The first drug found to slow dementia onset has had trial results confirmed in what scientists say could “herald a new era” for people with Alzheimer’s.
Fortnightly injections of lecanemab significantly slowed signs of disease in patients with early stage Alzheimer’s and stalled memory decline.
Follow-up of 1,800 patients aged 50 to 90 after 18 months confirmed cognitive decline was slowed by 27%.
The drug is the source of huge excitement amount scientists as it works by clearing a the amyloid protein from patients’ brains - potentially confirming the “amyloid hypothesis”.
If confirmed in further analysis by regulators then this drug and others could eventually be offered diagnosed with Alzheimer’s.
Dr Susan Kohlhaas, director at Alzheimer’s Research UK, said: “These exciting findings represent a major step forward for dementia research and could herald a new era for people with Alzheimer’s disease.
“This is the first time a drug has been shown to both reduce the disease in the brain and slow memory decline in clinical trials.
“Although the benefits were small and came with significant side effects, it marks the arrival of a treatment that can slow the course of Alzheimer’s disease.”
After early results were revealed in September Japanese drugmaker Eisai said the US trial proved the long-standing theory that removing sticky deposits of amyloid beta from brains could delay the advance of the disease.
Professor John Hardy, group leader at the UK Dementia Research Institute at University College London, said: "This trial is an important first step, and I truly believe it represents the beginning of the end.
"The amyloid theory has been around for 30 years so this has been a long time coming. It's fantastic to receive this confirmation that we've been on the right track all along, as these results convincingly demonstrate, for the first time, the link between removing amyloid and slowing the progress of Alzheimer's disease.
"The first step is the hardest, and we now know exactly what we need to do to develop effective drugs. It's exciting to think that future work will build on this, and we will soon have life-changing treatments to tackle this disease."
Unlike previous drugs lecanemab - developed with drugs firm Biogen which created the Pfizer Covid jab - targets forms of the protein that have not yet clumped together.
However it is unclear how much benefit the 27% result would be in real life and more research is needed to see of the benefit continues longer than 18 months.
Dr Richard Oakley, associate Director of Research at the Alzheimer’s Society, said: “Today’s exciting results could be game-changing.
“They give us hope that in the future people with early Alzheimer’s disease could have more time with their loved ones.
“This isn’t the end of the journey. The safety of drugs is crucial and lecanemab did have side effects.
“There is still a long way to go before we could see lecanemab available on the NHS, and we await clarity for how and when the approval process will take place in the UK.”
There have previously been reports of two deaths from strokes attributed to a side-effect of the drug.
The US Food and Drug Administration will now start independent analysis of the data as part of the drug licensing process before regulators do the same in Europe.
Dr Ivan Koychev, of Oxford University, said: “There is concern about the safety of the drug with further evidence that this drug class is linked to brain swelling and small haemorrhages seen on imaging.”
Prof Tara Spires-Jones, of Edinburgh University, said: “While this is good news it is important to note that this is not a cure.
“Both groups in the trial had worsening symptoms, but people taking the drug did not decline as much in their cognitive skills.
“It is not clear yet whether the modest reduction in decline will make a big difference to people living with dementia.”
