Two drugs designed to prevent Alzheimer’s appeared safe in preliminary testing and reduced levels of the protein beta-amyloid, according to researchers at the ninth International Conference on Alzheimer’s Disease in Philadelphia. A third showed promise, though tests were halted more than two years ago because of safety concerns.

Eli Lilly researchers reported a drug designed to prevent the formation of beta-amyloid was safely tested in 37 healthy adults and reduced the levels of the protein in the blood.

Researchers who analyzed the drug Alzhemed made by the Canadian company Neurochem said it was safely given to 58 patients and reduced beta-amyloid in spinal fluid, which might signal a reduced level of the protein in the brain.

“Given the history of Alzheimer’s disease, and the total hopelessness early on in the research, the small victories seem like a big deal,” said Zaven Khachaturian, former director of Alzheimer’s research at the National Institutes of Health and a senior science adviser to the Alzheimer’s Association.

Elan Corp. of Ireland and Wyeth of New Jersey made tests of the vaccine that were halted in January 2002 when 18 of the 300 people in the trial developed a potentially fatal brain inflammation. Researchers said Wednesday 59 of them, in follow up studies, developed antibodies in response to the vaccine and scored better on a composite of nine tests of memory and attention.