Roche launches prevention trial for Alzheimer's antibody in race with Lilly

Roche (RHHBY) has unveiled plans for a pivotal trial of its experimental Alzheimer's antibody, seeking to demonstrate it can prevent symptoms from developing as the Swiss drugmaker races Eli Lilly (LLY) and Japan's Eisai (ESAIY) to push the disease's treatment frontier from therapy into prevention.

The study, called PrevenTRON, will enroll 1,600 people who show biological signs of Alzheimer's disease but have not yet experienced any cognitive impairment. It will deploy trontinemab, Roche's experimental antibody built on its proprietary Brainshuttle technology, which is designed to deliver higher and more consistent concentrations of the drug across the blood-brain barrier for faster clearance of the amyloid plaques that accumulate years before symptoms appear.

Roche disclosed the trial's key design elements at the Alzheimer's Association International Conference in London on Tuesday, saying enrollment would begin later this year. Rather than running for a fixed duration, the event-driven study will continue until enough participants develop measurable cognitive impairment — a design that will allow the company to determine whether trontinemab meaningfully delays the progression from the disease's silent early phase to its first clinical manifestations.

To identify eligible participants, Roche will use blood tests measuring elevated levels of plasma pTau217, a biomarker that can flag cognitively normal individuals at heightened risk of developing Alzheimer's symptoms within several years. Researchers said the approach could make large-scale prevention trials significantly more practical and less costly than studies relying on brain imaging.

"We are entering a new stage in the field," said Azad Bonni, Roche's head of neuroscience and rare diseases, adding that the company hopes its medicines will help patients avoid ever becoming symptomatic.

Roche is not alone in pursuing that ambition. Lilly has been running a prevention study of its approved Alzheimer's drug Kisunla for roughly four years, which could become the first large prevention trial using an approved anti-amyloid therapy to report results. Like Roche, Lilly is relying on blood-based screening to identify those at highest risk before symptoms emerge.

"We absolutely can see a future where patients are identified through blood tests years before symptoms emerge and we can intervene," said Carole Ho, president of Lilly Neuroscience.

Outside researchers echoed that optimism. Jessica Langbaum, senior director of Alzheimer's prevention and research at Banner Alzheimer's Institute, said anti-amyloid drugs appear to be more effective the earlier they are administered, making prevention studies the logical next step. Laura Nisenbaum, interim chief science officer at the Alzheimer's Drug Discovery Foundation, said Roche's Brainshuttle platform could further strengthen that approach by maximizing drug delivery to the brain.