Changes sourcing throughout

July 27 (Reuters) - Swiss drugmaker Roche Holding ROG.S plans to investigate whether an experimental medicine can delay or prevent Alzheimer's disease symptoms, it said on Sunday, as a part of the company's growing development programme for the disease.

The clinical trial of the drug, Trontinemab, will target people who are at risk of cognitive decline and will aim to delay or prevent the symptoms of Alzheimer's, Roche said in a statement.

Trontinemab is designed so that the drug is transported across the blood brain barrier—protective blood vessels that prevent chemicals in the bloodstream from entering the brain — in hopes of delivering more of the treatment to the brain.

Rivals like Eli Lilly LLY.N have been making progress in the complicated field of Alzheimer's recently, with Lilly's drug Kisunla getting a recommendation for approval for certain patients from the European Medicines Agency last week. Kisunla is already approved in the U.S.

Treatments for Alzheimer's approved so far, including Eisai 4523.T and Biogen's BIIB.O Leqembi and Lilly's Kisunla, are designed to clear sticky clumps of a protein called amyloid beta in the brain. They carry hefty price tags as well as the risk of serious brain swelling and bleeding.

(Reporting by Angela Christy and Rishabh Jaiswal in Bengaluru; Editing by Leslie Adler)

((AngelaChristy.M@thomsonreuters.com;))