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Three PD-L1 tests run on the same tumours called 46, 75 and 73 percent of them positive and agreed only 69 percent of the time. With atezolizumab withdrawn, pembrolizumab's test (22C3, combined positive score of 10) is the only one that matters, yet laboratories still run whichever kit they have. One assay, one score and a proficiency scheme would end answers that vary by postcode.
Rugo's IMpassion130 analysis of 614 tumours found PD-L1 immune cell positivity of 46.4 percent by SP142, 74.9 by SP263 and 73.1 by 22C3, concordance of 69 percent, and harmonised cut-offs reaching only about 75 percent; atezolizumab's benefit lay in the tumours all three called positive. KEYNOTE-355 selected on 22C3 combined positive score of 10 or more, which the ASCO 2022 biomarker guideline made the recommended test, and the atezolizumab indication was withdrawn in the United States in 2021. Practice has not caught up: SP142 remains in use where atezolizumab was adopted, laboratories score immune cells and combined positive score interchangeably, and scoring of the combined positive score at the 10 threshold has known inter-observer variation. Digital scoring and external quality assurance schemes exist for HER2 and could be extended.
Confirms that the TROP2 antibody-drug conjugates are given without a TROP2 test and that PD-L1 remains the one selection assay in metastatic triple-negative disease, which is why assay harmonisation matters.
PD-L1 testing with the combined positive score decides first-line treatment in metastatic triple-negative breast cancer; pembrolizumab-chemotherapy is the standard for scores of 10 or more.
The clearest demonstration that PD-L1 positive in triple-negative breast cancer means different things depending on the kit; with atezolizumab withdrawn, pembrolizumab's 22C3 combined positive score of 10 is the surviving standard, and roughly a quarter of patients get a different answer depending on which assay their laboratory runs.
Shares American Society of Clinical Oncology (ASCO), Immunohistochemistry (IHC), Digital pathology & AI, Biomarkers are not validated or standardised and the tag tnbc-evidence.
Shares Immunohistochemistry (IHC), Digital pathology & AI, Knowledge reaches practice too slowly, Biomarkers are not validated or standardised and the tag tnbc-evidence.
Shares American Society of Clinical Oncology (ASCO), Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem, Pembrolizumab, Triple-negative breast cancer (TNBC) and the tag tnbc-evidence.
Shares Immunohistochemistry (IHC), Digital pathology & AI, Biomarkers are not validated or standardised, Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem and the tag tnbc-evidence.
Shares Digital pathology & AI, Biomarkers are not validated or standardised, Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem, Triple-negative breast cancer (TNBC) and the tag tnbc-evidence.
Shares Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem, Pembrolizumab, Triple-negative breast cancer (TNBC), Immune checkpoint inhibitors and the tag tnbc-evidence.
Shares Immunohistochemistry (IHC), Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem, Triple-negative breast cancer (TNBC) and the tag tnbc-evidence.
Shares Digital pathology & AI, Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem, Pembrolizumab, Triple-negative breast cancer (TNBC) and the tag tnbc-evidence.