With Alzheimer's though, the clinical trials are going to take a long time. Probably 10 years at least, because our current understanding of the disease is that it begins in your mid to late 40s, and only manifests as severe memory loss decades later. Our current method of trying to treat it is like putting someone in pallatiave care with stage 12 cancer through chemo. Just doesn't work.
But drug companies have no choice because if they run 10-15 year trials, their drug will be off patent before the FDA/EMA even looks at it.
If I were King for a day, one thing I'd do is a blanket 40 year patent life on Alzheimer's drugs. It's worth the cost. This disease will bankrupt every nation otherwise.