The role of PD-L1 as a patient selection biomarker is emerging, with clinical outcome data from numerous studies demonstrating enrichment of responders. PD-L1 expression as a continuous variable measured via IHC presents a number of challenges to the clinical community including: 1) the relevant expression levels for treatment decision making 2) how well the cut-off can be deployed routinely in the clinical setting and 3) the lack of a ‘gold standard’ that establishes PD-L1 truth, and against which assays in development can compare.
To fully determine the clinical utility of PD-L1 as a predictor of response, it is critical to first remove concerns that relate to test performance. During companion diagnostic development, the assay undergoes a comprehensive analysis of performance and evaluation in the population of intended use. Prior to pre market approval (PMA), the assay must demonstrate that it meets the criteria for safe and effective use as determined through statistically relevant acceptance criteria established by the sponsor.
Following commercialisation of the assay, performance is assessed in the real world setting through various external quality assurance schemes with the goal of reducing inter-laboratory variation and establishing assay standardisation. The latter is critical to the maintenance of test quality and ensuring patient care.
We will present a detailed overview of the quality standards observed for IHC-based companion diagnostic approvals. Previously approved PMA and cleared 510(k) assay summaries of safety and effectiveness data (SSED) will be reviewed. Published EQA Quality assessments will be compared to data obtained from SSED. Set against this is the quality level that has been achieved with the Ventana SP263 PD-L1 assay.
Citation Format: Anita Midha, Jill Walker, Marlon C. Rebelatto, Costi Sabalos, Amita Mistry, Nicole Schechter. The importance of quality standards to support test performance for the purpose of treatment decision making. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B004.
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