Alzheimer’s: new drug which slows progression of disease hailed as ‘turning point’ - what is donanemab?

A new drug has been hailed as a “turning point in the fight against Alzheimer’s” after it was found to slow the progression of the devastating disease.

Donanemab, an antibody medicince, was found to slow “clinical decline” by up to 35 per cent - allowing people with Alzheimer’s to continue performing day-to-day tasks such as shopping, cooking, managing their finances, and enjoying a hobby. Although not a cure, charities have said the trial findings reported in the Journal of the American Medical Association (JAMA) are a “breakthrough” and represent new treatment possibilites for the disease.

Alzheimer’s Research UK said “we’re entering a new era” where the Alzheimer’s “could become treatable”, while Alzheimer’s Society said the use of donanemab could one day mean the disease is comparable to long-term conditions such as asthma or diabetes. The health spending watchdog in England, the National Institute for Health and Care Excellence (NICE), is already assessing whether the drug can be used in the NHS.

What is donanemab?

Donanemab is an antibody medicine manafactured by a pharmaceutical company in the United States called Eli Lilly. It can help people with Alzheimer’s in the early stages of the disease by clearing an abnormal protein called beta-amyloid, which typically builds up in the brains of those with this type of dementia.

‘Plaques’ of beta-amyloid are considered to be one of the pathological hallmarks of Alzheimer’s. Removing this from the brain could therefore change the course and development of a person’s disease, experts have said.

What were the findings of the trial?

Researchers set up a trial in which they examined almost 1,800 people with early-stage Alzheimer’s, aged between 60 and 85, giving half of them a monthly infusion of donanemab - and the other half a ‘dummy’ drug, also known as placebo, over an 18-month period.

Publishing findings on the safety and efficacy of the drug, scientists concluded that after the treatment period, donanemab slowed clinical decline by 35.1% in people with early Alzheimer’s whose brain scans showed low or medium levels of a protein called tau. When the results were combined for people who had different levels of this protein, there was a 22.3% slowing in disease progression.

Some 47% of people taking the drug who had early-stage disease and low or medium levels of tau were found to stall the disease for a year. Eli Lilly and Company also said that some people taking the drug would be able to finish the course of treatment in six months once their amyloid plaque cleared.

Are there any dangers?

While donanemab is a promising development in the fight against Alzheimer’s, the drug is not a risk-free treatment - with trials finding that brain swelling was a side-effect in up to a third of patients. For the majority, this resolved without causing symptoms, but two volunteers and possibly a third tragically died as a result of the dangerous swelling in the brain.

It comes after another antibody drug, called aducanumab, was recently rejected by regulators in Europe over safety concerns and a lack of evidence that it was effective enough for patients.

It is also worth noting that the beta-amyloid protein is just one part of the complex picture of Alzheimer’s, and experts have cautioned that it is unclear if the treatment will continue to make more difference over a longer period of time.

What have people said?

Mike Colley, who has been on the global trial of donanemab for two years, told BBC News: “I am one of the luckiest people you will ever meet, just for this. I seem to get more confident every day and I am sure this is going to be successful.”

Although Mr Colley’s memory and ability to process information have still been impacted by the illness, he is “confident” in the drug, remarking: “I am sure they will get all the rubbish off the top of my brain and I will be back to normality.”

His son Mark Colley added: “I never thought I would see my dad just so full of life again. Now we have hope, a few years ago we didn’t and that is just an incredible difference.”

Meanwhile, Dr Richard Oakley, associate director of research and innovation at Alzheimer’s Society, said: “This is truly a turning point in the fight against Alzheimer’s and science is proving that it is possible to slow down the disease. Treatments like donanemab are the first steps towards a future where Alzheimer’s could be considered a long-term condition alongside diabetes or asthma.

“People may have to live with it, but they could have treatments that allow them to effectively manage their symptoms and continue to live fulfilled lives. Just as we’ve seen a transformation in cancer treatment in recent decades, we’re really hopeful we’re on the same path for dementia.”

And Dr Susan Kohlhaas, executive director of research and partnerships at Alzheimer’s Research UK, said: “Today’s announcement marks another milestone. Thanks to decades of research, the outlook for dementia and its impact on people and society is finally changing. We’re entering a new era where Alzheimer’s disease could become treatable.

“As a potential first-generation treatment, donanemab’s effects are modest. But these results provide further confirmation that removing amyloid from the brain can change the course of Alzheimer’s, and may help people affected by this devastating disease if they’re treated at the right time.”