That depends on how long you have had it for and/or how serious it is. At the level when you are still cognitively aware (ie the drawing clock phase) its usually in the early stages and the placebo would work as well as with any other illness.
My dad has had it for the best part of 15 years, and is now complely reliant on carers to live. We tried everything with him in the early to mid stages but found nothing worked.
TBH this is a complicated alteration of the brain, a cancer of the mind, and its cure (if it ever arrives) will most probably be just as complicated. However, I know that if i knew somebody in the same situation i would give this a go, as someone said, why not!
Horrible disease!