Alzheimer's drug slows decline but with side-effects

STORY: An experimental Alzheimer's drug from Eisai and Biogen was seen to slow cognitive decline in a closely watched trial.

It's the first big breakthrough in 30 years of Alzheimer’s research, but the detailed data presented on Tuesday (November 29) also showed a possible risk of serious side-effects for certain patients.

The drug, lecanemab, was associated with a dangerous type of brain swelling in nearly 13% of patients.

The trial spanned 18 months and enrolled nearly 1,800 participants with early-stage Alzheimer's.

Some patients also experienced bleeding in the brain - a symptom linked to the deaths of two people receiving the drug in a follow-on study.

Eisai said it believes the deaths "cannot be attributed to lecanemab".

Lecanemab is an antibody, designed to remove sticky deposits of a protein called amyloid beta in the brain.

Eisai and Biogen reported in September it reduced the rate of cognitive decline by 27% compared to a placebo.

It's still early days, scientists say.

But the Alzheimer's Association said the data confirms the drug "can meaningfully change the course of the disease," and called on U.S. regulators to green-light accelerated approval.

They're slated to decide by January 6.

The finding has strengthened support from some scientists for simultaneously targeting another protein linked to Alzheimer's called tau, alongside amyloid.

That provides momentum for clinical trials of “cocktail” treatments targeting both proteins, similar to those used against cancers and HIV.