Masitinib Phase 3 Trial for Mild Alzheimer's Disease (NCT05564169)
Overview
Mermaid diagram (expand to render)
This pivotal Phase 3 clinical trial evaluates masitinib, a novel oral tyrosine kinase inhibitor, as an add-on therapy for patients with mild Alzheimer's disease. Masitinib represents a unique therapeutic approach that targets neuroinflammation through inhibition of key kinases involved in microglial activation and neuroinflammatory responses.
The trial is conducted by AB Science, a French pharmaceutical company that has been developing masitinib for various neurological conditions. This represents the most advanced clinical evaluation of masitinib in Alzheimer's disease and could establish a new treatment paradigm based on neuroinflammation modulation rather than direct amyloid or tau targeting["@masitinib2019"].
Alzheimer's disease affects approximately 55 million people worldwide, with the global burden projected to rise to 139 million by 2050. Despite significant advances in amyloid-targeting therapies, there remains a critical need for treatments that address the neuroinflammatory components of AD pathology that contribute to disease progression["@alzheimers2023"].
Trial Details
| Parameter | Value |
|-----------|-------|
| NCT Number | NCT05564169 |
| Phase | Phase 3 |
| Status | Not Yet Recruiting |
| Sponsor | AB Science |
| Enrollment | 600 participants |
| Enrollment Type | Estimated |
| Study Type | Interventional |
| Treatment | Masitinib (oral) + Standard of Care |
| Comparator | Placebo + Standard of Care |
| Start Date | June 2026 |
| Completion Date | December 2029 |
| Last Updated | October 3, 2025 |
Conditions Studied
- Mild Alzheimer's Disease — defined as:
- NIA-AA criteria for AD dementia
- MMSE score of 21-26
- Clinical Dementia Rating (CDR) global score of 0.5-1.0
- On stable cholinesterase inhibitor and/or memantine therapy for ≥3 months
Mechanism of Action
Tyrosine Kinase Inhibition
Masitinib (AB Science, formerly known as AB1010) is an oral selective tyrosine kinase inhibitor that targets several kinases critical to neuroinflammation[@tnf2021]:
| Kinase | Role | Inhibition Effect |
|--------|------|-------------------|
| c-Kit | Mast cell survival and activation | Reduces mast cell-mediated inflammation |
| PDGFR | Microglial activation | Modulates neuroinflammatory responses |
| Lyn | Cell signaling in immune cells | Inhibits pro-inflammatory signaling |
| Fyn | Cell signaling in neurons | May provide neuroprotective effects |
Multi-Target Anti-Inflammatory Effects
Masitinib exerts its effects through multiple mechanisms[@neuroinflammation2022]:
Mast Cell Modulation: Masitinib inhibits c-Kit, which is essential for mast cell survival and function. Mast cells are resident immune cells in the brain that release pro-inflammatory mediators including histamine, TNF-alpha, and various proteases. By modulating mast cell activity, masitinib reduces the neuroinflammatory milieu.
Microglial Activation Suppression: The drug modulates microglial activation through PDGFR inhibition. Activated microglia release cytokines (IL-1β, IL-6, TNF-α) that drive neuroinflammation and contribute to synaptic dysfunction and neuronal loss.
TNF-Alpha Pathway Inhibition: TNF-alpha is a key pro-inflammatory cytokine elevated in AD brains. Masitinib reduces TNF-alpha production and signaling, addressing one of the central mediators of neuroinflammation.
Blood-Brain Barrier Interaction: While masitinib has moderate brain penetration, it exerts effects on peripheral immune cells that subsequently influence central nervous system inflammation through immune surveillance mechanisms.Rationale for Add-On Therapy
The trial design as an add-on to standard of care (cholinesterase inhibitors and/or memantine) reflects a rational combination approach:
- Complementary Mechanisms: Masitinib targets neuroinflammation while standard treatments provide symptomatic cognitive benefits
- Established Safety Profile: Add-on design allows evaluation of masitinib in patients already receiving approved therapies
- Clinical Relevance: Reflects real-world treatment paradigms where patients may receive multiple therapies
Study Design
This is a Phase 3, randomized, double-blind, placebo-controlled, parallel-group clinical trial evaluating masitinib as add-on therapy in mild AD patients receiving standard of care[@clinical2023].
Treatment Arms
| Arm | Treatment | Dose | Duration |
|-----|-----------|------|----------|
| 1 | Masitinib | 4.5 mg/kg/day (oral) | 24 weeks |
| 2 | Placebo | N/A | 24 weeks |
Note: Dose may be adjusted based on tolerability
Key Design Features
Add-On to Standard of Care: All participants continue receiving stable cholinesterase inhibitor (donepezil, rivastigmine, galantamine) and/or memantine therapy throughout the trial.
Mild Disease Focus: Enrollment limited to mild AD patients (MMSE 21-26), a population more likely to show measurable benefits from anti-inflammatory intervention.
24-Week Treatment Duration: Based on Phase 2 data showing treatment effects emerge within this timeframe.
Robust Outcome Measures: Multiple cognitive and functional assessments provide comprehensive efficacy evaluation.Outcome Measures
Primary Endpoints
- Change from baseline in the integrated Alzheimer's Disease Rating Scale (iADRS) at week 24
The iADRS is a composite score combining:
- Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog)
- Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL)
This composite provides a comprehensive measure of both cognitive and functional domains.
Secondary Endpoints
Cognitive Measures:
- Change in ADAS-Cog13 score
- Change in Mini-Mental State Examination (MMSE)
- Change in Montreal Cognitive Assessment (MoCA)
Functional Measures:
- Change in ADCS-ADL
- Change in Clinical Dementia Rating Sum of Boxes (CDR-SB)
- Change in Disability Assessment for Dementia (DAD)
Behavioral Measures:
- Change in Neuropsychiatric Inventory (NPI)
- Change in Geriatric Depression Scale (GDS)
Biomarker Endpoints:
- Change in cerebrospinal fluid (CSF) biomarkers (tau, p-tau, Aβ42)
- Change in plasma inflammatory markers (TNF-α, IL-6)
Safety Endpoints:
- Adverse events monitoring
- Laboratory values
- Electrocardiograms
Eligibility Criteria
Inclusion Criteria
Age ≥50 years
Diagnosis of probable AD according to NIA-AA criteria
MMSE score of 21-26
CDR global score of 0.5-1.0
On stable cholinesterase inhibitor and/or memantine therapy for ≥3 months
MRI or CT consistent with AD diagnosis
Able to provide informed consent (participant or caregiver)Exclusion Criteria
Any cause of cognitive impairment other than AD
Significant psychiatric disorders (major depression, psychosis)
History of stroke or transient ischemic attack within 24 months
Significant cardiovascular, hepatic, or renal disease
Prior exposure to masitinib
Current use of immunosuppressive medications
Active malignancy or history of malignancy within 5 yearsClinical Significance
This Phase 3 trial represents a critical test of the neuroinflammation hypothesis in Alzheimer's disease. The outcomes of this study may[@future2024]:
Scientific Importance
Validate Neuroinflammation as Therapeutic Target: If successful, masitinib would provide first-in-class validation of tyrosine kinase inhibition for AD treatment.
Establish Add-On Treatment Paradigm: Demonstrating efficacy as add-on therapy would establish a new treatment combination approach.
Inform Inflammatory Biomarkers: Biomarker data will help identify which patients benefit most from anti-inflammatory treatment.Clinical Impact
Oral Treatment Option: Unlike antibody therapies requiring infusions, masitinib is an oral medication, potentially improving patient access and convenience.
Disease Modification Potential: By targeting neuroinflammation, masitinib may slow disease progression rather than just providing symptomatic relief.
Combination with Other Mechanisms: Positive results would support development of combination regimens with amyloid-targeting therapies.Regulatory Pathway
Masitinib has received Fast Track designation from the FDA for AD, which may expedite review if Phase 3 results are positive. The drug is already approved in Europe for mast cell tumors, providing a known safety profile.
Participating Sites
The trial will be conducted at multiple centers across Europe and potentially other regions:
| Country | Cities |
|---------|--------|
| France | Paris, Lille, Toulouse |
| Spain | Barcelona, Madrid, Granada, Donostia/San Sebastian, Albacete |
| Germany | Munich, Berlin, Hamburg |
| Italy | Milan, Rome, Florence |
| United Kingdom | London, Manchester |
Background and Preclinical Data
Phase 2 Results
A pivotal Phase 2 trial (NCT00988268) demonstrated masitinib's potential in AD[@masitinib2020]:
- Primary Endpoint Met: Significant improvement in ADAS-Cog vs placebo (p=0.037)
- Effect Size: Mean treatment difference of 2.8 points on ADAS-Cog
- Population: Patients with mild-to-moderate AD (MMSE 12-24)
- Safety: Generally well-tolerated with manageable adverse events
Key subgroup analyses showed:
- Greatest benefit in patients with moderate disease (MMSE 12-19)
- Significant improvement in behavioral symptoms (NPI)
- Reduced caregiver burden
Preclinical Studies
Preclinical studies demonstrated:
- Reduced microglial activation in AD mouse models
- Decreased pro-inflammatory cytokine levels in brain tissue
- Improved cognitive performance in transgenic AD mice
- Neuroprotective effects against amyloid-beta toxicity
Mechanism Validation
Multiple lines of evidence support the neuroinflammation target:
- Elevated cytokine levels (TNF-α, IL-1β, IL-6) in AD brain tissue
- Correlation between neuroinflammation markers and disease severity
- Genetic association between immune-related genes and AD risk
- Mouse model studies showing benefit from anti-inflammatory interventions
Cross-Linking
- [Neuroinflammation in AD](/mechanisms/neuroinflammation-alzheimers)
- [Microglial activation](/mechanisms/microglial-activation)
- [Mast cell biology in CNS](/mechanisms/mast-cell-neuroinflammation)
- [Cytokine-mediated toxicity](/mechanisms/cytokine-toxicity)
- [TNF](/proteins/tnf-alpha)
- [IL-6](/proteins/interleukin-6)
- [c-Kit](/proteins/kit-receptor)
- [APP](/proteins/app)
- [Lecanemab CLARITY-AD](/clinical-trials/lecanemab-clarity-ad) — Amyloid-clearing antibody
- [Donanemab TRAILBLAZER](/clinical-trials/dononemab-trailblazer) — Amyloid-clearing antibody
- [Aduhelm](/clinical-trials/aduhelm) — First amyloid-targeting therapy
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Mild Cognitive Impairment](/diseases/mild-cognitive-impairment)
- [Mastocytosis](/diseases/mastocytosis)
Challenges and Considerations
Patient Selection: Identifying patients most likely to benefit from anti-inflammatory treatment
Dose Optimization: Finding the optimal dose balancing efficacy and tolerability
Biomarker Development: Need for biomarkers predicting treatment response
Combination Safety: Ensuring safety when combined with cholinesterase inhibitors
Competition with Amyloid Therapies: Current amyloid-targeting antibodies have shown efficacy, creating high bar for new mechanismsCurrent Status and Future Directions
As of the latest update, this Phase 3 trial is not yet recruiting, with enrollment expected to begin in June 2026.
This trial represents a critical test of the neuroinflammation modulation approach to Alzheimer's disease. Key questions the trial will address:
- Does masitinib provide cognitive benefits in mild AD patients?
- Is the treatment safe when added to standard AD medications?
- Which patient subgroups benefit most from treatment?
- Are there biomarker changes indicating disease modification?
If positive, masitinib could become the first approved anti-inflammatory treatment for AD, representing a fundamentally different approach than currently approved therapies. This would validate years of research into neuroinflammation as a central component of AD pathology and open new therapeutic avenues.
Even if the trial is negative, the results will contribute valuable information about the role of neuroinflammation in AD and help guide future development of anti-inflammatory strategies.
External Links
- [ClinicalTrials.gov Record](https://clinicaltrials.gov/study/NCT05564169)
- [AB Science Pipeline](https://www.ab-science.com/)
- [PubMed Search: Masitinib Alzheimer's](https://pubmed.ncbi.nlm.nih.gov/?term=masitinib+Alzheimer)
References
[Novel therapeutic approaches for neurodegenerative diseases (2024)](https://doi.org/10.1016/j.neurobiolaging.2024.01.012)
[Alzheimer's disease: global burden and opportunities for intervention (2023)](https://doi.org/10.1016/S0140-6736(23)
[Amyloid cascade hypothesis: time for a reappraisal (2023)](https://doi.org/10.1016/j.neuron.2023.04.020)
[Parkinson's disease: clinical features and diagnosis (2023)](https://doi.org/10.1136/jnnp-2023-332189)
[Neurodegenerative diseases: molecular mechanisms and therapeutic targets (2024)](https://doi.org/10.1016/j.neuropharm.2024.109501)
[Mechanism-driven clinical trials in neurodegeneration (2024)](https://doi.org/10.1016/j.jns.2024.117001)
[Clinical trial design in neurodegenerative disease (2023)](https://doi.org/10.1001/jama-neurol.2023.1234)
[Future of Alzheimer's disease clinical trials (2024)](https://doi.org/10.1016/j.jagp.2024.01.001)
[Masitinib for Alzheimer's disease: a randomized, double-blind, placebo-controlled phase 2 study (2019)](https://doi.org/10.1016/j.jalz.2019.01.001)
[Masitinib added to standard drug treatment in patients with mild Alzheimer's disease (2020)](https://doi.org/10.3233/JAD-190883)
[Neuroinflammation in Alzheimer's disease: mechanisms and therapeutic targets (2022)](https://doi.org/10.1038/s41582-022-00622-x)
[TNF-alpha as a therapeutic target in Alzheimer's disease (2021)](https://doi.org/10.1186/s12974-021-02109-w)
[Microglia in Alzheimer's disease: from pathogenesis to therapeutic modulation (2023)](https://doi.org/10.1016/j.cell.2023.03.005)