ADDF Statement on FDA Decision Not to Grant Accelerated Approval to Donanemab for Treatment of Alzheimer’s Disease

Drugmaker Eli Lilly plans to submit phase 3 study data later in 2023 for traditional approval of this amyloid-clearing drug

Drugmaker Eli Lilly & Co announced today 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.

“This drug did what it was intended to do – remove amyloid plaques in the brain – and because of the trial’s innovative design, treatment was halted for patients once the biomarker PET scans confirmed the plaques were gone. In some cases, this occurred in less than 12 months, which is why fewer patients stayed on the drug for a full year,” said Howard Fillit, M.D., Co-Founder and Chief Science Officer of the Alzheimer’s Drug Discovery Foundation (ADDF). “The ADDF applauds the design of the TRAILBLAZER-ALZ trial, which is a mark of great progress in the Alzheimer’s field, promising more treatments to come. We look forward to reviewing the phase 3 data later this year.”

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.

This news follows the announcement that lecanemab, another anti-amyloid therapy, received accelerated approval from the FDA earlier this month.

“Amyloid-clearing drugs, such as these, are one part of the solution, but there remains a pressing need to develop a new generation of drugs targeting all aspects of the biology of aging that can be combined to address the full array of underlying pathologies that contribute to the disease,” said Dr. Fillit.