Tests could lead to new treatments, which rely on early detection says Tom Whipple, Science Editor.
The country’s two leading dementia charities are funding a £5 million study to bring already-developed blood tests “the final mile” into clinical use. Dr Fiona Carragher, from the Alzheimer’s Society, said that this would tackle the heartbreaking struggles faced by families in getting a diagnosis, and help to prepare the way for new treatments, which rely on early detection.
Most people are diagnosed with Alzheimer’s after experiencing memory difficulties and going to their GP. They are then referred to a memory clinic where cognitive tests are performed. For almost all of those who do receive a diagnosis, it will come through a patchwork of different assessments. Currently the only specialist tests are spinal lumbar punctures or PET scans, but they are expensive and difficult to implement. The UK has just one PET scanner for every two million people.
Carragher said many cases were missed. Dementia affects 900,000 people in the UK but an estimated 250,000 go undiagnosed. “We hear stories day in day out of people waiting two, three, four years plus to get their diagnosis. That is heartbreaking for the individuals and families, not knowing what’s going on,” she added.
There is an extra urgency because in the past two years drugs have passed clinical trials that for the first time can slow the progression of Alzheimer’s, provided it is caught early enough.
Dr Susan Kohlhaas, from Alzheimer’s Research UK, said: “We need to get this right and we need to get this right as quickly as possible.”
The drugs, which slow progression by around a third, are being assessed by the National Institute for Health and Care Excellence. If they are approved, the challenge will then be using them. “We expect that when those treatments become available there will be a surge in people coming forward for diagnosis. We know we don’t have the adequate infrastructure to cope with that demand,” Kohlhaas said.
Blood tests could reveal the toxic proteins that indicate Alzheimer’s
This is one reason why developing simple blood tests that can spot the toxic proteins that are a hallmark of Alzheimer’s has been a key goal of scientists. Another is that drug research itself would become far easier if there were quick ways to judge whether a treatment was working.
At least 20 such tests from companies such as Roche and Lilly are now in a late stage of development and showing success in trials, able to tease out the subtle signals that indicate something might be wrong.
The goal of the study, backed by the Alzheimer’s Society and Alzheimer’s Research UK, is to translate that research success into clinical practice on the NHS. The charities have not said yet which tests they would use, but it is possible they would assess a suite together to find the best combination.
Initially, researchers expect that tests would be used in existing memory clinics, in conjunction with other measures such as cognitive tests. Dr Joanne Rodda, consultant psychiatrist at Kent and Medway NHS and Social Care Partnership Trust, said that her expectation was for the tests to be used in her practice within five years.
Charles Marshall, professor of clinical neurology at Queen Mary University of London, welcomed the trials. “We desperately need better ways to diagnose the diseases that cause dementia that can be used throughout the NHS,” he said.
Behind the story - Diagnosis is difficult but necessary
Why is it so hard to get diagnosed with Alzheimer’s? There has been an easy reply to this question (Tom Whipple writes). Why have a diagnosis for a disease you can’t do anything about?
Actually, as dementia charities are keen to stress, that response is glib. Most people want a diagnosis. They want to prepare, to access help and understand what is happening to them. Today, even that simplistic answer doesn’t work. In the past two years, for the first time, drugs have passed clinical trials that can change the course of Alzheimer’s. Their effect is only moderate but it is hoped better drugs are on the way.
Obviously, to use them you have to know you have Alzheimer’s — and know early. This is where blood tests come in. The tests will not do anything we can’t already do. We already have ways to detect Alzheimer’s using clinical biomarkers. We just don’t use them very much because, for instance, a PET scanner is hard to get booked on to, and very expensive.
The development of blood tests is a reminder that while science can be about swishy technology and exciting biochemistry, public health is often more mundane. It is about logistics and costs. As the UK’s approval body, Nice, considers whether to recommend expensive Alzheimer’s drugs on the NHS, this is one of their considerations. It is a harder to approve a drug if the only way to find the patients who would benefit involves building a national PET scanner screening programme.
We are a long way from a statin for Alzheimer’s. But if we do get there, it begins with a blood test.
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Blood tests for Alzheimer’s could be available on the NHS within five years, leading to faster, wider diagnoses and earlier treatment.
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