Experimental drug could slow Alzheimer's progression by up to 35%

Donanemab, a new drug designed to remove amyloid plaque, could be a major breakthrough in treatment of dementia

Scientists are calling recent Alzheimer's treatment developments a 'milestone' as new drug donanemab shows promise despite modest effects and potential side effects. Getty Images

Scientists are hailing a new drug, donanemab, as a potential turning point in the fight against Alzheimer's.

According to a new study published in journal JAMA, the experimental drug was shown to slow the progression of the disease by up to 35 per cent in clinical trials, suggesting a significant step forward in Alzheimer's treatment.

The drug is designed to remove a protein called amyloid, which builds up in the brains of people with Alzheimer's.

In recent trials known as TRAILBLAZER ALZ-2, the drug demonstrated its ability to slow clinical decline, allowing those with Alzheimer's to continue their day-to-day activities such as shopping, housekeeping and medication management.

As a result, both the Alzheimer’s Research UK and the Alzheimer’s Society believe that donanemab's discovery is paving the way for a new era in Alzheimer's treatment.

They suggested that Alzheimer's could one day be managed similarly to other chronic diseases, such as diabetes or asthma.

The trial involved nearly 1,800 participants with early-stage Alzheimer's. Half of the participants received a monthly infusion of donanemab, while the other half were given a placebo.

After 76 weeks of treatment, the researchers found that the donanemab group exhibited a 35.1 per cent slower rate of clinical decline compared to the placebo group, in patients with low or medium levels of tau protein – another protein implicated in Alzheimer's.

When data from all the patients were considered, including those with higher tau levels, the drug still demonstrated a 22.3 per cent reduction in disease progression.

However, researchers also observed some serious side effects, such as brain swelling.

There were also three deaths in the donanemab group and one in the placebo group considered “treatment-related”.

Eli Lilly and Company, the manufacturer of donanemab, announced that the drug reduced amyloid plaque by an average of 84 per cent at 18 months, compared to a 1 per cent decrease in the placebo group.

Furthermore, for 47 per cent of patients with early-stage disease and low or medium levels of tau, the drug was found to stall the disease for a year.

“People living with early, symptomatic Alzheimer's disease are still working, enjoying trips, sharing quality time with family – they want to feel like themselves, for longer,” said Dr Mark Mintun, group vice president of neuroscience research and development at Lilly.

“The results of this study reinforce the importance of diagnosing and treating disease sooner than we do today.”

The company added that some patients could finish their treatment course in as little as six months once their amyloid plaque is cleared.

Dr Richard Oakley, associate director of research and innovation at Alzheimer’s Society, commented on the advancements: “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.”

However, it is crucial to recognise the potential side effects and the need for more diverse trials.

Dr Oakley added: “It’s also important to note that side effects did occur, although serious side effects only occurred in 1.6 per cent of people receiving the drug. Regulators will need to balance these side effects against the benefits of the drug.”

Dr Susan Kohlhaas, the executive director of research and partnerships at Alzheimer’s Research UK, labelled the recent developments as significant, she said: “Today’s announcement marks another milestone.”

She expressed optimism about the potential of Alzheimer's disease becoming treatable, saying: “Thanks to decades of research, the outlook for dementia and its impact on people and society is finally changing.”

Dr Kohlhaas indicated that the recent results confirm the potential of removing amyloid from the brain to change the course of Alzheimer's disease, suggesting it might aid those affected if administered at the right time.

However, she warned that regulators must weigh these benefits against the risks before granting donanemab a license for use.

Sir John Hardy, professor of neuroscience and group leader at the UK Dementia Research Institute, UCL, echoed the sentiment.

He pointed out that disease progression is slowed by about 30 per cent but warned about occasional serious complications which require monitoring.

Anne White, executive vice president of Eli Lilly and Company, expressed optimism about the drug's potential. She said: “If approved, we believe donanemab can provide clinically meaningful benefits for people with this disease and the possibility of completing their course of treatment as early as six months after their amyloid plaque is cleared.”

These promising results follow similar success from another Alzheimer's drug, lecanemab, which was also found to reduce memory decline in patients with early-stage disease.

These advancements, while promising, underline the importance of diagnosing Alzheimer's early and accurately.

With effective treatments on the horizon, it is vital that patients are identified at the disease's early stages to maximise the potential benefits of these new therapies.