FosgonimetonATH-1017 — an HGF/MET neurotrophic modulator with target engagement and biomarker signals, but a failed pivotal Alzheimer's trial
Fosgonimeton (ATH-1017) is an investigational drug studied for Alzheimer's disease and other dementias. It is designed to enhance the HGF/MET neurotrophic pathway involved in neuron survival, synaptic health, and repair. Early studies suggested brain target engagement using EEG-based markers, but the larger Phase 2/3 trial (LIFT-AD) did not prove clinical benefit over placebo. Intrasigna shows trial-dose references and results only — never a treatment or self-use protocol.
Fosgonimeton is a subcutaneously administered prodrug rapidly converted to the active metabolite ATH-1001, a positive modulator of HGF/MET. Phase 1 reported acceptable safety, dose-proportional PK, qEEG gamma induction, and ERP P300 latency normalization in an Alzheimer's cohort. The pivotal LIFT-AD trial evaluated 40 mg once-daily SC over 26 weeks in mild-to-moderate AD and missed the primary Global Statistical Test and key ADAS-Cog11/ADCS-ADL23 secondary endpoints; the program is discontinued.
Fosgonimeton is the drug-like successor to Dihexa, selected from >50 HGF/MET-active compounds for superior solubility and PK. Its active metabolite ATH-1001 crosses the blood-brain barrier and enhances HGF–MET interaction, driving MET phosphorylation and downstream PI3K/Akt and MAPK signaling and augmenting NMDA-receptor-mediated LTP via PKC. In LIFT-AD, biomarkers moved directionally — notably a significant pTau217 reduction — without translating into clinical benefit.
B (target engagement/safety) · D (clinical efficacy)
FAILED PIVOTAL TRIAL · NOT APPROVED · trial-reference only
The Phase 2/3 LIFT-AD trial did not meet its primary Global Statistical Test endpoint or its key secondary cognition (ADAS-Cog11) and function (ADCS-ADL23) endpoints, and the program was discontinued. Intrasigna displays clinical-trial dose records only as source-backed references with the failed-endpoint warning. Personalized dosing, self-injection, vial reconstitution, Alzheimer treatment and disease-modification claims, and healthy-user/nootropic protocols are blocked.
01 · At a glance
A model case: mechanism vs outcome.
Fosgonimeton is the atlas's reference for a compound with a coherent mechanism, real human target engagement, and directional biomarkers — that still failed its pivotal efficacy trial. That gap is the lesson: positive EEG/ERP and biomarker signals are not clinical proof. The engine surfaces the trial arms and results (including the LIFT-AD failure) and blocks any treatment, self-injection, or disease-modification output.
🧬
What it is
HGF/MET modulator
An investigational subcutaneous small molecule (ATH-1017) from Athira Pharma. Grade B.
🔁
Prodrug
→ ATH-1001
Rapidly converts to the brain-penetrant active metabolite ATH-1001. Grade B.
📡
Target engagement
ERP P300 · qEEG
Phase 1 showed gamma induction and ERP P300 latency normalization in AD. Grade B/C.
❌
LIFT-AD
Primary failed
Missed the GST primary and key ADAS-Cog11/ADCS-ADL23 secondaries at 26 weeks. Grade D.
🧪
Biomarkers
pTau217 ↓
pTau217 fell −0.12 pg/mL vs placebo (p<0.01), but no clinical benefit. Grade C.
💊
Trial dose
40 mg QD SC
The LIFT-AD arm — shown as a reference only, with the failure warning. Grade D efficacy.
⚠️
AChEI interaction
Antagonism
Acetylcholinesterase inhibitors appear to antagonize fosgonimeton's HGF/MET effect. Grade C.
⛔
Blocked
Treatment / self-use
Treatment, self-injection, reconstitution, and nootropic protocols are blocked. Admin rule.
02 · Mechanism of action
A neurotrophic pathway, amplified.
Fosgonimeton doesn't replace a missing molecule — it tunes up an existing repair system. The HGF/MET pathway supports neuronal survival, synaptic plasticity, and tissue repair, and is diminished in the Alzheimer's hippocampus. Fosgonimeton's active metabolite enhances HGF–MET signaling, with downstream effects on plasticity and survival. The mechanism is coherent and supported by human target-engagement markers — which makes its clinical failure the instructive part of this page.
Grade B
🧬
1 · The HGF/MET neurotrophic system
It targets a growth-factor pathway that keeps neurons alive and connected.
Mechanism: Hepatocyte growth factor (HGF) signaling through its receptor MET promotes neuronal proliferation and survival, enhances hippocampal synaptic plasticity, and supports learning and memory; the system is a pleiotropic neurotrophic/repair pathway.
Detail: Hippocampal expression of MET receptors is diminished in Alzheimer's disease, providing the rationale for positively modulating HGF/MET rather than supplying HGF directly.
Grade B
🔁
2 · Prodrug → ATH-1001 (BBB-penetrant)
An inactive injectable converts to a brain-penetrant active form.
Mechanism: Fosgonimeton (ATH-1017) is an inactive prodrug given subcutaneously that is rapidly converted in plasma to the active metabolite ATH-1001, which crosses the blood-brain barrier.
Detail: The prodrug strategy was chosen because ATH-1017 has superior drug-like properties (solubility, PK) compared with Dihexa, the WSU-discovered HGF/MET compound it succeeds; the active moiety is also referred to as fosgo-AM.
Grade B
⚡
3 · MET phosphorylation → PI3K/Akt · MAPK
It switches on the survival and growth signals downstream of MET.
Mechanism: ATH-1001 enhances the HGF–MET interaction, inducing MET phosphorylation and downstream signaling through the PI3K/Akt and MAPK pathways — the prosurvival/regenerative cascades of the system.
Detail: In vitro, the active metabolite significantly enhanced MET phosphorylation and activated downstream signaling, promoting synaptogenesis and neurite outgrowth — the cellular basis for the procognitive hypothesis.
Grade B/C
🔗
4 · NMDA-mediated LTP via PKC
It strengthens the synaptic signaling behind memory formation.
Mechanism: ATH-1001 augments NMDA-receptor-mediated long-term potentiation (LTP) through protein kinase C (PKC) — linking HGF/MET modulation to the synaptic plasticity that underlies learning and memory.
Detail: Preclinically, fosgonimeton reversed learning and memory deficits in a rodent scopolamine-induced amnesia model and stimulated dendritic arborization/synaptogenesis, consistent with a plasticity-restoring mechanism.
Grade C
🌊
5 · Pulsatile once-daily signaling
A daily pulse matches how the pathway naturally fires.
Mechanism: HGF/MET is a pulsatile system — MET phosphorylation decays over time in the presence of HGF — so once-daily prodrug dosing is aligned with the pathway's natural regulation, and a steady-state plasma level of ATH-1001 may not be required for a lasting effect.
Detail: Downstream transcriptional/translational effects on gene expression likely outlast the brief drug-target interaction, which is the rationale for intermittent rather than continuous exposure.
Grade B/C
🛡️
6 · Preclinical neuroprotection
In models it counters several drivers of neurodegeneration.
Mechanism: In dementia models, fosgonimeton produced neurotrophic and procognitive effects, including confirmed cognition benefit in an LPS-induced neuroinflammatory mouse model.
Detail: Preclinical work describes attenuation of amyloid-beta toxicity along with prosurvival signaling, oxidative-stress reduction, improved synaptic/mitochondrial function, and decreased inflammation — a broad neuroprotective profile that did not translate to clinical efficacy.
L3 · prodrug-to-plasticity cascade
From SC injection to synaptic effect
💉 ATH-1017
SC prodrug
→
🔁 ATH-1001
active · BBB
→
⚡ HGF/MET ↑
PI3K/Akt · MAPK
→
🔗 plasticity
LTP · synaptogenesis
→
📡 engagement
qEEG · P300
⇒
❌ no efficacy
LIFT-AD failed
L2 · mechanism vs evidence
Where each layer stands
Layer
Finding
Evidence
HGF/MET rationale
Coherent neurotrophic target
B
Preclinical neuroprotection
Neurotrophic/procognitive in models
B/C
Target engagement (human)
qEEG gamma · ERP P300 normalization
B/C
Biomarkers (human)
Directional; pTau217 significant
C
Clinical efficacy (human)
LIFT-AD primary + secondary failed
D
L3 · downstream signaling
HGF/MET effectors engaged
Node
Role
Effect
MET phosphorylation
Receptor activation
↑ in vitro
PI3K/Akt
Prosurvival
Neuron survival
MAPK
Growth/repair
Neurite outgrowth
NMDA / PKC
Plasticity
↑ LTP
03 · Clinical-trial dosing engine & lanes
A computational trial-reference engine — with the failure attached.
Fosgonimeton has real human doses, but the engine must never produce a recommendation, because the pivotal Phase 2/3 trial failed. It computes the dose arithmetic for each documented trial arm — total daily mg, mg/kg/day, and cumulative exposure over a chosen duration — and pairs every arm with its actual endpoints and result, including the LIFT-AD failure warning. Route is subcutaneous-only; any non-SC route returns BLOCKED. The lanes below mirror the trial program: Phase 1 target engagement, ACT-AD Phase 2, the failed LIFT-AD Phase 2/3, the SHAPE PDD/DLB study, and biomarker research.
Engine mode · subcutaneous clinical-trial reference (computational, failed-endpoint flagged)
The engine is route-gated (SC only), approval-gated, and trial-context-gated; it computes dose math for documented arms but blocks personalized dosing, self-injection, reconstitution, treatment plans, and disease-modification claims. Any LIFT-AD reference displays with the failed-primary-endpoint warning.
AChEI interaction note
In ACT-AD the ERP P300 primary was not significant for the full population, because combining fosgonimeton with acetylcholinesterase-inhibitor standard-of-care appeared to diminish its effect; AChEIs may antagonize fosgonimeton's HGF/MET signaling, so trial design and the engine flag concurrent AChEI use.
Lane A — Phase 1 target engagement
NCT03298672 · subcutaneous
Grade B
Design
Randomized, placebo-controlled, double-blind; healthy young, healthy older, and Alzheimer's cohorts.
Doses
SAD 2/6/20/40/60/90 mg; MAD 20/40/60/80 mg QD; AD cohort 40 mg QD × 9 days.
Endpoints
qEEG gamma power; ERP P300 latency.
Result
Safe/well tolerated; dose-proportional PK, no accumulation over 9 days; gamma induction; ERP P300 latency normalization in the AD cohort.
Claim boundary
Target engagement only — not efficacy.
qEEG served as a translatable biomarker to confirm CNS penetration/target engagement; human recommendation blocked.
Phase 1 · dose arms
Escalation reference
Cohort
Doses
Output
SAD (healthy young)
2–90 mg single
Reference
MAD (healthy older)
20–80 mg QD × 9 d
Reference
AD cohort
40 mg QD × 9 d
Target engagement
Lane B — ACT-AD Phase 2 proof-of-concept
NCT04491006 · subcutaneous
Grade C
Population
Mild-to-moderate Alzheimer's disease.
Dose arms
40 mg and 70 mg once daily, 26 weeks.
Primary
ERP P300 latency (pharmacodynamic).
Result
Primary ERP P300 not significant in the full population (AChEI co-use diminished effect); a monotherapy subgroup improved on ERP P300 and ADAS-Cog11.
Global Statistical Test (GST) combining ADAS-Cog11 + ADCS-ADL23.
Result
Did NOT meet the primary GST (−0.08 change, P=0.70) or key ADAS-Cog11/ADCS-ADL23 secondary endpoints vs placebo.
Subgroups
Numerically greater effect in moderate-AD and APOE4-carrier subgroups (not significant).
Biomarkers
pTau217 reduced −0.12 pg/mL vs placebo (p<0.01); other markers directional.
Investigators cited a lack of placebo decline and short study duration as possible reasons for the failure; the program was discontinued. Treatment claims blocked.
LIFT-AD · result
Failed pivotal endpoints
Endpoint
Result
Note
GST (primary)
NOT significant
P=0.70
ADAS-Cog11 / ADCS-ADL23
NOT significant
Key secondary
pTau217
↓ −0.12 pg/mL
p<0.01 · biomarker only
Lane D — SHAPE Phase 2 (PDD / DLB)
Subcutaneous · exploratory
Grade C/D
Population
Parkinson's disease dementia / dementia with Lewy bodies.
Dose
40 or 70 mg once daily, injected; 26 weeks.
Primary
Combined ADAS-Cog13 + ERP P300 latency.
Result
Stopped recruiting at 28 participants; primary endpoint not met; a small mITT subgroup showed a positive cognitive signal.
Limitation
Very small exploratory dataset — no protocol output.
Exploratory secondary-dementia lane only; human recommendation blocked.
Fosgonimeton has real human trial doses, but this engine does not output personalized dosing, a treatment plan, self-injection or reconstitution guidance, disease-modification claims, or healthy-user protocols. It computes the dose arithmetic (total daily mg, mg/kg/day, cumulative exposure over a chosen duration) for each documented trial arm, and pairs it with that trial's endpoints and result — including the LIFT-AD failure. Any non-subcutaneous route returns BLOCKED. Trial reference only — provider review required; not medical advice. Intrasigna classifies fosgonimeton as an advanced neurodegeneration trial dossier with the peptide vial calculator disabled and the biomarker and qEEG/ERP endpoint engines enabled.
Total daily dose
—
Weight-normalized
—
Cumulative exposure
—
Documented trial arm
—
Endpoints
—
Trial result
—
Output status
—
04 · Interactions & stack logic
Stacking is blocked by default.
Fosgonimeton is an investigational injectable studied in vulnerable dementia populations, so there is no open consumer stacking. The most important interaction is clinical, not recreational: acetylcholinesterase inhibitors appear to antagonize its HGF/MET effect, which shaped the trial designs. Every combination below is provider/trial-protocol-only or blocked — and because HGF/MET is a growth-factor pathway, anything touching oncology is a specialist gate.
+ AChE inhibitors
Antagonism · trial-context only
FosgonimetonDonepezil etc.
AChE inhibitors may antagonize fosgonimeton's effect on HGF/MET signaling; ACT-AD's full-population primary missed partly because of this co-use. Trial-context only.
Combo
Rule
Watch
AChEI
Antagonism
Diminished effect
+ Memantine
Provider review
FosgonimetonMemantine
NMDA-antagonist dementia medication — a confounder given the NMDA/LTP mechanism. Provider review.
Combo
Rule
Watch
Memantine
Provider review
NMDA confounder
+ Anti-amyloid antibodies
Specialist-only
Fosgonimetonlecanemab etc.
Different mechanism with its own biomarker/safety (ARIA) complexity; no combination data. Specialist-only.
Combo
Rule
Watch
Anti-amyloid mAb
Specialist-only
No combo data
+ Dihexa
Blocked
FosgonimetonDihexa
Same HGF/MET family (fosgonimeton is the Dihexa successor) — redundant target, no combination data, overclaim risk. Blocked.
Combo
Rule
Watch
Dihexa
Blocked
Same pathway
+ Noopept
Blocked (public)
FosgonimetonNoopept
CNS-active nootropic overclaim risk; no combination evidence. Blocked for public output.
Combo
Rule
Watch
Noopept
Blocked
Overclaim
+ Humanin
Research-only
FosgonimetonHumanin
Neuroprotective-mechanism overlap but no combination evidence. Research framing only.
Combo
Rule
Watch
Humanin
Research-only
No combo data
+ MOTS-c / SS-31
Research-only
FosgonimetonMito peptides
Mitochondrial-protection overlap; no direct trial evidence with fosgonimeton. Research-only.
Combo
Rule
Watch
MOTS-c/SS-31
Research-only
No combo data
+ Cancer therapeutics
Specialist-only
FosgonimetonOncology drugs
HGF/MET biology is oncology-relevant, so any cancer-context use requires specialist review. Specialist-only.
Combo
Rule
Watch
Oncology drugs
Specialist-only
HGF/MET growth biology
Stack safety note — Fosgonimeton stacks are blocked by default. Any combination requires a source-backed rationale, medication review, diagnosis match, a biomarker plan, and provider/IRB oversight. AChE inhibitors are a documented antagonist; Dihexa and other HGF/MET-family compounds are blocked for redundancy; cancer-context use is specialist-only because of HGF/MET growth-factor biology.
05 · Safety & screening
A high-gate neurodegeneration-trial safety model.
Fosgonimeton was generally well tolerated in trials, with injection-site reactions the main adverse-event driver — but it is unapproved, failed its pivotal trial, and works on a growth-factor pathway, so the safety model is high-gate. It pairs one of the atlas's most complete neurodegeneration assessment panels (cognition, function, AD biomarkers, EEG/ERP) with hard blocks on treatment use, self-injection, and any HGF/MET cancer-context use without specialist review.
⛔ Investigational · failed trial · not approved — Fosgonimeton is not approved and was discontinued after LIFT-AD missed its primary endpoint. It was generally well tolerated, with higher treatment-emergent adverse events driven mainly by injection-site reactions, similar serious-AE incidence, and no deaths. Intrasigna provides no treatment, self-injection, or dose-conversion output.
Baseline · cognition + function + biomarkers + EEG/ERP
What the engine assesses
Marker
Purpose
Use
Diagnosis context (AD/MCI/PDD/DLB)
Determines lane
Lane selection
Disease stage (mild/moderate/severe)
LIFT-AD subgroup relevance
Interpretation
ADAS-Cog11
Cognition endpoint
LIFT-AD
ADAS-Cog13
Cognition endpoint
SHAPE/PDD/DLB
ADCS-ADL23
Function endpoint
LIFT-AD
CDR-SB / MMSE / MoCA
Severity & global cognition
Context
APOE4 status
Subgroup interpretation
LIFT-AD subgroup
Plasma pTau217
AD pathology biomarker
Significant in LIFT-AD
pTau181
Tau biomarker
Tracking
Aβ42/40 ratio
Amyloid marker
Tracking
NfL
Neurodegeneration marker
Tracking
GFAP
Neuroinflammation marker
Tracking
qEEG gamma power
Target engagement
CNS penetration
ERP P300 latency
Synaptic/processing marker
Target engagement
Injection-site reaction
Main tolerability issue
Monitoring
AChEI / memantine use
Interaction / confounder
Screening
Monitoring
Cognition & function endpoints
ADAS-Cog11/13, ADCS-ADL23, CDR-SB, MMSE/MoCA, with caregiver-rated change for dementia-endpoint validity — research/trial context only, since the pivotal endpoints were not met.
Biomarker & target-engagement tracking
Plasma pTau217, pTau181, Aβ42/40, GFAP, and NfL, plus qEEG gamma and ERP P300 latency. Biomarker movement is interpreted as mechanism/engagement, never as proven clinical benefit.
Tolerability
Track injection-site reactions (the main TEAE driver), serious adverse events, and bleeding risk around the injection. Screen concurrent AChEI/memantine and any oncology context (HGF/MET biology).
Safety gates & claim boundaries
Condition / request
Concern
Action · grade
Alzheimer's treatment protocol
Not approved; failed primary
Block
Disease-modification claim
No efficacy proof
Block
Self-injection protocol
No administration output
Block
Dose conversion / vial mixing
No reconstitution output
Block
Healthy nootropic use
Not studied
Block
Non-subcutaneous route
SC trials only
Block
Pediatric use
No basis
Block
Pregnancy / breastfeeding
No safety basis
Block
Unknown product / source
Unapproved compound
Block
Dihexa / HGF-MET-family stack
Redundant target
Block
Active cancer (no specialist)
HGF/MET oncology biology
Provider/block
Cancer history
Growth-factor pathway
Specialist review
Concurrent AChE inhibitor
Antagonism
Trial-context only
Memantine use
Confounder
Provider review
Anti-amyloid antibody co-use
No combo data
Specialist-only
Injection-site reaction history
Main TEAE
Monitor
Anticoagulant / bleeding risk
Injection procedure
Provider review
Advanced dementia / frailty
Population mismatch
Provider review
Parkinsonism / DLB
Small exploratory only
Specialist
Older-adult polypharmacy
Interaction load
Provider review
Biomarker over-interpretation
Not efficacy
Interpret carefully
GRADE summary — The HGF/MET mechanism (B), preclinical neuroprotection (B/C), Phase 1 safety/PK (B), and qEEG/ERP target engagement (B/C) are all reasonably supported. But clinical efficacy is graded D: LIFT-AD missed its primary GST and key ADAS-Cog11/ADCS-ADL23 secondary endpoints, and the program was discontinued. The decisive levers are the approval/trial-result gate (failed pivotal → treatment claims blocked), route gating (SC only), the biomarker-interpretation gate (pTau217 movement ≠ benefit), the injection-site/AChEI/cancer gates, and trial-arm-reference-only output — never a personalized or treatment protocol.
06 · Clinical trial program
The full arc: signal, then failure.
Fosgonimeton's value to the atlas is its complete, honest trial record — a Phase 1 with genuine target engagement, an exploratory Phase 2 that flagged an AChEI interaction, a pivotal Phase 2/3 that failed, and a small secondary-dementia study that also failed. Each is tied to its grade and its allowed output. The throughline: mechanism and biomarkers moved, clinical endpoints did not.
Phase 1
P300 ✓
Safe; qEEG gamma + ERP P300 normalization in AD. NCT03298672.
Primary GST + key secondaries not met at 26 wk. NCT04488419.
SHAPE
FAILED
PDD/DLB primary not met; n=28. Phase 2.
Program · timeline
Development arc at a glance
Phase
What happened
Output
Dihexa (WSU)
HGF/MET lead; poor drug-like properties
Superseded
Phase 1 (2022)
Safe; qEEG/ERP target engagement
Grade B
ACT-AD (2022)
Full-pop primary missed; AChEI signal
Grade C
LIFT-AD (Sep 2024)
Pivotal primary + secondary failed
Grade D
SHAPE (2023–24)
PDD/DLB primary not met (n=28)
Grade C/D
Post-2024
AD/DLB/PDD discontinued; oral ATH-1105 in ALS
Pipeline
BPhase 1 · NCT03298672
Safety, PK & qEEG/ERP target engagement
The randomized, placebo-controlled, double-blind Phase 1 dosed 88 subjects across healthy-young, healthy-older, and Alzheimer's cohorts by subcutaneous injection (SAD 2–90 mg; MAD 20–80 mg QD; AD cohort 40 mg); it reported acceptable safety, dose-proportional PK with no accumulation over 9 days, qEEG gamma induction, and ERP P300 latency normalization in the AD cohort.
The Phase 1 trial used qEEG as a translatable biomarker to confirm CNS penetration and target engagement in humans, and framed once-daily dosing around the pulsatile nature of HGF/MET signaling, where a steady-state plasma level of the active metabolite may not be required for a lasting effect.
ACT-AD's primary ERP P300 endpoint was not statistically significant in the full population, as combining fosgonimeton with AChEI standard-of-care showed a potential diminished effect; a pre-specified monotherapy subgroup suggested improvement in ERP P300 latency and ADAS-Cog11 at week 26, with a favorable 26-week safety profile that informed LIFT-AD.
LIFT-AD evaluated 40 mg once-daily subcutaneous fosgonimeton over 26 weeks in mild-to-moderate Alzheimer's disease and did not meet the primary Global Statistical Test (−0.08, P=0.70) or the key ADAS-Cog11 and ADCS-ADL23 secondary endpoints versus placebo. Moderate-AD and APOE4 subgroups showed a numerically greater (non-significant) effect.
Prespecified plasma biomarkers (NfL, GFAP, pTau181, pTau217, Aβ42/40) showed consistent directional improvements favoring fosgonimeton, with pTau217 reduced −0.12 pg/mL versus placebo (p<0.01) — but because the clinical endpoints failed, these biomarker movements cannot be read as proven benefit.
Athira's chief medical officer pointed to a lack of clinical decline in the placebo group and the short duration of the study as possible reasons for the failure — a reminder that trial design (placebo trajectory, duration) can obscure a real effect, which is exactly why the engine treats this as a failed reference rather than a refutation of mechanism.
SHAPE tested 40 or 70 mg daily fosgonimeton in Parkinson's disease dementia / dementia with Lewy bodies against a combined ADAS-Cog13 + P300 primary, stopped recruiting at 28 of a planned 75 participants, and failed its primary endpoint; a small mITT subgroup showed a positive cognitive signal — exploratory only.
A Neurotherapeutics study showed fosgonimeton's active metabolite positively modulates HGF/MET in vitro — enhancing MET phosphorylation, synaptogenesis, and neurite outgrowth — and that fosgonimeton reversed deficits in scopolamine-amnesia and LPS-neuroinflammation dementia models; preclinical work also describes attenuation of amyloid-beta toxicity.
Athira (formerly M3 Biotechnology) first pursued Dihexa, then screened >50 HGF/MET-active compounds and selected ATH-1017, a prodrug with superior solubility and PK; after subcutaneous administration the body rapidly converts it to an active metabolite — the basis for treating Dihexa stacks as redundant and blocked.
Following the LIFT-AD failure, fosgonimeton's development for Alzheimer's, DLB, and PDD was discontinued and the open-label extension was terminated; Athira shifted toward a next-generation orally administered candidate, ATH-1105, in ALS.
HGF signaling through MET promotes neuronal proliferation and survival, enhances hippocampal synaptic plasticity, and supports learning and memory, and hippocampal MET expression is diminished in Alzheimer's disease — the rationale for positively modulating an under-active repair pathway rather than supplying HGF directly.
Fosgonimeton is an inactive prodrug given subcutaneously that is rapidly converted in plasma to the active metabolite ATH-1001, which crosses the blood-brain barrier; the prodrug was selected over Dihexa for superior solubility and pharmacokinetics.
ATH-1001 enhances HGF–MET interaction, inducing MET phosphorylation and downstream PI3K/Akt and MAPK signaling and augmenting NMDA-receptor-mediated long-term potentiation through PKC — connecting receptor activation to the plasticity that underlies memory.
Because HGF/MET is a pulsatile system whose MET phosphorylation decays over time, once-daily prodrug dosing is aligned with the pathway's natural regulation, and a steady-state plasma level of ATH-1001 may not be required for a lasting effect — the basis for intermittent rather than continuous exposure.
Athira presented data suggesting acetylcholinesterase inhibitors antagonize fosgonimeton's effect on HGF/MET signaling, which helped explain why ACT-AD's full-population ERP P300 primary missed while a monotherapy subgroup improved — a key design lesson carried into the engine's screening.
The tracked panel spans NfL (neurodegeneration), GFAP (neuroinflammation), Aβ42/40 (amyloid), and pTau181/pTau217 (tau pathology); pTau217 is a hallmark AD marker, but its reduction in a trial that missed clinical endpoints cannot be read as proven benefit.
Fosgonimeton's defining contrast is internal: strong mechanism and human target-engagement markers on one side, a failed pivotal endpoint on the other. Against its predecessor Dihexa it is the drug-like, clinically tested form; against the broader dementia field it is a discontinued investigational agent whose biomarker story outran its clinical results.
L1 · Consumer — Fosgonimeton (ATH-1017) is an experimental injected drug that was tested for Alzheimer's disease. It works on a brain-repair pathway called HGF/MET, and early studies showed it reached the brain and changed some markers. But the big, decisive trial (LIFT-AD) did not show that it actually helped memory or daily function compared with placebo, and the program was stopped. Intrasigna only shows the doses used in the trials and what those trials found — it does not provide a treatment plan, a way to inject it, or any healthy-person "brain booster" use.
L2 · Clinical — Fosgonimeton/ATH-1017 is a subcutaneous prodrug (→ ATH-1001) positively modulating HGF/MET. Phase 1 supported safety, dose-proportional PK, and qEEG/ERP P300 target engagement; ACT-AD flagged an AChEI antagonism; LIFT-AD (40 mg QD × 26 wk, ~315 mild-moderate AD) missed the primary GST and key ADAS-Cog11/ADCS-ADL23 secondaries despite a significant pTau217 reduction; SHAPE (PDD/DLB) also failed. The engine shows SC trial arms with computed exposure and the failed-endpoint warning; treatment, self-injection, reconstitution, and disease-modification outputs are blocked.
L3 · Research — ATH-1001 crosses the BBB and enhances HGF–MET → MET phosphorylation → PI3K/Akt and MAPK, augmenting NMDA-mediated LTP via PKC; preclinically it drives synaptogenesis/neurite outgrowth and attenuates amyloid-β toxicity, with pulsatile QD dosing matched to HGF/MET biology. Human translation: Phase 1 target engagement (qEEG gamma, ERP P300) and LIFT-AD biomarker movement (pTau217 −0.12 pg/mL, p<0.01) without clinical efficacy (GST −0.08, P=0.70). A model case of mechanism + engagement + biomarkers ≠ clinical benefit; discontinued, with oral ATH-1105 advancing in ALS.
08 · References & evidence
Source register.
Evidence grades reflect the strength of support for the specific claim cited, not the prestige of the journal. Fosgonimeton's mechanism, Phase 1 safety, and target engagement are well supported; its clinical efficacy is graded down to D because the pivotal LIFT-AD trial failed its primary and key secondary endpoints. Biomarker and subgroup signals are cited as exactly that — signals, not proof. Trial-registry and admin sources anchor the SC-only, trial-reference-only gating.
A · Established fact / primary trial result
B · Strong mechanism / human safety / target engagement