Beyond lecanemab: unravelling the future of Alzheimer’s treatments

Updated July 2025

The latest Alzheimer’s treatments work by removing the build-up of a protein in the brain, called amyloid. But is this the only way we will treat the disease in the future?

Alzheimer’s is the most common disease that causes dementia, and one of its hallmarks is the build-up of a protein called amyloid in the brain. Recently, two treatments, lecanemab and donanemab, have made headlines. Both work by removing amyloid from the brain. In rigorous clinical trials, these treatments were shown to slow the rate at which people with early Alzheimer’s got worse – the first time any drug has been able to do this.

Despite being licensed for use in the UK, lecanemab isn’t yet available on the NHS, as its benefits are not thought to outweigh the associated costs, including monitoring for side effects.  Nevertheless, it’s a milestone – the first time a drug’s been licensed in the UK that can slow down Alzheimer’s disease, rather than just treating its symptoms.

At the time of writing, UK regulators are still looking at the data about donanemab and have yet to make a decision.

But these drugs are just the start. As with many first-generation treatments, they only have a modest effect. They only seem effective for early-stage Alzheimer’s. And their side effects can occasionally be serious. They’re a welcome development, but they’re not a cure for Alzheimer’s.

“Amyloid-removing therapies are a vital first step forward into the world of treatments that can slow down Alzheimer’s disease,” says Dr Emma Mead, Chief Scientific Officer at Alzheimer’s Research UK’s Oxford Drug Discovery Institute.

“But even as these advances take centre stage, research is revealing even more complexities around how Alzheimer’s disease starts and progresses, and this goes beyond amyloid.”

To truly find a cure for Alzheimer’s and other diseases that cause dementia, researchers like Dr Mead are working hard to uncover the next generation of therapies. It’s likely that, just as with diseases like cancer, truly effective treatment will involve a combination of therapies, each targeting different disease processes.

Let’s take a look at what future dementia treatments could look like.

Our journey towards a cure

“Are the current crop of treatments the full story for us at Alzheimer’s Research UK? Absolutely not”, says Dr Susan Kohlhaas, our Executive Director of Research and Partnerships. “We’re incredibly excited about the hard-won progress we’re making in research, but it’s important for people to realise that this first generation of treatments will not be the last.”

“We’re unapologetically working towards a cure, and the challenge and opportunity for the research community is to focus efforts on developing treatments that tackle different aspects of Alzheimer’s disease,” she says. “Finding treatments for the range of processes in the brain that go wrong in Alzheimer’s, and tackling those in combination is what we think will be a game-changer for people with Alzheimer’s disease. That’s what we need to see in the coming years.”

Despite the complexity of Alzheimer’s disease, we believe that there are three fundamental things that treatments will need to do, to slow, stop and reverse the disease:

• Remove proteins that build up in the brain (as lecanemab and donanemab do)
• Protect brain cells from the effects of diseases that cause dementia
• Restore damage that has been caused by disease

According to a recent analysis, there are now 138 experimental Alzheimer’s treatments being studied in clinical trials around the world. How do they fit into these categories?

Removing build-up of proteins

Around 3 in 10 drugs in clinical trials for Alzheimer’s specifically focus on clearing amyloid from the brain.

But reducing amyloid is just one piece of the complex dementia puzzle. There are lots of different proteins that build up in the brain, both in Alzheimer’s and in other diseases that cause dementia. These proteins include:

• Tau in Alzheimer’s disease and frontotemporal dementia
• TDP-43 in Motor Neurone Disease and frontotemporal dementia
• Alpha-synuclein in Parkinson’s disease and Lewy Body dementia

Scientists across the world have been working for decades to figure out how to reduce levels of these proteins, and others, in the brain.

In Alzheimer’s disease and frontotemporal dementia, tau clumps together into ‘tangles’ inside nerve cells, and these seem to spread around the brain as the disease progresses and damage accumulates. Just like amyloid, researchers are developing drugs to target and remove tau and – hopefully – stop the associated nerve cell damage.

“We’ve seen a couple of breakthroughs with drugs that remove amyloid, and following closely behind are drugs targeting tau”, says Dr Mead.

One that’s going through trials right now is called BIIB080, which switches off tau production inside nerve cells. Prof Catherine Mummery, a consultant neurologist at University College London Hospitals, is leading the early phase trials of this drug, and the first results were published in April 2023.

“We will need further research to understand the extent to which the drug can slow progression of physical symptoms of disease,” says Prof Mummery. “But the results are a step forward in demonstrating that we can successfully target tau to slow – or possibly even reverse – Alzheimer’s disease, and other diseases caused by tau build-up, in the future.”

Over the years, Alzheimer’s Research UK has funded a range of projects investigating tau and how it can spread in the brain, revealing further potential targets for drugs that might lower tau levels.

Protecting brain cells from damage

It’s likely, however, that removing proteins like amyloid and tau won’t be enough, on its own, to stop the advance of diseases like Alzheimer’s.

So we’ll also need drugs that target other mechanisms that help to protect the brain – and there are a range of ways that this could be achieved. Roughly a half of the treatments in Alzheimer’s trials right now are designed to protect brain cells from damage. And drugs that protect the brain will likely be important in other types of dementia too.

A focus on the immune system

Many of these drugs aim to protect nerve cells by influencing the immune system.

“The role of the immune system is becoming increasingly apparent, so it’s becoming a new focus for therapies and treatments.” says Dr Mead, who is leading a team at our Oxford Drug Discovery Institute who are developing drugs that protect the brain from the effects of an overactive immune response.

Normally, our immune system helps protect us from infections. But research suggests that in Alzheimer’s disease, the immune system becomes overactive. This contributes to damage to the brain that makes the disease worse.

Among the key players in this overactive response are immune cells called microglia. Alzheimer’s Research UK scientists at UCL were among the first to highlight microglia’s involvement in dementia in 2012. They discovered that changes in a microglia gene, TREM2, is linked to an increased risk of Alzheimer’s disease. This landmark discovery threw the spotlight on the role of the immune system in Alzheimer’s, leading to many new drugs in clinical trials today.

Aside from the immune system, there are many other processes within the brain that could – if precisely targeted with drugs – help protect against damage, and so help treat dementia. For example, research has shown that the way brain cells use energy is different in people with Alzheimer’s. There’s also evidence that the release of chemical messages in the brain called neurotransmitters can become overactive, leading to damage. These processes, and others that are linked to diseases like Alzheimer’s, could be potentially targeted with drugs to protect the brain.

Researchers funded by Alzheimer’s Research UK are working across these fields, and we’ll be looking at them more closely in future articles.

Restoring lost brain functions

Even if drugs exist to remove harmful proteins, and protect surviving brain cells from future damage, there’s still work to do. Diseases like Alzheimer’s take years to develop, and over these years, they cause substantial damage to brain systems and processes. So, for a cure, we’ll also need drugs that are designed to restore the brain back to health.

This is a particularly challenging area of research, and only around 1 in 10 drugs currently being tested in clinical trials fall in this category.

Restoring the brain to health is challenging because, by the time most people are diagnosed, the nerve cells in their brains will have already been significantly affected – either damaged or killed.

But could there be ways to restore the brain’s cells and systems back to health? Current ways researchers are looking into this are:

• Regrowing nerve cells.
• Regrowing vital supporting cells in the brain that nurture nerve cells back to health.
• Promoting nerve cells’ ability to adapt to handle changes to the brain.
• Reforming networks between nerve cells

“It would be amazing if one day we can actually reverse the damage caused by diseases that cause dementia”, Dr Mead says. “Although we are still in the very early stages of this complex area of research, we are hopeful this will one day become reality.”

Another, non-drug method that’s shown potential is deep-brain stimulation, although this is in the very earliest stages of research. Scientists in the US have shown that stimulating specific areas in the brains of mice with light pulses can help ease Alzheimer’s-like symptoms by helping new nerve cells form. There is, needless to say, a lot more work to be done to refine this technique, let alone use it in people with dementia.

Looking to the future

Alzheimer’s disease is a complex condition, but scientists are making great progress in finding new ways to treat it.

Anti-amyloid drugs are just the tip of the iceberg when it comes to dementia treatments, as they will not be enough to completely stop diseases like Alzheimer’s and other causes of dementia. But this has spurred on dementia research, and the momentum is growing, with each new finding bringing us closer to new treatments.

“The questions we’re asking now, about how to find ways of ensuring that cells are protected from changes in the brain as we age, and even thinking about how to restore lost function, are going to be incredibly important for developing next-generation treatments,” says Dr Kohlhaas. “It’s only by starting to understand the complex biology of Alzheimer’s and other dementias that we’ll really start to make gains.”

At Alzheimer’s Research UK, thanks to our incredible supporters, we’re leading the way  towards a cure. Our Drug Discovery Alliance (DDA) is fuelling the dementia drug discovery engine, bringing the worlds of academia and industry closer together so discoveries in the lab are rapidly transformed into new potential treatments.  To date, they have explored over 35 potential treatment avenues for dementia, collaborating with scientists across 13 countries. This effort is to find potential drugs that can remove proteins, protect nerve cells, and restore brain activity. Any one of these could become the next life-changing treatment, and every discovery made is helping to redefine the story of dementia.

And we’re also supporting discoveries that could open up even more profound shifts in understanding. By helping to found and now supporting the UK Dementia Research Institute (UKDRI), we are catalysing further research across seven centres in the UK. Right now, researchers across the UKDRI are developing new ways to identify treatments not just for Alzheimer’s, but for rarer causes of dementia like frontotemporal dementia (FTD), Motor Neuron Disease and Parkinson’s Disease.

Research initiatives like these are tackling the diseases that cause dementia from multiple avenues. They give us the best chance to make much-needed breakthroughs to build on the success of lecanemab and donanemab.

It’s only through research that we will be able to change the lives of people affected by dementia, and find our way to a cure.