"I suspect that the reality is that attacking the amyloid cascade is a complicated issue, and no single therapeutic strategy is likely to be the final answer," Petersen says.
Scientists are optimistic that even with Flurizan's demise, a plausible treatment will emerge soon.
"History has shown that when you have a new mechanism and a new target, inevitably the first wave of drugs is usually the worst," Tanzi says, referring to the findings from Flurizan. "In these situations you need to be patient and wait for the second or third wave of drugs. ... That wave is coming."