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The IC score measures how much of the tumour area is covered by PD-L1-stained immune cells rather than tumour cells. It belongs to the SP142 assay used with atezolizumab and is read differently from every other PD-L1 score.
The VENTANA SP142 assay scores PD-L1 on tumour-infiltrating immune cells as the proportion of tumour area they occupy: IC0 (< 1 percent), IC1 (1 to < 5 percent), IC2 (5 to < 10 percent), IC3 (>= 10 percent). Atezolizumab's current US label uses IC >= 10 percent as one arm of the first-line NSCLC single-agent gate (the other being TC >= 50 percent). Earlier atezolizumab indications that used IC scores, IC >= 5 percent in cisplatin-ineligible urothelial cancer and IC >= 1 percent in triple-negative breast cancer (IMpassion130), were withdrawn in the United States in 2022 and 2021; the FDA companion diagnostic list still carries the urothelial SP142 approval of 2016. Blueprint comparison studies found SP142 stains fewer tumour cells than 22C3, 28-8 or SP263, so an SP142 result cannot be swapped for a TPS or CPS.
In plain words · PD-L1 is the tumour's side of the PD-1 brake, and also the biomarker that decides who gets immunotherapy.
If your report says SP142 and gives an IC percentage, it is measuring immune cells around the tumour, not the tumour itself. In lung cancer an IC of 10 percent or more (or tumour cells at 50 percent or more) allows atezolizumab alone as first treatment. The older uses of this score in bladder and triple-negative breast cancer were withdrawn in the United States, so ask which label your country follows.
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.
Proportion of the tumour area occupied by PD-L1-staining tumour-infiltrating immune cells of any intensity, in bands IC0 to IC3; read on the SP142 assay only.
“PD-L1 protein expression (PD-L1 stained tumor-infiltrating immune cells [IC] covering ≥ 5% of the tumor area)”
FDA: List of FDA-Authorized Companion Diagnostic Devices| Threshold | Drug | Cancer | Regulator | Source |
|---|---|---|---|---|
| IC >= 10% (or TC >= 50%) | Atezolizumab | Non-small-cell lung cancer | FDA | label |
| Threshold | Drug | Cancer | Regulator | Source |
|---|---|---|---|---|
| IC >= 5% (cisplatin-ineligible)withdrawn The first-line urothelial indication was withdrawn in the United States in November 2022; the SP142 companion diagnostic approval (P160002, 18 May 2016) remains on the FDA list. | Atezolizumab | Bladder & urothelial cancer | FDA | label |
| IC >= 1%withdrawn Accelerated approval with nab-paclitaxel (IMpassion130, 2019) was withdrawn in the United States in August 2021; the indication remains authorised in the European Union. | Atezolizumab | Metastatic triple-negative breast cancer | FDA | label |
| Device | Maker | Indication and sample | Drug | PMA / 510(k) |
|---|---|---|---|---|
| Ventana PD-L1 (SP142) Assay | Ventana Medical Systems (Roche) | Non-Small Cell Lung Cancer (NSCLC) - Tissue | Atezolizumab | P160002/S006 (07/02/2018) |
| Ventana PD-L1 (SP142) Assay | Ventana Medical Systems (Roche) | Urothelial Carcinoma - Tissue | Atezolizumab | P160002 (05/18/2016) |
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.
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.
For the minority of patients whose tumours express a lot of PD-L1, a single antibody outperforms chemotherapy and is far easier to take. The word minority is the point: the same drug in the same disease at lower PD-L1 gives much less.
This is the paper Europe PMC returns for registry id NCT02425891 with the most citations, so it is the natural first reading for anyone following the IMpassion130 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.
It is the reason a laboratory can run one stain and report against several drug labels, and the reason any decision resting on an immune-cell score rests on the least reproducible number in lung pathology.
Together with the Blueprint work it establishes that a PD-L1 percentage reports the assay as much as it reports the tumour, so the threshold and the antibody have to be quoted together.
Two bottleneck pages on OnCo cite this paper by its DOI; this record gives the citation a page of its own so a reader can follow it without leaving OnCo. Read the abstract above alongside the citing pages listed under Related; the record was created automatically from the Europe PMC entry and its figures have not been checked by hand.
Shares PD-L1 TC score (tumour-cell score, SP263 and 28-8), VENTANA PD-L1 (SP142) Assay, PD-L1 TPS (tumour proportion score), PD-L1 Immunohistochemistry Assay Comparison in Atezolizumab Plus nab-Paclitaxel-Treated Advanced Triple-Negative Breast Cancer.
Shares Comparison of SP142 and 22C3 PD-L1 assays in a population-based cohort of triple-negative breast cancer patients in the context of their clinically established scoring algorithms, VENTANA PD-L1 (SP142) Assay, PD-L1 TPS (tumour proportion score), PD-L1 Immunohistochemistry Assay Comparison in Atezolizumab Plus nab-Paclitaxel-Treated Advanced Triple-Negative Breast Cancer.
Shares PD-L1 CPS (combined positive score), Immunohistochemistry (IHC) and the tag biomarker.
Shares Atezolizumab for first-line treatment of PD-L1-selected patients with NSCLC, Metastatic triple-negative breast cancer, Bladder & urothelial cancer, Triple-negative breast cancer (TNBC) and the tag biomarker.
Shares Immunohistochemistry (IHC), Metastatic triple-negative breast cancer, Bladder & urothelial 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 Immunohistochemistry (IHC), Non-small-cell lung cancer and the tag biomarker.