Analysis of Real-World PD-L1 Testing for Clinical Use in Patients with Lung Cancer

Targeting the programmed death-1/programmed death ligand 1 (PD-1/PD-L1) pathway has improved clinical outcomes, expediting the US FDA approval of 5 agents as treatment for several tumor types. PD-L1 immunohistochemistry (IHC) diagnostic assays have been developed to guide treatment with anti–PD-1/PD-L1 agents. The Dako PD-L1 IHC 22C3 pharmDx and Ventana PD-L1 (SP142) assays are FDA-approved diagnostics for non-small cell lung cancer (NSCLC) as a companion to pembrolizumab and complementary to atezolizumab, respectively. The Dako PD-L1 IHC 28-8 pharmDx is approved for nonsquamous NSCLC, complementary to nivolumab. We sought to overcome barriers to PD-L1 testing by characterizing the use of 22C3, 28-8, and SP142 PD-L1 IHC assays on real-world lung cancer samples.