biomarkersBiomarker

PD-L1 IC score (immune-cell score, SP142)

aka PD-L1 IC, IC score, immune cell score, tumor-infiltrating immune cell score, SP142 IC, IC >= 1%, IC >= 5%, IC >= 10%, IC≥1%, IC2/3

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= 1 percent in triple-negative breast cancer (IMpassion130), were withdrawn in the United States in 2022 and 2021; the FDA companion diagnostic list still carries the urothelial SP142 approval of 2016.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.

Part ofPD-L1· CD274Other readoutsPD-L1 CPS PD-L1 TC score PD-L1 TPS All readouts

PD-L1: what it is and how drugs act on it · animated schematic, not to scale

Target · the protein and the cell it sits on
Drug · antibody, small molecule, cell or radioligand
Effect · signal, damage or kill

In plain words · PD-L1 is the tumour's side of the PD-1 brake, and also the biomarker that decides who gets immunotherapy.

IC score 1 approval threshold

What it means for a patient

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 The older uses of this score in bladder and triple-negative breast cancer were withdrawn in the United States, so ask which label your country follows.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.

Scoring rule

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

Thresholds used in approvals

Threshold	Drug	Cancer	Regulator	Source
IC >= 10% (or TC >= 50%)	Atezolizumab	Non-small-cell lung cancer	FDA	label

2 historic or withdrawn thresholds

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

Drugs whose label names it

Atezolizumab

Companion diagnostics (FDA list)

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)