Abstract
BackgroundAtezolizumab is an inhibitor of programmed death-ligand 1 (PD-L1), used to treat advanced or metastatic bladder cancer, and in trials for non-invasive disease. In order to be eligible for treatment, patients require a PD-L1 immune cell score ≥ 5%, using the Ventana SP142 PD-L1 assay. Many laboratories do not have access to the required Ventana Benchmark Ultra stainer, and it is unclear if the assay performs similarly on other stainers. In this study, we compare SP142 assay results between Ventana Benchmark Ultra and Leica Bond-III stainers.MethodsSerial sections of 90 samples of transurethral bladder resections (comprising 51 pTaHG, 8 pTis, 18 pT1, 10 pT2 tumors) were stained using the SP142 PD-L1 antibody on Ventana Benchmark Ultra and Leica Bond-III stainers, manually scored, and compared using accuracy and Cohen’s kappa measures.ResultsBoth devices yielded highly concordant PD-L1 immune cell scores (accuracy 0.84, Cohen’s κ 0.732). Moreover, we found similar tumor cell (TC) PD-L1 scores using both stainers, and a trend towards greater TC scores in pT2 stage samples (p = 0.05).ConclusionThis study is the first to compare the SP142 antibody in bladder cancer on two different stainers. Our results indicate that both Benchmark Ultra and Bond-III stainers yield highly concordant results using the SP142 PD-L1 antibody.
Highlights
The European Association of Urology (EAU) and European Society of Medical Oncology (ESMO) recommend Atezolizumab, an inhibitor of programmed death-ligand 1 (PD-L1), Eva Compérat and André Oszwald have contributed .GRC n°5, Predictive Onco-Urology, Sorbonne Université, 75020 Paris, FranceDepartment of Pathology, Hôpital Tenon, AP-HP, 4, Rue de la Chine, 75020 Paris, FranceDepartment of Pathology, Medical University of Vienna, Vienna, AustriaDepartment of Urology, Hôpital Pitié-Salpêtrière, Urology, AP-HP, 75013 Paris, FranceDepartment of Urology, Hôpital Tenon, AP-HP, 75020 Paris, France as an alternative to carboplatin-based chemotherapy for cisplatin-ineligible patients with treatment-naive locally advanced or metastatic bladder cancer (BC) [1]
Ongoing trials are evaluating the benefit in non-muscle-invasive bladder cancer (NMIBC) as well [2]
Since stainers use proprietary reagents, specific protocol timings, and working dilutions, it is unclear if using the SP142 antibody on different stainers yields comparable IC score results
Summary
The European Association of Urology (EAU) and European Society of Medical Oncology (ESMO) recommend Atezolizumab, an inhibitor of programmed death-ligand 1 (PD-L1), Eva Compérat and André Oszwald have contributed .GRC n°5, Predictive Onco-Urology, Sorbonne Université, 75020 Paris, France. The American Food and Drug Administration (FDA) and European Medical Agency (EMA) have approved the use of Atezolizumab for patients with PD-L1 expression in ≥ 5% of immune cells in tumor tissue (IC score) using the Ventana SP142 PD-L1 immunohistochemistry assay [3]. This test is licensed exclusively for performance on the Ventana Benchmark Ultra stainer, which is not available in every laboratory. Our results indicate that both Benchmark Ultra and Bond-III stainers yield highly concordant results using the SP142 PD-L1 antibody
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