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Agilent Receives FDA Approval for PD-L1 IHC 22C3 pharmDx in Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma

Patients with gastric or GEJ adenocarcinoma whose tumors express PD-L1 can now be identified for potential treatment with KEYTRUDA® (pembrolizumab) using PD-L1 IHC 22C3 pharmDx (SK006)

Agilent Technologies Inc. (NYSE: A) today announced that it has received FDA approval for the use of PD-L1 IHC 22C3 pharmDx as a diagnostic tool to aid in identifying patients with Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma who may be eligible for treatment with KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy.

PD-L1 IHC 22C3 pharmDx is the only FDA-approved companion diagnostic that can identify gastric or GEJ adenocarcinoma patients suitable for treatment with KEYTRUDA in combination with chemotherapy and trastuzumab plus fluoropyrimidine. This marks the sixth cancer type for which PD-L1 IHC 22C3 pharmDx has gained FDA approval.

Lou Welebob, vice president and general manager of Agilent’s Pathology Division, stated, “PD-L1 expression is a critical biomarker for response to anti-PD-1 therapies such as KEYTRUDA. This endorsement underscores Agilent’s leadership in the development of companion diagnostics for groundbreaking anti-PD-1 therapies.”

In addition to gastric or GEJ adenocarcinoma, PD-L1 IHC 22C3 pharmDx also helps physicians identify patients with non-small cell lung cancer (NSCLC), esophageal squamous cell carcinoma (ESCC), cervical cancer, head and neck squamous cell carcinoma (HNSCC), and triple-negative breast cancer (TNBC) who may benefit from treatment with KEYTRUDA.

KEYTRUDA, in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of patients with locally advanced unresectable or metastatic HER2‑positive gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.

Gastric cancer is a leading cause of cancer-related mortality worldwide1. The incidence of GEJ adenocarcinoma is on the rise and is considered one of the fastest growing cancers in the country 1,2.

KEYTRUDA is a humanized monoclonal antibody that enhances the immune system’s ability to detect and fight tumor cells. It works by blocking the PD-1 pathway, activating T lymphocytes that may affect both tumor cells and healthy cells. KEYTRUDA and other targeted immunotherapies are revolutionizing cancer treatment across a growing list of cancer types.

PD-L1 IHC 22C3 pharmDx was developed by Agilent in partnership with Merck (known as MSD outside the United States and Canada) as a companion diagnostic for KEYTRUDA.

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

About Agilent Technologies

Agilent Technologies Inc. (NYSE: A) is a global leader in analytical and clinical laboratory technologies, delivering insights and innovation that help our customers bring great science to life. Agilent’s full range of solutions includes instruments, software, services, and expertise that provide trusted answers to our customers' most challenging questions. The company generated revenue of $6.85 billion in fiscal 2022 and employs 18,000 people worldwide. Information about Agilent is available at To receive the latest Agilent news, please subscribe to the Agilent Newsroom. Follow Agilent on LinkedIn and Facebook.


  1. Bartel, M.; Brahmbhatt, B.; Bhurwal, A. Incidence of gastroesophageal junction cancer continues to rise: Analysis of Surveillance, Epidemiology, and End Results (SEER) database. J Clin Oncol. 2019, 37 (4), 40–40.
  2. Rawal, P.; Barsouk, A. Epidemiology of gastric cancer: global trends, risk factors and prevention. Prz Gastroenterol. 2019, 14 (1), 26–38. 4. Luo, H.; Xu, R. Novel Targeted Therapy for Advanced Gastric Cancer. Biochem Pharmacol. 2014, 4 (1).


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