PD-L1 Testing in Urothelial Carcinoma: Analysis of a Series of 1401 Cases Using Both the 22C3 and SP142 Assays.
Author
Evans, HarrietO'Sullivan, Brendan
Hughes, Frances
Charles, Kathryn
Robertson, Lee
Taniere, Philippe
Diaz-Cano, Salvador
Affiliation
Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation TrustPublication date
2022-04-11Subject
Oncology. Pathology.
Metadata
Show full item recordAbstract
Immune checkpoint blockade (ICB) drugs are a novel, effective treatment for advanced urothelial carcinoma. Worldwide, several different ICB drugs are approved, each developed and clinically validated with a specific PD-L1 compound diagnostic assay. As a result, PD-L1 testing workflows in routine practice are complex: requiring multiple assays across two platforms, with each assay having a different method of interpretation. Our service tested 1,401 urothelial carcinoma cases for PD-L1 expression, using both the 22C3 PharmDx assay (required prior to Pembrolizumab therapy) and SP142 assay (required prior to Atezolizumab therapy). Of the 1,401 cases tested, 621 cases (44%) were tested with both the 22C3 PharmDx and SP142 assays, 492 cases (35%) with 22C3 PharmDx only, and 288 cases (21%) with SP142 only. Each assay was used and interpreted according to the manufacturer's guidelines. The rate of positivity we observed was 26% with the 22C3 assay and 31% with the SP142 assay, similar to the pre-licensing studies for both drugs. The discrepancy observed between the assays was 11%, which reinforces the requirement for utilisation of the correct assay for each agent, and limits potential cross-utility of assays. This aspect must be considered when setting up a PD-L1 testing strategy in laboratories where both Pembrolizumab and Atezolizumab are available for the treatment of urothelial carcinoma but also has broader implications for testing of other cancers where multiple ICB drugs and their respective assays are approved.Citation
Evans H, O'Sullivan B, Hughes F, Charles K, Robertson L, Taniere P, Diaz-Cano S. PD-L1 Testing in Urothelial Carcinoma: Analysis of a Series of 1401 Cases Using Both the 22C3 and SP142 Assays. Pathol Oncol Res. 2022 Apr 11;28:1610260. doi: 10.3389/pore.2022.1610260Type
ArticlePMID
35478498Journal
Pathology and Oncology ResearchPublisher
Frontiers Mediaae974a485f413a2113503eed53cd6c53
10.3389/pore.2022.1610260