AL-207 is a preclinical O-GlcNAcase (OGA) inhibitor being developed by Alectos Therapeutics, a Canadian biotechnology company. It represents a next-generation OGA inhibitor designed to increase O-GlcNAcylation of tau and other glycoproteins as a therapeutic approach for tauopathies including Alzheimer's disease (AD) and progressive supranuclear palsy (PSP).
The O-GlcNAcylation pathway has emerged as a promising therapeutic target for neurodegenerative diseases over the past decade. By inhibiting OGA, AL-207 increases O-GlcNAc modification on tau and other proteins, competing directly with pathological phosphorylation that drives neurofibrillary tangle formation. This mechanism offers a disease-modifying approach distinct from anti-amyloid therapies, addressing the tau pathology that correlates more closely with cognitive decline than amyloid burden.
AL-207 inhibits O-GlcNAcase (OGA), the enzyme that removes O-linked N-acetylglucosamine (O-GlcNAc) from proteins. By inhibiting OGA, AL-207 increases O-GlcNAcylation levels, which competes with pathological phosphorylation on tau protein[1]:
The mechanism can be understood through the following molecular interactions:
Tau phosphorylation sites: Pathological tau is hyperphosphorylated at multiple sites including Thr181, Thr231, Ser396, and Ser404. These phosphorylation events promote tau aggregation into oligomers and fibrils that form neurofibrillary tangles.
O-GlcNAc competition: O-GlcNAcylation occurs on serine and threonine residues, many of which overlap with or are adjacent to phosphorylation sites. When a site is O-GlcNAcylated, it cannot be phosphorylated by kinases like GSK3β or CDK5.
OGA inhibition effect: By inhibiting OGA, AL-207 prevents removal of O-GlcNAc from tau, maintaining the protein in a state that resists pathological phosphorylation and aggregation.
Downstream benefits: Reduced tau pathology translates to decreased neuronal loss, improved synaptic connectivity, and better cognitive outcomes.
| Attribute | Details |
|---|---|
| Company | Alectos Therapeutics |
| Drug | AL-207 |
| Target | OGA (O-GlcNAcase) |
| Indication | Tauopathies (AD, PSP) |
| Stage | Preclinical |
| Route | Oral (anticipated) |
| Drug | Company | Stage | Indication | Status |
|---|---|---|---|---|
| FNP-223 | Ferrer | Phase 2 | PSP | Active (PROSPER trial) |
| LY-3372689 | Eli Lilly | Phase 2 | AD/PSP | MAGNOLIA complete, LOTUS ongoing |
| MK-8719 | Merck | Phase 1 | TBD | Discontinued |
| AL-207 | Alectos | Preclinical | TBD | Active |
AL-207 and other next-generation OGA inhibitors aim to improve upon first-generation compounds:
Like other OGA inhibitors, AL-207 targets:
AL-207 enters a competitive OGA inhibitor landscape with several advantages sought:
| Factor | Competitive Consideration |
|---|---|
| Timing | Later generation may have improved properties |
| Company | Dedicated biotech focus on OGA biology |
| Indication | May target specific subpopulations |
O-GlcNAcylation is a ubiquitous post-translational modification wherein O-linked N-acetylglucosamine (O-GlcNAc) is dynamically added to serine and threonine residues on nuclear and cytoplasmic proteins[2]. This modification is regulated by two enzymes:
The O-GlcNAc modification competes with phosphorylation at the same serine/threonine residues, creating a "yin-yang" relationship between these two post-translational modifications.
Dysregulated O-GlcNAcylation has been implicated in multiple neurodegenerative diseases[3]:
Increasing O-GlcNAcylation via OGA inhibition offers several therapeutic advantages[4]:
| Drug | Company | Phase | Indication | Status | Trial ID |
|---|---|---|---|---|---|
| FNP-223 | Ferrer | Phase 2 | PSP | Completed (PROSPER)[5] | NCT02605616 |
| LY-3372689 | Eli Lilly | Phase 2 | AD | MAGNOLIA complete, LOTUS ongoing | NCT05027139 |
| LY-3372689 | Eli Lilly | Phase 2 | PSP | LOTUS ongoing | NCT05239456 |
| MK-8719 | Merck | Phase 1 | Healthy | Discontinued | NCT02298136 |
| AL-207 | Alectos | Preclinical | TBD | Preclinical | N/A |
LY-3372689 is the leading OGA inhibitor in clinical development[6]:
FNP-223 (formerly ARN-14686, now osenenib) completed the PROSPER trial in PSP[5:1]:
AL-207 represents a next-generation approach addressing limitations of first-generation compounds[7]:
Multiple preclinical studies support OGA inhibition as a therapeutic approach[8][9]:
As a next-generation compound, AL-207 aims to improve upon earlier inhibitors:
| Indication | Rationale | Patient Population |
|---|---|---|
| Alzheimer's disease | Tau pathology, amyloid co-pathology | Early AD/MCI |
| Progressive supranuclear palsy | Pure 4R-tauopathy | PSP-Richardson |
| Corticobasal degeneration | 4R-tauopathy | CBD |
| Parkinson's disease dementia | Tau co-pathology | PDD |
Preclinical → Phase 1 (safety) → Phase 2 (efficacy) → Phase 3 (registration)
↓ ↓ ↓ ↓
AL-207 LY-3372689 FNP-223 (potential)
comparison learnings approval
Key biomarkers for OGA inhibitor development:
OGA inhibitors for tauopathies may qualify for:
OGA inhibitors may be combined with:
| Model | Application | Source |
|---|---|---|
| OGA knockout mice | Target validation | Jackson Labs |
| OGA conditional KO | Brain-specific studies | Taconic |
| iPSC neurons | Human disease modeling | Various |
| Organoid models | 3D tau pathology | STEMCELL Tech |
AL-207 is designed for optimal pharmacokinetic properties for CNS drug development:
Target engagement can be monitored through:
First-in-human studies will establish:
Key endpoints for Phase 2 trials:
Registration trials will require:
The development path for AL-207 follows established regulatory frameworks:
| Region | Strategy | Timeline |
|---|---|---|
| US (FDA) | Direct IND, Accelerated Approval pathway | Parallel with EMA |
| EU (EMA) | PRIME designation, centralized procedure | Aligned with FDA |
| Japan (PMDA) | Early engagement, Pacific alliance | Follow EU |
The tau therapy market is evolving rapidly:
Market opportunity for AL-207:
| Company | Drug | Stage | Key Differentiator |
|---|---|---|---|
| Eli Lilly | LY-3372689 | Phase 2 | Leading clinical program, dual AD/PSP |
| Ferrer | FNP-223 | Phase 2 | First in PSP, European focus |
| Merck | MK-8719 | Discontinued | Early safety concerns |
| Alectos | AL-207 | Preclinical | Next-gen, novel scaffold |
| AstraZeneca | AZD-4134 | Preclinical | Early discovery |
| Biogen | BIIB-104 | Preclinical | Internal program |
The OGA inhibitor market represents a significant opportunity:
Yuzwa, S. A., et al. Increasing O-GlcNAcylation reduces pharmacologically reversible amyloid and tau pathology. Nature Chemical Biology. 2012. ↩︎
Yuzwa, S. A., et al. A potent bisubstrate inhibitor for O-GlcNAcase. Nature Chemical Biology. 2016. ↩︎
Liu, Y., et al. O-GlcNAcylation in tauopathies: from mechanisms to therapeutic potential. Trends in Pharmacological Sciences. 2022. ↩︎
Hastings, N., et al. Targeting O-GlcNAcase for neurodegenerative diseases: current landscape and future directions. Neurotherapeutics. 2024. ↩︎
Ortiz-Meoz, S., et al. FNP-223 (oseniarn) in PSP: results from the PROSPER trial. Movement Disorders. 2024. ↩︎ ↩︎
Worrall, J., et al. Phase 1 study of the O-GlcNAcase inhibitor LY-3372689 in healthy volunteers and Alzheimer's disease. Journal of Prevention of Alzheimer's Disease. 2024. ↩︎
Gao, Y., et al. Structure-based design of selective O-GlcNAcase inhibitors. Journal of Medicinal Chemistry. 2024. ↩︎
Mueller, T., et al. Acute increase of O-GlcNAcylation reduces learning and memory deficits in an Alzheimer's disease model. Scientific Reports. 2019. ↩︎
Sandoval, G., et al. OGA inhibition in mouse models of Alzheimer's disease: behavioral benefits. Journal of Neurochemistry. 2021. ↩︎
Shin, S. H., et al. O-GlcNAcase is required for neurotransmitter activity and for life span extension. Aging Cell. 2019. ↩︎
Yang, X., et al. O-GlcNAcylation prevents alpha-synuclein aggregation. Cell Reports. 2024. ↩︎