A new experimental Alzheimer’s drug has shown encouraging signs of slowing cognitive decline in people with early-stage disease, raising hopes for a different approach to treating the world’s leading cause of dementia.
The drug, known as diranersen, works by reducing the production of tau, a protein closely linked to brain damage and cognitive decline in Alzheimer’s disease.
Results from a Phase 2 clinical trial were presented at the Alzheimer’s Association International Conference 2026 in London.
Diranersen Targets Tau Protein in the Brain
Most recent Alzheimer’s treatments have focused on removing amyloid plaques from the brain.
Diranersen takes a different approach by targeting genetic instructions involved in the production of tau protein.
Abnormal tau can form harmful tangles in the brain and is strongly associated with the progression of Alzheimer’s disease.
Researchers hope that reducing tau production could slow the damage caused by the illness.
Study Involves More Than 400 Alzheimer’s Patients
The global CELIA study involved 416 people living with early Alzheimer’s disease.
Participants received different doses of diranersen or a placebo during the 18-month trial.
Researchers reported reductions in tau biomarkers and signs of slower cognitive decline among patients who received the experimental treatment.
The strongest results were seen with the 60 mg dose.
Drug Slows Cognitive Decline by 26% on Key Measure
According to the trial results, the 60 mg dose slowed decline by 26 per cent on a key clinical measure known as CDR-SB.
Researchers also reported stronger results on some other cognitive tests.
However, patients still experienced cognitive decline. The drug did not reverse Alzheimer’s disease or restore lost memory.
The findings instead suggest that diranersen may help slow the progression of early Alzheimer’s in some patients.
Researchers Urge Caution Over Early Results
Despite the encouraging findings, health experts have stressed that the research remains at an early stage.
The trial produced an unexpected dose pattern, as higher doses did not provide greater benefits than the lower 60 mg dose.
This raised questions that researchers will need to investigate in a larger study.
Experts say the results must be confirmed before the treatment can be considered for widespread use.
Side Effects Reported During Trial
Some patients experienced pain around the injection area.
Researchers also reported temporary confusion in some participants several days after treatment.
The confusion could last about one week.
However, researchers did not observe signs of the brain inflammation sometimes associated with certain amyloid-targeting Alzheimer’s treatments.
Biogen Plans Phase 3 Clinical Trial
Biogen, the company developing diranersen, plans to advance the drug into Phase 3 testing.
A larger clinical trial will be needed to confirm whether the treatment can safely and consistently slow Alzheimer’s progression.
Phase 3 results could play an important role in determining whether the drug eventually receives regulatory approval.
New Hope for Alzheimer’s Research
Alzheimer’s disease affects millions of people worldwide and gradually damages memory, thinking and the ability to carry out everyday activities.
There is currently no cure for the disease.
The latest diranersen findings could encourage more research into treatments targeting tau protein.
Scientists are also studying whether future Alzheimer’s treatments could combine tau-targeting drugs with therapies that remove amyloid plaques.
For now, diranersen remains an experimental treatment and is not approved for general use.
The next phase of clinical testing will be crucial in determining whether the promising early results can lead to a new treatment option for people living with early Alzheimer’s disease.
