People in Britain could benefit from a key medical breakthrough next year. They may be given access to 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 soon, and next year it is anticipated that the UK medical authorities will consider both of them for approval in Britain.
The prospect has raised hopes that, after years of effort, scientists may be closing in on ways to directly tackle the UK’s dementia crisis. About a million people are living with the condition in this country, and this is expected to rise to about 1.7 million by 2040 – with potentially grim consequences. Last year dementia took the lives of 66,000 people in England and Wales, and it is now the leading cause of death in Britain, with Alzheimer’s accounting for two-thirds of cases.
Until now doctors have only been able to prescribe medicines that help patients manage their symptoms, so the arrival of the first drugs that treat the actual cause of the condition has been welcomed – although experts have warned that their use should be treated with some caution.
“The new drugs slow down the development of Alzheimer’s by six months to a year and are useful only for those in the early stages of the condition, so they are certainly not miracle medicines,” said David Thomas, head of policy at Alzheimer’s Research UK.
“However, after decades of research, they are the first to improve patients’ lives directly, and that is a justifiable cause for excitement. If nothing else, they suggest we are probably on the right road to tackling Alzheimer’s.”
This point was backed by neurologist Cath Mummery, of the Dementia Research Centre at University College London. “It has been a very long, hard road, but finally we have something positive to look at. That is very welcome.”
Alzheimer’s disease is triggered by the buildup of a protein called amyloid in the brain, although symptoms may not appear for decades after this accretion has started. Scientists have tried for more than 20 years to find ways to stop amyloid from forming these plaques, in the hope this would stop the progression of the disease.
Lecanemab, which is produced by Japanese pharmaceutical company Eisai, and donanemab, produced by Eli Lilly of the US, are the first medicines to achieve this aim – though they only slow but do not ultimately halt the disease’s progression.
Both drugs are to be considered for approval in the UK next year. The Medicines & Healthcare products Regulatory Agency (MHRA) will first decide if they are safe and effective, then the National Institute for Health and Care Excellence (Nice) will rule on whether they offer value for money.
Both medicines are expensive – lecanemab costs about $25,000 (£19,700) a year – and are given by regular intravenous infusions. “That is a challenge from a health-service point of view, because you need 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 involved in pinpointing dementia not just in its early stages but even in its later phases. 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, diagnosing 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 spotted 17 years ago, when Eleanor was 11. “However, it took over 10 years from the start of his symptoms and four separate tests between 2009 and 2017 to get my dad’s final diagnosis, when he was 65. It was distressing not knowing what was happening. Too many families, like mine, have had to watch as dementia takes hold of our loved ones while we are left without a diagnosis and the support and access to treatments.”
Another grim illustration of the problem facing patients is provided by Graeme Armstrong. His wife, Trina, began having trouble recognising faces and reading telephone numbers in 2006 and was told, after a CT scan three years later, that she had probably had 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.
“Had we had an accurate diagnosis four years earlier, Trina could have been placed on the correct medication, which may have been more effective and helped her day to day,” Armstrong said.
One solution sought by doctors involves the creation of blood tests which could pinpoint the disease quickly and effectively. “These are under research, but we are several years away from having them in widespread use,” said Thomas. “Meanwhile, we have got to get the NHS to a state where it is much more focused and better organised in getting better and earlier dementia diagnoses. That will be crucial in our battle against the condition.”
Mummery agreed: “By the time you have dementia, you will have had Alzheimer’s disease developing 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 be thinking about how to diagnose people at the very earliest stages of disease, when they may only have very, very subtle symptoms.
“Our current service isn’t good for doing that, and we need to develop brain health clinics where we can pinpoint the disease much earlier, then help to build resilience against dementia in a patient when it is only in a very early stage.”
In the long term, scientists also point to a number of recent developments which 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 to pass through the blood-brain barrier, which controls the movement of ions and molecules from our bodies to our brains. That 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 for getting drugs across the blood-brain barrier,” said Mummery. “For example, we are now exploring ways of helping drugs get into the brain much more efficiently, and that could have a major impact.”
Such developments will take years to realise, scientists caution, and a great deal needs to be done in the short term to deal with dementia.
“It is clear we have taken a step in the right direction but there is much more to do before we can have successfully dealt with these processes that are happening to our brains,” said Thomas. “It is a challenge, and a very important one.”
