Anti-Tau Therapeutics
Introduction
Anti Tau Therapeutics is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
<div class="infobox">
<table>
<tr><th colspan="2" style="background:#f0f0f0;">Anti-Tau Therapeutics</th></tr>
<tr><td><b>Category</b></td><td>Disease-Modifying Therapy</td></tr>
<tr><td><b>Target Diseases</b></td><td>Alzheimer's Disease, Progressive Supranuclear Palsy, Corticobasal Degeneration, Primary Tauopathies</td></tr>
<tr><td><b>Mechanism</b></td><td>Reduce tau phosphorylation, aggregation, and propagation</td></tr>
<tr><td><b>Approaches</b></td><td>Kinase inhibitors, aggregation inhibitors, immunotherapy, microtubule stabilizers</td></tr>
</table>
</div>
Overview
Mermaid diagram (expand to render)
Anti-tau therapeutics aim to modify the course of tauopathies by targeting the pathological accumulation and spread of hyperphosphorylated tau protein. Tau normally stabilizes microtubules, but in disease states it becomes hyperphosphorylated, dissociates from microtubules, aggregates into neurofibrillary tangles (NFTs), and spreads between neurons in a prion-like manner. These therapies represent the most advanced disease-modifying approaches for Alzheimer's disease and primary tauopathies["@wang2016"].
Tau Biology and Therapeutic Targets
Tau isoforms and post-translational modifications
- Six isoforms: Generated by alternative splicing of MAPT gene
- 3R vs 4R tau: Primary tauopathies characterized by isoform ratios
- PTMs: Phosphorylation (60+ sites), acetylation, truncation, ubiquitination
Therapeutic target nodes
Kinases: Reduce tau phosphorylation
Phosphatases: Enhance dephosphorylation
Aggregation inhibitors: Prevent fibril formation
Immunotherapy: Clear existing tau pathology
Microtubule stabilizers: Preserve neuronal functionKinase Inhibitors
Glycogen Synthase Kinase-3 (GSK-3β)
GSK-3β is the primary kinase responsible for pathological tau phosphorylation.
- Lithium: First-generation inhibitor, modest efficacy in clinical trials[@forlenza2019]
- Tideglusib: Selective GSK-3β inhibitor, failed in PSP Phase II[@tolosa2014]
- AZD1089: Advanced GSK-3 inhibitor, discontinued due to toxicity
Cyclin-Dependent Kinase-5 (CDK5)
Critical for normal tau phosphorylation; hyperactivation contributes to pathology.
- Roscovitine: CDK2/5/7 inhibitor, limited brain penetration
- CYC202 (Seliciclib): Broad CDK inhibitor, in clinical trials
Other kinases
- DKK1 inhibitors: Block Wnt pathway activation
- JNK inhibitors: Target stress-activated kinase pathway
- CK1δ/ε inhibitors: Casein kinase inhibitors
Aggregation Inhibitors
Small Molecule Inhibitors
- Methylene Blue derivatives: First-generation aggregation inhibitors, mixed clinical results[@wischik2015]
- Phenylthiazolyl-hydrazide compounds: Inhibit tau fibrillization
- NPT200-1: Calcium/calmodulin-dependent protein kinase inhibitor
Microtubule Stabilizers
Tau loss-of-function leads to microtubule destabilization.
- Paclitaxel: Poor BBB penetration limits use
- Epothilone D: Blood-brain barrier penetrant, failed in Phase I[@zhang2012]
- Davunetide (AL-108): Nasal peptide, positive in Phase II for MCI[@muresanu2016]
Immunotherapy
Active Immunization
AADvac1 (Axon Neuroscience)
- Tau peptide vaccine targeting phosphorylated tau
- Phase I: Generated robust antibody response[@novak2017]
- Phase II ADAMANT: Did not meet primary endpoint in AD[@novak2023]
ACI-35 (AC Immune)
- Liposome-based vaccine targeting phosphorylated Ser396/404
- Strong immune response in Phase Ib[@theunis2013]
Passive Immunization
Lecanemab (BAN2401) (Eisai/Biogen)
- Anti-amyloid antibody with anti-tau activity
- Phase III CLARITY-AD: Slowed cognitive decline, reduced tau spread[@van2023]
- FDA approved for early AD
Donanemab (LY3002813) (Eli Lilly)
- N-terminal tau antibody
- Phase III TRAILBLAZER-ALZ 2: Slowed cognitive decline[@sims2023]
- FDA approved for early AD
Anti-tau antibodies in development:
- Gantenerumab (Roche): Bivalent antibody, failed in Phase III
- Semorinemab (Roche): Failed in Phase II AD
- Tilavonemab (AbbVie): Failed in PSP
Clinical Trial Landscape
Comprehensive Anti-Tau Drug Ranking Table
| Rank | Drug | Company | Mechanism | Target Epitope | Phase | NCT ID | Key Results | IgG Subclass | Status |
|------|------|---------|-----------|----------------|-------|--------|-------------|--------------|--------|
| 1 | Etalanetug (E2814) | Eisai | Anti-tau mAb | MTBR (p-tau396/404) | Phase III | NCT05355493 | MTBR-tau-243 ↓30-70%, pTau217 ↓50% | IgG1 | Active |
| 2 | BIIB080 (MAPTRx) | Biogen/Ionis | ASO | MAPT mRNA | Phase II | NCT05399888 | 50-60% CSF tau reduction | N/A | Active |
| 3 | Bepranemab | UCB | Anti-tau mAb | aa 235-250 (MTBR) | Phase II | NCT05462106 | 58% tau-PET reduction, subgroup benefit | IgG4 | Active |
| 4 | JNJ-63733657 | Janssen | Anti-tau mAb | p-tau217 | Phase II | NCT04619420 | CSF p-tau217 reduction | IgG1 | Active |
| 5 | LY3372689 (Oglemilide) | Eli Lilly | OGA Inhibitor | O-GlcNAcylation | Phase II | NCT05063552 | Target engagement demonstrated | N/A | Active |
| 6 | PRX005 | Prothena/BMS | Anti-tau mAb | MTBR | Phase I | NCT05394125 | Ongoing | IgG1 | Active |
| 7 | Posdinemab (BMS-986446) | BMS | Anti-tau mAb | Mid-domain | Phase II | NCT05514899 | Ongoing | IgG1 | Active |
| 8 | MK-2214 | Merck | Anti-tau mAb | p-tau413 | Phase I | NCT05828832 | Ongoing | IgG1 | Active |
| 9 | Semorinemab | Roche | Anti-tau mAb | N-terminus | Phase II | NCT04382253 | TAURIEL failed, LAURIET mixed | IgG4 | Active |
| 10 | LU-AF87908 | Lundbeck | Anti-tau mAb | p-tau396/404 | Phase I | NCT06310149 | Phase I ongoing | IgG1 | Active |
| 11 | APNMAB005 | Alector | Anti-tau mAb | Synaptic oligomeric tau | Phase I | NCT05693922 | First-in-human ongoing | IgG1 | Active |
| 12 | NIO752 | Roche | ASO | MAPT mRNA | Phase I | NCT05838953 | Dose-escalation ongoing | N/A | Active |
| 13 | ASN90 | Asceneuron | OGA Inhibitor | O-GlcNAcylation | Phase I/II | NCT05239017 | Phase I complete, Phase II planned | N/A | Active |
| 14 | AADvac1 | Axon Neuroscience | Vaccine | p-tau | Phase II | NCT02579252 | Did not meet primary endpoint | N/A | Active |
| 15 | ACI-35 | AC Immune | Vaccine | p-tau396/404 | Phase Ib/IIa | NCT04445831 | Strong immune response | N/A | Active |
| 16 | LMTX (HMTM) | TauRx | Aggregation Inhibitor | Tau aggregates | Phase III | NCT03446001 | Controversial, not approved | N/A | Discontinued |
| 17 | Gosuranemab | Biogen | Anti-tau mAb | N-terminal | Phase II | NCT02460094 | Failed: no clinical benefit | IgG1 | Discontinued |
| 18 | Tilavonemab | AbbVie | Anti-tau mAb | N-terminal | Phase II | NCT02880991 | Failed in PSP | IgG1 | Discontinued |
| 19 | Zagotenemab | Eli Lilly | Anti-tau mAb | MC1 epitope | Phase II | NCT03518028 | Failed: no clinical benefit | IgG1 | Discontinued |
Mechanism Clustering
Tau Immunotherapy (Passive Antibodies)
MTBR-Targeting (Showing Promise):
- [Etalanetug (E2814)](/therapeutics/etalanetug-e2814) — Eisai, IgG1, p-tau396/404, Phase III
- [Bepranemab](/therapeutics/bepranemab) — UCB, IgG4, aa 235-250, Phase II
- [PRX005](/therapeutics/prx005) — Prothena/BMS, IgG1, MTBR, Phase I
p-tau217 Targeting:
- [JNJ-63733657](/therapeutics/jnj-63733657) — Janssen, IgG1, Phase II
Mid-Domain Targeting:
- [Posdinemab (BMS-986446)](/therapeutics/posdinemab) — BMS, IgG1, Phase II
p-tau413 Targeting:
- [MK-2214](/therapeutics/mk-2214) — Merck, IgG1, Phase I
p-tau396/404 Targeting:
- [LU-AF87908](/therapeutics/lu-af87908) — Lundbeck, IgG1, Phase I
Synaptic Oligomeric Tau:
- [APNMAB005](/therapeutics/apnmab005) — Alector, IgG1, Phase I
N-Terminal Targeting (FAILED):
- [Semorinemab](/therapeutics/semorinemab) — Roche, IgG4, Phase II (mixed results)
- [Gosuranemab](/therapeutics/gosuranemab) — Biogen, IgG1, Phase II (discontinued)
- [Tilavonemab](/therapeutics/tilavonemab) — AbbVie, IgG1, Phase II (discontinued)
- [Zagotenemab](/therapeutics/zagotenemab) — Eli Lilly, IgG1, Phase II (discontinued)
Tau Gene Therapy (ASOs)
- [BIIB080 (MAPTRx)](/therapeutics/biib080-maptrx) — Biogen/Ionis, MAPT mRNA knockdown, Phase II
- [NIO752](/therapeutics/nio752) — Roche, MAPT mRNA knockdown, Phase I
Tau Small Molecules
- [LY3372689 (Oglemilide)](/therapeutics/ly3372689) — Eli Lilly, OGA inhibition, Phase II
- [ASN90](/therapeutics/asn90) — Asceneuron, OGA inhibition, Phase I/II
- [LMTX/HMTM](/therapeutics/lmtx-trx0237) — TauRx, aggregation inhibitor, Phase III (discontinued)
Tau Vaccines (Active Immunization)
- [AADvac1](/therapeutics/aadvac1) — Axon Neuroscience, p-tau, Phase II
- [ACI-35](/therapeutics/aci-35-liposomal-vaccine) — AC Immune, p-tau396/404, Phase Ib/IIa
Key Insights
N-terminal antibodies FAILED: Gosuranemab, Tilavonemab, Semorinemab (failed or mixed)
MTBR-targeting showing promise: E2814, Bepranemab, PRX005
IgG1 > IgG4: TRIM21-mediated intracellular clearance favors IgG1
ASO approach validated: BIIB080 showing dose-dependent tau reduction
OGA inhibitors emerging: LY3372689 represents novel small-molecule approachApproved/Late-Stage Anti-Tau Approaches
| Drug | Company | Mechanism | Phase | Indication |
|------|---------|-----------|-------|------------|
| Lecanemab | Eisai/Biogen | mAb (Aβ/tau) | III/Approved | Early AD |
| Donanemab | Eli Lilly | mAb (N-tau) | III/Approved | Early AD |
| AADvac1 | Axon | Vaccine | II | AD/PSP |
Detailed Clinical Trial Evidence: E2814, BIIB080, and Bepranemab
This section provides comprehensive clinical trial data for the three lead anti-tau therapeutics: E2814, BIIB080, and bepranemab.
Etalanetug (E2814) — Phase III
DIAN-TU Study (NCT05355493)
| Parameter | Details |
|-----------|---------|
| Sponsor | Eisai |
| Phase | Phase III |
| Population | Autosomal dominant AD (PSEN1, PSEN2, APP mutations) |
| Enrollment | ~200 participants |
| Design | Randomized, placebo-controlled |
| Primary Endpoints | Cognitive decline (DIAN-MCI), tau PET |
| Key Results | MTBR-tau-243 reduced 30-70%; CSF pTau217 reduced 50% at 2 years |
| Status | Active, enrolling |
⚠️ 4R-Tauopathy Trial (NCT05615614) — DOES NOT EXIST IN CLINICALTRIALS.GOV
| Parameter | Details |
|-----------|---------|
| NCT ID | NCT05615614 — DOES NOT EXIST |
| Status | No active 4R-tauopathy (PSP/CBS) trial for E2814 |
Current E2814 trials:
- NCT06602258: Phase 2, AD with lecanemab (Active, not recruiting)
- NCT04971733: Phase 1/2, AD (Completed)
Phase II Dose-Finding with Lecanemab (NCT06602258)| Parameter | Details |
|-----------|---------|
| NCT ID | NCT06602258 |
| Population | MCI due to AD (n=105, target 90) |
| Design | E2814 + lecanemab combination |
| Duration | 18 months |
| Sites | 34 sites in U.S. and Japan |
| Primary Endpoint | Change in CSF MTBR-tau-243 at 6 months |
| Expected Completion | August 2027 |
BIIB080 (MAPTRx) — Phase II
Phase I Study (NCT03119818)
| Parameter | Details |
|-----------|---------|
| Population | Healthy volunteers, mild AD |
| Key Results | Dose-dependent CSF tau reduction up to 50-60% |
| Publication | Nature Medicine (2022) |
| Status | Completed |
Phase I/II Study (NCT04784160)
| Parameter | Details |
|-----------|---------|
| Population | Mild Alzheimer's disease |
| Key Results | Sustained dose-dependent CSF tau reductions |
| Publication | JAMA Neurology (2023) |
| Status | Completed |
Phase II Study (NCT05399888)
| Parameter | Details |
|-----------|---------|
| NCT ID | NCT05399888 |
| Population | Early Alzheimer's disease |
| Phase | Phase II |
| Enrollment | ~300 participants |
| Primary Endpoints | Safety, tolerability, cognitive endpoints |
| Secondary Endpoints | CSF tau reduction, tau PET |
| Design | Randomized, placebo-controlled |
| Status | Active/recruiting (2026) |
| Designation | FDA Fast Track |
Bepranemab — Phase II
Phase II Alzheimer's Disease (NCT04867616)
| Parameter | Details |
|-----------|---------|
| NCT ID | NCT04867616 |
| Population | 466 participants with MCI or mild AD dementia |
| Primary Endpoint | CDR-SB change from baseline |
| Status | Completed (primary endpoint not met) |
| Key Results | Primary not met; 58% tau-PET reduction; 33% slower decline in low-tau, non-ApoE4 carriers |
| Safety | No ARIA observed |
Phase I PSP Study
| Parameter | Details |
|-----------|---------|
| Population | 25 PSP patients |
| Duration | December 2019 – November 2021 |
| Status | Completed |
| Results | Safe, no concerns |
| Extension | Open-label extension (n=19, expected March 2027) |
Phase II PSP Trial
| Parameter | Details |
|-----------|---------|
| NCT ID | NCT05318985 |
| Target | pSer208 epitope (abundant in PSP) |
| Status | Active development |
| Rationale | 4R tauopathy with prominent brainstem pathology |
Summary of Key Clinical Trial Endpoints
| Drug | Phase | NCT ID | Primary Endpoint | Key Efficacy Finding |
|------|-------|--------|-------------------|---------------------|
| E2814 | III | NCT05355493 | Cognitive, tau PET | MTBR-tau-243 ↓30-70%, pTau217 ↓50% |
| BIIB080 | II | NCT05399888 | Safety, CSF tau | 50-60% CSF tau reduction |
| Bepranemab | II | NCT04867616 | CDR-SB | Not met; 58% tau-PET reduction |
Biomarkers for Anti-Tau Trials
Tau PET Imaging
- [^18F]Flortaucipir (AV-1451): FDA-approved tau PET ligand[@xia2017]
- [^18F]MK-6240: Next-generation tau PET tracer
- Correlates with clinical severity and progression
CSF Biomarkers
- Total tau (t-tau): Marker of neuronal damage
- Phosphorylated tau (p-tau181, p-tau217): Disease-specific[@zetterberg2019]
- Tau RT-QuIC: Seed amplification for detection
Blood-Based Biomarkers
- p-tau217: Highly specific for AD, correlates with PET[@palmqvist2020]
- p-tau181: Emerging clinical utility
- NfL: Neurodegeneration marker
Primary Tauopathies
Progressive Supranuclear Palsy (PSP)
- 4R tauopathy with characteristic brainstem pathology
- No approved disease-modifying treatments
- Anti-tau immunotherapies in clinical trials
Corticobasal Degeneration (CBD)
- 4R tauopathy with asymmetric cortical involvement
- Often responds poorly to standard therapies
Frontotemporal Dementia (FTD-Tau)
- Includes Pick's disease (3R) and others
- Genetic forms (MAPT mutations) inform therapeutic development
Combination Approaches
- Anti-amyloid + anti-tau: Lecanemab's dual mechanism
- Kinase inhibitor + immunotherapy: Complementary mechanisms
- Symptomatic + disease-modifying: Integrated treatment strategies
Challenges
Tau isoform complexity: Different diseases require different approaches
BBB penetration: Many compounds fail to reach brain
Biomarker validation: Need better surrogate endpoints
Patient selection: Genetic and biomarker stratification neededBackground
The study of Anti Tau Therapeutics has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
See Also
- [Tau Pathology Pathway](/mechanisms/tau-pathology)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Progressive Supranuclear Palsy](/diseases/progressive-supranuclear-palsy)
- [Biomarkers: p-tau 181](/content/biomarkers)
- [Biomarkers: p-tau 217](/content/biomarkers)
- [Ibudilast](/therapeutics/ibudilast)
External Links
- [Alzheimer's Association - Tau Research](https://www.alz.org/research/tau)
- [CurePSP - Tauopathies Research](https://www.psp.org/)
- [Alzheimer's Drug Discovery Foundation - Tau-Targeting Therapies](https://www.alzdiscovery.org/)
References
[Wang Y, Mandelkow E, Tau in physiology and pathology (2016)](https://pubmed.ncbi.nlm.nih.gov/26631930/))
Forlenza OV, Radanovic M, Talib LL, et al, Lithium and dementia: a systematic review and meta-analysis (2019)
[Tolosa E, Litvan I, Höglinger GU, et al, A Phase II trial of tideglusib in PSP (2014)](https://doi.org/10.1002/mds.25824))
[Wischik CM, Staff RT, Aberg KA, et al, Tau aggregation inhibitor therapy: an exploratory Phase 2 study (2015)](https://doi.org/10.3233/jad-142874))
Zhang B, Carroll J, Trojanowski JQ, et al, The microtubule stabilizer Epothilone D reduces tau-mediated neurodegeneration (2012)
Muresanu V, Buzoianu A, Marschall T, et al, Davunetide for the treatment of mild cognitive impairment (2016)
[Novak P, Schmidt R, Kontsekova E, et al, Safety and immunogenicity of the tau vaccine AADvac1 in patients with Alzheimer's disease: a randomised, double-blind, placebo-controlled, phase 1 trial (2017)](https://pubmed.ncbi.nlm.nih.gov/27955995/))
[Novak P, Kovacech B, Katina S, et al, ADAMANT: a placebo-controlled randomized phase 2 study of AADvac1, an active immunotherapy against pathological tau in Alzheimer's disease (2023)](https://pubmed.ncbi.nlm.nih.gov/37117834/))
[Theunis C, Crespo-Biel N, Gafner V, et al, Efficacy and safety of a liposome-based vaccine against protein Tau, assessed in tau.P301L mice that model tauopathy (2013)](https://pubmed.ncbi.nlm.nih.gov/23977276/))
[van Dyck CH, Swanson CJ, Aisen P, et al, Lecanemab in Early Alzheimer's Disease (2023)](https://pubmed.ncbi.nlm.nih.gov/36449413/))
[Sims JR, Zimmer JA, Evans CD, et al, Donanemab in early Alzheimer's disease (2023)](https://doi.org/10.1001/jama.2023.13239))
Xia CF, Arteaga J, Chen G, et al, \[^18F\]Flortaucipir (AV-1451) binds to tau pathology in AD brain (2017)
Zetterberg H, Tau in cerebrospinal fluid: a classic biomarker with new applications (2019)
[Palmqvist S, Janelidze S, Quiroz YT, et al, Discriminatory accuracy of plasma p-tau217 for Alzheimer disease (2020)](https://doi.org/10.1001/jama.2020.12134))From the [SciDEX Exchange](/exchange) — scored by multi-agent debate
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