Tackling Alzheimer’s disease might be even harder than assumed. A report out today casts serious doubt on the latest drugs approved to treat the fatal neurodegenerative condition.
Researchers examined the clinical trial data surrounding anti-amyloid medications for Alzheimer’s. While the drugs were effective at clearing away amyloid beta from the brain, they had next to little benefit on people’s cognition and memory, the authors found. What’s more, the medications can cause significant complications like bleeding in the brain.
“Future research on disease‐modifying treatments for Alzheimer’s disease should focus on other treatments,” they concluded in their paper, published Thursday in the Cochrane Database of Systematic Reviews.
Not clinically meaningful
The Cochrane Library is a British-based group that regularly publishes comprehensive reviews. It specifically asks scientists, clinicians, and even patients themselves to analyze the clinical trial literature relevant to important public health topics, including Alzheimer’s disease.
The brains of people with Alzheimer’s become cluttered with the misfolded forms of two proteins, amyloid beta and tau. Some research has suggested that amyloid beta in particular drives the brain’s destruction in Alzheimer’s. And that’s led scientists to develop antibody-based drugs that try to eliminate amyloid from the brain, hoping to slow or even reverse Alzheimer’s symptoms.
In this latest review, researchers looked at 17 studies of anti-amyloid drugs that collectively included over 20,000 participants. These studies involved seven different drugs, three of which were approved in the U.S. and other countries to treat Alzheimer’s.
All told, the researchers found little to be excited about. Though these medications do reliably clear amyloid from the brain, this removal seemingly doesn’t translate to practical benefits. Compared to placebo, the drugs’ effect on people’s cognition or dementia severity was overall “trivial” over a 18-month period, the authors reported. Similarly, any effect on people’s functional ability was “small at best.”
At the same time, these drugs are known to cause something known as amyloid-related imaging abnormalities, or ARIAs, which are markers of swelling or bleeding of the brain. Though ARIAs can be a serious issue, the review did not find evidence that anti-amyloid drugs increase the risk of death compared to placebo. Still, the verdict in general is plenty gloomy.
“Unfortunately, the evidence suggests that these drugs make no meaningful difference to patients,” said lead author Francesco Nonino, a neurologist and epidemiologist at the IRCCS Institute of Neurological Sciences of Bologna, Italy, in a statement from the C