NEW YORK – Agilent Technologies announced on Wednesday that the US Food and Drug Administration has expanded its approval of the firm's Dako PD-L1 IHC 22C3 pharmDx assay as a companion diagnostic test for Merck's anti-PDL-1 immunotherapy pembrolizumab (Keytruda) for esophageal squamous cell carcinoma (ESCC).
Keytruda is approved for patients with recurrent locally advanced or metastatic ESCC whose tumors express PD-L1 as determined by an FDA-approved test, with disease progression on or after one prior line of systemic therapy. Agilent's test is the only CDx approved by the FDA to aid in the identification of ESCC patients for treatment with Keytruda, the company said.
"PD-L1 has been established as an essential biomarker for PD-1/PD-L1 checkpoint inhibitors," Sam Raha, president of Agilent's diagnostics and genomics group, said in a statement. "As a growing number of patients are becoming eligible for treatment with these inhibitors, pathologists' confidence in their PD-L1 test is critical. With the approval of expanded use of our PD-L1 IHC 22C3 pharmDx assay, Agilent is able to aid in the identification of patients with ESCC for treatment with Keytruda, while providing pathologists the quality, reliability, and accuracy they need to ensure diagnostic confidence."
Merck and Agilent's Dako subsidiary developed the assay in partnership, and the FDA initially approved it in October 2015 to determine whether patients with advanced non-small cell lung cancer (NSCLC) were likely to respond to Keytruda. In October 2016, the FDA expanded the assay's approval as a CDx for Keytruda to determine expression status and inform treatment in a broader range of metastatic NSCLC patients.
In September 2017, the FDA approved the assay as a CDx for Keytruda for gastric or gastroesophageal junction adenocarcinoma, and followed that with an approval for use in cervical cancer patients in June 2018 and in urothelial carcinoma patients in August 2018.
This past April, Agilent said the assay had also been approved to identify patients with Stage III NSCLC who are not candidates for surgical resection or definitive chemoradiation, or patients with metastatic NSCLC whose tumors express a PD-L1 Tumor Proportion Score greater than or equal to 1 percent, and who are eligible for first-line treatment with Keytruda. And in June, the FDA approved the assay as a CDx for Keytruda for patients with head and neck squamous cell carcinoma.
The diagnostic was also granted CE marking in August 2016 as a CDx for Keytruda for patients with previously treated, advanced NSCLC with PD-L1-expressing tumors. In January 2017, the CE marking was expanded to include patients with metastatic NSCLC with no EGFR or ALK mutations who had not yet been treated. And in August 2018, the CE marking was expanded again to include urothelial carcinoma.