Agilent receives FDA approval for PD‑L1 IHC 22C3 pharmDx in esophageal and GEJ carcinoma
Test enables identification of patients whose tumors express PD-L1 for potential treatment with KEYTRUDA (pembrolizumab)
5 May 2026Industry news
Agilent Technologies Inc. has received U.S. Food and Drug Administration (FDA) approval for PD-L1 IHC 22C3 pharmDx, Code SK006, as a companion diagnostic to help identify patients with esophageal or gastroesophageal junction (GEJ) carcinoma who may be eligible for treatment with KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy. This approval enables clinicians across the United States to use the assay to determine PD-L1 expression status in tumors and guide treatment decisions for appropriate patients.
Expanded FDA approval for PD-L1 IHC 22C3 pharmDx in esophageal and GEJ carcinoma
PD-L1 IHC 22C3 pharmDx, Code SK006, is now the only FDA-approved companion diagnostic indicated to identify patients with esophageal or GEJ carcinoma whose tumors express PD-L1 with a Combined Positive Score (CPS) greater than or equal to 1 and who may be eligible for treatment with KEYTRUDA.
This latest decision marks the eighth FDA-approved companion diagnostic indication currently available for PD-L1 IHC 22C3 pharmDx, Code SK006, for use with KEYTRUDA.
The approval strengthens the role of PD-L1 IHC 22C3 pharmDx, Code SK006, in precision oncology by providing a standardized, FDA-approved method to assess PD-L1 expression and support treatment decisions involving pembrolizumab.
Additional cancer indications for PD-L1 IHC 22C3 pharmDx, Code SK006
Beyond esophageal and GEJ carcinoma, PD-L1 IHC 22C3 pharmDx, Code SK006, is also indicated to help physicians identify patients who may benefit from treatment with KEYTRUDA across multiple tumor types, including:
- Non-small cell lung cancer (NSCLC)
- Esophageal squamous cell carcinoma (ESCC)
- Cervical cancer
- Head and neck squamous cell carcinoma (HNSCC)
- Triple-negative breast cancer (TNBC)
- Gastric or GEJ adenocarcinoma
- Epithelial ovarian, fallopian tube, or primary peritoneal carcinoma (EOC)
These indications highlight the broad clinical utility of PD-L1 IHC 22C3 pharmDx, Code SK006, as a companion diagnostic for pembrolizumab in solid tumors.
KEYTRUDA indication in esophageal and GEJ carcinoma
KEYTRUDA (pembrolizumab) is indicated for the treatment of patients with locally advanced or metastatic esophageal or gastroesophageal junction (GEJ) carcinoma, including tumors with an epicenter 1 to 5 centimeters above the GEJ, that are not amenable to surgical resection or definitive chemoradiation. In this setting, KEYTRUDA is used in combination with platinum- and fluoropyrimidine-based chemotherapy for patients whose tumors express PD-L1 with a Combined Positive Score (CPS) greater than or equal to 1.
The PD-L1 IHC 22C3 pharmDx, Code SK006, assay provides the PD-L1 expression information needed to determine whether patients with esophageal or GEJ carcinoma meet this CPS threshold and may be eligible for treatment with pembrolizumab-based regimens.
Esophageal cancer burden in the United States
In 2025, esophageal cancer caused approximately 16,250 deaths in the United States, with a 5-year relative survival rate of 21.9 percent. These statistics underscore the high mortality associated with esophageal malignancies and the need for effective, biomarker-driven treatment strategies.
By enabling accurate assessment of PD-L1 expression, PD-L1 IHC 22C3 pharmDx, Code SK006, supports the identification of patients who may benefit from KEYTRUDA and helps address the significant clinical burden of esophageal and GEJ carcinoma.
Collaboration between Agilent and Merck
PD-L1 IHC 22C3 pharmDx, Code SK006, was developed by Agilent in partnership with Merck (known as MSD outside the United States and Canada) as a companion diagnostic for KEYTRUDA. This collaboration combines Agilent’s expertise in clinical diagnostics with Merck’s leadership in immuno-oncology to deliver a validated assay that supports the use of pembrolizumab across multiple cancer types.
KEYTRUDA (pembrolizumab) is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.
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Frequently asked questions
What is PD-L1 IHC 22C3 pharmDx (Code SK006) and how is it used as an FDA-approved companion diagnostic for esophageal and gastroesophageal junction (GEJ) carcinoma?
PD-L1 IHC 22C3 pharmDx, Code SK006, is an FDA-approved companion diagnostic assay developed by Agilent Technologies Inc. to assess PD-L1 expression in tumor tissue. It is the only FDA-approved companion diagnostic indicated to identify patients with esophageal or gastroesophageal junction (GEJ) carcinoma whose tumors express PD-L1 with a Combined Positive Score (CPS) greater than or equal to 1.
Clinicians use the assay to determine PD-L1 status and guide treatment decisions for patients who may be eligible for KEYTRUDA (pembrolizumab), Merck’s anti-PD-1 therapy, in combination with platinum- and fluoropyrimidine-based chemotherapy.
For which cancer types is PD-L1 IHC 22C3 pharmDx, Code SK006, indicated as a companion diagnostic to help select patients for treatment with KEYTRUDA (pembrolizumab)?
Beyond esophageal and gastroesophageal junction (GEJ) carcinoma, PD-L1 IHC 22C3 pharmDx, Code SK006, is indicated to help physicians identify patients who may benefit from treatment with KEYTRUDA across multiple solid tumor types. These include non-small cell lung cancer (NSCLC), esophageal squamous cell carcinoma (ESCC), cervical cancer, head and neck squamous cell carcinoma (HNSCC), triple-negative breast cancer (TNBC), gastric or GEJ adenocarcinoma, and epithelial ovarian, fallopian tube, or primary peritoneal carcinoma (EOC).
These indications highlight the broad clinical utility of the assay as a standardized, FDA-approved method to support pembrolizumab-based treatment decisions.
How does the collaboration between Agilent Technologies and Merck support precision oncology and anti-PD-1 therapy selection with KEYTRUDA?
PD-L1 IHC 22C3 pharmDx, Code SK006, was developed by Agilent Technologies in partnership with Merck (known as MSD outside the United States and Canada) specifically as a companion diagnostic for KEYTRUDA (pembrolizumab). This collaboration combines Agilent’s expertise in clinical diagnostics with Merck’s leadership in immuno-oncology to deliver a validated assay that supports the use of pembrolizumab across multiple cancer types.
By providing a standardized, FDA-approved method to assess PD-L1 expression and determine whether tumors meet the CPS ≥1 threshold in esophageal and GEJ carcinoma, the partnership advances precision medicine and helps clinicians select appropriate anti-PD-1 therapy for patients facing a high esophageal cancer burden in the United States.