Vaccine may be effective with modifications.

2002 NOV 6 - (NewsRx.com & NewsRx.net) -- Trials of a promising new therapy for Alzheimer disease were abruptly halted this year when several of the more than 360 patients enrolled developed inflammation in the brain.

But two new studies in Nature Medicine raise the possibility that, with modifications, the basic approach may still effectively counteract Alzheimer disease. One of the studies provides the first data on the patients themselves.

The patients in the trials were treated with a vaccine designed to clear the tangles of amyloid-beta (A-beta) protein, called plaques, that accumulate in the brains of Alzheimer patients. The researchers, with the pharmaceutical company Elan and its corporate partner, American Home Products, had reason to believe this approach would work. Previous data had indicated that in mice, the vaccine resulted in antibodies directed against A-beta, cleared the plaques and reversed symptoms of neurodegeneration. Furthermore, a Phase I trial for safety was completed successfully in the year 2000.

Roger Nitsch and colleagues at the University of Zurich have now presented evidence that the human patients actually did accumulate antibodies against A-beta, which is a critical step in plaque clearance. The antibodies recognized only A-beta in tangles, diffuse A-beta deposits and A-beta in blood vessels of the brain. In these patients, the antibodies are able to cross the blood-brain barrier, ...