Related Experiment Video
Updated: Dec 22, 2025
Using 22C3 Anti-PD-L1 Antibody Concentrate on Biopsy and Cytology Samples from Non-small Cell Lung Cancer Patients
Published on: September 25, 2018
Programmed Death-Ligand 1 Immunohistochemistry Assay Comparison Studies in NSCLC: Characterization of the 73-10 Assay
Hans Juergen Grote1, Zheng Feng2, Michael Schlichting1
1Merck KGaA, Darmstadt, Germany.
Insights
This study compared two programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) assays, 73-10 and 22C3, in non-small cell lung cancer (NSCLC) samples. The 73-10 assay showed comparable efficacy to the 22C3 assay at specific PD-L1 expression cutoffs.
Area of Science:
- Oncology
- Immunotherapy
- Diagnostic Assays
Background:
- Multiple programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) assays exist for anti-PD-1/PD-L1 therapies.
- Assay comparability is crucial for consistent clinical application.
Purpose of the Study:
- To characterize the Dako PD-L1 IHC 73-10 assay used in avelumab/bintrafusp alfa trials.
- To compare the 73-10 assay with the Dako PD-L1 IHC 22C3 pharmDx assay in non-small cell lung cancer (NSCLC).
Main Methods:
- Formalin-fixed, paraffin-embedded NSCLC tumor samples were stained using both 73-10 and 22C3 IHC assays.
- Standard protocols were applied to commercial and clinical trial samples.
Main Results:
- Both assays showed expected PD-L1 staining patterns.
- The 73-10 assay stained a higher percentage of samples positive for PD-L1 compared to the 22C3 assay at certain cutoffs.
- Avelumab efficacy was similar between subgroups defined by the 73-10 (≥80% PD-L1+) and 22C3 (≥50% PD-L1+) assays.
Conclusions:
- The Dako PD-L1 IHC 73-10 assay demonstrates high sensitivity for PD-L1 detection.
- The ≥80% cutoff for the 73-10 assay showed comparable results to the ≥50% cutoff for the 22C3 assay in terms of efficacy.
Introduction:
Several programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) assays have been developed independently within clinical programs for therapeutic anti-programmed cell death protein 1 (anti-PD-1) or PD-L1 antibodies, necessitating assessment of assay comparability. We characterized the Dako PD-L1 IHC 73-10 assay used in clinical trials of avelumab (anti-PD-L1) or bintrafusp alfa (M7824; bifunctional immunotherapy) and compared it with the Dako PD-L1 IHC 22C3 pharmDx assay, an approved companion diagnostic for pembrolizumab monotherapy in patients with advanced NSCLC.
Methods:
Formalin-fixed, paraffin-embedded NSCLC tumor samples from a commercial source and from the JAVELIN Solid Tumor phase 1 trial of avelumab (NCT01772004) were stained using the 73-10 and 22C3 IHC assays with a standard protocol.
Results:
Both assays displayed expected PD-L1 staining patterns. In 148 commercial NSCLC samples, the 73-10 assay stained greater than or equal to 1%, greater than or equal to 50%, and greater than or equal to 80% of tumor cells as PD-L1+ in 64.2%, 36.5%, and 23.6% of the samples, respectively, whereas the 22C3 assay stained 20.3% of the samples as greater than or equal to 50% PD-L1+. In 83 NSCLC clinical trial samples, the 73-10 assay stained 79.5% and 31.3% of the samples as greater than or equal to 1% and greater than or equal to 80% PD-L1+, respectively, whereas the 22C3 assay stained 59.0% and 21.7% as greater than or equal to 1% and greater than or equal to 50% PD-L1+, respectively. Efficacy of avelumab was similar in the subgroups classified with the 73-10 and 22C3 assays using greater than or equal to 80% and greater than or equal to 50% PD-L1+ cutoffs, with objective response rates of 26.9% and 33.3%, respectively.
Conclusions:
The 73-10 assay demonstrated high sensitivity for PD-L1 staining, and staining was comparable between the greater than or equal to 80% cutoff of the 73-10 assay and greater than or equal to 50% cutoff of the 22C3 assay.
More Related Videos
10:29Semi-automatic PD-L1 Characterization and Enumeration of Circulating Tumor Cells from Non-small Cell Lung Cancer Patients by Immunofluorescence
Published on: August 14, 2019
10:49Automated Multiplex Immunofluorescence Panel for Immuno-oncology Studies on Formalin-fixed Carcinoma Tissue Specimens
Published on: January 21, 2019