This page connects to the broader neurodegenerative disease knowledge graph:
- Diseases: [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), ALS, FTD, [Huntington's disease](/diseases/huntingtons-disease), PSP, MSA
- Brain regions: [substantia nigra](/brain-regions/substantia-nigra), striatum, motor cortex, hippocampus, frontal cortex
- Cell types: [dopaminergic neurons](/cell-types/mesencephalic-dopaminergic-neurons), [astrocytes](/cell-types/astrocytes), [microglia](/cell-types/microglia), motor neurons, oligodendrocytes
- Proteins/Genes: tau, [alpha-synuclein](/proteins/alpha-synuclein), TDP-43, SNCA, GBA, LRRK2, C9orf72, HTT
- Mechanisms: [neuroinflammation](/mechanisms/neuroinflammation), [mitochondrial dysfunction](/mechanisms/mitochondrial-dysfunction), [lysosomal dysfunction](/mechanisms/lysosomal-dysfunction), [protein aggregation](/mechanisms/protein-aggregation), [oxidative stress](/mechanisms/oxidative-stress), [autophagy](/mechanisms/autophagy), [synaptic dysfunction dysfunction](/mechanisms/synaptic dysfunction-dysfunction)
- Therapeutics: [gene therapy](/therapeutics/gene-therapy-neurodegeneration), ASOs, CRISPR gene editing, deep brain stimulation
- Pathways: complement system, neurotrophic signaling, cell death pathways
This therapeutic strategy targets focal adhesion kinase (FAK, PTK2) — a non-receptor tyrosine kinase that integrates extracellular matrix signals with intracellular inflammatory and metabolic pathways. FAK is centrally involved in microglial phagocytosis, astrocyte reactivity, and synaptic dysfunction remodeling, making it a high-value target for neurodegeneration. Unlike approaches that target individual receptors, FAK inhibition blocks a central signaling hub that coordinates cell adhesion, inflammation, and survival across multiple glial and neuronal cell types. In Alzheimer's disease, Parkinson's disease, and ALS, hyperactive FAK drives excessive synapse elimination, astrocyte reactivity, and chronic neuroinflammation.
- Primary Target: FAK (PTK2) catalytic domain (ATP-binding site)
- Target Type: Small-molecule FAK inhibitor (defactinib, VS-4718 class) or allosteric inhibitor
- Expression: Expressed in microglia, astrocytes, and neurons; activity increases in disease states
- Localization: Cytoplasmic protein; localizes to focal adhesions at cell membrane upon activation
FAK is a central integrator of extracellular signals through its role in focal adhesion signaling complexes. In neurodegeneration, pathological protein aggregates (Aβ, tau, α-syn) engage integrins and other adhesion receptors, over-activating FAK and driving harmful cellular responses:
- Microglial hyper-phagocytosis: Aβ and other pathological proteins activate integrin-FAK signaling in microglia, leading to excessive synapse elimination and engulfment of healthy neurons
- Astrocyte reactivity: FAK mediates astrocyte responses to damage signals, promoting the neurotoxic A1 reactive phenotype
- Synaptic dysfunction: FAK regulates actin cytoskeleton at synapses; dysregulation contributes to synaptic dysfunction loss
- Inflammatory amplification: FAK activates downstream pathways including NF-κB, driving cytokine production in glia
- Cell migration: FAK controls glial migration; overactive FAK may contribute to inappropriate glial recruitment
FAK inhibitors have been extensively developed for oncology (defactinib reached Phase 2), providing a strong foundation for CNS repurposing.
flowchart TD
A["Aβ/Tau/α-Syn Aggregates"] --> B["Integrin Activation"]
B --> C["FAK Autophosphorylation Y397"]
C --> D["FAK Catalytic Activation"]
D --> E["p85 PI3K Recruitment"]
D --> F["Grb2/SOS → Ras/MAPK"]
D --> G["NF-κB Activation"]
E --> H["Akt Survival Signaling"]
F --> I["ERK/MAPK Proliferation"]
G --> J["Inflammatory Gene Expression"]
K["Microglial Phagocytosis"] --> C
L["Astrocyte Reactivity"] --> C
M["Synaptic Remodeling"] --> C
N["FAK Inhibitor"] -->|"Blocks"| D
O["Defactinib"] -->|"Blocks"| C
style N fill:#4CAF50,color:white
style O fill:#4FAI50,color:white
style J fill:#f44336,color:white
Cross-links to relevant mechanisms:
- Microglia and Neuroinflammation
- Astrocyte Reactivity
- Synapse Elimination
- Neuroinflammation
- Integrin Signaling
- NF-κB Signaling
| Dimension |
Score |
Rationale |
| Novelty |
8/10 |
FAK inhibitors well-developed in oncology but CNS repurposing for neurodegeneration is unexplored; addresses distinct pathway from receptor-based therapies |
| Mechanistic Rationale |
8/10 |
Strong preclinical data linking FAK to microglial phagocytosis and astrocyte reactivity; oncology drugs provide proof-of-concept |
| Addresses Root Cause |
6/10 |
Modulates downstream inflammatory responses to protein aggregation; doesn't directly clear aggregates |
| Delivery Feasibility |
8/10 |
Defactinib and VS-4718 have demonstrated BBB penetration in oncology trials; established PK profiles |
| Safety Plausibility |
7/10 |
FAK inhibitors well-tolerated in cancer trials; expected CNS side effects manageable; cardiac monitoring may be needed |
| Combinability |
8/10 |
Highly compatible with anti-aggregation therapies; blocks harmful glial responses while aggregate-clearing works |
| Biomarker Available |
6/10 |
CSF p-FAK levels and downstream inflammatory markers (IL-6, TNF-α) can track target engagement; less validated |
| De-risking Path |
8/10 |
Oncology repurposing provides established safety data; FAK KO mice viable; tool compounds available |
| Multi-disease Potential |
8/10 |
Relevant to AD, PD, ALS where neuroinflammation and glial dysfunction drive progression |
| Patient Impact |
7/10 |
Modulating microglial phagocytosis could preserve synapses; modulating astrocyte reactivity could reduce toxic signaling |
| Total |
74/100 |
|
- Phase 1 — CNS-focused formulation: Repurpose defactinib or VS-4718 with enhanced brain exposure; assess BBB penetration vs. peripheral exposure
- Phase 2 — Cellular validation: Test in iPSC-derived microglia and astrocytes from AD/PD patients; measure phagocytosis rate, cytokine release, and reactivity markers
- Phase 3 — Model efficacy: Test in 5xFAD mice (synapse loss), MPTP mice (microglial activation), and SOD1 mice (astrocyte reactivity); measure microglial phagocytosis, astrocyte phenotype, and functional outcomes
- Phase 4 — Safety: Leverage oncology toxicology data; focus on CNS-specific safety and drug-drug interactions
| Disease |
Relevance |
Rationale |
| Alzheimer's Disease |
High |
Aβ activates integrin-FAK pathway in microglia → excessive synapse phagocytosis; FAK inhibition reduces synapse loss in AD mouse models |
| Parkinson's Disease |
High |
α-syn activates microglia via integrin-FAK; FAK inhibition reduces dopaminergic neuron loss in MPTP model |
| ALS/FTD |
High |
Astrocyte reactivity driven by FAK contributes to motor neuron toxicity; microglia-mediated phagocytosis of synapses |
| Frontotemporal Dementia |
Medium |
Tau pathology engages integrin-FAK signaling; FAK role being characterized |
| Aging/Inflammaging |
Medium |
Age-related changes in cell adhesion molecules; FAK activity increases with aging |
| PSP |
Medium |
Tau-driven neuroinflammation involves glial FAK activation |
- With anti-amyloid therapies (lecanemab, donanemab): FAK inhibition blocks the microglial over-activation triggered by antibody-mediated amyloid clearance, reducing ARIA risk
- With anti-tau immunotherapy: Reduce tau-induced synapse loss by blocking downstream FAK-mediated phagocytosis
- With neurotrophic factors (BDNF, GDNF): Coordinate neurotrophic support with FAK inhibition to avoid interference with beneficial plasticity
- Objective: Evaluate oncology FAK inhibitors for CNS use
- Activities:
- PK/PD analysis of defactinib brain penetration
- In vitro blood-brain barrier permeability assessment
- Off-target profiling for CNS safety
- Estimated Cost: $500K-750K
- Milestone: Identified compound with acceptable CNS exposure
- Objective: Demonstrate efficacy in disease models
- Activities:
- iPSC-derived microglia and astrocyte testing
- In vivo efficacy in 5xFAD mice and MPTP mice
- Biomarker development (CSF p-FAK, cytokines)
- Estimated Cost: $2-3M
- Milestone: Demonstrated neuroprotection with biomarker engagement
- Objective: Complete regulatory toxicology
- Activities:
- GLP toxicology (rodent and non-rodent)
- Formulation for clinical use
- IND package preparation
- Estimated Cost: $3-4M
- Milestone: IND filing
- Objective: First-in-human for neurodegeneration
- Activities:
- Phase 1 in healthy volunteers with CNS biomarker substudy
- Phase 2 in early AD or PD patients
- Exploratory biomarker endpoints
- Estimated Cost: $8-12M
- Milestone: Safety and biomarker data in target population
- Immediate (Week 1-2): Engage with defactinib rights holder (Astellas/Verastem) for repurposing partnership; contract academic collaborator for iPSC glial models
- Short-term (Month 1-2): Commission PK studies comparing brain penetration of defactinib, VS-4718, and newer FAK inhibitors
- Medium-term (Month 3-6): Establish mouse model efficacy studies with 5xFAD and MPTP; partner with preclinical CRO
- Partnership (Month 6-12): Identify pharma partner with CNS franchise; target companies with existing glial modulation programs
- Alzheimer's Disease — Synapse loss and microglial hyper-phagocytosis
- Parkinson's Disease — Microglial activation and neuroinflammation
- ALS — Astrocyte reactivity and motor neuron toxicity
- Integrin Signaling — Upstream FAK activator
- Microglial Phagocytosis — FAK-regulated process
- Synapse Elimination — FAK-mediated pathology
- NF-κB Signaling — FAK downstream inflammatory pathway
- TREM2-LXR Microglia Editing — Alternative microglial modulation
- CSF1R Modulation — Microglial survival pathway
- NLRP3 Inflammasome Inhibition — Downstream inflammatory pathway