An advisory panel of experts is meeting Friday to discuss whether the U.S. Food And Drug Administration should approve an experimental drug that developers claim is the first to slow mental decline in Alzheimer's patients.

Aducanumab, from Cambridge, Massachusetts-based Biogen Inc. and Eisai Co. in Japan, doesn't cure or reverse Alzheimer's. Still, the companies say it modestly slows the rate of mental decline, The Associated Press reported.

However, there's no firm evidence that the drug works. Last year, the companies halted two studies when the drug didn't appear to be effective, but then claimed that additional findings from one study suggest it's effective at a high dose. No results have been published.

The consumer group Public Citizen has also warned that the drug could be very expensive and "could bankrupt our healthcare system" while giving patients false hope, the AP reported.