Multicenter Comparison of 22C3 PharmDx (Agilent) and SP263 (Ventana) Assays to Test PD-L1 Expression for NSCLC Patients to Be Treated with Immune Checkpoint Inhibitors.

Among the several agents targeting the programmed cell death 1 (PD-1) pathway, pembrolizumab is currently the only one approved for the treatment of patients with NSCLC in association with a companion diagnostic assay, the anti-PD-L1 immunohistochemical (IHC) 22C3 PharmDx (Agilent Technologies, Santa Clara, CA) using the Dako Autostainer (Dako, Carpinteria, CA). However, the Dako platform is not present in each pathology department, and this technical limitation is a major problem for the diffusion of the PD-L1 IHC predictive test for pembrolizumab. The Italian Society of Anatomic Pathology and Cytopathology and the Italian Association of Medical Oncology in an independent, multicenter study compared the in vitro diagnostics PD-L1 IHC 22C3 pharmDx test (Agilent) on the Dako Autostainer and the in vitro diagnostics Ventana PD-L1 (SP263) test on the Ventana BenchMark platform (Ventana Medical Systems, Tucson, AZ). Using serial sections from tissue microarrays, 100 lung adenocarcinomas were locally stained and scored in four centers with the same antibody batches. A high analytical correlation (more than 90% at the lower 95% confidence interval [CI] value) between PD-L1 expression levels obtained with the 22C3 and SP263 assays was observed. At the proposed clinically relevant cutoffs (≥50% and ≥1%), the overall concordances between 22C3 and SP263 data were 0.99 (95% CI: 0.96-1) and 0.80 (95% CI: 0.68-0.91), respectively. The lower agreement between data obtained with the 22C3 and SP263 clones at the cutoff of 1% or higher was mainly related to the lower (about 80%) interrater agreement at this cutoff with each clone. These results indicate a high correlation between PD-L1 IHC expression data obtained with the Agilent PD-L1 IHC 22C3 pharmDx and the Ventana PD-L1 (SP263) tests in NSCLC and suggest that the two assays could be utilized interchangeably as an aid to select patients for first-line and second-line treatment with pembrolizumab and potentially with other anti-PD-1/PD-L1 checkpoint inhibitors.

Marchetti A ，Barberis M ，Franco R ，De Luca G ，Pace MV ，Staibano S ，Volante M ，Buttitta F ，Guerini-Rocco E ，Righi L ，D'antuono T ，Scagliotti GV ，Pinto C ，De Rosa G ，Papotti M ... -  《-》

Use of the 22C3 anti-PD-L1 antibody to determine PD-L1 expression in multiple automated immunohistochemistry platforms.

Ilie M ，Khambata-Ford S ，Copie-Bergman C ，Huang L ，Juco J ，Hofman V ，Hofman P ... -  《PLoS One》

A Harmonization Study for the Use of 22C3 PD-L1 Immunohistochemical Staining on Ventana's Platform.

Immunotherapy is a novel treatment for lung cancer. Pembrolizumab (Merck Sharp and Dohme, Kenilworth, NJ) is a monoclonal antibody against programmed cell death 1 that has been approved for use with NSCLC together with a companion diagnostic by Dako (Carpinteria, CA). Ventana's BenchMark XT (Ventana Medical Systems, Tucson, AZ) is a widely used immunohistochemical (IHC) platform. However, data on its reliability and reproducibility with the 22C3 antibody are scant. We performed a comprehensive calibration of 22C3 programmed cell death ligand 1 (PD-L1) staining on the BenchMark XT platform using Dako's prediluted 22C3 anti-PD-L1 primary antibody with two of Ventana's detection systems. Forty-one random cases of NSCLC were then independently evaluated by two pathologists. Each case was scored using Dako- or Ventana-stained slides. The scores obtained with the two 22C3 Ventana assays were compared with those obtained using the Dako 22C3 IHC platform. The Dako IHC platform stratified eight, seven, and 26 cases as being strongly positive, weakly positive, and negative for PD-L1, respectively, whereas 36 of 41 cases (87.8%) had the same results with Ventana's UltraView 22C3 protocol (Pearson's correlation score 0.91, p < 0.0001). Moreover, 35 of 41 cases (85.3%) had the same results with Ventana's OptiView 22C3 protocol (Pearson's correlation score 0.89, p < 0.0001). The results of this study demonstrate that the same PD-L1 IHC algorithm can be reliably applied to Ventana's BenchMark XT platform. Furthermore, we were able to detect all of the strongly positive cases with high interobserver and intraobserver agreement by using the Ventana platform. These findings suggest that the Ventana platform can be used to stratify patients for pembrolizumab-based immunotherapy.

Neuman T ，London M ，Kania-Almog J ，Litvin A ，Zohar Y ，Fridel L ，Sandbank J ，Barshak I ，Vainer GW ... -  《-》

PD-L1 Assays 22C3 and SP263 are Not Interchangeable in Non-Small Cell Lung Cancer When Considering Clinically Relevant Cutoffs: An Interclone Evaluation by Differently Trained Pathologists.

Munari E ，Rossi G ，Zamboni G ，Lunardi G ，Marconi M ，Sommaggio M ，Netto GJ ，Hoque MO ，Brunelli M ，Martignoni G ，Haffner MC ，Moretta F ，Pegoraro MC ，Cavazza A ，Samogin G ，Furlan V ，Mariotti FR ，Vacca P ，Moretta L ，Bogina G ... -  《-》

Comparison of PD-L1 Assays in Non-small Cell Lung Cancer: 22C3 pharmDx and SP263.

While the PD-L1 22C3 pharmDx assay is an FDA-approved diagnostic assay for pembrolizumab use, not every pathology laboratory has the Dako Autostainer to use this assay. Since Ventana BenchMark platforms are more common, the Ventana SP263 assay can be used to inform treatment decisions involving nivolumab and pembrolizumab in non-small cell lung cancer (NSCLC). However, some studies have shown discordant results between the two assays. This study aimed was to compare PD-L1 expression using these two assays. A total of 100 samples from consecutive cases of resected NSCLC were tested using the two PD-L1 assays. The agreement rates of the two assays were 88-97% at various cut-offs. There was no significant difference between 22C3 and SP263 in tumour proportion score (p=0.455). The SP263 assay can be used in the place of the 22C3 assay for PD-L1 testing, for guiding therapy with PD-1 axis inhibitors in NSCLC.

Fujimoto D ，Yamashita D ，Fukuoka J ，Kitamura Y ，Hosoya K ，Kawachi H ，Sato Y ，Nagata K ，Nakagawa A ，Tachikawa R ，Date N ，Sakanoue I ，Hamakawa H ，Takahashi Y ，Tomii K ... -  《-》