Eli Lilly & Co announced that the FDA has issued a complete response letter, meaning it has not granted accelerated approval for amyloid-clearing antibody donanemab. The FDA decision was due to the limited number of patients who stayed on the drug for at least 12 months, which is the timeframe the agency wants to see to assess the drug's safety. The company's plans are to file phase 3 clinical trial data later this year for a traditional, or full, FDA approval.

The donanemab trial used a 'goldilocks strategy' to enroll patients who were in the early stages of Alzheimer's and who were most likely to benefit from treatment due to the levels of amyloid and tau in their brains. A unique aspect of this trial was the use of both Amyvid® and Tauvid™ PET scans to enroll patients with proven amyloid and tau build-up, allowing investigators to confirm clearance or reduction of these plaques and tangles in later scans. Today's Alzheimer's drug pipeline is incredibly robust and productive, with more and more trials employing advanced strategies like donanemab's to speed and improve the drug development process.

In addition to donanemab and other anti-amyloid drugs already approved and still in development, the pipeline also includes more clinical trials exploring non-amyloid targets in the aging brain than ever before. Combination treatments with a precision medicine approach are needed to not just slow but stop Alzheimer's in its tracks.