‘Miracle drugs’ for Alzheimer’s could shrink patients’ brains, experts warn

  • The Alzheimer’s drug donanemab is currently awaiting approval in the US and UK

Experts have warned that ‘miracle drugs’ for Alzheimer’s should be treated with caution amid fears they may shrink patients’ brains.

Last year, the medical community rejoiced when the first drug to significantly slow the progression of Alzheimer’s disease was approved in the US.

Manufacturers said the study 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 equates to a five-month delay in the progression of the disease, and an approval decision in Britain is expected next week.

Donanemab is another drug currently awaiting approval in the US and Britain, and has also been shown to slow the progression of Alzheimer’s disease by as much as 35 percent.

Last year, the medical community rejoiced when the first drug to significantly slow the progression of Alzheimer’s disease was approved in the US (stock image)

Study results for lecanemab show that about 21 percent of participants who received the drug experienced swelling or bleeding in the brain (stock image)

But experts have warned that people taking the drugs actually lose volume in their brains, putting the UK’s approval of these treatments at risk.

Rob Howard, professor of geriatric psychiatry at University College London, said he believes the benefits of taking the “miracle cure” are “literally too small to be noticeable” by a patient or doctor.

“Patients who have been given these drugs seem to have their brains shrink more quickly than in people who receive a placebo,” he told the American Association for the Advancement of Science (AAAS) conference in Denver.

‘Clearly, losing brain volume is something that we have always considered a very bad thing. If you look at the studies, the imaging data seems to indicate that people probably lose a little more than a teaspoon of brain.”

He added that when he looks at MRI scans that show swelling or bleeding in the brain, it “reminds me of looking at MRI scans of patients who have had a stroke or some type of traumatic brain injury.”

He has previously said he would not give lecanemab to his patients or to a member of his family with Alzheimer’s disease.

“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.

Study results for lecanemab show that about 21 percent of participants who received the drug experienced swelling or bleeding in the brain, compared to 9 percent of those who received a placebo.

The majority of patients had no side effects or had very mild symptoms, while most patients who experienced swelling or bleeding in the brain saw these problems resolved by the end of the trial.

Donanemab is manufactured by Lilly. In the photo a Lilly pharmaceutical factory

Experts have warned that people taking the drugs actually lose volume in their brains, putting the UK’s approval of these treatments at risk (stock image)

However, the drug comes with a ‘boxed warning’ because of its potential side effects. It also warns that patients with two copies of a genetic variant that increases the risk of developing Alzheimer’s disease appear to be at greater 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 manufacturer of donanemab, said: ‘Brain volume changes in potential therapies for Alzheimer’s disease have been widely observed but are admittedly not well understood.

‘Some experts think this could be an effect seen on MRI due to the removal of amyloid plaques themselves or from reducing inflammation in the brain.’

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