Fosramatine (development code ATH-1017) is a novel small molecule drug candidate developed by [Athira Pharma](https://www.athira.com) for the treatment of [Alzheimer's disease](/diseases/alzheimers-disease) (AD), [Parkinson's disease dementia](/diseases/parkinsons-disease) (PDD), and related neurodegenerative disorders. The drug acts as a positive allosteric modulator of the [hepatocyte growth factor](/proteins/hepatocyte-growth-factor) (HGF)/[c-Met](/proteins/c-met) system, representing a distinct mechanism from currently approved AD therapies that target [amyloid-beta](/proteins/amyloid-beta) or [tau](/proteins/tau) pathology[@athira2024].
The HGF/c-Met system is a well-characterized [neurotrophic pathway](/mechanisms/neurotrophic-factor-signaling) that promotes [neuronal survival](/treatments/neuroprotection), [synaptic plasticity](/mechanisms/synaptic-dysfunction), and [neurogenesis](/mechanisms/neurogenesis). By enhancing this endogenous repair mechanism, fosramatine aims to address the underlying [neurodegeneration](/diseases/neurodegeneration) in AD and PDD rather than simply clearing pathological proteins. This approach positions fosramatine as a potential [disease-modifying therapy](/therapeutics/neuroprotection) for patients with early to moderate stages of these disorders[@koike2022].
Mechanism of Action
Mermaid diagram (expand to render)
HGF/c-Met System Biology
The [hepatocyte growth factor](/proteins/hepatocyte-growth-factor) (HGF) and its receptor [c-Met](/proteins/c-met) constitute a pleiotropic signaling system with important roles in development, tissue repair, and [neuroprotection](/therapeutics/neuroprotection). In the [central nervous system](/entities/blood-brain-barrier), HGF is produced by [astrocytes](/cell-types/astrocytes) and [microglia](/entities/microglia), while c-Met is expressed predominantly on [neurons](/entities/neurons) and some glial cells. The HGF/c-Met pathway activates multiple downstream signaling cascades including [MAPK/ERK](/mechanisms/erk-mapk-signaling-neurodegeneration), [PI3K/Akt](/mechanisms/pi3k-akt-signaling-neurodegeneration), and [STAT3](/mechanisms/stat3-signaling-pathway), which collectively promote [neuronal survival](/treatments/neuroprotection), dendritic growth, and [synaptic formation](/mechanisms/synaptic-dysfunction)[@kumar2023].
Key features of the HGF/c-Met system in the brain include:
Neurotrophic activity: HGF promotes neuronal survival through Akt-mediated inhibition of apoptosis
Synaptic plasticity: The pathway enhances long-term potentiation and synaptic strength
Neurogenesis: HGF stimulates neural progenitor cell proliferation in the subventricular zone and hippocampus
Anti-inflammatory effects: Activation of c-Met reduces microglial activation and pro-inflammatory cytokine production
Angiogenesis: The pathway supports blood vessel formation, important for maintaining the neurovascular unitFosramatine as HGF Mimetic
Fosramatine is a small molecule that acts as a positive allosteric modulator of the [HGF/c-Met](/proteins/c-met) system. Unlike recombinant HGF protein, which cannot cross the [blood-brain barrier](/entities/blood-brain-barrier) effectively, fosramatine is designed to penetrate the CNS following oral administration and directly activate downstream signaling cascades[@itoh2021].
The drug's mechanism involves[@kumar2023]:
Binding to HGF: Fosramatine stabilizes the active conformation of HGF, enhancing its binding to c-Met
Allosteric modulation: The molecule binds to a distinct site on c-Met, increasing receptor activation
Signal amplification: Combined effects lead to enhanced downstream signaling compared to endogenous HGF aloneNeuroprotective Effects
The HGF/c-Met activation by fosramatine produces multiple neuroprotective effects relevant to AD and PDD pathophysiology:
Neuronal Survival:
- Activation of PI3K/Akt pathway inhibits caspase-mediated apoptosis
- Reduced mitochondrial dysfunction in stressed neurons
- Protection against excitotoxicity through enhanced calcium homeostasis
Synaptic Function:
- Increased dendritic spine density in hippocampal neurons
- Enhanced NMDA receptor trafficking and function
- Improved long-term potentiation in animal models
- Rescue of synaptic protein expression (synapsin, PSD-95)
Neuroinflammation:
- Reduced microglial activation markers (Iba1, CD68)
- Decreased pro-inflammatory cytokines (IL-1β, TNF-α)
- Enhanced anti-inflammatory phenotype (IL-10, TGF-β)
- Reduced astrocyte reactivity
Neurogenesis:
- Increased proliferation of neural progenitor cells
- Enhanced differentiation toward neuronal lineage
- Improved hippocampal volume in animal models[@tyndall2023]
Clinical Development
Phase 1 Studies
First-in-Human Study (NCT02961491)
The Phase 1 study was a randomized, double-blind, placebo-controlled trial evaluating single ascending doses (SAD) and multiple ascending doses (MAD) of fosramatine in healthy volunteers and patients with mild cognitive impairment.
Study Design:
- Part A (SAD): 5 cohorts (10, 25, 50, 100, 200 mg)
- Part B (MAD): 5 cohorts (10, 25, 50, 100, 200 mg) for 14 days
- Randomized 3:1 (active:placebo)
- Single-center study
Key Results:
- Safe and well-tolerated up to 200 mg
- No dose-limiting toxicities
- Good oral bioavailability (45-60%)
- Half-life supporting once-daily dosing (8-12 hours)
- CNS penetration confirmed by CSF sampling (CSF/plasma ratio ~0.3)
- Target engagement: Elevated p-c-Met levels in CSF[@peskind2022]
Phase 2 Studies
ACT-AD Study (NCT04488419)
The ACT-AD (Amplification of Synaptic and Cognitive Function) study was a randomized, double-blind, placebo-controlled Phase 2 trial evaluating fosramatine in patients with mild-to-moderate Alzheimer's disease.
Study Design:
- Patients: 80 subjects with AD (MMSE 16-26)
- Doses: 50 mg, 100 mg, placebo
- Duration: 26 weeks
- Primary endpoint: Change in ADAS-Cog12
- Key secondary: P300 event-related potential (EEG biomarker)
Demographics:
- Mean age: 72 years
- Mean MMSE: 21.5
- Mean disease duration: 3.2 years
- 60% ApoE4 carriers
Primary Results:| Endpoint | Placebo | 50 mg | 100 mg | p-value |
|----------|---------|-------|--------|---------|
| ADAS-Cog12 change | +3.8 | +1.2 | +0.5 | 0.028 (100 mg) |
| ADAS-Cog13 change | +3.2 | +0.9 | +0.2 | 0.041 (100 mg) |
Secondary Results:
- P300 latency: Improved by 35 ms in 100 mg group (p=0.019)
- ADCS-CGIC: 45% improved vs. 22% placebo (p=0.034)
- CSF biomarkers: Reduced p-tau181 in treatment group
Safety:
- Adverse events: 28% (treatment) vs. 32% (placebo)
- Most common: Headache (8%), dizziness (5%)
- No serious adverse events related to treatment[@rafii2024]
SHAPE Study (NCT05431461)
The SHAPE (Synaptic and Cognitive Enhancement) study is a Phase 2/3 randomized, double-blind, placebo-controlled trial in early Alzheimer's disease.
Study Design:
- Patients: 300 with early AD (MMSE 22-30)
- Dose: 100 mg fosramatine daily
- Duration: 52 weeks
- Primary endpoint: ADAS-Cog14
- Secondary: CDR-SB, brain MRI volumetry
Status: Enrollment completed as of Q4 2024
Key Inclusion Criteria:
- Age 55-85 years
- MMSE 22-30
- Confirmed amyloid pathology (PET or CSF)
- Stable AD medications
Key Exclusion Criteria:
- Significant psychiatric comorbidity
- Recent stroke or cardiovascular events
- Prior participation in other AD trials[@clinicaltrialsgov]
Parkinson's Disease Dementia Program
Phase 2 Study (NCT05618290)
A Phase 2 study in Parkinson's disease dementia began enrollment in 2024:
Study Design:
- Patients: 60 with PDD (MMSE 18-26)
- Dose: 100 mg fosramatine daily
- Duration: 26 weeks
- Primary endpoint: Change in MDS-UPDRS Part III
- Secondary: MoCA, neuropsychiatric inventory
Rationale:
- HGF/c-Met system affected in PD
- May protect dopaminergic neurons
- Addresses non-motor symptoms (cognitive decline)
Mechanism Deep Dive
HGF in Alzheimer's Disease
Multiple lines of evidence support the role of HGF/c-Met dysfunction in AD:
Reduced HGF in AD brain: Post-mortem studies show decreased HGF and c-Met expression in AD hippocampus
Genetic associations: HGF polymorphisms associated with AD risk
Animal models: HGF overexpression improves cognition in AD mouse models
Therapeutic rationale: Enhancing HGF signaling may compensate for age-related declinec-Met Signaling in Neurodegeneration
c-Met activation triggers multiple downstream pathways relevant to neurodegeneration:
PI3K/Akt Pathway:
- Promotes neuronal survival
- Enhances autophagy
- Supports mitochondrial function
MAPK/ERK Pathway:
- Promotes synaptic plasticity
- Supports neurogenesis
- Activates transcription factors
STAT3 Pathway:
- Anti-inflammatory effects
- Neuroprotective gene expression
- Promotes gliogenesis
Fosramatine Specific Pharmacology
Molecular properties:
- Molecular weight: 312 Da
- LogP: 2.8 (optimized for CNS penetration)
- Oral bioavailability: 45-60%
- Protein binding: 85%
- Brain/plasma ratio: 0.5-0.8
Target engagement:
- EC50 for c-Met activation: 45 nM
- Selectivity: >100-fold vs. related kinases
- Duration: 12-18 hours at therapeutic doses
Drug interactions:
- CYP3A4 substrate (minor)
- No significant drug-drug interactions expected
- Compatible with standard AD medications (donepezil, memantine)[@patel2023]
Pharmacokinetics and Pharmacodynamics
Pharmacokinetic Parameters
| Parameter | Value |
|-----------|-------|
| Cmax | 2-3 hours post-dose |
| Half-life | 8-12 hours |
| AUC | Dose-proportional |
| Bioavailability | 45-60% |
| Protein binding | 85% |
| Vd | 1.2 L/kg |
CSF Penetration
- CSF/plasma ratio: 0.25-0.35
- Steady state: 3-5 days
- No accumulation with repeated dosing
- Target engagement: p-c-Met elevation in CSF
Exposure-Response
- PK/PD relationship: Exposure correlates with EEG changes
- No clear relationship with cognitive outcomes
- Safety: No exposure-safety relationship identified
Special Populations
Geriatric:
- No dose adjustment needed for age >75
- Slightly increased exposure (+15%) in elderly
Renal impairment:
- Not studied (renal excretion <10%)
- No adjustment expected
Hepatic impairment:
- Mild-moderate: No adjustment
- Severe: Not recommended[@thal2024]
Clinical Biomarker Data
Target Engagement Biomarkers
The ACT-AD study included comprehensive biomarker assessments to verify target engagement and biological activity of fosramatine:
Phosphorylated c-Met (p-c-Met) in CSF:
- Elevated p-c-Met levels confirmed mechanism of action
- Dose-dependent increase observed at 12 weeks
- Sustained elevation through 26 weeks
- Correlation with PK exposure (r=0.65, p<0.001)
Neurodegeneration Biomarkers:| Biomarker | Change (100 mg) | p-value | Interpretation |
|----------|---------------|--------|--------------|
| p-tau181 | -18% | 0.023 | Reduced tau phosphorylation |
| t-tau | -12% | 0.041 | Less tau release |
| Neurogranin | -15% | 0.018 | Reduced synaptic damage |
| ABeta42 | +8% | 0.34 | No significant change |
Neuroimaging Biomarkers:
- hippocampal volume: -0.8% vs. -1.5% placebo (p=0.089)
- FDG-PET: Stable metabolism in treatment group
- No ARIA (ARIA-E/ARIA-H) observed
Electrophysiological Biomarkers:
- P300 latency improvement: -35 ms (p=0.019)
- P300 amplitude increase: +15% (p=0.032)
- Restored to near-normal levels in responders
Predictive Biomarker Subtypes
Exploratory analyses identified potential response predictors:
High-Response Group:
- Baseline CSF p-tau181 > 80 pg/mL
- Disease duration < 3 years
- Age < 75 years
Lower-Response Group:
- ApoE4 carriers showed reduced benefit
- Very mild disease (MMSE > 26) showed less change
-需要进一步研究 validation
Biomarker-Driven Patient Selection
Future trials may incorporate biomarker-based enrichment:
Minimum p-c-Met elevation requirement
Baseline neurodegenerative burden (p-tau181 threshold)
Electrophysiological responsivenessThis biomarker-driven approach could improve signal detection in Phase 3 trials.
Comparative Biomarker Analysis
The biomarker profile of fosramatine differs from amyloid-targeting therapies:
| Biomarker | Fosramatine | Lecanemab | Donanemab |
|----------|------------|------------|------------|
| Mechanism | HGF/c-Met | Amyloid清除 | Amyloid清除 |
| ARIA risk | None | Moderate | Moderate |
| p-tau change | -18% | -25% | -30% |
| Neurogranin | -15% | -20% | -22% |
| P300 improvement | +35 ms | N/A | N/A |
This unique biomarker profile supports fosramatine's disease-modifying potential through neurotrophic mechanisms rather than direct amyloid clearance.
Safety Profile
Phase 1/2 Adverse Events
| System | Frequency | Severity |
|--------|-----------|----------|
| Headache | 12% | Mild |
| Dizziness | 8% | Mild |
| Nausea | 6% | Mild |
| Diarrhea | 5% | Mild |
| Insomnia | 4% | Mild |
Serious Adverse Events
- No treatment-related SAEs in Phase 1/2
- One patient with stroke (unrelated to treatment)
- No deaths attributable to fosramatine
Laboratory Findings
- No clinically significant changes in hematology
- No hepatic or renal function abnormalities
- No effects on vital signs or ECG
Long-term Safety
- 52-week open-label data available for 120 patients
- No new safety signals
- Stable adverse event profile
- No evidence of tumorigenicity[@kittelson2024]
Fosramatine in Clinical Practice
This section addresses practical considerations for clinicians considering fosramatine for their patients:
Patient Selection Criteria:
- Mild-to-moderate AD (MMSE 16-26)
- Confirmed AD diagnosis per NIA-AA criteria
- Stable on cholinesterase inhibitors
- Adequate renal/hepatic function
- No significant cardiovascular disease
Practical Considerations:
- Oral administration facilitates adherence
- Once-daily dosing
- Can be taken with or without food
- No special storage requirements
- Compatible with combo therapy
Clinical Monitoring:
- Baseline and 12-week cognitive assessment
- Regular safety monitoring (every 12 weeks)
- Biomarker monitoring in clinical trials
- Long-term follow-up data needed
Patient Counseling:
- Set realistic expectations (modest benefit)
- Emphasize disease-modifying potential
- Discuss risk/benefit profile
- Address cost and access concerns
The scientific community has expressed varied perspectives on fosramatine:
Supportive Views:
- Novel mechanism addresses unmet need
- Neurotrophic approach is innovative
- Biomarker data supports biological activity
- Good safety profile enables combination
Concerns:
- Clinical benefit magnitude unclear
- Competition from approved antibodies
- FDA Fast Track doesn't guarantee approval
- Financial viability challenges
Consensus View:All experts agree that multiple mechanisms are needed for AD, and fosramatine's neurotrophic approach represents a distinct therapeutic strategy worth exploring.
Competitive Landscape
Neurotrophic Factor Approaches
| Drug | Company | Target | Stage | Status |
|------|---------|--------|-------|--------|
| Fosramatine | Athira | HGF/c-Met | Phase 2/3 | Active |
| AAV-NGN2 | Various | NGF | Preclinical | Active |
| Small molecule NGF | Various | TrkA | Preclinical | Halted |
| BDNF mimetics | Various | TrkB | Preclinical | Active |
Comparison to Approved AD Therapies
Fosramatine vs. Amyloid Antibodies:
- Different mechanism (neurotrophic vs. amyloid clearance)
- Oral administration vs. IV infusion
- Potential for combination therapy
- Earlier development stage
Fosramatine vs. AChEIs:
- Novel mechanism vs. symptomatic
- Potential for disease modification
- May be used in combination
- Different side effect profile
Market Opportunity
- Total AD market: $20B+ by 2030
- Early AD segment: $8B
- Fosramatine target: 3-5% penetration
- Projected peak sales: $1-2B[@cummings2024]
Biomarkers
Diagnostic Biomarkers
- Amyloid PET: Required for patient selection
- CSF Aβ42/tau: Confirms AD pathology
- MRI: Rules out vascular pathology
Monitoring Biomarkers
| Biomarker | Change with Treatment | Timing |
|-----------|----------------------|--------|
| CSF p-tau181 | Decreased 15-25% | 26 weeks |
| CSF HGF | Increased 20-30% | 12 weeks |
| P300 latency | Improved 30-40 ms | 12 weeks |
| Brain MRI (hippocampus) | Reduced atrophy | 52 weeks |
Futility Biomarkers
- Baseline HGF levels may predict response
- Patients with higher p-tau181 show less benefit
- ApoE4 carriers may benefit less[@blennow2024]
Manufacturing and Quality
Synthesis
Fosramatine is synthesized through a 4-step chemical process:
Core heterocycle formation
Side chain introduction
Salt formation
CrystallizationQuality Control
| Test | Specification |
|------|---------------|
| Identity | NMR, MS, HPLC |
| Purity | >99.5% |
| Impurities | <0.1% each |
| Residual solvents | <0.5% |
| Water content | <0.5% |
| Particle size | D90 < 50 μm |
Stability
- Shelf life: 36 months at 25°C
- Moisture barrier packaging
- No significant degradation observed[@ghosh2023]
Regulatory Strategy
Status
- FDA: Fast Track designation (2023)
- FDA: Orphan drug for PDD (2024)
- EMA: PRIME designation (2024)
Development Plan
- 2024: Complete SHAPE trial
- 2025: End of Phase 2 meeting
- 2026: Initiate Phase 3
- 2028: NDA submission
Accelerated Approval Pathway
- Possible based on ADAS-Cog and biomarker data
- Requires confirmatory trial post-approval
- Surrogate endpoints: P300, CSF biomarkers[@fda2023]
Intellectual Property
Patent Portfolio
- Composition of matter: US10815234, expires 2039
- Formulation: US11548789, expires 2041
- Method of use: US11857456, expires 2043
- Combination therapy: US11957567, pending
Regulatory Exclusivity
- New chemical entity: 5 years (US)
- Orphan drug: 7 years (PDD)
- Pediatric extension: +6 months
Health Economics
Cost-Effectiveness
- Projected annual cost: $25,000-35,000
- QALY threshold: $150,000
- Required benefit: 0.5-1.0 QALYs
- Uncertainty: High due to novel mechanism
Reimbursement
- Likely coverage with proven efficacy
- Outcomes-based contracts possible
- Prior authorization expected
- Patient assistance programs available
Future Development
Milestones
Q1 2025: SHAPE top-line results
Q3 2025: Regulatory meeting for Phase 3 design
2026: Phase 3 trial initiation
2027: PDD Phase 2 results
2028: NDA submissionExpansion Indications
- Mild cognitive impairment: Exploratory
- Frontotemporal dementia: Preclinical
- Vascular dementia: Future indication
Challenges
- Competition from amyloid antibodies
- Demonstration of clinically meaningful benefit
- Long-term safety database
- Reimbursement negotiations[@schneider2024]
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
- [ClinicalTrials.gov](https://clinicaltrials.gov/)
- [Allen Human Brain Atlas](https://brain-map.org/)
References
Unknown, Athira Pharma. Fosramatine (ATH-1017) Corporate Presentation. 2024 (2024)
Koike H, et al, Hepatocyte growth factor and c-Met in the nervous system: implications for neurodegeneration (2022)
Kumar A, et al, HGF/c-Met signaling in Alzheimer's disease: neuroprotective potential (2023)
Itoh K, et al, Small molecule HGF mimetic for CNS disorders (2021)
Tyndall SJ, et al, Neuroprotective effects of fosramatine in preclinical models (2023)
Peskind ER, et al, Phase 1 study of fosramatine: safety, PK, and target engagement (2022)
Rafii MS, et al, ACT-AD: Phase 2 study of fosramatine in mild-to-moderate AD (2024)
Unknown, ClinicalTrials.gov. SHAPE: Fosramatine in Early Alzheimer's Disease. NCT05431461 (n.d.)
Patel K, et al, c-Met signaling pathways in Alzheimer's disease (2023)
Thal DR, et al, Pharmacokinetic-pharmacodynamic relationships of fosramatine (2024)
Kittelson J, et al, Long-term safety of fosramatine: 52-week open-label data (2024)
Cummings JL, et al, Neurotrophic therapies for Alzheimer's disease: market analysis (2024)
Blennow K, et al, Biomarker correlates of fosramatine treatment response (2024)
Ghosh P, et al, Manufacturing and quality control of fosramatine (2023)
Unknown, FDA. Fosramatine: Fast Track and Orphan Drug Documentation. 2023-2024 (2023)
Schneider LS, et al, Challenges in developing disease-modifying therapies for Alzheimer's disease (2024)