The biomarker showed independent associations with cognitive and functional decline, offering complementary information alongside p-tau217 in early symptomatic Alzheimer’s disease.

C2N Diagnostics has highlighted the first use of its eMTBR-tau243 plasma assay in a Phase 3 clinical dataset, marking a step in the application of tau-related blood-based biomarkers to predict disease progression in patients with early symptomatic Alzheimer’s disease.

The data were presented at the AD/PD 2026 Alzheimer’s & Parkinson’s Diseases Conference during the Evoke/Evoke+ Trial Symposium, which focused on cerebrospinal fluid (CSF) and plasma biomarker analyses as well as exploratory subgroup analyses from the Evoke and Evoke+ trials.

What the Phase 3 Data Showed

According to Evoke/Evoke+ Phase 3 evaluation data, baseline levels of p-tau217 and eMTBR-tau243 each showed independent associations with longitudinal measures of cognitive and functional decline. The two biomarkers also provided complementary information when assessed together, suggesting that combining them could offer a more complete picture of disease trajectory than either marker alone.

The analysis included eMTBR-tau243—a research-use-only biomarker commercialized and measured by C2N—as part of the examination of participants enrolled in the trials.

“The inclusion of eMTBR-tau243 in Evoke/Evoke+ analyses reflects the growing interest in looking at tau biology in ways that may better predict which patients with early symptomatic Alzheimer’s disease will progress more quickly than others,” says Joel Braunstein, MD, chief executive officer and president of C2N Diagnostics, in a release. “This information may be instrumental for future precision medicine strategies in novel treatment development and patient care.”

The Role of eMTBR-tau243 in Tau Biology

The eMTBR-tau243 assay measures a fragment of the microtubule-binding region of tau, a protein whose abnormal accumulation is one of the hallmarks of Alzheimer’s disease. While p-tau217 has emerged as a leading blood-based biomarker for Alzheimer’s detection and staging, the Evoke/Evoke+ data suggest that eMTBR-tau243 captures distinct biological signals that are not fully reflected by p-tau217 alone.

The results point to a potential role for multi-marker tau panels in future clinical and research applications, particularly as the field moves toward precision medicine approaches in neurodegeneration.

C2N’s Broader Tau Research Portfolio

C2N continues to advance multiple tau-related research tools, including early elements of its PrecivityTauDx program development, to help bring together scientific insights in both research and clinical settings in Alzheimer’s disease, according to the company.

The St. Louis-based specialty diagnostics company uses high-resolution mass spectrometry-based biomarker services and products for clinical decision-making, treatment monitoring, and clinical trial support. C2N assays have been used in over 200 Alzheimer’s disease and other research studies throughout the US and internationally, the company says.

Growing Interest in Blood-Based Biomarkers

The Evoke/Evoke+ findings come amid broader momentum in the Alzheimer’s diagnostics field. Earlier this year, the Alzheimer’s Association released its first clinical practice guideline on the use of blood-based biomarker tests, providing evidence-based recommendations for clinicians evaluating patients with cognitive impairment.

C2N says it remains focused on scientific collaborations and on providing analytically sound biomarker support to partners across academia, biopharma, and translational research programs as interest in blood-based biomarkers for therapeutic development continues to grow.

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