The world’s first ever drug shown to work against Alzheimer’s disease has been developed by scientists.
A “historic” trial of 1,800 participants with early stage disease showed lecanemab reduced decline in memory and thinking skills by 27% over 18 months.
If approved by regulators, it will be the only drug available to treat the underlying disease rather than temporarily manage symptoms.
Dr Susan Kohlhaas, director at Alzheimer’s Research UK, said: “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.”
Drugmaker Eisai said the results from the US trial prove the longstanding theory that removal of sticky deposits of a protein called amyloid beta from brains can delay the advance of the debilitating disease.
Administered via a cannula into the bloodstream, the trial results follow a series of failed dementia drugs over decades.
Unlike previous drugs lecanemab, developed with drugs firm Biogen, targets forms of amyloid that have not yet clumped together.
Prof Rob Howard, old age psychiatrist at University College London, said: “This is something of an historic moment when we see the first convincing modification of Alzheimer’s disease.
“God knows, we’ve waited long enough for this.”
Dr Liz Coulthard, associate professor in dementia neurology at Bristol University, said: “Although not curative, lecanemab slowed decline in day-to-day function compared to placebo.
“So lecanemab potentially offers prolonged good quality life in people with early signs of Alzheimer’s disease.
“This heralds a transformation in outlook for people with the first signs of Alzheimer’s disease.”
US regulators are expected to approve the drug in January which could then see EU and UK regulators follow suit.
If the trial data is confirmed, lecanemab could be available to patients in Britain in the early stages of Alzheimer’s in two to three years.
Dr Kohlhaas added: “In preparation for this it’s vital that the Government focuses on ensuring the NHS is ready to roll out new licenced therapies as quickly as possible.
“Right now only one in three psychiatry services would be ready to deliver a new treatment within a year.
“These results offer new hope to people affected by this cruel and devastating disease.”
Dr Tom Russ, director of the Alzheimer Scotland Dementia Research Centre, said: “Health services need to start thinking now how such drugs could be provided fairly, allowing everyone areas equal access to new treatments.”
It follows the controversial failure of an earlier dementia drug by Biogen called aducanumab.
The Food and Drug Administration approved the drug based on limited evidence but many in the scientific community felt the US regulator had lowered its standards.
European regulators refused to approve it and many US health insurers declined to provide it. It is thought the drug cost between £21,000 and £35,000 a year.
Trials of aducanumab had been initially stopped when statistical analyses suggested that it was having no effect but months later Biogen reversed that position.
It claimed that a larger dataset showed that in patients with the first symptoms, who received a very high dose, it slowed their cognitive decline. However there was also a significant risk of brain swelling as a side effect.
The FDA’s approval was conditional on Biogen conducting follow-up studies to confirm its benefits in patients.
Eisai has already applied for a similar “accelerated approval” from the FDA for lecanemab and will have to prove the benefit outweighs the risk of side effects.
The rate of a brain swelling side effect was 12.5% in the lecanemab group versus 1.7% in the placebo group.
Haruo Naito, chief executive officer at Japanese firm Eisai, said: “The positive result of the lecanemab... is an important milestone for Eisai in fulfilling our mission to meet the expectations of the Alzheimer’s disease community.
“Alzheimer’s disease not only presents a great challenge for patients and their families, but it also negatively impacts society, including decreased productivity, increased social costs and disease-related anxiety.
“We believe that helping to alleviate these burdens will positively impact society as a whole.”
