There is a new class of drug that disrupt and can reverse the build up of the aggregated proteins that lead to Alzheimer's disease. The drug is in final clinical trials in the UK and, if successful, will be available in 4-5 years. Here is a brief video that explains how the drug targets the protein responsible for the aggregates: http://link.brightcove.com/services/link/bcpid1488655367/bctid1697193507 and an article that discusses the new drug:
I don't believe it reduces the amyloid plaque, I believe it dissolves the tau tangles. I'm not 100% sure but those are two different approaches. Wyeth is working on a drug called bapineuzimab or something like that, which works with the amyloid plaque. They released Phase II results that are compelling enough to go to Phase III, but the results showed no change to cognitive function. This tau tangle approach is supposed to be different from that.
My professor was talking about that over the phone (he's getting an award at that very conference). It sounds promising but may not be that effective in the early stages (we're working more on immune treatments).