It's one step forward, one step back in the search for treatments against Alzheimer's disease. In one of two studies in the July 19 issue of The Lancet, an older drug called dimebon significantly improved Alzheimer's symptoms. But in a second report, a once-promising vaccine failed to prevent the progression of Alzheimer's — even though it cleared dementia-linked amyloid plaques in the brain.

Full story: medicinenet.com