Labcorp launches nationwide PD-L1 IHC 22C3 pharmDx testing to identify platinum-resistant ovarian cancer patients eligible for KEYTRUDA therapy following FDA approval.
Written By: Chikkula Pavan Kumar, PharmD
Reviewed By: Pharmacally Editorial Team
Labcorp has announced nationwide availability of the PD-L1 IHC 22C3 pharmDx assay developed by Agilent Technologies. The test is the only companion diagnostic approved by the U.S. Food and Drug Administration to identify patients with platinum-resistant ovarian cancer who may be eligible for treatment with KEYTRUDA.
The approval also includes KEYTRUDA QLEX, a combination formulation of pembrolizumab and berahyaluronidase alfa. These therapies represent the first PD-1 inhibitors approved as part of a treatment regimen for patients with platinum-resistant ovarian cancer, a population with historically limited options.
Addressing a High-Unmet-Need Population
Ovarian cancer remains difficult to treat in advanced stages. Around 80% of patients experience recurrence following initial therapy, and many eventually develop resistance to platinum-based chemotherapy. This progression is associated with poor survival outcomes and a lack of effective treatment alternatives.
Clinical data supporting the recent approvals indicate that pembrolizumab-based therapies can reduce the risk of disease progression and improve overall survival in eligible patients. The availability of a validated companion diagnostic is essential for identifying those most likely to benefit.
Role of PD-L1 Testing
The PD-L1 IHC 22C3 pharmDx assay detects PD-L1 expression levels in tumor tissue, helping clinicians determine eligibility for immunotherapy. With Labcorp’s nationwide rollout, oncologists can now access standardized testing more rapidly, supporting timely treatment decisions.
Early Readiness Following FDA Approval
Following the FDA’s approval of the therapies and companion diagnostic in February, Labcorp participated in Agilent’s Early Validation Program. This initiative included training and operational readiness efforts designed to enable immediate scaling of testing services after regulatory clearance.
Executive Perspective
Marcia Eisenberg, Ph.D., chief scientific officer at Labcorp, emphasized the clinical challenge posed by platinum-resistant ovarian cancer, noting that existing treatments often provide limited and short-term benefit. She stated that expanding access to this diagnostic allows clinicians to quickly identify eligible patients and connect them to newly approved therapies that may improve outcomes.
Expanding Oncology Diagnostics Infrastructure
The nationwide deployment reflects broader efforts to integrate companion diagnostics into oncology care. By aligning testing availability with newly approved therapies, diagnostic providers and pharmaceutical companies aim to streamline patient selection and improve access to precision medicine.
Labcorp indicated that its oncology testing network is positioned to support clinicians with rapid turnaround times and standardized protocols, facilitating broader adoption of biomarker-driven treatment strategies.
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About the Writer
Chikkula Pavan Kumar, Pharm.D is a Doctor of Pharmacy with a keen interest in clinical pharmacy, pharmacovigilance, and evidence-based practice. In his words, he is passionate about patient safety and translating complex medical information into clear, research-driven communication.
