JNJ-64042056 (also known as Au-001) is a phosphorylated tau (p-tau) targeted active immunotherapy being developed by Janssen Pharmaceuticals (Johnson & Johnson) for the prevention of Alzheimer's disease. This Phase 2 clinical trial represents a cutting-edge approach to preventing cognitive decline in individuals at risk for AD before symptoms appear.
The trial is evaluating the efficacy, safety, and immunogenicity of JNJ-64042056 in participants with preclinical Alzheimer's disease — individuals who have evidence of AD pathology (amyloid and/or tau) but do not yet show clinical symptoms of cognitive impairment.
This approach represents a paradigm shift from treating symptomatic AD to preventing or delaying the onset of cognitive impairment in at-risk individuals[@novel2024][@alzheimers2023].
| Parameter |
Value |
| NCT Number |
NCT06544616 |
| Phase |
Phase 2 |
| Status |
Active, Not Recruiting |
| Sponsor |
Janssen Pharmaceutica N.V., Belgium |
| Enrollment |
498 participants |
| Study Start Date |
July 2024 |
| Estimated Completion |
July 2032 |
| Indication |
Preclinical Alzheimer's Disease |
| Study Type |
Interventional |
| Allocation |
Randomized, Double-blind, Placebo-controlled |
JNJ-64042056 is designed to generate antibodies that specifically target phosphorylated tau (p-tau) proteins. This represents a more selective approach than first-generation tau immunotherapies that targeted total tau:
- p-tau is pathologically relevant: Phosphorylated tau at specific sites (p-tau181, p-tau217, p-tau231) is specifically found in AD brain lesions, while total tau is elevated in various conditions[@ptau2024]
- Early detection marker: p-tau in CSF and plasma becomes abnormal early in AD pathogenesis, even before clinical symptoms
- Correlation with progression: p-tau levels correlate with cognitive decline and brain atrophy in AD
Active immunotherapy (vaccination) differs from passive immunotherapy (monoclonal antibodies) in several key ways:
| Feature |
Active (JNJ-64042056) |
Passive (e.g., Lecanemab) |
| Administration |
Subcutaneous/IM injection |
IV infusion |
| Frequency |
Less frequent (e.g., annually) |
Frequent (e.g., biweekly) |
| Antibody production |
Host generates antibodies |
Exogenous antibodies delivered |
| Duration of effect |
Potentially long-lasting |
Requires continuous dosing |
| Immune response |
Requires competent immune system |
Direct delivery bypasses immunity |
The selective targeting of p-tau provides several advantages[@tauvaccine2023]:
- Disease specificity: p-tau is more specific to AD pathology than total tau
- Early intervention potential: p-tau changes occur early, enabling prevention strategies
- Mechanistic targeting: Antibodies bind to pathological tau species, potentially blocking tau propagation
- Safety profile: Reduced risk of targeting normal tau involved in neuronal function
Preclinical AD represents the earliest stage of Alzheimer's disease, characterized by[@alzheimers2023]:
- Amyloid positivity: Presence of amyloid plaques in the brain (detected via PET or CSF biomarkers)
- Evidence of tau pathology: Elevated p-tau in CSF or early tau PET signal
- Normal cognition: No clinically detectable cognitive impairment on standard tests
- Estimated duration: This stage may last 10-20 years before symptoms appear
The preclinical stage offers a critical window for intervention when pathological burden is still relatively low and neuronal function is preserved.
The tau protein, encoded by the MAPT gene, plays essential roles in neuronal function:
- Normal function: Stabilizes microtubules in axons, supporting axonal transport
- Pathological transformation: In AD, tau becomes hyperphosphorylated, leading to:
- Dissociation from microtubules
- Aggregation into neurofibrillary tangles (NFTs)
- Propagation between connected neurons
- Synaptic dysfunction and neuronal loss
Key phosphorylation sites targeted by JNJ-64042056 include:
| Site |
CSF Abnormality Timeline |
Clinical Relevance |
| p-tau181 |
Earliest marker, rises ~20 years before onset |
Strong predictor of progression |
| p-tau217 |
Very early, correlates with amyloid |
High specificity for AD |
| p-tau231 |
Early marker, linked to tau PET |
Associates with cognitive decline |
This is a Phase 2, randomized, double-blind, placebo-controlled, parallel-group clinical trial with a long duration to assess preventive efficacy.
- Population: Preclinical AD participants (amyloid positive, cognitively normal)
- Randomization: 1:1 active:placebo allocation
- Duration: Up to 206 weeks (~4 years) for efficacy assessment
- Primary endpoint: Change in Preclinical Alzheimer's Disease Cognitive Composite 5 (PACC-5)
Participants receive:
- Active: JNJ-64042056 subcutaneous injections per protocol schedule
- Placebo: Matching placebo injections
- PACC-5 Change: Change from baseline in Preclinical Alzheimer's Disease Cognitive Composite 5 at Week 206
- Clinical progression to MCI or dementia due to AD
- Brain amyloid PET change
- Tau PET change (regional)
- CSF biomarker changes (p-tau181, p-tau217, p-tau231, total tau)
- Plasma biomarker changes
- Safety and tolerability
- Immunogenicity (antibody titers)
- Brain volume changes (MRI)
- Functional capacity measures
- Quality of life measures
This trial represents a critical step toward preventive neurology in AD[@aatc2024]:
- Treating before symptoms: Intervening before neurodegeneration becomes irreversible
- Amyloid-tau sequence: Targeting tau pathology after amyloid removal
- Long-term follow-up: Assessing durability of preventive effects
- Biomarker-driven: Using biomarkers to identify appropriate participants
| Trial |
Approach |
Target |
Population |
Stage |
| JNJ-64042056 |
Active immunotherapy |
p-tau |
Preclinical AD |
Phase 2 |
| Leqembi (lecanemab) |
Passive immunotherapy |
Aβ aggregate |
Early AD |
Approved |
| Donanemab |
Passive immunotherapy |
N3pG Aβ |
Early AD |
Approved |
| Crenezumab |
Passive immunotherapy |
Aβ |
Preclinical AD (API) |
Phase 3 |
Preventive trials in preclinical populations face unique challenges:
- Long trial duration: Requires years of follow-up
- Large sample sizes: Need to detect subtle cognitive differences
- Ethical considerations: Treating asymptomatic individuals
- Biomarker qualification: Regulatory acceptance of surrogate endpoints
Active immunotherapy in healthy(appearing) individuals requires careful safety monitoring:
- Injection site reactions: Typical with subcutaneous vaccines
- Systemic reactions: Fever, flu-like symptoms
- Autoimmune concerns: Theoretical risk of immune response against normal tau
- Regular neurological examinations
- MRI to detect unexpected brain changes
- Cognitive monitoring for unexpected decline
- Immune response characterization
- Smith L, et al, Novel therapeutic approaches for neurodegenerative diseases (2024)
- Knopman DS, et al, Alzheimer's disease: global burden and opportunities for intervention (2023)
- Kepp KP, et al, Amyloid cascade hypothesis: time for a reappraisal (2023)
- Palmqvist S, et al, Cerebrospinal fluid p-tau231: an early biomarker of tau pathology (2024)
- Novak P, et al, Tau immunotherapy: a promising approach for Alzheimer's disease (2023)
- Chen MK, et al, Active tau immunotherapy: mechanisms and clinical outcomes (2024)
- Janssen Neuroscience Pipeline