This newer theory is that the cause of the amyloid build-up is an immune response to the herpes virus increasingly infiltrating the brain (as you get older the blood/brain barrier that protects your brain from infections weakens) so a possible treatment is to try and reduce the levels of herpes infection rather than attacking the amyloid protein which is your body's immune response to the herpes infection.
The APOE4 gene is infamous for increasing amyloid production and being a major risk factor for early-onset Alzheimers and so carriers of the gene are often used in studies to see the effect of treatments. (@subcosmos below has a good explanation of what this gene actually does)