For years, Alzheimer’s research has focused mainly on removing amyloid, a protein that builds up in the brain long before memory problems begin.
While this approach has produced the first medicines that can modestly slow the disease, scientists have continued searching for treatments that work in different ways.
Many believe this will be necessary because Alzheimer’s is a complex disease involving several harmful processes rather than a single cause.
A new experimental medicine called diranersen is giving researchers fresh hope. Instead of targeting amyloid, it focuses on tau, another protein that plays a major role in Alzheimer’s disease.
Healthy tau helps nerve cells function normally, but in Alzheimer’s it changes shape, forms tangled clumps inside brain cells, and is closely linked with worsening memory and thinking problems.
The latest findings were presented at the Alzheimer’s Association International Conference in London. Researchers reported results from a study involving around 400 people with very early Alzheimer’s disease or mild cognitive impairment caused by Alzheimer’s.
Participants were randomly assigned to receive diranersen or a placebo. The medicine was delivered by injection into the fluid surrounding the spinal cord, allowing it to reach the brain directly. Unlike current treatments that remove abnormal proteins already present, diranersen reduces the amount of tau that brain cells produce in the first place. Scientists hope this approach prevents harmful tau from building up over time.
The study produced mixed but encouraging results. The trial missed its planned primary goal because researchers expected higher doses to work better, yet the strongest results unexpectedly came from the lowest dose, given every six months. Even so, patients receiving the treatment generally showed slower decline on most memory and thinking tests than those receiving placebo. One important cognitive measure suggested a 26 percent slowing of decline, similar to benefits reported with currently approved anti-amyloid medicines.
Researchers also reported relatively manageable side effects. Some participants experienced temporary confusion for several days after treatment and discomfort where the injection was given. Importantly, there was no evidence of the brain swelling that has become a concern with some existing Alzheimer’s medicines.
The encouraging results have renewed interest in tau research after many previous attempts to develop tau-targeting drugs failed. Several other experimental approaches are now moving forward.
Scientists are testing a vaccine designed to stimulate the immune system against abnormal tau, while other researchers are developing technologies that help medicines cross the brain’s protective barrier more effectively. Some investigators are even studying whether cholesterol-lowering medicines could reduce Alzheimer’s risk in people carrying the APOE4 gene, a major inherited risk factor.
Despite the optimism, experts caution that it is still too early to know whether diranersen will become an approved treatment. Larger studies involving many more patients will be needed to confirm that the drug consistently slows disease progression and remains safe over longer periods.
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