A preliminary trial has revealed that a nasal spray version of the drug aducanumab, widely viewed as a breakthrough for dementia, prevented symptoms in some people with mild to moderate cases of the disease.
Alzheimer’s disease is the sixth-leading cause of death in the US, and causes affect more than 4 million people in the country.
A study published in the New England Journal of Medicine showed how aducanumab, developed by Eli Lilly, reversed some symptoms in patients treated with the drug, as part of an ongoing trial in the US and Europe.
It is one of only two experimental drugs that are thought to have the potential to halt or slow the onset of Alzheimer’s.
Dr Michael E Goff, the director of the dementia and Alzheimer’s program at Beth Israel Deaconess Medical Center, said: “This clinical trial has shown that aducanumab at this stage does improve cognition in approximately one third of the patients who’ve received the medication.
“It’s hard to say what’s going to happen in the long term and will it prevent these patients from becoming sicker and ultimately needing a more intensive form of therapy.”
According to Alzheimer’s Society, Alzheimer’s is the most common form of dementia and there is currently no cure. Its onset usually comes with gradual physical decline and with no identifiable risk factors that can be reversed. Alzheimer’s costs the NHS £11bn a year in England.
Goff said he was hopeful the drug would develop into a useful long-term therapy for those suffering with the disease, but that more research was needed before that happened.
“This trial [of aducanumab] has identified modest benefits in reducing the cognitive decline, but it needs to be a bit more complicated to determine what has happened in this particular group of patients,” he said.
There were a number of reasons why the drug might help Alzheimer’s patients, Goff said. Aducanumab blocks amyloid plaques, which build up in the brain.
Another theory suggested that it might affect “beta amyloid”, a type of protein that causes Alzheimer’s disease. While it is difficult to tell whether the protein breaks down when the drug works, according to Goff, it does make people more resilient to other brain disorders such as depression and other dementias.
Funded by the National Institute on Aging, the trial, which ran from April 2013 to September 2015, involved 67 people who were between the ages of 65 and 90.
Each was given varying doses of aducanumab. After a year, they were repeated, and after a further year, three patients who had taken more than one dose of the drug were given sham (“placebo”) treatment.
From this limited, albeit promising data, researchers concluded that an estimated 17% to 24% of those who took one dose of the drug had neuropsychiatric improvement, defined as increases in “progression-free day”, decreased or no new adverse events and increased language abilities, as measured by language tasks.
Goff said: “What this suggests is that there is a short-term benefit for participants, and that if given once a month for about a year, you can cause substantial improvement.
“In these conditions, I think it’s less likely to be the presence of amyloid and more likely to be improved cognition.”
This drug might not be developed into a treatment for the long term. “It’s being developed in anticipation of a good long-term treatment, but it’s not a targeted drug for a particular disease. It’s something to be used while you monitor the symptoms and do the minimum necessary to slow [their progression],” Goff said.
Another problem is that it was not tested as a treatment for more advanced symptoms of Alzheimer’s.
“We always thought that if we could slow the impact of the disease in these more advanced conditions, it would increase the chances of a cure for these patients. At this stage, we don’t know what this will do,” Goff said.
Alzheimer’s Society points out that people with Alzheimer’s disease may already have an effective treatment. All drugs are not effective at all people may get better or worse, and one dose may not be sufficient to solve all of the problems.