Blood tests to help diagnose Alzheimer’s at an early stage could be rolled out across the NHS within five years, overcoming a major stumbling block to the success of a breakthrough new drug.
On Tuesday i reported that the NHS was not ready for the donanemab drug – this week found to slow “clinical decline” in Alzheimer’s patients by up to 35 per cent – meaning it could only achieve a fraction of its potential in the early years, due to significant shortages of the staff and equipment needed to diagnose patients.
But thanks to promising blood tests, experts hope patients will be able to take full advantage of the new generation of “game-changing” drugs by diagnosing them earlier when the treatments will be at their most effective.
Pilots of the most promising blood tests could begin in the NHS in less than five years, before being rolled out more widely within the health service by 2028, Alzheimer’s Research UK said.
While these tests would not give a final diagnosis, they would identify people with high levels of amyloid, a protein that builds up in the brain and plays a central role in the development of the disease.
These people could then be prioritised for a Positron emission tomography (PET) scan to confirm they have the disease so they can start being treated with one of two new drugs that could be available on the NHS within 18 months.
There are currently no Alzheimer’s blood tests approved for use in the UK.
There is a huge shortage of PET scanners, which are found at just 70 NHS and university clinics in the UK, as well as the staff needed to operate them.
This means just 2 per cent of those who could benefit from the new drugs are likely to do so if, as expected, the new drugs – donanemab and lecanemab, which clear amyloid plaques – are approved by UK regulators.
But with the new blood tests, thousands more people with high levels of amyloid could be diagnosed much earlier and benefit from the drugs, experts say.
Hilary Evans, chief executive at Alzheimer’s Research UK, told i she is hopeful that at least one blood test could be rolled out to the NHS within five years.
“Donanemab is just the first treatment but in the next few years we’d hope to see many more treatments starting to come through that will help target some of the other underlying causes of dementia. So the blood tests would be the real game changer here,” she said.
“We need provision of scanners in the short terms to be able to deliver first wave of patients to access treatments as they come through.
“But longer term, our hope would be that in in the next five years, we’ll see blood tests rolled out across the NHS. We’re looking at what biomarkers [tests] are starting to come through and which of those would be most viable on the NHS.
“This would allow access to treatments as they come through and we see which patients are going to benefit most from these treatments – while we could diagnose much faster,” Ms Evans said.
Richard Oakley, associate director of research and innovation at Alzheimer’s Society, added: “We know blood tests can diagnose Alzheimer’s disease in the lab – now we need to get them tested in a UK clinical setting with the hope of rolling blood tests out within the next four to five years.”
The new tests could mean a much higher proportion of the 720,000 people in the UK that could potentially benefit will do so. The tests can also be used to help monitor the progression of the disease and the effects of any drugs.
Alzheimer’s Research UK and Alzheimer’s Society are in the early stages of a major project to identify the most promising blood tests that are being tested and developed and is currently recruiting scientists for a £4.5m trial to assesses several of the most promising “in real-world populations in the UK”.
This is funded by the People’s Postcode Lottery and is the biggest single gift it has made.
Ms Evans said that, as things stand, the way people are diagnosed with dementia in the UK is “simply not good enough”.
Far too often, they are left anxiously waiting for a diagnosis – up to two years on average, and more than four years if they are under 65. And that’s if people even go to their doctor about their symptoms, with one in three people with dementia never receiving a diagnosis, she said.
Ms Evans is co-chair of the government’s Dame Barbara Windsor dementia mission to tackle the disease, which involves conversations with the NHS, regulators and Nice – the National Institute for Health and Care Excellence, which is responsible for approving new methods of diagnosis.
She said: “You need to align the rate of progress in diagnosis and treatment. When you combine mass scale blood tests with effective new treatments you can halt the progression of the disease and also ease the wider burden on the NHS and social care system massively.”
The Alzheimer’s Society is also involved in the search for the most suitable blood tests to help diagnose the disease.
Meanwhile, Ivan Koychev, a consultant neuropsychiatrist at Oxford University Hospitals NHS Foundation and senior adviser to Dementias Platform UK, a Medical Research Council project to speed up detection of the disease, is hopeful the blood tests could become available even sooner.
“I expect the blood tests to become available within three years. The field is rapidly moving towards recognising blood tests as potentially equivalent to PET or lumbar punctures,” he said.
Dr Koychev and Ms Evans both point to a series of blood tests designed to spot “p-tau217” a protein marker associated with Alzheimer’s as being a particularly promising indicator of the disease.
Several drug companies are developing tests with this marker, including Eli Lilly, which developed donanemab. Some of these are more accurate than others and none have yet been clinically validated for use in the UK.
Dr Koychev also sees blood tests looking at levels of a protein called neurofilament light chain (NfL) and at glial fibrillary acidic protein (GFAP), another protein, as promising.
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