News|Articles|February 11, 2026

FDA Clears PD-L1 Test to Guide Keytruda Use in Ovarian Cancer

Author(s)CURE staff
Fact checked by: Spencer Feldman
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FDA approved a PD-L1 companion test to identify patients with ovarian, fallopian tube or primary peritoneal cancer who may receive first-line Keytruda.

The U.S. Food and Drug Administration (FDA) has approved PD-L1 IHC 22C3 pharmDx, Code SK006, as a companion diagnostic to help identify patients with epithelial ovarian, fallopian tube, or primary peritoneal carcinoma whose tumors express PD-L1 and who may be eligible for first-line treatment with Keytruda (pembrolizumab), according to a news release from Agilent Technologies.

The approval gives pathologists a tool to assess PD-L1 expression at diagnosis so treatment decisions can be better tailored to individual patients with cancer.

The test is now the only FDA-approved companion diagnostic specifically indicated to guide first-line use of Keytruda in these gynecologic cancers. According to Agilent, the decision represents the first immuno-oncology approval for this disease setting and is intended to expand precision medicine options for patients whose therapeutic choices may be limited.

How does PD-L1 testing help guide first-line Keytruda use?

PD-L1 IHC 22C3 pharmDx, Code SK006, allows pathologists to measure PD-L1 expression in tumor tissue at the time of diagnosis. This information can help determine whether a patient may benefit from treatment with Keytruda in the first-line setting.

PD-L1 expression in epithelial ovarian cancer was evaluated using the diagnostic in the KEYNOTE-B96 clinical trial. Results from that trial supported the use of the test to identify patients who may be candidates for Keytruda.

Agilent said the approval expands first-line PD-L1 testing and enables more informed treatment decisions in a disease where options remain limited for many patients. The company also noted that this is the seventh FDA-approved companion diagnostic indication for PD-L1 IHC 22C3 pharmDx for use with Keytruda.

The need for additional options remains significant. In the United States, ovarian cancer caused approximately 12,730 deaths in 2025. The reported five-year survival rate was 51.6% between 2015 to 2021. These figures underscore the importance of tools that may help match patients with therapies earlier in care.

In a statement, Nina Green, vice president and general manager of Agilent’s Clinical Diagnostics Division, said the approval reflects collaboration between diagnostic and therapeutic development and supports identifying patients with epithelial ovarian cancer who may benefit from immunotherapy in the first-line setting.

What study supported the FDA approval?

The approval was supported by findings from the KEYNOTE-B96 clinical trial. In this study, PD-L1 expression was evaluated using PD-L1 IHC 22C3 pharmDx, Code SK006, to help determine which patients might benefit from treatment with Keytruda.

The diagnostic was developed by Agilent in partnership with Merck & Co. as a companion diagnostic specifically for Keytruda. Companion diagnostics are tests designed to provide information about whether a treatment may be appropriate for an individual patient.

With this approval, the test becomes available to help guide first-line decisions in epithelial ovarian, fallopian tube, or primary peritoneal carcinoma. Pathologists can use the assay during initial evaluation of tumor samples, which may help care teams consider immunotherapy earlier in the treatment process for eligible patients.

Beyond gynecologic cancers, PD-L1 IHC 22C3 pharmDx, Code SK006, is already indicated in the United States to help identify patients with non-small cell lung cancer, esophageal squamous cell carcinoma, cervical cancer, head and neck squamous cell carcinoma, triple-negative breast cancer and gastric or gastroesophageal junction adenocarcinoma who may benefit from Keytruda.

What should patients know about the safety of this approval?

The FDA action applies to the diagnostic test, not to new safety findings for the treatment itself. The approval focuses on identifying which patients may be eligible for Keytruda based on PD-L1 expression.

No new safety data were reported in the announcement for either the diagnostic or Keytruda. Patients considering testing or treatment should discuss potential risks, benefits and next steps with their care team to understand how PD-L1 testing may fit into their individual care plan.

Reference

  1. “PD-L1 IHC 22C3 pharmDx in Epithelial Ovarian, Fallopian Tube, or Primary Peritoneal Carcinoma (EOC).” News Release. Business Wire.

Editor's note: This article is for informational purposes only and is not a substitute for professional medical advice, as your own experience will be unique. Use this article to guide discussions with your oncologist. Content was generated with AI and reviewed by a human editor.

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