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CPS counts every PD-L1-stained cell in the tumour, immune cells included, and divides by the number of tumour cells. Pembrolizumab labels use CPS 1 or CPS 10 as the gate in head and neck, stomach, oesophageal, cervical, ovarian and triple-negative breast cancer.
The combined positive score is the 22C3 pharmDx read used outside lung cancer: the number of PD-L1-staining cells (tumour cells, lymphocytes and macrophages) divided by the total number of viable tumour cells, multiplied by 100, so it can exceed 100 in principle and is reported as a whole number. Pembrolizumab's US label gates first-line head and neck cancer, HER2-negative and HER2-positive gastric or GEJ adenocarcinoma, first-line oesophageal cancer with chemotherapy, cervical cancer and platinum-resistant ovarian cancer at CPS >= 1, and triple-negative breast cancer and second-line oesophageal squamous cancer at CPS >= 10. Nivolumab's label now restricts its gastric, GEJ and oesophageal indications to tumours expressing PD-L1 (>= 1), measured with the 28-8 pharmDx. Because the denominator is tumour cells only, CPS is not interchangeable with TPS or with the SP142 immune-cell score.
In plain words · PD-L1 is the tumour's side of the PD-1 brake, and also the biomarker that decides who gets immunotherapy.
Your report gives a CPS number. Whether it counts as positive depends on the cancer: the pembrolizumab label asks for 1 or more in head and neck, stomach, oesophageal, cervical and platinum-resistant ovarian cancer, and 10 or more in triple-negative breast cancer. The same number can open a treatment in one cancer and not in another, and a score below the cut-off does not mean immunotherapy can never be used, only that this particular indication does not apply.
Written only from the label or guideline text cited on this page. Not medical advice; your own report and the reading your team gives it come first.
Count PD-L1-positive tumour cells, lymphocytes and macrophages; divide by the number of viable tumour cells; multiply by 100. A specimen must hold at least 100 viable tumour cells to be scored.
“PD-L1 protein expression [Combined Positive Score (CPS) ≥ 1]”
FDA: List of FDA-Authorized Companion Diagnostic Devices| Threshold | Drug | Cancer | Regulator | Source |
|---|---|---|---|---|
| CPS >= 1 | Pembrolizumab | Head and neck squamous cell carcinoma | FDA | label |
| CPS >= 1 | Pembrolizumab | Gastric & gastro-oesophageal junction cancer | FDA | label |
| CPS >= 1 | Pembrolizumab | HER2-positive gastric cancer | FDA | label |
| CPS >= 1 (with chemotherapy); CPS >= 10 (single agent, squamous, after prior therapy) | Pembrolizumab | Oesophageal cancer | FDA | label |
| CPS >= 1 | Pembrolizumab | Cervical cancer | FDA | label |
| CPS >= 10 | Pembrolizumab | Metastatic triple-negative breast cancer | FDA | label |
| CPS >= 10 | Sacituzumab govitecan | Metastatic triple-negative breast cancer | FDA | label |
| CPS >= 1 | Pembrolizumab | Platinum-resistant ovarian cancer | FDA | label |
| PD-L1 >= 1 (28-8 pharmDx) | Nivolumab | Gastric & gastro-oesophageal junction cancer | FDA | label |
| PD-L1 >= 1 (28-8 pharmDx) | Nivolumab | Oesophageal squamous cell carcinoma | FDA | label |
| Device | Maker | Indication and sample | Drug | PMA / 510(k) |
|---|---|---|---|---|
| PD-L1 IHC 22C3 pharmDx | Agilent Technologies (Dako) | Head and Neck Squamous Cell Carcinoma (HNSCC) - Tissue | Pembrolizumab | P150013/S014 (06/10/2019) |
| PD-L1 IHC 22C3 pharmDx | Agilent Technologies (Dako) | Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma - Tissue | Pembrolizumab | P150013/S027 (11/07/2023) |
| PD-L1 IHC 22C3 pharmDx | Agilent Technologies (Dako) | Esophageal or Gastroesophageal Junction (GEJ) Carcinoma - Tissue | Pembrolizumab | P150013/S032 (02/11/2026) |
| PD-L1 IHC 22C3 pharmDx | Agilent Technologies (Dako) | Cervical Cancer - Tissue | Pembrolizumab | P150013/S009 (06/12/2018) |
| PD-L1 IHC 22C3 pharmDx | Agilent Technologies (Dako) | Triple-Negative Breast Cancer (TNBC) - Tissue | Pembrolizumab | P150013/S020 (11/13/2020) |
| PD-L1 IHC 22C3 pharmDx | Agilent Technologies (Dako) | Epithelial Ovarian, Fallopian Tube Cancer, or Primary Peritoneal Carcinoma (EOC) - Tissue | Pembrolizumab | P150013/S033 (02/10/2026) |
| PD-L1 IHC 28-8 pharmDx | Agilent Technologies (Dako) | Esophageal squamous cell carcinoma (ESCC), and gastric, gastroesophageal junction (GEJ), and esophageal adenocarcinoma - Tissue | Nivolumab | P150025/S018 (07/01/2026) |
Matched on the name and aliases of the readout in the title, setting and summary of each trial; a match is a mention, not proof the readout was an entry criterion.
This is the population-based prevalence for the two label thresholds in early TNBC, and it shows the KEYNOTE-355 CPS 10 gate would admit only about a quarter of unselected patients.
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.
The Western counterpart to the Indian series, with lower rates and a prognostic signal in the opposite direction from what immunotherapy enthusiasts might hope. The TIGIT and CD155 finding names a second checkpoint for future trials.
This is the paper Europe PMC returns for registry id NCT02819518 with the most citations, so it is the natural first reading for anyone following the KEYNOTE-355 trial. Read the abstract above alongside the trial page and the registry entry; the record was linked automatically and its figures have not been checked by hand.
Shares Tissue factor expression, Platinum-resistant ovarian cancer, Immunohistochemistry (IHC), Ovarian cancer and the tag biomarker.
Shares Claudin 18.2 expression (>= 75% of tumour cells, moderate to strong), HER2-positive gastric cancer, Immunohistochemistry (IHC), Gallbladder cancer and the tag biomarker.
Shares HER2-positive gastric cancer, Immunohistochemistry (IHC), Gallbladder cancer and the tag biomarker.
Shares Immunohistochemistry (IHC), Nivolumab, Gallbladder cancer, Triple-negative breast cancer (TNBC) and the tag biomarker.
Shares Immunohistochemistry (IHC), Metastatic triple-negative breast cancer, Triple-negative breast cancer (TNBC) and the tag biomarker.
Shares Immunohistochemistry (IHC), Metastatic triple-negative breast cancer, Triple-negative breast cancer (TNBC) and the tag biomarker.
Shares Metastatic triple-negative breast cancer, Gallbladder cancer, Triple-negative breast cancer (TNBC), Pembrolizumab and the tag biomarker.
Shares Nivolumab, Gallbladder cancer, Triple-negative breast cancer (TNBC), Pembrolizumab and the tag biomarker.