The Alzheimer Society of Ireland (ASI) has welcomed a major breakthrough in research into the disease and described a new drug that slows cognitive decline as the “most credible treatment” for decades.
An experimental Alzheimer’s drug from Eisai and Biogen slowed cognitive decline in a closely watched trial, but it may carry a risk of serious side effects for certain patients, according to detailed data presented on Tuesday.
Eisai, a Japanese pharmaceutical company, has already applied for regulatory approval in the United States, with applications to regulators in Japan and Europe expected before the end of next March.
The drug lecanemab is believed to reduce the rate of cognitive decline on a clinical dementia scale by 27 per cent compared to a placebo.
Professor Sean Kennelly, consultant geriatrician in Tallaght University Hospital, said the new drug was a “game changer” in future treatment for Alzheimer’s disease.
“After 30 years of trialing different medicines, this is the first time we’ve had a study with positive and consistent results,” he said.
The “big challenge” would now be to ensure Ireland’s healthcare system had the capacity to deliver the treatment to patients if it was approved by regulators, he told The Irish Times.
The drug was not without side effects, which meant patients would require regular MRI monitoring scans in the first six months of treatment, he said.
The research noted lecanemab was associated with a dangerous type of brain swelling in nearly 13 per cent of patients in the trial that spanned 18 months and enrolled nearly 1,800 participants with early-stage Alzheimer’s.
Some patients also experienced bleeding in the brain, with five suffering macrohemorrhages and 14 per cent suffering microhemorrhages – a symptom linked to two deaths of people receiving the drug in a follow-on study.
The results of the study were announced at an annual conference on Alzheimer’s clinical trials in San Francisco.
In a statement, the ASI welcomed the drug as “huge news” in a major step forward in finding a treatment for the disease.
Dr Laura O’Philbin, ASI research and policy officer, said lecanemab was “the most credible treatment option for mild cognitive impairment and early Alzheimer’s disease the world has seen after decades of work”.
“While the clinical benefits appear small, scientifically, this is a pivotal development and brings hope to people concerned about dementia worldwide,” she said.
Dr O’Philbin cautioned that despite the positive results there was still “a long way” to go when it came to research. “This is a positive day, and it’s only the beginning of a better future in dementia,” she said.
The drug could “potentially” be available within a year or two, following a regulatory approval process, she told RTÉ Radio 1. There had been many attempts over the last 20 to 30 years to create a drug like this, she said.
“They have all failed and we’re finally moving into a zone now where we actually have a potential treatment for people with mild cognitive impairment in early Alzheimer’s disease and that is huge,” she said.
“What’s really important is that scientifically now this is something that we can really build on, and that’s incredibly exciting,” Dr O’Philbin said.
There are currently an estimated 64,000 people with dementia in Ireland, with that projected to more than double over the coming decades as more people live longer.
Alzheimer’s disease is the most common and well-known cause of dementia, which damages the brain and leads to memory loss and a decline in cognitive ability.