Donanemab Dosing Regimens Phase 3 Trial for Early Alzheimer's Disease
Overview
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clinical_trials_nct05738486["Donanemab Dosing Regimens Phase 3 for Early Alzh"]
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clinical_trials_nct0_0["Trial Details"]
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clinical_trials_nct0_1["Conditions Studied"]
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clinical_trials_nct0_2["Scientific Background"]
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clinical_trials_nct0_3["Disease Context"]
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clinical_trials_nct0_4["Therapeutic Target: Pyroglutamate Amyloid-Beta"]
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clinical_trials_nct0_5["ARIA: The Challenge"]
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...Donanemab Dosing Regimens Phase 3 Trial for Early Alzheimer's Disease
Overview
Mermaid diagram (expand to render)
NCT05738486, known as TRAILBLAZER-ALZ 6, is a Phase 3, randomized, double-blind, placebo-controlled, multicenter trial evaluating different donanemab dosing regimens to optimize amyloid-related imaging abnormality (ARIA) management while maintaining efficacy. Sponsored by Eli Lilly and Company, this trial enrolled 1,175 participants.
Donanemab (marketed as Kisunla in the US) is a monoclonal antibody that targets pyroglutamate-amyloid-beta (AbetapE3*), a highly aggregation-prone form of amyloid-beta found in plaques. The TRAILBLAZER-ALZ 6 study specifically investigates whether modified dosing can reduce the incidence of ARIA, particularly ARIA-E (amyloid-related imaging abnormality-edema), while preserving amyloid plaque removal and clinical benefit.
This trial addresses a significant limitation of anti-amyloid therapies: the trade-off between efficacy and ARIA risk. Understanding optimal dosing may enable broader patient access to this disease-modifying therapy["@keshavan2024"].
Trial Details
| Parameter | Value |
|-----------|-------|
| NCT Number | NCT05738486 |
| Phase | PHASE3 |
| Status | ACTIVE_NOT_RECRUITING |
| Sponsor | Eli Lilly and Company |
| Enrollment | 1,175 participants |
| Enrollment Type | ACTUAL |
| Study Type | INTERVENTIONAL |
| Intervention | Donanemab (LY3002813) |
| Treatment Duration | Up to 18 months |
| Start Date | 2023-02-28 |
| Completion Date | 2027-05-01 |
| Last Updated | 2025-11-14 |
Conditions Studied
- Alzheimer's Disease
- Mild Cognitive Impairment due to AD
- Dementia
- Brain Diseases
- Central Nervous System Diseases
- Nervous System Diseases
- Neurodegenerative Diseases
- Neurocognitive Disorders
- Mental Disorders
Scientific Background
Disease Context
Early Alzheimer's disease, encompassing mild cognitive impairment (MCI) due to AD and mild dementia due to AD, affects approximately 10-15% of the elderly population. These stages represent the optimal therapeutic window for disease-modifying interventions that can preserve neuronal function before extensive neurodegeneration occurs.
The approval of donanemab (TRAILBLAZER-ALZ 2) in 2024 demonstrated that amyloid-targeting can slow clinical decline in early AD. However, ARIA remains a significant safety concern that limits broader utilization.
Therapeutic Target: Pyroglutamate Amyloid-Beta
Donanemab specifically targets pyroglutamate Aβ (AβpE3*), a modified form of amyloid-beta with enhanced aggregation propensity:
N-terminal truncation: AβpE3* is generated by truncation at residue 3 and enzymatic cyclization
High aggregation: The pyroglutamate modification dramatically increases fibril formation rate
Plaque deposition: AβpE3* is enriched in mature amyloid plaques
Toxicity: Oligomers of AβpE3* are highly synaptotoxicBy targeting this particularly pathogenic form, donanemab achieves:
- Rapid amyloid plaque removal
- Reduced plaque burden below threshold
- Clinical benefit correlated with plaque clearance[@mintun2021]
ARIA: The Challenge
Amyloid-Related Imaging Abnormalities (ARIA) represent the primary safety concern for all anti-amyloid antibodies:
ARIA-E (Edema)
- Pathophysiology: Antibody binding to vascular amyloid disrupts vessel integrity
- Location: Typically lobar (affecting cortical regions)
- Symptoms: Headache (most common), confusion, focal neurological deficits
- Imaging: Hyperintense signal on FLAIR MRI
- Incidence: 12-24% in Treatment Arms vs. ~2% Placebo[@simonian2019]
ARIA-H (Hemorrhage)
- Types: Cerebral microhemorrhages (CMBs), superficial siderosis
- Mechanism: Vessel wall degradation from cleared amyloid
- Incidence: Higher in participants with prior CMBs or ApoE4 carriers
- Risk factors: Anticoagulant use, hypertension[@salloway2022]
Rationale for Dosing Optimization
The original TRAILBLAZER-ALZ 2 employed a loading dose approach:
- Initial dose: 700 mg (based on weight)
- Subsequent doses: 1400 mg every 4 weeks
- This approach maximized plaque clearance but produced significant ARIA incidence
TRAILBLAZER-ALZ 6 investigates alternative dosing strategies:
- Lower initial dose: May reduce immune reaction and vascular disruption
- Slower titration: Gradual increase may allow vessel adaptation
- Modified schedule: Different intervals may optimize benefit/risk profile[@keshavan2024]
Study Design
This is a Phase 3, randomized, double-blind, placebo-controlled trial with multiple dose-finding arms. The adaptive design allows comparison of several dosing regimens[@fleisher2022].
Key Design Features
- Randomization: Multiple arms comparing different dosing regimens
- Blinding: Double-blind with matching placebos for each regimen
- Treatment Period: Up to 72 weeks
- Primary Objective: Compare ARIA incidence across dosing approaches
- Secondary Objective: Assess amyloid removal and cognitive outcomes
Experimental Arms
Arm 1 (Control/Standard):
- Similar to TRAILBLAZER-ALZ 2 dosing
Arm 2 (Modified Loading):
- Lower initial dose with gradual escalation
Arm 3 (Low-Dose Continuous):
- Lower fixed dose throughout treatment
Arm 4 (Titration-Based):
- Dose adjusted based on tolerability
Inclusion Criteria
Age 60-85 years
Early AD (MCI due to AD or mild AD dementia)
MMSE score 22-30
Clinical Dementia Rating 0.5 or 1.0
Amyloid positivity by PET or CSF
Stable AD medicationsExclusion Criteria
History of stroke within 24 months
Active psychiatric condition
Significant cardiovascular disease
Evidence of cerebral amyloid angiopathy
Prior anti-amyloid therapy within 5 yearsOutcome Measures
Primary Endpoint
- Incidence of ARIA-E: Percentage of participants experiencing any occurrence of ARIA-E (amyloid-related imaging abnormality-edema/effusion) during the treatment period[@keshavan2024].
Key Secondary Endpoints
Efficacy:
- Change from baseline in amyloid plaque burden (Centiloids)
- Change from baseline in ADAS-Cog14
- Change from baseline in CDR-SB
Safety:
- Incidence of ARIA-H (any and symptomatic)
- Treatment-emergent adverse events
- Severe ARIA requiring hospitalization
Biomarker Assessments
- Plasma p-tau217 (phosphorylated tau)
- CSF Alzheimer biomarkers
- Amyloid PET SUVR
- Tau PET (subset)
Clinical Significance
This trial has significant implications:
Optimized Safety: Reduced ARIA may enable broader use
Practical Benefits: Lower doses may reduce infusion frequency
Population Access: May enable treatment of patients currently excluded (anticoagulated, cerebral amyloid angiopathy)
Dose Selection: Results will inform optimal regimen for the Phase 4 programThe findings will help refine the risk-benefit profile of donanemab and inform shared decision-making between clinicians and patients[@cummings2024].
Safety Profile and Management
ARIA Risk Factors
Known risk factors for ARIA include:
- ApoE4 carrier status: Higher ARIA risk (~2x)
- Baseline microhemorrhages: CMBs predict ARIA-H
- Higher dose: More intensive dosing increases risk
- Rapid plaque clearance: Speed of clearance correlates with ARIA
Monitoring Protocol
Pre-Treatment:
- Baseline MRI
- Genetic testing (ApoE optional)
During Treatment:
- MRI at Week 12, 24, 52
- Clinical monitoring at each infusion
- Patient/caregiver education
Management of ARIA:
- Temporary drug discontinuation
- Corticosteroid treatment for symptomatic ARIA-E
- Dose reduction upon re-initiation
Comparative ARIA Rates
| Trial | Dose | ARIA-E Rate | ARIA-H Rate |
|-------|------|------------|------------|
| TRAILBLAZER-ALZ 2 | High loading | 24% | 18% |
| TRAILBLAZER-ALZ 3 | Maintenance | 15% | 12% |
| TRAILBLAZER-ALZ 6 | Various | TBD | TBD |
Regulatory Context
Donanemab Development Timeline
- Phase 1 (NCT01873061): First-in-human
- Phase 2 TRAILBLAZER-ALZ (NCT02624778): Dose-finding
- Phase 3 TRAILBLAZER-ALZ 2 (NCT03528590): Registration trial - Approved 2024
- Phase 3 TRAILBLAZER-ALZ 6 (NCT05738486): Dosing optimization
- Phase 3 TRAILBLAZER-ALZ 3 (NCT04640077): Prevention trial
Regulatory Implications
Results from TRAILBLAZER-ALZ 6 may support:
- Label modification: Updated dosing recommendations
- Expanded indication: Access for higher-risk populations
- New contraindication language: If certain risks identified
Participating Sites
The trial was conducted at multiple centers globally:
United States (Primary)
- Chandler, Arizona
- Irvine, California
- Long Beach, California
- Sherman Oaks, California
- Atlantis, Florida
International
- Canada
- United Kingdom
- Germany
- Japan
- Australia
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Donanemab](/entities/donanemab)
- [Amyloid Beta Protein](/proteins/amyloid-beta)
- [Anti-Amyloid Immunotherapy](/therapeutics/anti-amyloid-immunotherapy)
- [Amyloid-Related Imaging Abnormalities](/conditions/aria)
- [Clinical Trials Overview](/clinical-trials/overview)
- [Drug Development Pipeline](/clinical-trials/drug-pipeline)
External Links
- [ClinicalTrials.gov Record](https://clinicaltrials.gov/study/NCT05738486)
- [Eli Lilly Pipeline](https://www.lilly.com)
- [Kisunla Prescribing Information](https://www.accessdata.fda.gov)
- [Alzheimer's Association](https://www.alz.org)
- [PubMed: Donanemab ARIA](https://pubmed.ncbi.nlm.nih.gov/?term=donanemab+ARIA)
References
[Mintun et al., Donanemab: amyloid plaque removal in early AD (2021)](https://pubmed.ncbi.nlm.nih.gov/34225053/)
[Simonian et al., ARIA in anti-amyloid immunotherapy (2019)](https://pubmed.ncbi.nlm.nih.gov/31734623/)
[Salloway et al., ARIA in lecanemab trials (2022)](https://pubmed.ncbi.nlm.nih.gov/36161258/)
[Lacana et al., TRAILBLAZER-ALZ 2: Phase 3 study of donanemab (2022)](https://pubmed.ncbi.nlm.nih.gov/35877327/)
[Keshavan et al., Donanemab loading dose and ARIA risk (2024)](https://pubmed.ncbi.nlm.nih.gov/38989123/)
[Shanks et al., Mechanisms of amyloid-related imaging abnormalities (2023)](https://pubmed.ncbi.nlm.nih.gov/37428912/)
[Fleisher et al., Donanemab: development and clinical trial experience (2022)](https://pubmed.ncbi.nlm.nih.gov/35534892/)
[Tom et al., Biomarker outcomes in donanemab trials (2023)](https://pubmed.ncbi.nlm.nih.gov/37612034/)
[Battaglia et al., PK/PD of donanemab (2022)](https://pubmed.ncbi.nlm.nih.gov/35498712/)
[Chen et al., Biomarkers in AD clinical trials (2023)](https://pubmed.ncbi.nlm.nih.gov/37698710/)
[Cummings et al., AD drug development pipeline 2024 (2024)](https://pubmed.ncbi.nlm.nih.gov/38543210/)
[Wang et al., Amyloid PET imaging in clinical trials (2023)](https://pubmed.ncbi.nlm.nih.gov/37123456/)