For decades scientists and families have been frustrated by the intractable nature of Alzheimer’s disease.

As the population ages and more people develop the devastating condition, there have been no new treatments coming onto the market and for many, no hope in sight.

That was until two years ago.

In a short time, decades of research have started to come to fruition, with at least three new drugs demonstrating the first glimmers of promise.

The latest is called donanemab, with the findings of a global trial involving 1,700 patients presented at a major Alzheimer’s conference in The Netherlands.

Sixteen Australians took part in the trial at eight sites in Victoria and New South Wales.

The drug, from pharmaceutical giant Eli Lilly, was able to slow Alzheimer’s disease progression by 35 per cent in patients in the earliest stages of the disease.

Across the whole study, there was a 22 per cent slowdown in the disease’s progress at the 18-month mark.

Michael Woodward, a geriatrician who has been involved in Alzheimer’s research for decades, was at the Alzheimer’s conference and said the results have the medical community excited.

“I would regard this as the end of the beginning in Alzheimer’s therapies,” he said.

“The word breakthrough is used perhaps a little too often, but this is a major breakthrough.

How does the new drug work?

Donanemab is a monoclonal antibody designed to clear the brain of amyloid plaque, which experts believe plays a role in Alzheimer’s disease.

Researchers have long been trying to work out whether a protein called beta-amyloid plaque (BAP) or another protein called tau is responsible for Alzheimer’s, or a combination of the two.

Those in the study were all in the early stages of Alzheimer’s and aged between 60 and 85.

At the 12-month mark, the researchers said 47 per cent had no evidence of amyloid plaques, compared with 29 per cent in the placebo group.

Patients also did not need indefinite treatment, with injections being able to reduce amyloid to non-existent levels where they would not re-accumulate for many years.

Stephen Macfarlane had three patients in the study through his work with The Dementia Centre at HammondCare in Victoria.

He said the medication was the equivalent of slowing the rate of the disease by seven and a half months compared to someone who was not taking it.

“These drugs slow the progression of the disease, they don’t cause people to improve,” Dr Macfarlane said.

He said it was the most promising drug in two decades for Alzheimer’s research.

The findings show there was a risk of brain bleeding and swelling in a subset of patients, including 1.6 per cent of participants who experienced serious forms, and three who died.

“Bearing in mind that Alzheimer’s disease is a fatal and otherwise untreatable illness, some degree of risk is inherent in the process,” Dr Macfarlane said.

Drug follows on heels of another, lecanemab

The donanemab study findings were similar to those of its predecessor lecanemab, sold under the brand name Leqembi.

It reduced cognitive decline by 27 per cent in patients with early Alzheimer’s in a study published last year.

Lou Coenen is among the Australian patients in a lecanemab trial.

This drug from Japanese drug maker Eisa is being tested in four trials that include Australian sites across 18 locations.

The 72-year-old was diagnosed with Alzheimer’s about five years ago and had a family history of the disease.

“You just start feeling your thinking doesn’t work quite as fast,” Mr Coenen said.

“You start to wonder why.”

He decided to take part in a clinical trial of lecanemab through the KaRa Institute of Neurological Diseases to help give back to the health community.

He says he does notice a difference on the medication.

It is allowing him to spend more time with his wife and family and still participate in community activities such as The Men’s Shed.

“I know compared to other people this is working,” he said. “But I don’t have a comparative of another me that says otherwise.”

On June 30 Australia’s Therapeutic Goods Administration (TGA) started work to consider approving lecanemab in Australia.

This drug has shown similar results to donanemab in patients with early Alzheimer’s but also comes with risks of brain swelling and bleeding in a small subset of patients.

How much will it cost?

New Alzheimer’s drugs to the market are predicted to be hugely expensive for governments because of the significant time and cost they took to develop.

Leqembi is priced at about $US26,500 ($39,974) for a year’s supply of infusions every two weeks but there is no potential price for donanemab yet, which will involve monthly injections.

“That’s going to be a big challenge,” Dr Woodward said.

“But we’ve got to look also at the savings. The total cost of care for Alzheimer’s disease is probably closer to about $6-7 billion per year in Australia.”

Dr Macfarlane said the drug would also mean Australia would need to revamp its Alzheimer’s infrastructure so PET scans were more available for early diagnoses, regular hospital infusions were easier to access, and patients were diagnosed much sooner.

“We know in Australia that on average there’s about a three-year delay between people first experiencing symptoms of memory loss and actually receiving a diagnosis,” he said.

Biogen drug caused controversy

The drugs follow the groundbreaking but controversial release of Biogen’s Aducanumab in 2021.

It is another monoclonal antibody that also works by removing the build-up of amyloid plaque proteins.

It was controversial because of the way the research was structured and the pharmaceutical company’s relationship with US regulators.

In June this year the Therapeutic Goods Administration found the drug did not meet its safety and efficacy requirements for approval in Australia and Biogen withdrew its application.

Latest findings bring hope for patients

For Melbourne grandmother Jan Cody, the first sign she knew her memory was failing was when her three children met to discuss her declining mental state.

The 75-year-old had to give up her work as a psychologist, as well as cooking and driving.

“My world just shrank. There’s really no medication to take,” she said.

She has been involved in some Alzheimer’s trials but was not eligible for donanemab.

“The slowing it down takes a long time,” she said. “So one really doesn’t know whether you’re going to last.”

“But now I do have a glimmer of hope.”