May 22 (Reuters) - Japan's Otsuka Pharmaceutical said on

Wednesday it would stop developing an experimental drug to treat

agitation and restlessness caused by symptoms of Alzheimer's

disease.

The drug candidate, AVP-786, failed to show statistically

significant improvement of agitation associated with Alzheimer's

dementia in a late-stage study, Otsuka said.

Alzheimer's is a progressive brain disorder which causes a

decline in memory, thinking, learning and organizing skills. The

disease is the most common type of dementia.

Agitation associated with dementia has a large impact on the

quality of life for the patients, and is reported in about half

of all patients with Alzheimer's dementia, according to Otsuka.

Otsuka Pharmaceutical's parent Otsuka Holdings ( OTSKY ) is

mainly engaged in the medical and nutraceuticals related

business.

(Reporting by Mariam Sunny in Bengaluru; Editing by Maju Samuel

and Sriraj Kalluvila)