Next-generation vaccine trial under way
Elan Corp. plc and Wyeth Pharmaceuticals have launched a Phase II clinical trial of their second-generation Alzheimer vaccine AAB-001. The trial will enroll about 180 individuals age 50 to 85 with mild to moderate Alzheimer's disease at study centers nationwide. Participants are allowed to take currently approved Alzheimer drugs if they have been on a stable dose for at least four months.
Full details and a list of study sites are posted on ClinicalTrials.gov
AAB-001 contains monoclonal antibodies, synthetic, laboratory-produced molecules engineered to zero in on a specific target. AAB-001 targets beta-amyloid, a sticky protein fragment considered a prime suspect in disabling and destroying brain cells in Alzheimer's disease. Several new cancer drugs are based on monoclonal antibodies targeting key features of cancer cells.
Monoclonal antibodies can be given in set doses like any other drug because they do not stimulate the immune system to produce its own antibodies. AAB-001 is given by intravenous injection.
The developers hope the lack of impact on the immune system will help AAB-001 avoid triggering inflammation of the brain and spinal cord. Brain inflammation emerged as a serious side effect that prematurely ended studies of AN-1792, the first Alzheimer vaccine ever to reach clinical trials. AN-1792, also developed by Elan and Wyeth, was a form of beta-amyloid, designed to stimulate the immune system to produce its own antibodies to beta-amyloid.
The early end of the AN-1792 trial hampered efforts to evaluate its effects. Even though researchers didn't see any dramatic benefit from the drug, there were enough hopeful signs to keep this approach to treatment in the forefront of development efforts. Researchers are exploring a number of strategies to produce a robust immune response to beta-amyloid without triggering inflammation and other unwanted reactions.
For more information, please see:
- Alzheimer's Association fact sheet on the “amyloid hypothesis” and drugs targeting beta-amyloid
- May 11, 2005, Alzheimer's Association research news feature of final results of the AN-1792 original vaccine trial
- June 27, 2005, Alzheimer's Association research news feature on another approach to developing an Alzheimer vaccine based on a modified herpes virus