CORRECTED-Lilly says experimental Alzheimer's drug reduces amyloid in small study

(Corrects paragraph 2 to day data are from IV version of remternetug)

By Deena Beasley

March 31 (Reuters) - Eli Lilly and Co on Friday said early data from the first human study of its next-generation Alzheimer's treatment showed that it lowered levels of toxic amyloid plaques in the brains of people in the earliest stages of the mind-wasting disease.

The higher the dose of the antibody drug, the larger the effect, Lilly said. The treatment, remternetug, was given by intravenous infusion but has the possibility of a more convenient method of administration via subcutaneous injection.

The Indianapolis-based drugmaker is launching a Phase III study of the experimental antibody, but declined to comment on which doses will be selected for larger, later-stage trials.

"We are still trying to explore some of that," said Dawn Brooks, Lilly's global development leader for remternetug. She said the company's goal is to understand how best to balance dose level and treatment duration with safety.

Lilly, at a medical conference in Gothenburg, Sweden, presented interim data from 41 study participants. It showed that amyloid clearance was reached by 75% of the 24 patients who received remternetug at the three highest tested doses.

The most common treatment-related adverse side effect was a type of brain swelling known as ARIA-E, which was observed in 10 participants, with one patient discontinuing treatment due to a serious adverse event.

Eli Lilly is expected to announce before the end of June results from a Phase III trial designed to show the impact on cognition of donanemab, an amyloid-lowering antibody further along in development that is given by intravenous (IV) infusion.

Two IV Alzheimer's drugs developed by partners Eisai Co Ltd and Biogen Inc, Leqembi and Aduhelm, have been approved by the U.S. Food and Drug Administration under the agency's accelerated review program, based on evidence of their ability remove amyloid plaques.

Leqembi is currently undergoing the FDA's standard review process, which will weigh the drug's impact on cognitive function. Trial results published last year showed that, in patients with early Alzheimer's, Leqembi reduced the rate of cognitive decline by 27% compared with a placebo.

More than 6 million Americans are living with Alzheimer's, and by 2050 the number is projected to rise to nearly 13 million, according to the Alzheimer's Association.

Brooks said that sharing its early remternetug data "reinforces Lilly's commitment and investment in the Alzheimer's disease space ... This is not just going to be one and done." (Reporting By Deena Beasley Editing by Bill Berkrot)