Alzheimer's prevention trial to offer experimental drug to symptom-free people

An NHS trust in the UK is starting screening on Monday for the first European participants in an international trial aiming to prevent Alzheimer's disease before dementia symptoms emerge. The study, called PrevenTRON, plans to recruit around 1,600 people aged 55 to 80 worldwide, led by the Surrey and Borders Partnership NHS Foundation Trust.

Participants will first be checked to confirm they have no memory problems, then offered a blood test measuring p-tau217, a biomarker linked to cognitive decline and Alzheimer's risk. Earlier research found that people with the highest p-tau217 levels had roughly a 78% chance of developing cognitive impairment within 10 years, and that such blood tests can detect Alzheimer's with up to 95% accuracy.

In this phase III trial, participants with elevated p-tau217 levels who meet other criteria will be given Trontinemab, a drug developed by Swiss pharmaceutical company Roche that targets amyloid plaques — a toxic protein that builds up in the brain, damaging and eventually killing brain cells. Early research found the drug cleared amyloid plaques within 28 weeks in nine out of ten people with early-stage Alzheimer's or mild cognitive impairment.

Shifting focus from treatment to prevention

Prof Ramin Nilforooshan, the trial's chief investigator, said research has focused for decades on treating Alzheimer's after symptoms appear, while PrevenTRON explores whether acting earlier could help. He cautioned that the drug remains experimental and its effectiveness is not yet proven.

Participants will be randomly assigned to receive either Trontinemab or a placebo and monitored to see how quickly, if at all, dementia signs develop. The trial is expected to run for four to six years, with at least 15 UK hospitals and clinics set to join by the end of the year.

Alzheimer's disease can develop in the brain up to a decade before people typically seek help for memory problems. It affects about one in 14 people over 65 and one in six over 80.