Sept 24 (Reuters) - Eli Lilly ( LLY ) said on Tuesday

Japan's health ministry has approved donanemab, its drug for

Alzheimer's disease, providing patients with another treatment

option after Eisai ( ESALF ) and Biogen's Leqembi

received the nod in September last year.

Lilly said Japan is the second major market in which the

drug has received approval, after the United States where it is

sold under the same brand name Kisunla.

The Alzheimer's Association estimates that more than 4.6

million people are living with dementia in Japan and it is

expected to rise significantly as the country's population ages.

According to Japan's National Institute of Population and

Social Security Research, people aged over 65 are expected to

account for 32.3% of the country's population by 2035.

Like Leqembi, Lilly's Kisunla is designed to clear an

Alzheimer's-related protein called beta-amyloid from the brain.

In a large, late-stage trial, Kisunla slowed the progression

of memory and thinking problems by 29% compared with a placebo.

It also caused brain swelling in nearly a quarter of patients

and brain bleeding in nearly a third, but most cases were mild.

Kisunla is sold with the FDA's strongest "boxed" safety

warning on its prescribing label in the U.S., flagging the risk

of potentially dangerous brain swelling and bleeding, similar to

Leqembi.

Unlike Leqembi, Kisunla has finite dosing, which allows

patients to stop taking the treatment once brain scans no longer

show amyloid plaques.

A Japanese health ministry panel in August had recommended

approval for Lilly's treatment.

Alzheimer's is the most common cause of dementia and

accounts for about 60%-70% of the cases, according to the World

Health Organization.

Lilly estimates that the number of patients with dementia

could be more than 5 million in Japan by 2030.