FDA Approves Promega OncoMate MSI Dx Analysis System for endometrial carcinoma treatment guidance

The FDA has approved Promega's OncoMate MSI Dx Analysis System, a PCR-based assay that identifies MSI status in endometrial carcinoma, guiding treatment with KEYTRUDA and LENVIMA. This marks the first Promega companion diagnostic approval, enhancing personalized medicine strategies in oncology.
Nov. 18, 2025
2 min read

The U.S. Food and Drug Administration (FDA) has approved the Promega OncoMate MSI Dx Analysis System as a companion diagnostic designed to identify patients with microsatellite stable (MSS; defined as not MSI-high [not MSI-H]) endometrial carcinoma who may benefit from treatment with KEYTRUDA (pembrolizumab), Merck’s anti-PD-1 therapy, plus LENVIMA (lenvatinib), the orally available multiple receptor tyrosine kinase inhibitor discovered by Eisai. This is the first Promega companion diagnostic to receive FDA approval.

OncoMate MSI Dx Analysis System is a PCR-based assay designed to evaluate MSI status in tumor tissue. MSI status can be used to guide treatment decisions and support precision oncology strategies in endometrial carcinoma.

The approval was supported through a collaboration with Merck, which markets KEYTRUDA plus LENVIMA in collaboration with Eisai Co., Ltd. Together, the companies are working to advance personalized medicine and expand access to diagnostics that enable informed therapeutic choices.

OncoMate MSI Dx Analysis System was previously cleared by the FDA as the first PCR-based molecular diagnostic for identifying colorectal cancer patients who may benefit from additional testing to diagnose Lynch syndrome. This approval applies to the United States and its territories. Promega MSI technology has received additional regulatory approvals in China and the European Union.

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