UPDATE 1-Baxter Alzheimer's drug promising in small study

(Adds study details, background)

NEW YORK, April 17 (Reuters) - Baxter International Inc (BAX.N: Quote, Profile, Research) said on Thursday its Gammagard intravenous plasma-based treatment helped improve mental function in a small study of patients with mild-to-moderate Alzheimer's disease.

The treatment met the primary goals of the six-month, 24-patient trial by proving better than placebo at improving measures of cognitive function and global impression of change, the company said, although the study was too small to demonstrate statistical significance.

"This was the first placebo-controlled clinical trial of Gammagard for Alzheimer's disease, and the results are clearly promising," Dr. Norman Relkin said in a statement. Relkin presented the data at the American Academy of Neurology meeting in Chicago.

The study also met secondary endpoints that measured changes in beta-amyloid and anti-amyloid antibody levels in blood and cerebrospinal fluid, Baxter said.

The data suggest that levels of antibodies against beta-amyloid increased in the blood and cerebrospinal fluid of patients treated with Gammagard, while the levels of beta-amyloid increased in the blood.

Beta-amyloid is believed to contribute to the degeneration of the brain in Alzheimer's patients.

Should Gammagard show an ability to help clear beta-amyloid from the central nervous system, it could theoretically slow or reduce the development of Alzheimer's.

Gammagard, an intravenous immunoglobulin derived from human plasma, is currently approved to treat immune system disorders.

The company has said it intends to move on to larger, phase 3 trials of Gammagard in Alzheimer's disease. Phase 3 is typically the final stage of human testing before a company seeks approval to sell the medicine for that use. (Reporting by Bill Berkrot; Editing by Tim Dobbyn)