July 14, 2005 New Haven, Conn. -- July 8, 2005 -- Yale School of Medicine is recruiting patients with Alzheimer's disease to test a vaccine that appears to slow the accumulation of beta amyloid plaque in the brain.
Alzheimer's, which is marked by a progressive loss of mental ability and function, affects 4.5 million Americans.
This trial will test a humanized monoclonal antibody directed against the beta-amyloid protein and that will be administered by intravenous infusion. The antibodies, while not of human origin, have been engineered to have the structure of a natural human antibody. The Phase IIa placebo-controlled study will last 27 months and will involve a total of approximately 25 visits, including six visits to the General Clinical Research Center at Yale-New Haven Hospital.
A clinical trial of an earlier vaccine was halted three years ago when several participants developed meningoencephalitis, said Christopher van Dyck, associate professor and director of the Alzheimer's Disease Research Unit at Yale. The earlier trial differed by using "active" rather than "passive" vaccination. Because the new approach does not induce an active immune response--but rather administers antibodies that have already been engineered outside the body--it is believed to have much less risk of autoimmune reactions.
"The trial is based on the assumption that protecting the body's immune system against beta amyloid that builds up in Alzheimer's disease victims could slow or even prevent a disorder," van Dyck said. The amyloid hypothesis of Alzheimer's disease was bolstered in the late 1990s after mice bred to develop Alzheimer's-like disease were protected from beta-amyloid plaque formation and mental decline after they had been vaccinated at birth. Older mice receiving the vaccine also showed some benefit.
The earlier active vaccine, despite it's unacceptable safety profile, yielded some favorable results. Participants whose immune systems mounted a response against beta-amyloid performed significantly better on a series of memory tests than did those who received a placebo injection, according to a study in Neurology reporting the findings from the first trial.
Persons eligible to enroll in the trial have mild to moderate stage Alzheimer's disease and may be taking other approved treatments. To enroll or for more information please call 203-764-8100.
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