Focal Adhesion Kinase (FAK) Inhibition Therapy for Neurodegeneration

Cross-Linking Context

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

Overview

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.^{1Focal adhesion kinase: from structure to function2005 · Cellular and Molecular Life Sciences · PMID 15670078Open reference2Focal adhesion kinase in neuronal development and disease2022 · Developmental Neurobiology · PMID 37778912Open reference}

Target

• Primary Target: FAK (PTK2) catalytic domain (ATP-binding site)^{1Focal adhesion kinase: from structure to function2005 · Cellular and Molecular Life Sciences · PMID 15670078Open reference}

• Target Type: Small-molecule FAK inhibitor (defactinib, VS-4718 class) or allosteric inhibitor^{3Safety, pharmacokinetic and pharmacodynamic results from a phase I study of VS-4718 in patients with advanced solid tumors2015 · Journal of Clinical Oncology · PMID 25600540Open reference}

• Expression: Expressed in microglia, astrocytes, and neurons; activity increases in disease states^{2Focal adhesion kinase in neuronal development and disease2022 · Developmental Neurobiology · PMID 37778912Open reference}

• Localization: Cytoplasmic protein; localizes to focal adhesions at cell membrane upon activation

Mechanistic Rationale

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:^{1Focal adhesion kinase: from structure to function2005 · Cellular and Molecular Life Sciences · PMID 15670078Open reference}

1. Microglial hyper-phagocytosis: Aβ and other pathological proteins activate integrin-FAK signaling in microglia^{2Focal adhesion kinase in neuronal development and disease2022 · Developmental Neurobiology · PMID 37778912Open reference}, leading to excessive synapse elimination and engulfment of healthy neurons

2. Astrocyte reactivity: FAK mediates astrocyte responses to damage signals^{2Focal adhesion kinase in neuronal development and disease2022 · Developmental Neurobiology · PMID 37778912Open reference}, promoting the neurotoxic A1 reactive phenotype

3. Synaptic dysfunction: FAK regulates actin cytoskeleton at synapses^{2Focal adhesion kinase in neuronal development and disease2022 · Developmental Neurobiology · PMID 37778912Open reference}; dysregulation contributes to synaptic dysfunction loss

4. Inflammatory amplification: FAK activates downstream pathways including NF-κB^{1Focal adhesion kinase: from structure to function2005 · Cellular and Molecular Life Sciences · PMID 15670078Open reference}, driving cytokine production in glia

5. 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)^{2Focal adhesion kinase in neuronal development and disease2022 · Developmental Neurobiology · PMID 37778912Open reference}0, providing a strong foundation for CNS repurposing.^{2Focal adhesion kinase in neuronal development and disease2022 · Developmental Neurobiology · PMID 37778912Open reference}1

flowchart TD
    A["Abeta/Tau/alpha-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-kappaB 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:#1b5e20,color:white
    style O fill:#4FAI50,color:white
    style J fill:#b71c1c,color:white

Cross-links to relevant mechanisms:

• Microglia and Neuroinflammation

• Astrocyte Reactivity

• Synapse Elimination

• Neuroinflammation

• Integrin Signaling

• NF-kappaB Signaling

Rubric Score

De-risking Path

1. Phase 1 — CNS-focused formulation: Repurpose defactinib or VS-4718 with enhanced brain exposure; assess BBB penetration vs. peripheral exposure

2. Phase 2 — Cellular validation: Test in iPSC-derived microglia and astrocytes from AD/PD patients; measure phagocytosis rate, cytokine release, and reactivity markers

3. 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

4. Phase 4 — Safety: Leverage oncology toxicology data; focus on CNS-specific safety and drug-drug interactions

Disease Coverage

Combination Therapy Potential

• 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

Related NeuroWiki Pages

• Microglia and Neuroinflammation

• Astrocyte Reactivity

• Synapse Elimination

• Neuroinflammation

• Integrin Signaling

• NF-κB Signaling

• TREM2-LXR Microglia Editing — complementary microglial target

Implementation Roadmap

Phase 1: Repurposing Assessment (Months 1-6)

• 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

Phase 2: Preclinical Validation (Months 6-18)

• 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

Phase 3: IND-Enabling (Months 18-30)

• 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

Phase 4: Clinical Development (Months 30-48)

• 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

Actionable Next Steps

1. Immediate (Week 1-2): Engage with defactinib rights holder (Astellas/Verastem) for repurposing partnership; contract academic collaborator for iPSC glial models

2. Short-term (Month 1-2): Commission PK studies comparing brain penetration of defactinib, VS-4718, and newer FAK inhibitors

3. Medium-term (Month 3-6): Establish mouse model efficacy studies with 5xFAD and MPTP; partner with preclinical CRO

4. Partnership (Month 6-12): Identify pharma partner with CNS franchise; target companies with existing glial modulation programs

Cross-Links

Related Diseases

• Alzheimer’s Disease — Synapse loss and microglial hyper-phagocytosis

• Parkinson’s Disease — Microglial activation and neuroinflammation

• ALS — Astrocyte reactivity and motor neuron toxicity

Related Mechanisms

• Integrin Signaling — Upstream FAK activator

• Microglial Phagocytosis — FAK-regulated process

• Synapse Elimination — FAK-mediated pathology

• NF-κB Signaling — FAK downstream inflammatory pathway

Related Therapeutic Ideas

• TREM2-LXR Microglia Editing — Alternative microglial modulation

• CSF1R Modulation — Microglial survival pathway

• NLRP3 Inflammasome Inhibition — Downstream inflammatory pathway