An Alzheimer’s drug that had been hailed as a major breakthrough may actually increase patients’ chance of dying, according to new research.

The treatment, lecanemab, was found to triple the risk of death within a year, compared with dementia sufferers not prescribed the drug.

Previous studies have suggested it slowed the progression of the incurable brain disease by 25 per cent, providing patients with an estimated four to six months more of healthy life.

However, earlier this year the NHS spending watchdog, NICE, refused to fund the drug because it provides ‘relatively small benefits… which means it cannot be considered good value’.

And last month the watchdog also rejected donanemab, another drug that had showed promise in suppressing symptoms.

An Alzheimer's drug that had been hailed as a major breakthrough may actually increase patients' chance of dying (stock photo)

An Alzheimer’s drug that had been hailed as a major breakthrough may actually increase patients’ chance of dying (stock photo)

The treatment, lecanemab, was found to triple the risk of death within a year, compared with dementia sufferers not prescribed the drug (stock photo)

The treatment, lecanemab, was found to triple the risk of death within a year, compared with dementia sufferers not prescribed the drug (stock photo) 

Both lecanemab and donanemab are given every fortnight as an infusion. They work by reducing a toxic protein in the brain called amyloid, which is linked to dementia symptoms.

Although not available on the NHS, lecanemab has been approved as safe for use by the UK regulator, so is available to patients privately for a cost of around £20,000 a year.

However, the new research, which used data from America where the drugs have been used since last year, found that the risk of death was significantly higher than reported in the clinical trials.

This equates to an extra 21 excess deaths per 10,000 patients who take lecanemab.

Experts say that about 3,000 patients have started taking the drug since it was approved by US health officials in July 2023.

Patients taking the drugs are at an increased risk of life-threatening swelling and bleeding in the brain.

The experts behind the study warn that ‘there is a precedent for the removal of drugs if their side effects or mortality signals are of concern’.

Professor Robert Howard, one of the authors of the paper, said: ‘The idea that lecanemab is a miracle drug is not supported by the evidence from the trials. It’s even dubious to say that they slow down progression, as that is just an interpretation. Off the back of the NICE decision, these are important findings.’

Experts say that about 3,000 patients have started taking the drug since it was approved by US health officials in July 2023 (stock photo)

Experts say that about 3,000 patients have started taking the drug since it was approved by US health officials in July 2023 (stock photo) 

earlier this year the NHS spending watchdog, NICE, refused to fund the drug because it provides 'relatively small benefits (stock photo)

earlier this year the NHS spending watchdog, NICE, refused to fund the drug because it provides ‘relatively small benefits (stock photo) 

Prof Howard, an expert in old-age psychiatry at University College London, added: ‘We should thank NICE for their leadership in this area, evaluating the true costs – tiny benefits and huge risks with these drugs.

‘Anybody who has the money to afford lecanemab privately needs to carefully consider this, as the risks are real.’

The research is not currently peer-reviewed and Prof Howard notes that ‘the data is currently preliminary and there is uncertainty over the true numbers’.

The real-world data from the drug’s use in America follows a series of deaths during trials.

About one in ten trial participants experienced swelling in the brain and one in six had small brain bleeds, which in rare cases led to life-threatening symptoms.

Three patients died in the trial. One death was confirmed by Dr Lawrence Honig, a neurologist at Columbia University, New York. A second death was reported by the science website Alzforum.

Neither patient has been identified but, according to Dr Honig, one carried a gene called APOE4, which puts patients at greater risk of brain bleeds.

About 15 per cent of Alzheimer’s patients carry this gene.

Previous studies have suggested it slowed the progression of the incurable brain disease by 25 per cent (stock photo)

Previous studies have suggested it slowed the progression of the incurable brain disease by 25 per cent (stock photo)

Alzheimer's disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss

Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss

The Mail on Sunday was first to report the third death, that of lecanemab trial participant Genevieve Lane, 79, from Florida, who had a fatal seizure in 2022, just a week after her third dose.

An autopsy concluded that lecanemab was likely to have triggered the burst blood vessel in her brain that led to her death.

A spokesman for manufacturer Eisai said: ‘The manuscript posted online features a warning stating that it ‘should not be considered conclusive, used to inform clinical practice or referenced by the media as validated information’.

‘It is also important to note that these data have not undergone peer review nor been published in a journal.

‘Data presented at recent medical meetings demonstrates that lecanemab reports received to date have been consistent with the safety profile observed in

the clinical development programme and are continuously reviewed by the FDA [US Food and Drug Administration] and Eisai’s pharmacovigilance team.’

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