The companion diagnostic can now help identify patients with esophageal or gastroesophageal junction carcinoma who may be eligible for pembrolizumab treatment.

Agilent Technologies has received Food and Drug Administration (FDA) approval for its PD-L1 IHC 22C3 pharmDx test as a companion diagnostic for identifying patients with esophageal or gastroesophageal junction (GEJ) carcinoma who may be eligible for treatment with pembrolizumab, marking the eighth FDA-approved companion diagnostic indication for the test.

The approval expands the clinical utility of PD-L1 IHC 22C3 pharmDx, Code SK006, which 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 of 1 or greater, according to a release from Agilent. Those patients may be eligible for treatment with pembrolizumab, Merck’s anti-PD-1 therapy marketed as Keytruda, in combination with platinum- and fluoropyrimidine-based chemotherapy.

Esophageal cancer carries a significant disease burden. According to the National Cancer Institute, esophageal cancer caused approximately 16,250 deaths in the US in 2025, with a five-year relative survival rate of 21.9%.

A Growing Portfolio of Companion Diagnostic Indications

The newly approved indication adds esophageal and GEJ carcinoma to an already broad list of tumor types for which PD-L1 IHC 22C3 pharmDx is indicated. The test, developed by Agilent in partnership with Merck, can also aid in identifying patients with non-small cell lung cancer, esophageal squamous cell carcinoma, cervical cancer, head and neck squamous cell carcinoma, triple-negative breast cancer, gastric or GEJ adenocarcinoma, and epithelial ovarian, fallopian tube, or primary peritoneal carcinoma who may benefit from pembrolizumab treatment.

This expansion reflects a broader trend in the evolution of PD-L1 testing, as companion diagnostics become increasingly central to guiding immunotherapy treatment decisions across oncology.

“With the expanded FDA approval of PD-L1 IHC 22C3 pharmDx in esophageal or GEJ carcinoma, Agilent is proud to support clinicians in identifying patients eligible for treatment with Keytruda,” says Nina Green, vice president and general manager of Agilent’s Clinical Diagnostics Division, in a release. “This milestone reinforces Agilent’s commitment to advancing precision medicine and underscores its leadership in delivering trusted companion diagnostics that help enable treatment with anti-PD-1 therapies.”

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