Roche’s Genentech present data on trontinemab, Elecsys plasma test

Genentech announced that new data were presented at the AD/PD 2025 International Conference on Alzheimer’s and Parkinson’s Diseases in Vienna, Austria. Highlights included presentations from the ongoing trontinemab Phase Ib/IIa Brainshuttle AD study demonstrating dose-dependent rapid amyloid depletion from the brain and the potential of the Elecsys pTau181 plasma test to rule out amyloid pathology. A Phase III program for trontinemab will be initiated later this year. Preliminary results for trontinemab from 114 participants in the 1.8 or 3.6 mg/kg double-blind period suggest rapid and deep, dose-dependent reduction of amyloid plaques in the brain as measured by amyloid positron emission tomography. Trontinemab reduced amyloid levels below the 24 centiloid threshold in 81% of participants in the 3.6 mg/kg dose group after 28 weeks. Based on data in the field, both the speed of amyloid lowering, and the ability to lower below the amyloid positivity threshold early on, are important to achieve clinically meaningful benefit in early Alzheimer’s disease. These data were reinforced by early and significant reductions in fluid biomarkers of Alzheimer’s disease including total tau, phosphorylated Tau 181, pTau217 and neurogranin measured in cerebrospinal fluid and plasma. Trontinemab continues to show a favorable safety and tolerability profile. Amyloid-related imaging abnormalities-edema/effusion were observed in less than5% of participants, which were radiographically mild, and there was one case associated with mild symptoms. Trontinemab is currently being studied in the Phase Ib/IIa Brainshuttle AD study assessing the safety, tolerability, pharmacokinetics and pharmacodynamics of trontinemab in participants with Alzheimer’s disease. Results from 604 participants in a multicenter study of Roche’s (RHHBY) Elecsys pTau181 plasma test were presented, demonstrating its potential to accurately rule out amyloid pathology, a hallmark of Alzheimer’s disease, in people with cognitive impairment. The Elecsys pTau181 test is a minimally invasive blood test that measures pTau181 protein in plasma. By ruling out those without signs of amyloid pathology, the test can help to avoid unnecessary testing using CSF or PET, which are more invasive and often come with long waiting times and high costs. This can result in further delays to diagnosis and cost to healthcare systems. Roche anticipates tests being available in Europe by late 2025, with the U.S. following after.