- The Alzheimer’s drug donanemab is currently awaiting approval in the US and UK.
“Miracle” Alzheimer’s drugs should be treated with caution, experts warned, amid concerns they cause patients’ brains to shrink.
Last year, the medical world rejoiced when the first drug that clearly slows the progression of Alzheimer’s was approved in the United States.
The makers said trial results showed that lecanemab, also known as Leqembi, slowed cognitive and functional decline in early-stage Alzheimer’s patients by 27 percent over 18 months.
This amounts to a five-month slowdown in the progression of the disease, with the UK expected to make an approval decision next week.
Donanemab is another drug currently pending approval in the US and UK, and has also been shown to slow the progression of Alzheimer’s by up to 35 percent.
Last year, the medical world rejoiced when the first drug that clearly slows the progression of Alzheimer’s was approved in the US (file image)
Results from the lecanemab trial show that about 21 percent of participants who received the drug experienced brain swelling or bleeding (file image)
But experts have warned that people taking these drugs actually lose volume in the brain, putting the approval of these treatments in the UK at risk.
Rob Howard, professor of old-age psychiatry at University College London, said he believes the benefits of taking “miracle” drugs are “literally too small to be noticed” by a patient or doctor.
“The brains of patients who have received these drugs appear to shrink faster than those of people who receive a placebo,” he said at the American Association for the Advancement of Science (AAAS) conference in Denver.
‘Obviously, loss of brain volume is something that we have always considered a very bad thing. If you look at the studies, the imaging data seems to suggest that people are actually losing probably a little more than a teaspoon of brain.’
He added that when you look at MRI images that show swelling or bleeding in the brain, “it reminds me of MRIs of patients who have suffered strokes or some type of traumatic brain injury.”
He had previously said that he would not want to give lecanemab to any of his patients or any member of their family who had Alzheimer’s.
“Doctors, patients and families will have to weigh the risks of serious harm and even death against the small potential benefits of treatment,” he added.
Results from the lecanemab trials show that about 21 percent of participants who received the drug experienced brain inflammation or bleeding, compared with 9 percent of those who received a placebo.
Most patients had no side effects or very mild symptoms, while most of those who experienced swelling or bleeding in the brain saw these problems resolved by the end of the trial.
Donanemab is manufactured by Lilly. Pictured is a Lilly pharmaceutical manufacturing plant.
Experts have warned that people taking these drugs actually lose brain volume, putting the approval of these treatments in the UK at risk (file image)
However, the medication comes with a “boxed warning” due to its possible side effects. He also notes that patients with two copies of a genetic variant that increases the risk of developing Alzheimer’s appear to be at higher risk of complications.
A spokeswoman for Eisai, the company behind lecanemab, said any volume loss in patients’ brains “was not associated with a worsening of measured neurodegenerative outcomes.”
Meanwhile, a spokeswoman for Lilly, the maker of donanemab, said: “The change in brain volume with potential therapies for Alzheimer’s disease has been widely observed, although admittedly not well understood.”
“Some experts believe it may be an effect seen on MRI resulting from the removal of amyloid plaque or reduced inflammation in the brain.”