A vaccine in development at Canadian firm ID Biomedical, designed to block the production of beta amyloid plaques in the brains of Alzheimer’s disease patients, has shown preliminary efficacy in animal studies.

The vaccine, a nasal spray which delivers ID Biomedical’s proteasome-based adjuvant Protollin (IVX-908) and glatiramer acetate, the active ingredient in Teva Pharmaceutical Industries’ multiple sclerosis treatment Copaxone, has been shown to stimulate a type of immune cell in the central nervous system – called a microglial cell – to break down the amyloid deposits.

Some believe these deposits are the primary cause of the neurodegeneration in Alzheimer’s disease, and most drugs in development for Alzheimer’s disease are designed to disrupt the formation or stimulate the breakdown of these plaques.

The scientists behind the study, reported in the online edition of the Journal of Clinical Investigation, note that their vaccine is an immunological approach to resolving amyloid in the brain that does not rely on the production of an antibody-based response. An earlier vaccine for Alzheimer’s disease, developed by Ireland’s Elan and Wyeth of the USA, had to be discontinued from development because the antibodies it generated caused serious brain inflammation [[04/03/02a]].

The vaccine was administered to the mice once a week for six weeks, after an initial ‘loading’ regimen of four doses was given in the first week. Compared to control animals, amyloid levels in the vaccinated mice were reduced by 73%, and none of the vaccinated mice showed any evidence of brain inflammation or other side effects.

The researchers plan to begin clinical trials of the Alzheimer’s vaccine after this year or early in 2006, depending on the outcome of discussions with the US Food and Drug Administration.