A clinical trial has proven that a new treatment can slow the progress of Alzheimer’s disease by 30%.

The drug, Donanemab, is not a cure but it seems to offer people at least an extra year without the disease progressing.

That’s reason enough for researchers to describe it as a “potential turning point” in the fight against Alzheimer’s and the “most promising drug in two decades” of research.

Donanemab’s manufacturer, Eli Lilly and Company, published the final results of the trial, known as Trailblazer Alz-2, simultaneously at an Alzheimer’s conference and in the Journal of the American Medical Association.

In the trial about 1,700 patients aged between 60-85, including 16 Australians in Victoria and New South Wales, were given either Donanemab or a placebo as an intravenous infusion every four weeks for 18 months.

By the end of the trial, the drug appeared to have slowed cognitive decline in people with Alzheimer’s, if administered during early diagnosis.

It’s important to note that patients on the drug did not show improvement and the treatment did not halt their decline, but they experienced a slower decline than a control group that received a placebo.

Donanemab is administered as an intravenous infusion once every four weeks. Patients undergo regular brain scans to monitor side-effects, including brain swelling and bleeding. These mostly resolve on their own but in rare cases can be fatal. 

The drug is an antibody therapy that targets abnormal clumps of a protein called beta-amyloid (plaque) that can build up in the brain and is considered one of the pathological hallmarks of Alzheimer’s disease. 

The drug binds to the abnormal amyloid and removes it from the brain. Those who benefited most from the drug were in the earliest stages of disease and had low levels of another toxic protein called tau in their brains. 

Amyloid protein builds up between brain cells, but when the plaque reaches a certain level, it seems to aid the formation of tau tangles inside neurons, driving more severe brain damage. The trial results suggest it is important to remove amyloid before tau spreads.

Initially, the drug is predicted to be very expensive due to the significant time and cost in developing it.

However, Michael Woodward, a geriatrician and Alzheimer’s researcher, told the ABC that its use could create savings on the total cost of Alzheimer’s care, which is $6-7 billion a year.

Associate Professor Stephen Macfarlane, who had three patients in the trial, said if approved, the drug would mean revamping Australia’s 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.