UK patients are among the first in Europe to participate in a phase III Alzheimer’s trial testing Trontinemab, an experimental drug targeting amyloid plaques in asymptomatic individuals with elevated p-tau217 levels, as researchers debate the reliability of cognitive tests like ADAS-Cog.
The PrevenTRON trial, led by the Surrey and Borders Partnership NHS Foundation Trust, is recruiting 1,600 healthy adults aged 55 to 80 globally to test whether Trontinemab can prevent Alzheimer’s before symptoms emerge. Participants will undergo memory assessments and blood tests to measure p-tau217, a biomarker linked to cognitive decline with up to 95% accuracy, as reported by The Guardian. The first European participants in the trial, which is recruiting about 1,600 people aged 55 to 80 from around the world, will be screened on Monday by the Surrey and Borders Partnership NHS foundation trust, according to Source 1.
A Shift to Early Intervention
For decades, Alzheimer’s research focused on treating symptoms after diagnosis, but the PrevenTRON trial represents a pivot to prevention. Prof Ramin Nilforooshan, consultant psychiatrist and chief investigator for the trial, emphasized the shift: For decades, research has focused on treating Alzheimer’s disease after symptoms appear. PrevenTRON addresses a different question, whether we can act earlier, before symptoms begin,
as cited by The Guardian. The drug, developed by Roche, targets amyloid plaques—a toxic protein buildup in the brain. Early trials showed it cleared plaques in nine out of 10 people with early-stage Alzheimer’s or mild cognitive development within 28 weeks, according to Source 1. However, Nilforooshan cautioned: I’m not saying this trial is magic. It’s an investigational medicine. We need to wait and see: will it work or not?
as reported by Source 2.
Alzheimer’s trial to test drug on people without symptoms
The Role of p-Tau217 and Trial Design
Participants must have no memory problems but will be screened for p-tau217, a biomarker that predicts cognitive decline. Those with high levels will be randomly assigned to receive Trontinemab or a placebo for four to six years. Previous research found individuals with the highest p-tau217 levels had an estimated 78% chance of developing cognitive impairment within 10 years, as noted in Source 1. The trial’s design reflects growing evidence that Alzheimer’s develops inside the brain up to 10 years before people typically seek treatment for memory problems. Around 1 in 14 people over 65 and 1 in 6 over 80 are affected, but early intervention could reduce this burden, according to Source 1. At least 15 hospitals and clinics across the UK will participate, with recruitment led by the Surrey and Borders Partnership Trust, as stated in Source 1.
Challenges in Measuring Progress
While the trial focuses on biological markers, concerns persist about the reliability of cognitive tests. A study published in Alzheimer’s & Dementia found flaws in the ADAS-Cog test, which measures cognitive function in trials. Researchers identified ceiling effects where the test fails to capture subtle improvements in early-stage patients, potentially underestimating drug efficacy, as detailed in Source 3. The ADAS-Cog test, first published in 1984, may lack sensitivity for early-stage disease. A 2012 analysis using Rasch Measurement Theory highlighted its limitations, suggesting it has limitations with potentially serious implications for clinical trials, according to Source 3. These findings raise questions about how outcomes in the PrevenTRON trial will be evaluated.
UK patients among first in Europe to test drug
The trial’s success depends on both Trontinemab’s efficacy and the accuracy of diagnostic tools. If p-tau217 proves a reliable predictor, the approach could redefine Alzheimer’s care. However, the ADAS-Cog controversy underscores the need for updated testing methods. Researchers stress that results are years away, with final outcomes expected by 2030, as noted in Source 1. Additionally, the PrevenTRON trial is part of an international clinical trial aiming to prevent dementia, as mentioned in Source 1.
Methodological Concerns in Alzheimer’s Research
Recent research into clinical trial methodologies highlights vulnerabilities in Alzheimer’s drug development. A study published in the journal Alzheimer’s & Dementia identified flaws in the ADAS-Cog test, which is commonly used to assess patients. The test’s ceiling effects may hinder the detection of subtle cognitive improvements, potentially undermining drug efficacy evaluations. The study’s authors, including Jeremy Hobart, Stefan Cano, Holly Posner, Ola Selnes, Yaakov Stern, Ronald Thomas, and John Zajicek, emphasized the need for more sensitive tools, as detailed in Source 3. This aligns with broader concerns about methodological risks in Alzheimer’s trials, as noted in Source 4.
Source 4, a review of Alzheimer’s drug development, highlights that over 100 compounds tested as potential therapies were either abandoned or failed in clinical trials. While four drugs—donepezil (Aricept), rivastigmine (Exelon), galantamine (Reminyl), and memantine (Namenda)—are approved for Alzheimer’s, recent trials of cholinesterase inhibitors (ChEIs) have failed to prevent progression from Mild Cognitive Impairment (MCI) to Alzheimer’s. The review also notes that many new compounds are in clinical testing or will soon enter trials, but methodological challenges remain. The study’s authors, including Jeremy Hobart et al., stress the importance of addressing these issues to improve trial validity.
Test for Alzheimer's May Be Undermining Drug Trials
Trontinemab’s Mechanism and Regulatory Status
Trontinemab, developed by the Swiss pharmaceutical company Roche, is designed to attack toxic beta-amyloid plaques that build up between brain cells. The drug pairs the antibody gantenerumab with a specialized shuttle molecule to help it cross the blood-brain barrier more effectively, as outlined in Source 2. This mechanism aims to clear amyloid plaques, a key pathological feature of Alzheimer’s. However, the drug remains in the investigational phase, with the PrevenTRON trial evaluating its preventive potential. Regulatory approval is contingent on the trial’s outcomes, which are expected to take several years to finalize.
Practical Next Steps
For individuals interested in participating in the PrevenTRON trial, consulting qualified healthcare professionals is advised. The study’s eligibility criteria, including p-tau217 levels and cognitive assessments, require expert evaluation. While the trial represents a significant step in Alzheimer’s prevention, readers should note that the findings are still under investigation. As Prof Nilforooshan emphasized, We need to wait and see: will it work or not?
The results of the trial, along with ongoing research into diagnostic tools like ADAS-Cog, will shape future approaches to Alzheimer’s care.
