Eli Lilly’s quest to bring donanemab, a promising Alzheimer’s treatment, to market has encountered a roadblock. The U.S. Food and Drug Administration (FDA) has postponed its approval decision and intends to convene an advisory committee to delve deeper into the drug’s safety and efficacy data. This delay pushes back the expected availability of donanemab beyond the first quarter of 2024.
Why the Delay? FDA Seeks Advisory Committee Input on Donanemab
The FDA seeks additional insights from its external advisors on two key aspects of donanemab’s application:
- Safety: Brain swelling and micro-hemorrhages, known as ARIA (amyloid-related imaging abnormalities), are primary safety concerns associated with this class of Alzheimer’s drugs. In donanemab’s Phase 3 trial (Trailblazer-Alz 2), a significant portion (37%) of participants experienced ARIA, with three fatalities reported. Leqembi, another recently approved Alzheimer’s drug, has also been linked to patient deaths, albeit with a lower incidence of ARIA.
- Unique Trial Design: The design of Trailblazer-Alz 2 differed from conventional Alzheimer’s drug trials in a couple of ways. Firstly, it allowed participants to discontinue taking donanemab once their brain scans confirmed clearance of amyloid plaques. Secondly, the study categorized participants based on tau protein levels, another hallmark of Alzheimer’s disease. The trial observed a 35% slower cognitive decline in the “intermediate” tau group receiving donanemab compared to the placebo group. This benefit dipped to 22% when participants with high tau levels (indicative of advanced disease) were included.
Eli Lilly believes a comprehensive presentation of the Trailblazer-Alz 2 results, particularly in the context of safety concerns, will be instrumental in securing approval for donanemab.
Donanemab: A Potential New Weapon in the Fight Against Alzheimer’s
Alzheimer’s disease is a progressive neurodegenerative disorder that robs individuals of their memory and cognitive abilities. It currently affects over 6 million Americans. Donanemab, like Leqembi, targets amyloid plaque buildup in the brain, a pathological feature of Alzheimer’s disease. Early signs suggest donanemab might offer a meaningful benefit in slowing disease progression, particularly for patients in earlier stages with “intermediate” tau levels.
Challenges and Uncertainties on the Road to Approval
While donanemab’s potential is undeniable, several hurdles remain before it reaches patients:
- Safety Concerns: The high incidence of ARIA observed in the donanemab trial raises questions about its safety profile. The FDA will meticulously evaluate this aspect before granting approval.
- Trial Design Considerations: The unique features of Trailblazer-Alz 2, particularly the discontinuation strategy and tau-based stratification, warrant thorough examination by the advisory committee.
- Limited Treatment Uptake for Leqembi: Leqembi, the recently approved Alzheimer’s drug, has seen a slow uptake despite Medicare coverage. This sluggish adoption highlights the challenges associated with this class of drugs, including the need for frequent monitoring and scans.
The upcoming FDA advisory committee meeting will be pivotal in determining the fate of donanemab. A thorough review of safety data and the trial design is crucial to ensure patient well-being and establish the drug’s efficacy for the intended population.
