Because what works in animal studies doesn't often work in humans. This is why you hear about a novel cure for cancer in the news every month -- it's always animal studies.
If you want something to get your hopes up, look for stuff undergoing human studies. They're not new(s) -- in fact, it's stuff that is known and has shown promise for years -- but they're more likely to eventually work.
If you want something to get your hopes up, look for stuff undergoing human studies. They're not new(s) -- in fact, it's stuff that is known and has shown promise for years -- but they're more likely to eventually work.