The Food and Drug Administration doesn't appear to have much of an issue with the usefulness or safety of Eli Lilly's (NYSE: LLY) Amyvid, its dye for detecting beta-amyloid plaques in Alzheimer's disease patients.

But it isn't willing to approve Amyvid just yet either. The agency wants to confirm that it'll be used properly in the real world setting. Eli Lilly said today that the company had received a complete response letter that was "primarily focused on the need to establish a reader training program for market implementation that helps to ensure reader accuracy and consistency of interpretations of existing Amyvid scans."

Let's just hope the minority-focused part of the complete response letter will be as easy to address. The company didn't give investors any details on the rest of the FDA's concerns.

Neither did Eli Lilly give a time frame for responding, but I can't imagine it'll take all that long to set up a training system and confirm that it trains readers properly. Eli Lilly has already started on the process since this was brought up as an issue at an advisory panel meeting in January. The faster the better since General Electric (NYSE: GE) and Bayer are coming from behind with beta-amyloid plaque detection systems of their own.

Beyond Eli Lilly, manufacturers of Alzheimer's disease drugs are the biggest losers in the delay bringing Amyvid to market. Forest Labs' (NYSE: FRX) Namenda, Pfizer (NYSE: PFE) and Eisai's Aricept, and generic-drug makers selling copy-cat versions of Novartis' (NYSE: NVS) Exelon and Johnson & Johnson's (NYSE: JNJ) Razadyne will likely benefit from a tool like Amyvid by increasing the diagnosis rate for Alzheimer's patients.

Hopefully, they don't have to wait much longer. The baby boomers aren't getting any younger you know.

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