People in Britain could benefit from a major medical breakthrough next year. They can access the first drugs ever developed to slow the impact of Alzheimer’s disease.
The first of these medicines – lecanemab – was recently approved in the US and Japan, where treatments using it have already been launched. A second drug, donanemab, is expected to follow shortly, and next year British medical authorities are expected to consider both for approval in Britain.
The prospect has raised hopes that, after years of effort, scientists may be approaching ways to directly tackle the UK’s dementia crisis. Around a million people are living with the condition in this country, and this is expected to rise to around 1.7 million by 2040 – with potentially grim consequences. Last year, dementia claimed the lives of 66,000 people in England and Wales, and it is now the leading cause of death in Britain, with Alzheimer’s responsible for two-thirds of cases.
Until now, doctors have only been able to prescribe drugs that help patients manage their symptoms, so the arrival of the first drugs that treat the real cause of the condition has been welcomed – although experts have warned that they should be used with some caution should be treated.
“The new drugs slow the development of Alzheimer’s disease by six months to a year and are only useful for those in the early stages of the condition, so they are certainly not panaceas,” said David Thomas, head of policy at Alzheimer’s Research UK.
“However, after decades of research, they are the first to directly improve patients’ lives, and that is just cause for excitement. If nothing else, they suggest that we are probably on the right track to tackling Alzheimer’s.”
This point was backed up by neurologist Cath Mummery, of the Dementia Research Center at University College London. “It’s been a very long, difficult road, but finally we have something positive to look at. It is very welcome.”
Alzheimer’s disease is caused by the build-up of a protein called amyloid in the brain, although symptoms may not appear for decades after this build-up begins. For more than 20 years, scientists have been trying to find ways to stop amyloid from forming these plaques, in the hope that this will stop the progression of the disease.
Lecanemab, produced by the Japanese pharmaceutical company Eisai, and donanemab, produced by Eli Lilly of the USA, are the first medicines to achieve this goal – although they only slow down the disease’s progress but do not ultimately stop it.
Both drugs will be considered for approval in the UK next year. The Medicines and Healthcare Products Regulatory Agency (MHRA) will first decide whether it is safe and effective, then the National Institute for Health and Care Excellence (Nice) will determine whether they offer value for money.
Both drugs are expensive – lecanemab costs around $25,000 (£19,700) a year – and are given by regular intravenous infusions. “It’s a challenge from a health service point of view because you have to find the space and time to put someone in an infusion suite to treat them,” added Thomas.
However, the main problem facing doctors is the difficulty in diagnosing dementia, not only in its early stages, but even in its later stages. Most cases are first presented to GPs, who will then refer patients to memory clinics for a dementia test. However, there are long waiting times – up to two years on average – for appointments at these centres.
In addition, the diagnosis of Alzheimer’s and other forms of dementia is usually based on pen-and-paper tests, followed by lumbar punctures and brain scans before a final diagnosis.
About 65% of cases are confirmed this way. The remaining third of dementia cases are never diagnosed. Yet patients can only expect to receive treatments – including the new drugs – if their condition is identified.
Eleanor Mackenzie-Smith’s father, Mike, has young-onset Alzheimer’s. His first symptoms were noticed 17 years ago, when Eleanor was 11. “However, it took more than 10 years from the onset of his symptoms and four separate tests between 2009 and 2017 to get my father’s final diagnosis, when he was 65. unsettling not knowing what is going on. Too many families, like mine, have had to watch dementia take hold of our loved ones while we are left without a diagnosis and the support and access to treatments.”
Another stark illustration of the problem facing patients is provided by Graeme Armstrong. His wife, Trina, began having trouble recognizing faces and reading phone numbers in 2006 and was told after a CT scan three years later that she had probably suffered a stroke – although her symptoms did not suggest such a diagnosis . It took another three years before she was diagnosed with posterior cortical atrophy, a rare variant of Alzheimer’s disease that affects the way the brain interprets information from the eyes.
“If we had an accurate diagnosis four years earlier, Trina could have been put on the right medication, which may have been more effective and helped her on a daily basis,” Armstrong said.
One solution that doctors are looking for involves the creation of blood tests that can quickly and efficiently diagnose the disease. “It’s under research, but we’re a few years away from having it widely available,” Thomas said. “In the meantime, we have to the NHS to a state where it is much more focused and better organized to get better and earlier dementia diagnoses. This will be decisive in our fight against the condition.”
Mummery agreed: “By the time you have dementia, you will have developed Alzheimer’s disease in your brain for at least 20 years. Dementia is the latest stage; we need to pick up signals much earlier. So we need to think about how to diagnose people in the very earliest stages of disease, when they may only have very, very subtle symptoms.
“Our current service is not good at doing that, and we need to develop brain health clinics where we can identify the disease much earlier, and then help build resilience against dementia in a patient when it’s only at a very early stage .”
In the long term, scientists also point to a number of recent developments that have raised hopes that it may be possible to tackle dementia more directly and effectively. One major challenge they have faced is the problem of getting drugs through the blood-brain barrier, which controls the movement of ions and molecules from our bodies to our brains. This makes it difficult to get drugs into the central nervous system to tackle problems such as amyloid plaques.
“However, researchers are developing active transport methods to get drugs across the blood-brain barrier,” Mummery said. “For example, we’re now investigating ways to help drugs get into the brain much more efficiently, and that could have a big impact.”
Such developments will take years to realize, scientists warn, and much needs to be done in the short term to deal with dementia.
“It’s clear that we’ve taken a step in the right direction, but there’s a lot more to do before we can successfully deal with these processes that happen to our brain,” Thomas said. “It is a challenge, and a very important one.”
