PD-L1 IHC 22C3 pharmDx Demonstrates Precision and Reproducibility in Triple-negative Breast Cancer

Abstract

In the United States, the PD-L1 IHC 22C3 pharmDx indications for use have expanded to include the assay’s use as an aid in identifying triple-negative breast cancer (TNBC) patients for treatment with pembrolizumab (KEYTRUDA®). Analytical validation for TNBC was conducted by Agilent Technologies in support of the device performance and FDA-approval. Analytical validation studies included device precision (inter-instrument, inter-operator, inter-day, inter-lot, and intra-run) and external reproducibility (inter- and intra-site, inter- and intra-observer) using the Combined Positive Score (CPS) ≥ 10 cutoff. All precision and external reproducibility studies achieved confidence interval lower bound values of greater than 85% for positive, negative, and overall percent agreement. These analytical validation studies demonstrate that PD-L1 IHC 22C3 pharmDx is precise and reproducible in evaluating PD-L1 protein expression at a CPS ≥ 10 cutoff when used for testing TNBC tissues.