The search for a cure for Alzheimer’s disease is entering a new phase, with hundreds of clinical trials worldwide testing medicines, early-detection tools, lifestyle interventions and new approaches to dementia care.
The 2026 World Alzheimer Report says clinical trials are at the centre of efforts to understand the disease and determine which treatments can safely slow its progression or improve the lives of people living with Alzheimer’s.
More than 55 million people worldwide were living with dementia as of 2019, with the number projected to surpass 139 million by 2050 as populations age.
Alzheimer’s disease is the most common form of dementia.
Researchers are increasingly focusing on detecting the disease earlier, including before people develop noticeable memory and thinking problems. This could allow treatments to begin at a stage when there may be greater potential to slow or prevent further damage.
Clinical trials are critical to this process because they allow scientists to establish whether potential treatments are safe, whether they work, who is most likely to benefit and whether they make a meaningful difference in patients’ lives.
Even trials that fail to meet their main objectives can provide important scientific information and help researchers develop better treatments.
According to Professor Jeff Cummings of the University of Nevada, 158 potential therapies are currently being evaluated across 192 clinical trials worldwide, with eight Phase III trials expected to report results during 2026.
About three-quarters of the medicines in development are designed to modify the underlying disease process. Others aim to improve memory, thinking and daily functioning, while some target symptoms such as agitation and anxiety.
One of the biggest developments in recent years has been the approval of the disease-modifying treatments lecanemab and donanemab in several countries.
The drugs target amyloid, a protein associated with Alzheimer’s disease, and have provided evidence that directly targeting the disease process can slow clinical decline by about 30 percent.
Professor Cath Mummery, director of the UK’s Dementia Trials Network, described their development as a major milestone despite questions about the size of the benefit.
“Their arrival marked a huge moment, but it was also a bittersweet moment,” Mummery told Alzheimer’s Disease International.
“What you really hoped for was a bigger effect [on patients], but it was a huge moment because it showed you could change the course of the disease for the first time.”
She said the results represented an important foundation for future research.
“To those dissenting voices that say they don’t show significant change, they do. And they show consistent, significant change. So, for me, the breakthrough is that the amyloid hypothesis, which we’ve been chasing for decades, was confirmed at least in part, and that we’ve shown you can change things,” she said.
“That’s the foundation. It’s the first brick, and there’s an awful lot to build on.”
Researchers are now looking beyond amyloid and exploring several other biological pathways involved in Alzheimer’s disease.
Blood-based biomarkers are also emerging as potential tools for identifying people at risk much earlier. Research presented at the 2026 Alzheimer’s Association International Conference in London found that elevated levels of p-tau217 in cognitively healthy older adults were associated with a substantially increased risk of developing cognitive impairment over the following decade.
The findings raise the possibility that simple blood tests could eventually help identify people for prevention trials years before symptoms emerge.
The TRAILBLAZER-ALZ 3 study is among the trials examining whether treatment at the earliest biological stages of Alzheimer’s can alter the disease before symptoms develop.
Researchers are also testing existing medicines for possible new uses. More than a third of dementia drugs currently in development were originally developed for other conditions.
One example is atomoxetine, a treatment for attention deficit hyperactivity disorder, which has been tested in a Phase 2 trial involving people with mild cognitive impairment or early Alzheimer’s disease, with mixed results.
Another area attracting attention is combination treatment. Researchers are testing whether targeting different biological pathways simultaneously could provide greater benefits than using a single treatment.
A Phase 2 trial is investigating a combination of a tau vaccine and an anti-amyloid treatment, reflecting a growing belief that Alzheimer’s may eventually require multiple therapies working together.
Professor Cummings said the current treatments should be viewed as a beginning rather than a final solution.
“Anti-amyloid medicines such as lecanemab and donanemab have been a crucial breakthrough. They’ve shown that directly targeting the disease’s process can slow decline. But they are only the beginning of what people with Alzheimer’s will ultimately need,” he said.
The research pipeline also includes non-drug approaches such as cognitive rehabilitation, exercise programmes, psychosocial support, digital technologies and new models of care.
The growing research effort comes as the number of people at risk of dementia rises rapidly with global ageing.
United Nations projections show that the number of people aged 65 and above is expected to reach about 1.5 billion by 2050, while the population aged 80 and above — the group at highest risk of dementia — is expected to triple.
For scientists, the expanding clinical trial pipeline represents a shift in how Alzheimer’s disease is understood. Rather than being viewed solely as an inevitable consequence of ageing, it is increasingly being treated as a disease whose progression may be delayed or altered.
The first disease-modifying therapies have provided proof that the course of Alzheimer’s can be influenced. Researchers are now seeking to build on that breakthrough through earlier diagnosis, new medicines, combination therapies and prevention strategies.
With hundreds of trials underway, the next phase of Alzheimer’s research will determine whether these approaches can translate into treatments that are more effective, safer and accessible to the millions of people who may develop the disease in the coming decades.