FDA Issues Complete Response for Lilly Alzheimer’s Drug

The FDA has issued a complete response letter for Eli Lilly’s accelerated approval submission of donanemab to treat patients with early Alzheimer’s disease. The agency indicated that there too few patients with at least 12 months of data provided in the submission.

In the complete response letter, the FDA specifically requested that Lilly provide data from at least 100 patients who received a minimum of 12 months of treatment with donanemab. The phase 2 trial had been designed to allow patients to complete their course of treatment when they reached a predefined level of amyloid plaque clearance. While the trial included more than 100 patients treated with donanemab, many patients were able to stop as early as six months. The FDA indicated that the data to meet the exposure expectation would likely need to include the unblinded controlled safety data from TRAILBLAZER-ALZ 2.

Lilly’s confirmatory phase 3 TRAILBLAZER-ALZ 2 trial is ongoing, with topline data expected in the second quarter of 2023. The company said this will form the basis of donanemab’s application for traditional approval.

Anne White

“We look forward to our upcoming confirmatory TRAILBLAZER-ALZ 2 phase 3 results and subsequent FDA submission… We anticipate this study will confirm the benefit and safety profile we observed in the TRAILBLAZER-ALZ phase 2 study and believe that patients and physicians will be well served by having the full phase 3 data available alongside our phase 2 data when they need to make treatment decisions,” Anne White, executive vice president and president of Lilly Neuroscience, Eli Lilly, said in a press release.

In November 2022, Lilly released early results from TRAILBLAZER-ALZ 4 — a head-to-head study against Eisai/Biogen’s Aduhelm (aducanumab-avwa) — showed that donanemab met all primary and secondary endpoints for the six-month primary outcome analysis. Brain amyloid plaque clearance was achieved in 37.9% of donanemab-treated patients compared with 1.6% of Aduhelm-treated patients at six months; in the intermediate tau subpopulation, 38.5% of patients treated with donanemab reached brain amyloid clearance compared with 3.8% of Aduhelm-treated patients.