April 30 (HealthDay News) -- Patients with mild Alzheimer's disease who took 800 milligrams of the drug tarenflurbil twice a day had less decline in functional ability than those who took a placebo, according to a British phase II trial.

The findings support phase III studies of the drug at this dose, the researchers said. Tarenflurbil reduces production of 42-amino-acid peptide, which is believed to initiate brain damage characteristic of Alzheimer's disease. Previous research had found the drug prevented learning and memory defects in mice with Alzheimer's disease.

In this study, 210 patients were randomly assigned to receive either 400 milligrams of tarenflurbil twice per day (69 patients), 800 milligrams of tarenflurbil twice per day (70 patients), or a placebo (71 patients).

Patients with mild Alzheimer's who took 800 milligrams of tarenflurbil for 24 months had lower rates of decline than those who were in the placebo group for the first 12 months of the study and either tarenflurbil group for the last 12 months of the study.

Common side effects included diarrhea, nausea and dizziness.

The researchers concluded that "800 mg tarenflurbil twice per day was well-tolerated for up to 24 months of treatment, with evidence of a dose-related effect on measures of daily activities and global function in patients with mild AD ... these findings justify phase III studies of tarenfurbil at the 800 mg twice daily dose in patients with mild AD."

The study was published online in The Lancet Neurology.

The findings are sufficient to support Phase III studies of the drug, Dr. Paul Aisen of the University of California, San Diego, wrote in an accompanying commentary.

"With the need so enormous, and the potential effect of the benefit suggested [although not proven] by these phase II results, the effort is indeed justified despite the substantial uncertainty. In a few months, we will learn whether tarenflurbil will be the first anti-amyloid intervention to be efficacious in a pivotal trial," Aisen wrote.

SOURCE: The Lancet, news release, April 29, 2008