-line use of atezolizumab and pembrolizumab. Eur J Cancer 2019;106:234–243
  10. Hodgson A, Slodkowska E, Jungbluth A, et al. PD-L1 immunohistochemistry assay concordance in urothelial carcinoma of the bladder and hypopharyngeal squamous cell carcinoma. Am J Surg Pathol 2018;42:1059–1066
  11. Cree IA, Booton R, Cane P, et al. PD-L1 testing for lung cancer in the UK: recognizing the challenges for implementation. Histopathology 2016;69:177–186
  12. Hastings RJ, Howell RT. The importance and value of EQA for diagnostic genetic laboratories. J Community Genet 2010;1:11–17
  13. NordiQC. About NordiQC. 2020. Available from: https://www.nordiqc.org/about.php. Accessed: 15 May 2020
  14. UK.NEQAS. About Us. 2020. Available from: https://ukneqasiccish.org/about-us/the-scheme/. Accessed: 15 May 2020
  15. ESP. ESP Lung External Quality Assessment Scheme. 2020. Available from: http://lung.eqascheme.org/. Accessed: 15 May 2020
  16. NordiQC. Assessments. 2020. Available from: https://www.nordiqc.org/epitope.php. Accessed: 15 May 2020