After decades of unsuccessful research, two new drugs and a pioneering blood test have recently given Alzheimer’s patients hope of fighting back against the debilitating disease – but questions remain about their effectiveness.
Any path towards a cure also remains elusive for Alzheimer’s, which accounts for around 70% of dementia cases worldwide and is a leading cause of death among the elderly.
Here is what to know about recent advances to prevent, diagnose and treat the disease.
How effective are the new drugs?
Billions of dollars have been spent trying to find a treatment for Alzheimer’s disease over the decades, but those efforts have stubbornly fallen short − at least until recently.
US multinational Eli Lilly’s donanemab, sold under the brand name Kisunla, and Biogen and Eisai’s lecanemab sold as Leqembi are the first treatments proven to significantly slow the progression of Alzheimer’s.
But the expensive treatments are only modestly effective, and work only for patients at an early stage of the disease. There can also be serious side effects including potentially deadly brain haemorrhages.
That has sparked a debate about whether the benefits of the drugs outweigh the risks, leading to national health regulators taking different stances.
After an initial rejection, the EU on Thursday approved Kisunla under strict conditions. It may only be administered to patients in the early stages of Alzheimer’s, and only if they do not have a genetic mutation that predisposes them to side effects.
Leqembi was approved in the EU in late 2024, also under strict conditions and after an initial rejection.
The authorisation gives EU member states free rein regarding reimbursement.
In early September, France decided that Leqembi did not warrant an accelerated procedure for reimbursement approval, although it has not completely ruled out the possibility in the long term.
Outside the EU, the UK has approved both treatments but will not reimburse them, deeming the cost too high for such limited benefits.
In the US, both treatments have been authorised, but reimbursement is at the discretion of private health insurers.
What about early diagnosis?
Another debate roiling Alzheimer’s research − and which has also seen a growing divide between Europe and the US − revolves around how to diagnose the disease.
The standard method of diagnosing Alzheimer’s has required an invasive and expensive lumbar puncture, which can rule out some more at-risk patients.
But a simple blood test that detects “biological markers” of the disease has recently been developed.
US authorities have authorised the test since May, but Europe has not yet approved any Alzheimer’s blood test, one of which is the subject of a recently launched national clinical trial in Britain.
The question is whether the blood test will ever be enough by itself to confidently diagnose the disease.
Last year, the US non-profit Alzheimer’s Association changed its criteria to say that biomarkers alone were sufficient.
But in Europe, most specialists think a thorough clinical exam will still be needed to confirm a person’s cognitive and functional decline.
Many patients “with abnormal biomarkers never develop dementia”, Dutch neurologist Edo Richard said.
Richard is also sceptical of the two new Alzheimer’s drugs.
The two issues are linked, because proponents of the drugs believe that being able to diagnose the disease before noticeable symptoms appear could amplify the impact of the treatments.
Can Alzheimer’s be prevented?
One area of consensus is what makes people more at risk of getting Alzheimer’s disease and dementia more broadly.
Nearly half of all cases are linked to factors such as obesity, smoking, drinking alcohol, physical inactivity and hearing loss, according to an expert review in The Lancet last year.
There is an increasing amount of research seeking to determine whether programmes encouraging people to exercise and eat better are effective at fighting Alzheimer’s. But so far the randomised controlled trials “targeting these risk factors have shown limited to no effects on cognitive decline or dementia”, Richard said.
A recent JAMA study found that the cognitive decline of Alzheimer’s patients slowed slightly after undergoing two years of intensive support to be healthier. But for people suffering from Alzheimer’s and their families, this kind of progress may not look like much, French epidemiologist Cecilia Samieri acknowledged at a conference this month.