A volunteer attends to Alzheimer's patients at a center for Alzheimer's patients in Dax, southwestern France
A volunteer attends to Alzheimer's patients at a center for Alzheimer's patients in Dax, southwestern France AFP

US drugmaker Eli Lilly on Wednesday announced its experimental Alzheimer's drug significantly slowed cognitive and functional decline, results hailed as "remarkable" by experts.

In a placebo-controlled trial of nearly 1,200 people with early forms of the disease, donanemab slowed the progression of symptoms by 35 percent over a period of 18 months, as measured by their ability to carry out daily tasks like managing finances, driving, engaging in hobbies and conversing about current events.

This follows a 27 percent reduction in decline found for Biogen and Eisai's lecanemab, which was also declared a blockbuster and was approved by the US in January.

Lilly said it would rapidly submit its results to the US Food and Drug Administration as well as other global regulators.

"We are extremely pleased that donanemab yielded positive clinical results with compelling statistical significance for people with Alzheimer's disease in this trial," said Daniel Skovronsky, Lilly's chief scientific and medical officer, in a statement.

In Alzheimer's disease, two key proteins, tau and amyloid beta, build up into tangles and plaques, known together as aggregates, which cause brain cells to die and lead to brain shrinkage.

Like lecanemab (also known by its trade name Leqembi), donanemab targets amyloid beta.

Nick Fox, of the UK Dementia Research Institute, said that although the full dataset was not yet available, the results announced by press release "confirms that we are in a new era of disease modification for Alzheimer's disease."

"This clinical trial is a real breakthrough, demonstrating a remarkable 35% slowing of cognitive decline in Alzheimer's patients with high amyloid beta but low tau burden," added Marc Busche, UK Dementia Research Institute group leader at University College London.

Side effects included temporary swelling in other parts of the brain, which occurred in almost a quarter of the treated patients, as well as microhemorrhages that occurred in 31 percent of patients on the treatment arm and 14 percent patients in the placebo group.