CHICAGO, Oct 29 (Reuters) - Starting on a more gradual

dosing schedule of Eli Lilly's ( LLY ) Alzheimer's drug Kisunla

cut the percentage of patients experiencing potentially serious

brain swelling, according to interim results of a late-stage

trial presented at a medical meeting on Tuesday.

At week 24 of the year-long study, 14% of patients with

early-stage Alzheimer's who received a lower starting dose of

the monthly infusion had the brain swelling side effect known as

ARIA-E. That compared with 24% of those who received the

standard dosing schedule.

Reduction of toxic amyloid plaques was comparable to those

on the standard dose of Kisunla, known by the scientific name

donanemab, the company said in a statement.

Lilly said it plans to submit the results to various health

regulators for a potential label change modifying the dosing

regimen. Kisunla competes with Eisai ( ESALF ) and Biogen's

Leqembi, a similar treatment that also causes brain

swelling in some patients.

Kisunla is under review by the European Union's drugs

regulator. The body in July rejected Leqembi, saying the risk of

serious brain swelling did not outweigh its small impact on

slowing cognitive decline.

The UK's Medicines and Healthcare products Regulatory Agency

last week approved donanemab, but the country's

cost-effectiveness body deemed it too expensive for widespread

use within the state-run National Health Service.

Lilly neuroscience chief Anne White would not comment on the

European review, but said in an interview that she hopes

regulators will "take all of the data we have into consideration

and come to a place where they can offer access to patients in

Europe."

Interim results of Lilly's 52-week study in 843 people,

presented at the Clinical Trials on Alzheimer's Disease

conference in Madrid, included four treatment arms. One was the

standard monthly dosing used in the pivotal trial that Lilly

used to win U.S. approval in July.

The other three used alternative dosing regimens, including

the gradual dosing arm, a separate group in which volunteers

received half doses twice a month, and a third group that

received the same amount of drug but with a longer pause between

doses.

One patient on the gradual dosing arm developed stroke-like

symptoms, and died after receiving a clot-busting drug, a known

risk for brain hemorrhages in patients on amyloid-lowering

drugs. Kisunla carries an FDA warning cautioning against use of

the clot buster in those taking the medicine.

All alternate dosing schemes saw some benefit, Dr. Mark

Mintun, Lilly's neuroscience group vice president for research

and development, said in an interview, but the biggest benefit

was in the gradual dosing arm.

In that group, volunteers started with one 350 milligram

vial for the first dose, then added in an additional vial at

each of the next three monthly infusions.

The standard approved dosing starts with two 350 mg vials

for the first three monthly infusions, and then four vials at

the fourth and subsequent infusions.

The study's main goal was to document any occurrence of

brain swelling.

Patients who saw the most benefit were those with two copies

of a genetic variant known as APOE4 - a group that is at higher

risk of brain swelling with amyloid-lowering drugs. In these

patients, 19% had brain swelling on the gradual dosing regimen,

compared with 57% of those on standard dosing.

The dosing change had little impact on the amount of amyloid

removed by 24 weeks, with volunteers in the modified group

seeing a 67% reduction of plaques on average compared with 69%

in the standard dose arm.

Full 52-week results are expected early next year.