PD-L1 Testing

Programmed death-ligand 1 (PD-L1) is an immune-related biomarker that can be expressed on the surface of many tissue types, including tumor cells. For certain types and stages of cancer, testing for PD-L1 expression may help to select patients most likely to benefit from treatment with PD-L1 inhibitors. Novel immunotherapies, known as immune checkpoint inhibitors, can interrupt signals generated by immune checkpoint proteins, such as PD-L1, and enhance antitumor T-cell immunity.   Several PD-L1 inhibitors, including atezolizumab, durvalumab, nivolumab, and pembrolizumab, have been approved for a number of clinical indications and are being evaluated in multiple malignancies. The U.S. Food and Drug Administration (FDA) divides PD-L1 immunohistochemistry (IHC) tests into two groups: companion diagnostics, which provide information that is essential for the safe and effective use of a drug (test results are required for drug use), and complementary or codiagnostic tests, which may be used in treatment selection but are not considered essential for use of the corresponding therapy (test results are NOT required for drug use).  

Tabs Content
Content Review: 
November 2019

Last Update: November 2019