Another potential Alzheimer's drug failed in Phase 2 trials. The drug, MK-0677, increases levels of a hormone called insulin-like growth factor. Scientists had hoped that increasing levels of that hormone would decrease levels of the beta amyloid protein some think causes Alzheimer's, and would thereby slow the progression of the disease.
In a trial involving over 400 people with mild to moderate Alzheimer's, those taking MK-0677 did no better than those taking a placebo. It doesn't appear that the researchers tried to measure whether beta amyloid levels actually decreased.