One, an experimental drug called Flurizan, has begun late-stage testing to see if it at least helps slow Alzheimer's inevitable worsening. Government-funded researchers are planning a large study of the second approach, a therapy called intravenous immune globulin, or IVIG.
"Most scientists think if you get rid of amyloid, it'll moderate the disease," explained William Thies, scientific director of the Alzheimer's Association.
About 4.5 million Americans have Alzheimer's, a creeping brain degeneration that slowly robs its victims of memory and the ability to reason, communicate and care for themselves. With the aging population, a staggering 14 million may have it by 2050.
No one knows what causes Alzheimer's. But the leading theory is that something spurs abnormal production of a protein called beta-amyloid, which forms clumps that coat and then kill brain cells — plaque that is the disease's trademark.
Healthy people's immune systems produce antibodies that can get rid of at least some of the beta-amyloid that floats in everyone's bodies. But older people produce one-third fewer antibodies against the protein than younger people do, said Dr. Marc Weksler of the Weill Medical College of Cornell University.