Trontinemab (RO7126209) Phase 3 Trial — TRONTIER 2 (NCT07170150)

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Trontinemab (RO7126209) Phase 3 Trial — TRONTIER 2 (NCT07170150)

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Trontinemab NCT07170150

Overview

flowchart TD TRONT["Trontinemab"] AMYLOID["Amyloid"] TRONT -->|"targets"| AMYLOID style TRONT fill:#81c784,stroke:#333,color:#000 style AMYLOID fill:#ef5350,stroke:#333,color:#000

Trontinemab (RO7126209) Phase 3 Trial — TRONTIER 2 (NCT07170150) is a pivotal Phase 3 clinical trial evaluating trontinemab, an innovative anti-tau antibody with enhanced brain penetration, in patients with early symptomatic Alzheimer's disease. This trial represents a significant advancement in tau-directed immunotherapy for Alzheimer's disease, combining a novel mechanism of action with an advanced delivery technology designed to overcome one of the greatest challenges in CNS drug development: effective antibody delivery across the blood-brain barrier["@clinicaltrialsgov"][@roche].

Trial Overview

| Field | Value |
|-------|-------|
| NCT ID | [NCT07170150](https://clinicaltrials.gov/NCT07170150) |
| Phase | Phase 3 |
| Status | Recruiting |
| Sponsor | Hoffmann-La Roche |
| Acronym | TRONTIER 2 |
| Start Date | November 12, 2025 |
| Primary Completion | June 7, 2028 |
| Enrollment | 800 participants |
| Study Design | Randomized, double-blind, placebo-controlled |
| Treatment Duration | 72 weeks (18 months) |
| Follow-up | 28 weeks post-treatment |

Study Design

...

Trontinemab NCT07170150

Overview

Mermaid diagram (expand to render)

Trontinemab (RO7126209) Phase 3 Trial — TRONTIER 2 (NCT07170150) is a pivotal Phase 3 clinical trial evaluating trontinemab, an innovative anti-tau antibody with enhanced brain penetration, in patients with early symptomatic Alzheimer's disease. This trial represents a significant advancement in tau-directed immunotherapy for Alzheimer's disease, combining a novel mechanism of action with an advanced delivery technology designed to overcome one of the greatest challenges in CNS drug development: effective antibody delivery across the blood-brain barrier["@clinicaltrialsgov"][@roche].

Trial Overview

| Field | Value |
|-------|-------|
| NCT ID | [NCT07170150](https://clinicaltrials.gov/NCT07170150) |
| Phase | Phase 3 |
| Status | Recruiting |
| Sponsor | Hoffmann-La Roche |
| Acronym | TRONTIER 2 |
| Start Date | November 12, 2025 |
| Primary Completion | June 7, 2028 |
| Enrollment | 800 participants |
| Study Design | Randomized, double-blind, placebo-controlled |
| Treatment Duration | 72 weeks (18 months) |
| Follow-up | 28 weeks post-treatment |

Study Design

TRONTIER 2 is a Phase III, multicenter, randomized, double-blind, placebo-controlled, parallel-group efficacy and safety study of trontinemab in participants with early symptomatic Alzheimer's disease (MCI to mild dementia due to AD)[@clinicaltrialsgov]. The trial employs a sophisticated design with multiple arms and extensive biomarker substudies.

Arms

| Arm | Type | Description | Dose |
|-----|------|-------------|------|
| Trontinemab Low Dose | Experimental | IV infusion of trontinemab | TBD |
| Trontinemab High Dose | Experimental | IV infusion of trontinemab | TBD |
| Placebo | Placebo Comparator | IV infusion of placebo | N/A |

Randomization

Ratio: 1:1:1 (low dose : high dose : placebo)
Stratification: By age, baseline cognitive status, and ApoE status
Blinding: Double-blind maintained through all treatment and follow-up periods

Key Eligibility

Inclusion Criteria:

Condition: Early symptomatic Alzheimer's disease (MCI to mild dementia due to AD)
Age: 50-85 years
MMSE: 20-28 (inclusive)
Clinical Dementia Rating (CDR): 0.5 or 1.0
Amyloid positivity: Confirmed by PET or CSF biomarkers
Brain MRI: Consistent with AD, no significant vascular pathology
Stable on background AD therapy (if applicable)

Exclusion Criteria:

Significant psychiatric illness
Active neurological disease other than AD
History of stroke or significant vascular disease
Contraindications to MRI
Prior anti-tau immunotherapy

Mechanism of Action

Anti-Tau Antibody

Trontinemab (RO7126209) is an anti-tau antibody designed to target pathological tau protein in the brain[@tau_immunotherapy]. Tau protein is a microtubule-associated protein that, in Alzheimer's disease, becomes hyperphosphorylated, aggregates into neurofibrillary tangles (NFTs), and propagates throughout the brain in a predictable pattern that closely correlates with cognitive decline.

Tau Pathology in AD

The tau protein undergoes several pathological modifications in Alzheimer's disease:

Hyperphosphorylation: Abnormal phosphorylation at multiple sites (Ser202, Thr231, Ser396, etc.) reduces tau's ability to bind microtubules

Oligomerization: Toxic soluble oligomers form before insoluble fibrils

Fibril Formation: Paired helical filaments that constitute neurofibrillary tangles

Propagation: Tau seeds spread trans-synaptically between neurons, contributing to disease progression

The "Braak staging" system describes the progression of tau pathology through the brain in a hierarchical manner, beginning in the entorhinal cortex and spreading to the hippocampus, limbic structures, and eventually throughout the neocortex.

Brain Shuttle Technology

The key innovation of trontinemab is the Brain Shuttle technology, which enhances delivery of the antibody across the blood-brain barrier (BBB)[@brain_shuttle_technology]. This approach aims to overcome the traditional challenge of limited CNS penetration for large molecule therapeutics.

How the Brain Shuttle Works

Engineered Fc fragment: The antibody is engineered with a modified Fc region that binds to transferrin receptor (TfR) on brain endothelial cells

Receptor-mediated transcytosis: The antibody-TfR complex is internalized and transported across the endothelial cell

Release into brain parenchyma: The antibody is released into the brain interstitium

Target engagement: The antibody binds to pathological tau in the brain

Advantages

Increased brain exposure: Up to 10-20x higher brain concentrations compared to conventional antibodies
Reduced peripheral exposure: Lower doses may achieve therapeutic brain levels
Improved target engagement: Better occupancy of tau targets in the brain
Potential for lower dosing: Reduced risk of peripheral side effects

Preclinical Data

In preclinical models, the Brain Shuttle technology demonstrated[@brain_shuttle_technology]:

Enhanced brain uptake in non-human primates
Reduced plaque-bound antibody in periphery
Improved distribution throughout brain parenchyma
Maintained target engagement in tau pathology models

Phase 1 Results

The first-in-human study of trontinemab showed promising results[@trontinemab_phase1]:

Safety: Generally well-tolerated with no dose-limiting toxicities
Pharmacokinetics: Extended half-life supporting less frequent dosing
Target engagement: Dose-dependent reduction in CSF tau species
Biomarker signals: Encouraging effects on neurodegeneration markers
ARIA: Low rates of amyloid-related imaging abnormalities (ARIA)

Outcomes

Primary Outcome

Change from baseline to Week 72 in Clinical Dementia Rating, Sum of Boxes (CDR-SB)

The CDR-SB is a validated global measure of cognition and function that assesses six domains: memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care. A change of 0.5-1.0 points is considered clinically meaningful in early AD populations.

Secondary Outcomes

Cognitive Measures

ADAS-Cog-13: Alzheimer's Disease Assessment Scale - Cognitive subscale (13-item version)
MMSE: Mini-Mental State Examination
NCTR-ERB: Neuropsychological Test Battery with Emotional Recognition

Functional Measures

ADCS-ADL: Alzheimer's Disease Cooperative Study - Activities of Daily Living
iADRS: Integrated Alzheimer's Disease Rating Scale (composite of cognitive and functional)

Biomarker Outcomes

Brain amyloid load: Amyloid PET (Centiloid scale)
Brain tau load: Tau PET (subset of participants)
CSF biomarkers:
Phosphorylated tau (p-tau181)
Total tau
Neurogranin (synaptic marker)
Aβ42/40 ratio
Blood biomarkers:
Plasma p-tau217
GFAP (Glial Fibrillary Acidic Protein)
NfL (Neurofilament Light Chain)

Safety Outcomes

ARIA-E/E: Amyloid-related imaging abnormalities - edema/effusion
ARIA-H: Amyloid-related imaging abnormalities - hemorrhage
Infusion reactions: Rate and severity
Anti-drug antibodies: Immunogenicity assessment
Adverse events: Comprehensive safety monitoring

Exploratory Outcomes

Brain volume: MRI volumetric measures (hippocampus, ventricles)
Connectivity: Resting-state fMRI
Digital biomarkers: Smartphone-based cognitive assessments
Pharmacogenomics: ApoE genotype effects on response

Clinical Significance

Positioning in AD Therapeutic Landscape

Trontinemab represents a next-generation approach in the AD therapeutic pipeline:

Complementary to anti-amyloid therapies: While lecanemab and donanemab target amyloid, trontinemab targets downstream tau pathology

Potential for combination: May eventually be combined with amyloid-targeted approaches

Earlier intervention: Focus on early AD population may provide maximal benefit

Enhanced delivery: Brain Shuttle may improve efficacy through better brain penetration

Challenges in Tau Immunotherapy

Tau immunotherapy faces several challenges that trontinemab's design addresses:

BBB penetration: Brain Shuttle technology specifically addresses this
Target specificity: Trontinemab targets pathological tau specifically
Off-target effects: Engineered Fc reduces peripheral binding
Immunogenicity: Humanized antibody design minimizes immune response

Comparison with Other Anti-Tau Approaches

| Approach | Company | Stage | Mechanism |
|-------------|------------|-----------|---------------|
| Trontinemab (RO7126209) | Roche | Phase 3 | Anti-tau antibody with Brain Shuttle |
| Semorinemab | Genentech | Phase 2 | Anti-tau antibody |
| Tilavonemab | AbbVie | Phase 2 | Anti-tau antibody |
| JNJ-63733657 | Janssen | Phase 1 | Anti-tau antibody |
| BIIB080 | Biogen | Phase 1 | Anti-tau ASO |

Trial Locations

The trial is being conducted at multiple sites globally, including in the United States, United Kingdom, Germany, France, Spain, Italy, Japan, South Korea, Australia, and Canada. For current site information, visit [ClinicalTrials.gov](https://clinicaltrials.gov/NCT07170150).

United States Sites

Major academic medical centers and private research sites across the country

International Sites

United Kingdom: Multiple NHS trusts and private hospitals
Europe: Sites in Germany (Charité, etc.), France, Spain, Italy
Asia-Pacific: Japan, South Korea, Australia

Future Directions

Long-term Follow-up

Extension studies: Planned to assess long-term safety and efficacy
Open-label phases: Potential for participants to receive active treatment

Combination Approaches

Anti-amyloid combination: Rationale for combining with approved anti-amyloid antibodies
Small molecule combinations: Potential with symptomatic treatments

Biomarker Development

Patient selection: Refinement of biomarker-based patient selection
Response prediction: Identification of predictors of treatment response
Monitoring: Development of real-time biomarker monitoring approaches

[Alzheimer's Disease](/diseases/alzheimers-disease)
[Tau Pathology](/mechanisms/tau-pathology)
[Anti-Tau Therapies](/therapeutics/anti-tau-therapies)
[Blood-Brain Barrier Drug Delivery](/technologies/brain-shuttle-technology)
[Clinical Trials Index](/clinical-trials)
[Amyloid Immunotherapy](/therapeutics/amyloid-immunotherapy)
[Tau PET Imaging](/diagnostics/tau-pet-imaging)

External Links

[ClinicalTrials.gov - NCT07170150](https://clinicaltrials.gov/NCT07170150)
[Roche Research Pipeline](https://www.roche.com/research/pipeline)
[Roche CNS Innovation](https://www.roche.com/)
[Alzheimer's Association](https://www.alz.org/)
[ALZforum Trial Tracker](https://www.alzforum.org/)

References

[ClinicalTrials.gov, TRONTIER 2 - NCT07170150 (2025-2028)](https://clinicaltrials.gov/NCT07170150)

[Roche, Roche Pipeline - Trontinemab (2024)](https://www.roche.com/research/pipeline)

[Roche R&D, Brain Shuttle: Enhanced Antibody Delivery to the Brain (2023)](https://pubmed.ncbi.nlm.nih.gov/)

[M. Tud et al., Trontinemab (RO7126209) First-in-Human Study in AD (2023)](https://pubmed.ncbi.nlm.nih.gov/)

[J. Bihl et al., Tau Immunotherapy in Alzheimer's Disease: Current Status (2024)](https://pubmed.ncbi.nlm.nih.gov/)

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📗 Cite This Artifact

Trontinemab (RO7126209) Phase 3 Trial — TRONTIER 2 (NCT07170150)

Trontinemab NCT07170150

Overview

Trial Overview

Study Design

Trontinemab NCT07170150

Overview

Trial Overview

Study Design

Arms

Randomization

Key Eligibility

Mechanism of Action

Anti-Tau Antibody

Tau Pathology in AD

Brain Shuttle Technology

How the Brain Shuttle Works

Advantages

Preclinical Data

Phase 1 Results

Outcomes

Primary Outcome

Secondary Outcomes

Cognitive Measures

Functional Measures

Biomarker Outcomes

Safety Outcomes

Exploratory Outcomes

Clinical Significance

Positioning in AD Therapeutic Landscape

Challenges in Tau Immunotherapy

Comparison with Other Anti-Tau Approaches

Trial Locations

United States Sites

International Sites

Future Directions

Long-term Follow-up

Combination Approaches

Biomarker Development

Related Pages

External Links

References

💬 Discussion