Agilent Technologies Inc. (NYSE: A) today announced that the U.S. Food and Drug Administration (FDA) has approved its PD-L1 IHC 22C3 pharmDx assay for expanded use. The assay is now approved as an aid in identifying patients with head and neck squamous cell carcinoma (HNSCC) for treatment with KEYTRUDA? (pembrolizumab), anti-PD-1 therapy manufactured by Merck (known as MSD outside the United States and Canada). KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC whose tumors express PD-L1 (CPS ≥ 1) as determined by an FDA-approved test. PD-L1 IHC 22C3 pharmDx is the only companion diagnostic FDA-approved to aid in the identification of HNSCC patients for treatment with KEYTRUDA. HNSCC is the fifth cancer type for which PD-L1 IHC 22C3 pharmDx has gained FDA approval in the United States. "Targeted immunotherapies are redefining standards of care in cancer treatment, and PD-L1 testing plays a crucial role in identifying patients who may benefit from this treatment," said Sam Raha, president of Agilent's Diagnostics and Genomics Group. "The expanded FDA approval of PD-L1 IHC 22C3 pharmDx provides critical information to physicians managing first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC. By expanding the use of PD-L1 IHC 22C3 pharmDx, Agilent enables more patients to be identified for treatment with KEYTRUDA. Through these efforts, we reinforce our role as a worldwide leader in driving companion diagnostics to market in support of landmark therapies." HNSCC is the seventh most common cancer worldwide3 and accounts for more than 90% of head and neck cancer cases.4 In the United States, approximately 65,000 new head and neck cancer cases are diagnosed annually.5,6 The five-year overall survival rate for this form of cancer is approximately 40–50 percent7. KEYTRUDA is a humanized monoclonal antibody that increases the ability of the body's immune system to help detect and fight tumor cells. KEYTRUDA blocks the interaction between PD-1 and its ligands, PDL1 and PD-L2, thereby activating T lymphocytes, which may affect both tumor cells and healthy cells. KEYTRUDA and other targeted immunotherapies are revolutionizing cancer treatment, and their therapeutic value is being demonstrated across a growing list of cancer types. Agilent is a worldwide leader in partnering with pharmaceutical companies to develop immunohistochemical-based diagnostics for cancer therapy. Agilent developed PD-L1 IHC 22C3 pharmDx in partnership with Merck & Co. PD-L1 IHC 22C3 pharmDx also helps physicians identify non-small cell lung cancer (NSCLC), cervical cancer, gastric or GEJ adenocarcinoma, and urothelial carcinoma patients for treatment with KEYTRUDA. PD-L1 expression in NSCLC tissues is interpreted using Tumor Proportion Score (TPS). PD-L1 expression in HNSCC, urothelial carcinoma, cervical cancer, and gastric or GEJ adenocarcinoma tissues is interpreted using Combined Positive Score (CPS).