New drugs being developed to tackle Alzheimer’s disease “will not address dementia risk at scale”, researchers have warned.
Academics said there is “a lot of hyperbole” around medications such as lecanemab and donanemab which are said to slow down early stages of Alzheimer’s.
They added that rollout of the drugs could “involve considerable resources” which “will be extremely challenging for even the best-funded healthcare systems”.
A number of treatments including lecanemab and donanemab are being assessed for approval in the UK by medicine regulators.
Writing in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, the team from Cambridge Public Health said evidence does not make it clear if amyloid immunotherapy “can ever significantly reduce population-level dementia morbidity at scale”.
They also claim results from those involved in trials may not generalise to more complex patients.
Lead author Dr Sebastian Walsh, National Institute for Health and Care Research doctoral fellow in public health medicine at Cambridge Public Health, said: “If approved, the drugs are likely to be relevant only for a relatively small cohort of Alzheimer’s patients, so potential recipients will need to undergo a range of assessments before being given access to the drugs.
“Plus, effect sizes seen in the trials are very small and the drugs will need be administered as early in the disease process as possible, when symptoms are mild – and people in these phases of disease can be hard to identify.”
“But there is a lot of hyperbole around the reporting of these drugs, and significant effort will be needed to provide balanced information to patients to enable informed decisions.”
The paper said the short-term effects of the drugs are “small”, “adverse events are frequent, treatment regimens are burdensome, and crucially, long-term effects are unknown”.
“At a population level, there is always likely to be a trade-off between breadth of access and magnitude of benefit for any given individual,” the team wrote.
“At a health system level, rollout of treatment even for only narrowly defined patient groups will involve considerable resources to identify and treat eligible patients, with profound opportunity costs.”
According to the Alzheimer’s Society, about 982,000 people in the UK are living with dementia.
The figure is expected to rise to 1.4 million by 2040.
“Confirming eligibility for new treatment requires specific diagnostic tests and, currently, a third of people living with dementia in the UK don’t get a diagnosis at all.
“We need to see investment into diagnostic infrastructure and workforce to ensure that people who are eligible for new treatments can access them when they’re most effective, which appears to be in the early stages of Alzheimer’s.
“Meanwhile, regulators will scrutinise the evidence around these treatments and Alzheimer’s Society awaits decisions from the MHRA and Nice on both lecanemab and donanemab.
“These treatments are not a cure and they aren’t for everyone living with Alzheimer’s disease – they are a part of the puzzle. But improving dementia diagnosis can help us prepare for new treatments whilst also benefiting many more people living with dementia.
“Despite the issues raised in this research, we remain at an important and exciting moment for dementia. Scientists are learning more all the time about Alzheimer’s disease and our ability to slow it down.
“There are currently 164 active clinical trials for Alzheimer’s disease and we expect more treatments to be submitted for regulatory approval in the future.”
“Health systems in these countries are highly unlikely to have the resources required to offer these new drugs, even to a very narrow group.
“Other compelling evidence suggests that attention to inequalities and health experience across people’s lives could have greater impact on the rates of dementia in populations. Most dementia is more complicated than a single protein.
“With an ageing population, we urgently need effective ways to support people living with dementia, but while the current amyloid immunotherapies may show a glint of promise for very selected groups, it’s clear these drugs will not address dementia risk at scale.”
A spokesman for donanemab manufacturer Eli Lilly said: “Any new treatments are reviewed by the MHRA (Medicines and Healthcare products Regulatory Agency) and would subsequently be considered by Nice (National Institute for Health and Care Excellence) to determine clinical and cost-effectiveness and patient eligibility.
“Access to any new medicine will also depend on the appropriate diagnostic and treatment pathway being available for healthcare professionals and patients.
“Lilly is committed to partnering with the NHS and regulatory bodies to ensure new innovations can reach the people that need them.”
