Dementia is currently the seventh leading cause of death globally, and a recent study predicted that, by 2050, 153 million people will be living with Alzheimer’s disease, the most common form of the illness.
Between 50 and 60% of people with dementia are affected by Alzheimer's – a disorder that damages nerve cells so they are no longer able to communicate effectively, in turn impacting memory, thinking, behaviour and emotion. While the disease is more common among the older population, it can sometimes affect people who are under the age of 65, which is known as young onset dementia.
There is currently no cure for most types of dementia, and people living with Alzheimer's are usually given medication to manage their symptoms. While these drugs do not alter the way the disease progresses, a new treatment breakthrough that has been hailed momentous and historic, could change this.
A new medicine – lecanemab – is the first to successfully slow the destruction of the brain when taken at the early stages of the disease by attacking and removing the so-called "sticky gunge," a protein called beta-amyloid, that builds up in the brain of people with Alzheimer's. Its positive results follow a stream of unsuccessful trials with other drugs.
While these first results after 18 months of the trial, involving 1,795 people with either mild Alzheimer’s or mild cognitive impairment (MCI) due to Alzheimer’s, showed the disease continued to damage people's brains, the decline of their brainpower was slowed down by about a quarter and helped improve day-to-day activities.
But so far, it is no miracle cure: the drug only works in the early stages of the disease, meaning most would miss out – unless the techniques for detecting the disease also see a breakthrough. There are also risks involved, as brain scans revealed a risk of a brain haemorrhage and brain swelling. Two deaths have already been linked to the new drug.
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"Although the effects are modest, with the potential for some significant side effects, this nonetheless heralds a new era – the arrival of a treatment that is proven to slow the course of Alzheimer’s disease," Alzheimer's Research UK noted in a statement.
The data is already being evaluated by the FDA (the US drug regulators) which will soon decide whether it can be approved for wider use, while the developers — pharmaceutical companies Eisai and Biogen — also plan to start the approval process in other countries next year.