Trontinemab Phase 3 Alzheimer Trials to Launch Following Promising Amyloid Clearance Data

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At the Alzheimer’s Association International Conference (AAIC) 2025 in Toronto, Roche presented new data across its diagnostics and pharmaceutical portfolios focused on Alzheimer disease (AD), including results from the Phase Ib/IIa Brainshuttle™ AD study of trontinemab and new findings supporting the Elecsys® pTau217 blood test for detection of amyloid pathology.

According to the company, trontinemab, a bispecific monoclonal antibody designed using Roche’s Brainshuttle technology, achieved a 91% amyloid positron emission tomography (PET) negativity rate among participants in the 3.6 mg/kg cohort after 28 weeks of treatment. Additionally, 72% achieved deep amyloid plaque clearance below 11 centiloids. Amyloid-related imaging abnormalities-edema/effusion (ARIA-E) were reported in fewer than 5% of participants, and all cases were radiographically mild.

Roche announced the upcoming initiation of the TRONTIER 1 and 2 Phase III trials in individuals with early symptomatic Alzheimer disease, as well as plans for a new Phase III trial in a preclinical population at high risk of cognitive decline. The TRONTIER trials will assess cognition and function using the Clinical Dementia Rating–Sum of Boxes as a primary endpoint after 18 months of treatment, along with additional clinical and quality-of-life outcomes.

On the diagnostics side, Roche presented data supporting the performance of Elecsys pTau217 as a standalone blood test with diagnostic accuracy comparable to PET and cerebrospinal fluid (CSF) assays. According to the release, the test has the potential to enable earlier and more accessible diagnosis in a variety of care settings. The Elecsys pTau217 test will be used in the TRONTIER trial prescreening process.

Additional presentations highlighted health care resource modeling that suggested the Elecsys pTau181 blood test could reduce unnecessary confirmatory imaging in primary care settings. The test, which received Breakthrough Device Designation from the U.S. Food and Drug Administration, showed potential to rule out amyloid pathology in nearly all individuals with a negative result, potentially shortening time to diagnosis and reducing health system burden.

Roche stated that its Alzheimer disease pipeline includes investigational therapies for multiple targets and stages of disease, as well as approved and exploratory diagnostic tools designed to support early and accurate detection and treatment monitoring.

Source: Roche presents new insights in Alzheimer’s disease research across its diagnostics and pharmaceutical portfolios at AAIC. News release. Roche. July 27, 2025. Accessed July 28, 2025. https://www.roche.com/media/releases/med-cor-2025-07-28