On November 11, 2025 The U.S. Food and Drug Administration (FDA) reported it 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.

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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.

"This approval underscores the critical role diagnostics play in accurately matching the right patients, at the right time with the right therapy," says Alok Sharma, Global Clinical Market Director at Promega. "We are committed to delivering reliable tools that guide clinical decisions and help improve patient outcomes."

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.

Learn more about Promega MSI technology here.

KEYTRUDA is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

(Press release, Promega, NOV 11, 2025, View Source [SID1234659767])