Agilent Technologies Inc. shares climbed 3.2% in premarket trading Thursday after the company announced that it received European Union certification for its PD-L1 IHC 22C3 pharmDx companion diagnostic for ovarian cancer.
The CE mark authorizes use of the diagnostic to identify patients with epithelial ovarian, fallopian tube, or primary peritoneal carcinoma whose tumors express PD-L1 and who may be eligible to receive treatment with Merck's KEYTRUDA (pembrolizumab). The approval extends the diagnostic's role in guiding therapeutic decisions where treatment choices can be limited for many patients.
Agilent and Merck developed PD-L1 IHC 22C3 pharmDx, Code SK006, as a companion diagnostic for KEYTRUDA. In the European Union this indication represents the eighth CE-marked companion diagnostic use for the assay. The test enables pathologists to quantify PD-L1 expression to support physicians in identifying candidates for pembrolizumab therapy.
The regulatory decision is supported by data in which PD-L1 expression was evaluated using the diagnostic in the KEYNOTE-B96/ENGOT-ov65 clinical trial. That study's data underpin the diagnostic's intended use to identify patients who may be eligible for pembrolizumab in the platinum-resistant setting.
Beyond this new ovarian-related indication, the PD-L1 IHC 22C3 pharmDx assay is already indicated in the EU to help identify patients across several other tumor types who may be eligible for KEYTRUDA. Those tumor types include non-small cell lung cancer, esophageal cancer, cervical cancer, head and neck squamous cell carcinoma, triple-negative breast cancer, gastric or gastroesophageal junction adenocarcinoma, and urothelial carcinoma.
Agilent, which is based in Santa Clara, California, reported revenue of $6.95 billion in fiscal year 2025 and employs roughly 18,000 people worldwide. The company's collaboration with Merck on the PD-L1 IHC 22C3 pharmDx diagnostic links its pathology testing capabilities directly to a specific immunotherapy treatment option.
Key context
- Regulatory clearance covers epithelial ovarian, fallopian tube, and primary peritoneal carcinoma where PD-L1 expression is present.
- The diagnostic's use in the EU now includes eight CE-marked companion diagnostic indications for PD-L1 IHC 22C3 pharmDx, Code SK006.
- Clinical evidence from the KEYNOTE-B96/ENGOT-ov65 trial supports the diagnostic's role in identifying pembrolizumab candidates in the platinum-resistant setting.
Market reaction
The announcement coincided with a 3.2% premarket uptick in Agilent's shares as investors reacted to the expanded regulatory clearance for the diagnostic.