Mitophagy Activator Urolithin A Enters Phase 2 Alzheimer Trial of APOE4 Carriers

A newly launched phase 2 trial will evaluate whether urolithin A, a gut microbiome–derived metabolite that activates mitophagy, can slow cognitive decline in patients with mild cognitive impairment (MCI) because of Alzheimer disease (AD), with particular attention to APOE4 carriers. The study, presented at the 2026 Alzheimer’s Association International Conference (AAIC), held July 12-15, in London, United Kingdom, is being conducted in Prague, Czech Republic, and funded in part by the Alzheimer's Association.¹

The trial potentially matters clinically because it focuses a mechanism, mitochondrial dysfunction and impaired mitophagy, distinct from the amyloid- and tau-centered pathways underlying currently approved AD therapeutics. It also builds in genotype stratification, addressing a longstanding gap in AD trial design given that APOE4 carriers exhibit distinct bioenergetic and neuroinflammatory profiles compared with noncarriers.²

Trial Overview

The study is a double-blind, placebo-controlled trial that will enroll 60 participants with MCI because of AD, randomized 2:1 to receive oral urolithin A (1000 mg/day) or placebo over 12 months, stratified by APOE genotype. Outcome assessments reportedly include standard cognitive testing alongside mechanistic blood-based biomarkers of mitophagy and autophagy activity, oxidative stress, and multi-omic profiling. Lead author Shuqin Cao, PhD, a postdoctoral research fellow at the Department of Clinical Molecular Biology at the University of Oslo in Norway, presented the abstract of this study design at AACI 2026.

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Clinical Context

AD remains the leading cause of dementia, and despite recent approvals of antiamyloid monoclonal antibodies, no therapy reverses or halts the underlying neurodegenerative process, and disease-modifying options for the MCI stage remain limited.³ Mitochondrial dysfunction has drawn increasing attention as a contributor to AD pathophysiology, with impaired clearance of damaged mitochondria (mitophagy) implicated in amyloid-beta and tau accumulation in preclinical models.

Drug Background

Urolithin A is produced by gut bacterial metabolism of ellagitannins found in foods such as pomegranates, and it has been shown to induce mitophagy in preclinical systems.³ A phase 1 study in healthy older adults established a favorable safety and tolerability profile for oral UA and demonstrated molecular signatures consistent with improved mitochondrial gene expression, providing the safety basis cited for advancing to this phase 2 AD trial.⁴ UA does not currently hold an FDA- or EMA-approved indication for AD or any neurologic condition; it is more commonly marketed as a dietary supplement ingredient, a distinction clinicians should note when patients raise questions about over-the-counter products.

Click here for more coverage of AAIC 2026.

REFERENCES
1. Cao S, Veverová K, Vyhnálek M, Fang EF. A Phase II Clinical Trial On The Effect Of Urolithin A In Alzheimer's Disease. Presented at: 2026 Alzheimer’s Association International Conference; July 12-15; London, United Kingdom.
2. Yamazaki Y, Zhao N, Caulfield TR, Liu CC, Bu G. Apolipoprotein E and Alzheimer disease: pathobiology and targeting strategies. Nat Rev Neurol. 2019;15(9):501-518. doi:10.1038/s41582-019-0228-7
3. Fang EF, Hou Y, Palikaras K, et al. Mitophagy inhibits amyloid-β and tau pathology and reverses cognitive deficits in models of Alzheimer's disease. Nat Neurosci. 2019;22(3):401-412. doi:10.1038/s41593-018-0332-9
4. Andreux PA, Blanco-Bose W, Ryu D, et al. The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nat Metab. 2019;1(6):595-603. doi:10.1038/s42255-019-0073-4