Existing drugs identified by University of Cambridge and Exeter researchers that could aid fight against dementia
Several drugs already licensed and in use have the potential to be repurposed to treat dementia, a new study that looked at health data from 130 million individuals suggests.
The research found that antibiotics, antivirals, vaccinations and anti-inflammatory medication are associated with a reduced risk of dementia.
Now the leading cause of death in the UK and estimated to have a global economic cost of $1trillion, it has been the focus of intensive efforts from researchers.
But progress in finding drugs that slow or prevent dementia has been very limited to date, with many of those identified only having a modest effect on symptoms.
There was better news when lecanemab and donanemab were shown recently to reduce the build-up in the brain of amyloid plaques that are a key characteristic of Alzheimer’s disease, and to slow down progression of the disease.
However, the National Institute for Health and Care Excellence (NICE) concluded the benefits were insufficient to justify approving their use within the NHS.
Efforts to find existing, approved drugs that could be repurposed to treat dementia are growing, because if their safety profile is already known, clinical trials can happen much more quickly.
Dr Ben Underwood, from the Department of Psychiatry at the University of Cambridge and Cambridgeshire and Peterborough NHS Foundation Trust, said: “We urgently need new treatments to slow the progress of dementia, if not to prevent it. If we can find drugs that are already licensed for other conditions, then we can get them into trials and – crucially – may be able to make them available to patients much, much faster than we could do for an entirely new drug. The fact they are already available is likely to reduce cost and therefore make them more likely to be approved for use in the NHS.”
Dr Underwood and Dr Ilianna Lourida from the University of Exeter have now led a systematic review of existing scientific literature in search of evidence of prescription drugs that altered the risk of dementia.
Such reviews effectively pool studies where evidence may be weak, or even contradictory, to deliver more robust conclusions.
The team examined 14 studies that used large clinical datasets and medical records, meaning data from more than 130 million individuals and one million dementia cases was captured.
There was inconsistency between the studies in identifying particular drugs that affect the risk of dementia, but they did identify several drug classes associated with altered risk.
In particular, one unexpected finding was the association between antibiotics, antivirals and vaccines and a reduced risk of dementia.
This supports the hypothesis that common dementias may be triggered by viral or bacterial infections,
And it supports recent interest in the idea that some vaccines – such as the BCG vaccine for tuberculosis – may be associated with a decreased risk of dementia.
The researchers also found anti-inflammatory drugs such as ibuprofen were associated with reduced risk.
Inflammation is increasingly believed to be a major contributor to many diseases and some genes that increase the risk of dementia are part of inflammatory pathways.
But there was also conflicting evidence for several classes of drugs.
Some blood pressure medications and anti-depressants and, to a lesser extent, diabetes medication were associated with a decreased risk of dementia, while others were associated with increased risk.
Dr Ilianna Lourida, from the National Institute for Health and Care Research Applied Research Collaboration South West Peninsula (PenARC) at the University of Exeter, said: “Because a particular drug is associated with an altered risk of dementia, it doesn’t necessarily mean that it causes or indeed helps in dementia. We know that diabetes increases your risk of dementia, for example, so anyone on medication to manage their glucose levels would naturally also be at a higher risk of dementia – but that doesn’t mean the drug increases your risk.
“It’s important to remember that all drugs have benefits and risks. You should never change your medicine without discussing this first with your doctor, and you should speak to them if you have any concerns.”
The conflicts could also reflect the different ways studies were carried out and data collected, and the fact that different medications within the same class often target different biological mechanisms.
The government is supporting the development of an Alzheimer’s trial platform that can evaluate drugs – including ones in use for other conditions – rapidly and efficiently.
Dr Underwood said: “Pooling these massive health data sets provides one source of evidence which we can use to help us focus on which drugs we should try first. We’re hopeful this will mean we can find some much-needed new treatments for dementia and speed up the process of getting them to patients.”
The study was published on Tuesday (21 January) in Alzheimer’s and Dementia: Translational Research & Clinical Interventions.