How much progress has been made vs Alzheimer's disease?

After decades of unsuccessful research, two new drugs and a pioneering blood test have recently given Alzheimer's patients hope of fighting back against the debilitating disease -- but questions remain about their effectiveness.

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Any path toward a cure also remains elusive for Alzheimer's, which accounts for around 70 percent of dementia cases worldwide and is a leading cause of death among the elderly.

Ahead of Alzheimer's Day on Sunday, here is what to know about recent advances to prevent, diagnose and treat the disease.

HOW EFFECTIVE ARE THE NEW DRUGS?

Billions of dollars have been spent trying to find a treatment for Alzheimer's disease over the decades, but those efforts have stubbornly fallen short -- at least until recently.

Eli Lilly’s donanemab and Biogen and Eisai’s lecanemab are the first treatments proven to significantly slow the progression of Alzheimer’s.

But the expensive treatments are only modestly effective, and work only for patients at an early stage of the disease. There can also be serious side effects including potentially deadly brain haemorrhages.

That has sparked a debate about whether the benefits of the drugs outweigh the risks, leading to national health regulators taking different stances.

Lecanemab, which is sold under the brand name Leqembi, has been approved in many countries including the United States.