Elan Corp and Wyeth’s now-terminated Alzheimer’s vaccine may cut levels of the beta amyloid protein in sufferers of the disease, according to two new reports published in the journal Neurology. The authors believe that training the body's immune system to fight back against Alzheimer’s may still offer a promising option for slowing or even preventing the disease, which affects some 4.5 million Americans.

The study was stopped early in 2002 after a few participants developed brain inflammation [[04/03/02a]]. But the researchers continued to monitor the patients for up to a year after their last injection and results from the interrupted trial show that on the whole, study participants whose immune systems mounted a response against beta amyloid performed significantly better on a series of memory tests than those who received placebo.

Now, researchers at the University of Michigan are planning to recruit patients into a new 27-month, 180-patient Phase II study of a second-generation Alzheimer’s vaccine from Elan and Wyeth. The trial, which aims to stimulate an immune attack against beta amyloid without raising brain inflammation risk, is being conducted at 30 centers in the USA and dosing has already begun at some sites. Rather than injecting participants with beta amyloid itself, the new trial is based on injections of humanized antibodies against part of the beta amyloid molecule.

“The idea of inducing the immune system to view beta amyloid as a foreign protein, and to attack it, holds great promise,” says Sid Gilman, first author on one of the new papers and the head of the Data Safety Monitoring Board for both clinical trials. “We now need to see whether we can create an immune response safely and in a way that slows the progression of Alzheimer's disease and preserves cognition.”