FDA advisory committee meeting delays approval of donanemab


The US Food and Drug Administration (FDA) has revealed plans to convene a meeting of the Peripheral and Central Nervous System Drugs Advisory Committee (PCNS) to discuss the Phase III TRAILBLAZER-ALZ 2 trial.

The trial evaluated the efficacy and safety of Eli Lilly’s donanemab in early symptomatic Alzheimer’s disease.

The FDA has said it hopes to further understand topics related to evaluating the safety and efficacy of donanemab, including the safety results in donanemab-treated patients and the efficacy implications of the unique trial design of the TRAILBLAZER-ALZ 2 study.

This includes the trial’s limited-duration dosing regimen that allowed patients to complete treatment based on an assessment of amyloid plaque and the inclusion of participants based on tau levels.

“We are confident in donanemab’s potential to offer very meaningful benefits to people with early symptomatic Alzheimer’s disease. It was unexpected to learn the FDA will convene an advisory committee at this stage in the review process, but we look forward to the opportunity to further present the TRAILBLAZER-ALZ 2 results and put donanemab’s strong efficacy in the context of safety,” said Anne White, Executive Vice President of Eli Lilly and Company, and president of Lilly Neuroscience.

The FDA approved anti-amyloid Leqembi in July 2023, making it the first-ever disease modifying therapy for Alzheimer’s to receive traditional approval.


TRAILBLAZER-ALZ 2 is a Phase III, double-blind, placebo-controlled study to evaluate the safety and efficacy of donanemab in participants aged 60-85 years with early symptomatic Alzheimer’s disease (MCI or mild dementia due to Alzheimer’s disease) with the presence of confirmed Alzheimer’s disease neuropathology.

The trial enrolled 1,736 participants, across eight countries, selected based on cognitive assessments in conjunction with amyloid plaque imaging and tau staging by positron emission tomography (PET) imaging.

Compared to participants in similar trials of other amyloid plaque-targeting therapies, the TRAILBLAZER-ALZ 2 participants were more progressed in their disease. All groups of trial participants, regardless of tau level, benefited from treatment with donanemab, with patients in earlier stages of the disease experiencing the strongest results.

Donanemab also demonstrated clinical benefits using a limited-duration treatment regimen, with nearly half of clinical trial participants completing their course of treatment in six or 12 months. The key risk associated with donanemab is amyloid related imaging abnormalities, or ARIA, which can be serious and life-threatening.

“Today’s FDA decision is not a setback, but another step forward in the drug approval process, with the regulatory agency doing its due diligence before the distribution of the drug to patients,” commented Howard Fillit, MD, Co-Founder and Chief Science Officer of the Alzheimer’s Drug Discovery Foundation (ADDF). “The decision to hold an advisory committee before granting approval follows the regulatory process that was used for the other drugs in this class, including Leqembi.”

“The TRAILBLAZER-ALZ 2 trial is emblematic of a new era of Alzheimer’s research where we are now able to conduct innovative trials that can definitively tell us whether a drug is effective.”

Diana Spencer, Senior Digital Content Editor, DDW

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