An experimental drug has slowed the rate of memory and thinking decline in people with early-stage Alzheimer’s disease in what is being described as a ‘historic moment’ for dementia treatment.
The cognition of Alzheimer’s patients receiving the drug, developed by Eisai and Biogen, declined 27% less than those on placebo treatment after 18 months. This is a modest change in clinical outcomes, but the first time a drug has clearly changed the trajectory of disease.
“This is a historic moment for dementia research, as this is the first Phase 3 trial of an Alzheimer’s drug in a generation to successfully slow cognitive decline,” said Dr Susan Kohlhaas, research director at Alzheimer’s Research UK. “Many people think that Alzheimer’s disease is an inevitable part of aging. It’s clear: if you intervene early, you can have an impact on how people progress.
In the study, which recruited about 1,800 patients with early-stage Alzheimer’s disease, patients received twice-weekly infusions of the drug, called lecanemab. It has also been shown to reduce toxic plaques in the brain and slow patients’ memory decline and ability to perform daily tasks.
About one-fifth of patients experienced side effects, including brain swelling or cerebral bleeding visible on PET scans, and about 3% of these patients experienced symptomatic side effects.
The findings lend a boost to the ‘amyloid hypothesis’, which speculates that the sticky plaques seen in the brains of dementia patients play a role in brain cell damage and cognitive decline.
A series of earlier drug candidates have been shown to successfully reduce amyloid levels in the brain, but without any improvement in clinical outcomes, leading some to question whether the field of research has not taken a wrong turn.
Rob Howard, Professor of Old Age Psychiatry at University College London (UCL), said: “This is an unambiguous statistically positive result and represents something of a historic moment when we see the first change evidence of Alzheimer’s disease. God knows, we’ve waited long enough for this.
Eisai and Biogen are expected to seek regulatory approval in the United States and Europe by the end of the year. If approved, healthcare providers will have tough decisions about whether to fund the drug, which requires infusions every two weeks, and who will be eligible for it as clinical improvements seen by patients continue. fall just below a widely accepted benchmark.
On a 14-point scale used to assess the progression of Alzheimer’s disease, patients on the drug scored 0.45 higher than those on placebo, with an Alzheimer’s patient expected to decrease approximately 1 point per year.
Howard said: “The minimum valid difference accepted ranges from 0.5 to 1.0 points, [meaning] that there are going to be very difficult conversations and decisions in the weeks and months to come.
The overall benefits will depend on whether patients taking the drug maintain a better trajectory beyond the first 18 months, but the latest data cannot answer that question.
There are also questions about whether the drug could slow the decline at an even earlier stage. Eisai is recruiting people at high risk for Alzheimer’s disease who have not yet developed symptoms to participate in other trials to try to answer this question.
The prospect of effective therapy for Alzheimer’s disease will draw attention to the ability of health services to provide treatment for the nearly one million people affected in the UK – one in 14 people aged 65 and more.
Only one in three psychiatric wards would be ready to deliver a new treatment within a year, according to Alzheimer’s Research UK, and many patients in the UK are being diagnosed at a much later stage than those who took part in the last trial. .
“This will require a radical change in the way we deliver our services,” said Professor Jon Schott, chief medical officer at Alzheimer’s Research UK and professor of neurology at UCL.
“If it is dismissed and it goes through Nice [the National Institute for Health and Care Excellence], the demand will be huge. We are not ready to provide this on a large scale and we need to fix it now. »
