Abstract
Over the past decade, immune checkpoint inhibitors (ICIs) have transformed the treatment landscape for many types of cancers, leading to significant improvements in patient survival. Treatments like nivolumab, pembrolizumab, durvalumab, and atezolizumab have shown remarkable efficacy. Among the various biomarkers used to guide ICI therapy, PD-L1 is one of the most extensively studied. The PD-L1 SP263 assay is one of the most commonly used assays for identifying PD-L1 status. The Food and Drug Administration has approved the PD-L1 SP263 (Ventana) assay as a companion diagnostic test for atezolizumab in early-stage NSCLC and cemiplimab-rwlc in advanced non-small cell lung cancer (NSCLC), thus offering a standardized method to predict patient responses to immunotherapy based on PD-L1 expression levels. It is the product indicated for use in NSCLC that has received Conformité Européenne marking for in vitro diagnostic (CE-IVD) designation as a companion diagnostic assay for treatment with four immunotherapeutic drugs (durvalumab, pembrolizumab, cemiplimab-rwlc, and atezolizumab) and as a complementary diagnostic assay for nivolumab. In this review, we have consolidated the findings about the PD-L1 SP263 assay, focusing on its use and methodology in NSCLC and other tumors. We discuss why the SP263 assay is important, how it compares with the 22C3 assay—the other widely used PD-L1 assay in NSCLC—and its effectiveness across various types of cancer. The PD-L1 SP263 assay has been used in multiple clinical trials (such as ARCTIC, PACIFIC, and IMpower series) to quantify PD-L1 expression. Concordance studies between the PD-L1 SP263 assay and other PD-L1 assays, especially the 22C3 assay, highlight the SP263 assay’s reliability and the potential for interchangeability when quantifying PD-L1 in NSCLC cases. Beyond NSCLC, the PD-L1 SP263 assay demonstrates clinical utility in gastric, hepatocellular, head and neck squamous cell, urothelial, and renal cell carcinomas. Additionally, this review discusses future directions, including utilizing artificial intelligence to enhance diagnostic accuracy and predict treatment responses, thereby optimizing personalized cancer care.
Keywords
Cancer immunotherapy, PD-L1, Diagnostic assay, Clinical utility, Immune checkpoint inhibitor (ICI), SP263, Non-small cell lung cancer (NSCLC)