On June 11, 2026 Roche (SIX: RO, ROP; OTCQX: RHHBY) reported the European Union In Vitro Diagnostic Regulation (IVDR) approval of several label expansions for the VENTANA MMR RxDx Panel, an immunohistochemistry (IHC) companion diagnostic test that aids in identifying a cancer patient’s mismatch repair (MMR) status. MMR is a process that scans a person’s genetic code and fixes errors to prevent mutations that can lead to cancer. The test evaluates a panel of MMR proteins in tumours to provide this important treatment information to clinicians.

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"By providing a standardised testing option for mismatch repair status with our VENTANA MMR RxDx Panel, we are empowering clinicians to make more informed decisions and expanding access to important therapies for patients across multiple solid tumor types," said Laura Apitz, Head of Pathology Lab at Roche Diagnostics. "This milestone exemplifies our dedication to delivering high-medical-value solutions that help improve patient outcomes through precision medicine."

The VENTANA MMR RxDx Panel is now available in countries regulated by IVDR as a companion diagnostic for the following therapies and cancer types:

KEYTRUDA (pembrolizumab), Merck & Co., Inc., Rahway, NJ, USA’s anti-PD-1 therapy: For the treatment of mismatch repair deficient (dMMR) tumors in certain adults with: metastatic colorectal cancer; advanced or recurrent endometrial carcinoma; unresectable or metastatic gastric, small intestine or biliary cancer.
IMFINZI (durvalumab), AstraZeneca’s anti-PD-L1 therapy: For adult patients with dMMR primary advanced or recurrent endometrial cancer.
IMFINZI + LYNPARZA (olaparib), AstraZeneca’s anti-PD-L1 therapy and PARP inhibitor: For adult patients with mismatch repair proficient (pMMR) primary advanced or recurrent endometrial cancer.
JEMPERLI (dostarlimab-gxly), GSK’s anti-PD-1 therapy: for dMMR patients with endometrial cancer.1
About MMR
Cancer remains the second leading cause of death worldwide, resulting in nearly 10 million deaths annually.2, 3 Identifying specific biomarkers is critical to help identify patients who are eligible for certain therapies, as dMMR serves as a vital predictive biomarker for modern immunotherapies.

MMR is a naturally occurring mechanism that scans our DNA, correcting errors that cause disease. When MMR is deficient, cells mutate, which can lead to cancer. While MMR deficiency is most common in endometrial cancer, other high-prevalence dMMR tumour types include gastric, colorectal, small intestine and biliary tract cancers. Because dMMR tumours often have a high mutational burden they may respond well to immune checkpoint inhibitors (ICIs) such as PD-1 or PD-L1 inhibitors. For patients with endometrial cancer without MMR deficiency (pMMR), the addition of PARP inhibitors in maintenance to ICIs may further enhance the benefit of ICIs. PD-1 inhibitors may retain activity when combined with a tyrosine kinase inhibitor (TKI).

About the VENTANA MMR RxDx Panel
This IVDR approval for the VENTANA MMR RxDx Panel is a label expansion of Roche’s current on-market panel. The VENTANA MMR RxDx Panel is intended for the assessment of expression of MMR proteins in formalin-fixed, paraffin-embedded (FFPE) tumour tissue stained with OptiView DAB IHC Detection Kit and ancillary reagents in the panel for VENTANA anti-MLH1 (M1), VENTANA anti-MSH2 (G219-1129) and VENTANA anti-MSH6 (SP93), and OptiView DAB IHC Detection Kit with the OptiView Amplification Kit and ancillary reagents for VENTANA anti-PMS2 (A16-4) on a BenchMark ULTRA instrument.

MMR proteins have been clinically proven to be predictive biomarkers for PD-1 targeted therapy; specifically, a loss of expression of one or more MMR proteins might predict an increased likelihood of response to such therapy.4,5,6 PD-1 inhibitors can be effective in cancers with MMR deficiency.4,6 MMR is a conserved molecular mechanism that functions to correct the improper base substitutions that spontaneously occur during DNA replication. Defects in the MMR machinery have been attributed to mutations in the MMR proteins.

(Press release, Hoffmann-La Roche, JUN 11, 2026, View Source [SID1234666540])