One of the compounds that has now been tried on the demented mice is Bexarotene, which is an approved cancer drug:
Bexarotene is a compound chemically related to vitamin A that activates Retinoic X Receptors (RXR) found everywhere in the body, including neurons and other brain cells. Once activated, the receptors bind to DNA and regulate the expression of genes that control a variety of biological processes. Increased levels of APOE are one consequence of RXR activation by bexarotene.Got that? However it works, researchers have reported that bexarotene removed plaques from mouse brains. Now a group headed by Rada Koldamova of the University of Pittsburgh has found that bexarotene reversed the mice's memory loss.
Which is very cool, but these are transgenic mice, not people, and more often than not treatments that work in mice don't work in us. But sometimes they do.