A new drug is making headlines worldwide for being the first ever drug to slow the progression of Alzheimer’s disease.
After an 18-month study of 1,800 patients, lecanemab slowed patients’ mental decline by 27%.
Although scientists are hailing a ‘new era’ in treatment, tensions over the NHS and the scale and complexity of the disease mean it could be a long time before patients and their families can really reap the benefits in the UK.
What is Alzheimer’s and how is it different from dementia?
Alzheimer’s disease is the most common form of dementia.
Dementia is the umbrella term for a group of conditions that cause the brain to decline and result in memory loss, confusion, and difficulty performing daily activities.
Other types of dementia include vascular dementia, mixed dementia, dementia with Lewy bodies, and frontotemporal dementia.
Alzheimer’s causes proteins to build up in the brain and form abnormal structures sometimes called “plaques” or “tangles,” which kill nerve cells and brain tissue.
It also makes it more difficult for chemical signals to be sent between brain cells.
All forms of dementia are gradual and get worse over time.
The trajectory of the disease is different for each patient, and some will decline more rapidly than others.
It is generally divided into three stages: early or mild, moderate or medium, and severe or advanced.
Symptoms of Alzheimer’s disease include:
- Memory loss
- Reduced mental acuity
- Trouble remembering words or difficulty speaking
- Problems with movement, including eating, drinking and walking
- Changes in behavior or personality
- Low mood
Alzheimer’s limits life in two ways.
Studies have shown that it may be closely linked to other physical health conditions such as cardiovascular disease and diabetes.
But in the later stages of dementia a person’s immune system is weakened and they are likely unable to swallow or go to the toilet independently.
This increases the risk of infection and other conditions that can result in death.
Life expectancy depends on when a person is diagnosed, but is around 8-10 years, which is longer than for other forms of dementia.
How common is it?
More than 850,000 people in the UK have dementia, but it is expected to surpass one million by 2025 as more people live longer.
Most of them – 520,000 – have Alzheimer’s.
One in 14 people over the age of 65 suffers from dementia, increasing to one in six people over 80.
According to the latest Dementia UK report from 2014, it costs the UK £26.3 billion a year, more than cancer, heart disease and stroke.
Although the NHS pays £4.3bn for it – the social care sector pays more – £10.3bn.
This is because most dementia is managed in the community and nursing homes, not hospitals.
Hospitals are often only involved in diagnosing the condition and treating inpatients with other related medical problems.
Two-thirds of the £26bn total annual cost is paid by patients, their families and carers.
According to Paul Edwards, director of clinical services at Dementia UK: “The NHS is already struggling to provide care for the growing number of people with dementia, partly due to a lack of post-diagnostic and community support.”
His charity is calling on the government to honor a pledge it made in May to produce a 10-year dementia strategy.
Are the treatments available now?
Unlike other types of dementia, people with mild to moderate Alzheimer’s are offered medication.
People in the early to moderate stage of the condition can take donepezil, rivastigmine or galantamine, all of which work by boosting chemical messengers in the brain.
They can also help reduce anxiety, which is often experienced by dementia patients when their cognition wanes.
Those with moderate or severe Alzheimer’s may be offered a drug called memantine, which also boosts chemical messengers but can also reduce behavioral changes and challenging delusions.
There is no cure for dementia, so all currently available drug treatments will only work for a limited time and will not slow the progression of the disease, just the symptoms.
Why is lecanemab different?
As Dr Susan Kohlaas, director of research at Alzheimer’s Research UK explains: ‘This is the first time that a drug has been shown to reduce disease in the brain and slow memory decline in clinical trials.
“Although the benefits were small and carried significant side effects, it marks the arrival of a treatment that can slow the progression of Alzheimer’s disease.”
So while current treatments only reduce symptoms, lecanemab can reduce amyloid proteins in patients’ brains, which kill nerve cells and tissue.
In practical terms, the study suggests that over the course of 18 months, the drug delayed the worsening of the disease in the patients by five months.
This could be developed by other pharmaceutical companies and trials to give patients, their caregivers and loved ones more time with a better quality of life and fewer symptoms.
Will it be available on the NHS?
There are major barriers to the availability of lecanemab on the NHS.
That’s because it only works for people in the early stages of Alzheimer’s, and current pressures on the health service mean that one in six people wait more than a year to see a specialist after being referred by their GP.
By then, it would have been too late for most patients to benefit.
And because the drug works by reducing amyloid proteins, they need to be detectable on a brain scan before it can be prescribed.
According to the Alzheimer’s Society, one in 10 people wait more than six months for a brain scan, again narrowing the window in which lecanemab can be used.
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The brain scans used by the NHS to help diagnose dementia are often also MRI or CAT scans.
They just eliminate other possible conditions like tumors — or show brain shrinkage and blood vessel changes — not protein buildup.
A small percentage of patients are then referred for PET scans, which show amyloid proteins, but they aren’t widely available.
Third, many dementia patients are diagnosed with “unspecified dementia”: 6.6% of over-65s and 17.2% of under-65s in 2021.
This means that lecanemab cannot be offered because it only works for Alzheimer’s specifically.
What needs to be done?
Charities and dementia research bodies say it is vital to increase NHS access to PET scans and blood tests which can also help with Alzheimer’s diagnoses.
Dr Richard Oakley, associate director of research at the Alzheimer’s Society, says: ‘This highlights more than ever the need to prioritize early diagnosis, through wider access to PET brain scans and research to obtain blood tests in the clinic, so people can access these drugs when they become available.”
Her colleague Fiona Carragher, director of research and influence, also emphasizes the importance of early diagnosis in general.
“We could easily see a situation where people sit on waiting lists for so long that their disease progresses too far to receive what could have been a life-changing drug,” he says.
“We urgently need to focus on better ways to diagnose people quickly and accurately while they’re in the early stages.”