This category page catalogs companies developing GABA receptor modulators, glutamate transporter enhancers, NMDA antagonists, AMPA modulators, and related excitotoxicity therapies for Alzheimer's disease (AD). These approaches target the balance between inhibitory (GABAergic) and excitatory (glutamatergic) neurotransmission, which becomes dysregulated in AD pathology.
Excitotoxicity is a key pathological process in AD, where excessive glutamate signaling leads to neuronal damage through overactivation of NMDA and AMPA receptors. This can occur through:
GABAergic dysfunction in AD contributes to:
Companies in this space aim to restore the excitation-inhibition balance through multiple mechanisms[1][2][3].
Website: Sage Therapeutics
| Attribute | Details |
|---|---|
| Focus | GABA-A receptor neurosteroid modulators |
| Lead Candidate | SAGE-718 (Navoximod) |
| Indication | Alzheimer's disease (cognitive impairment) |
| Stage | Phase 2 |
| Mechanism | NMDA receptor antagonist (not GABA-A) |
SAGE-718 (Navoximod): An IDO1 inhibitor with NMDA receptor antagonist properties. While primarily an immunomodulatory candidate for depression, SAGE-718 has shown cognitive benefits in AD preclinical models through NMDA modulation.
SAGE-324 (Ganaxolone): A GABA-A receptor positive allosteric modulator. Originally developed for epilepsy and postpartum depression, ganaxolone is being evaluated for AD-related cognitive impairment due to its GABA-enhancing neuroprotective effects.
Clinical Status: SAGE-324 completed Phase 2 trials for essential tremor with safety data supporting CNS development. SAGE-718 in Phase 2 for AD cognitive impairment.
Relevance to AD:
Website: Supernus Pharmaceuticals
| Attribute | Details |
|---|---|
| Focus | AMPA and GABA modulators |
| Lead Candidate | SPN-820 |
| Indication | Treatment-resistant depression, AD cognitive impairment |
| Stage | Phase 2 |
| Mechanism | AMPA receptor modulator |
SPN-820: An AMPA receptor modulator being developed for treatment-resistant depression. AMPA modulation enhances synaptic plasticity and may provide cognitive benefits in AD through:
Relevance to AD: AMPA modulation represents a novel approach beyond NMDA-focused strategies, with potential for cognitive enhancement without the dissociative effects of ketamine.
| Company | Candidate | Stage | Notes |
|---|---|---|---|
| Biohaven | Various GABA-A PAMs | Discovery | Expanding CNS pipeline post-Pfizer acquisition |
| Cerevel | CVL-231 | Phase 2 | Kv7 opener, also modulates GABA |
| Zymeworks | ZY-OGD-01 | Preclinical | GABA-A selective PAM |
Glutamate transporters (EAAT1/EAAT2) clear glutamate from the synaptic cleft. Reduced transporter function leads to excitotoxicity in AD[2:1].
Website: AstraZeneca
| Attribute | Details |
|---|---|
| Focus | EAAT2 enhancers |
| Lead Candidates | Various small molecules |
| Indication | Alzheimer's disease, ALS |
| Stage | Discovery/Preclinical |
| Mechanism | Glutamate transporter (EAAT2) enhancement |
Research Focus: AstraZeneca has explored compounds that enhance glutamate transporter function to reduce extracellular glutamate levels and prevent excitotoxic neuronal damage.
Relevance to AD:
Website: Daiichi Sankyo
| Attribute | Details |
|---|---|
| Focus | Glutamate transporter modulators |
| Lead Candidates | Multiple programs |
| Stage | Discovery |
| Mechanism | EAAT1/EAAT2 modulation |
| Company | Target | Stage | Notes |
|---|---|---|---|
| EAAT modulators | Multiple | Preclinical | Academic/industry collaborations |
Traditional NMDA antagonists (memantine) provide modest benefits in AD. Newer approaches aim for more precise modulation[3:1].
Memantine (Namenda) represents the approved NMDA antagonist approach:
| Company | Candidate | Approach | Stage |
|---|---|---|---|
| relmada | REL-1017 | NMDA channel blocker | Phase 3 (depression) |
| Naurex (acquired) | GLYX-13 | Partial agonist | Phase 2 |
Website: Merck
| Attribute | Details |
|---|---|
| Focus | NMDA subunit-selective antagonists |
| Approach | GluN2A-selective targeting |
| Stage | Discovery |
| Relevance | More targeted neuroprotection |
AMPA receptor modulators enhance synaptic plasticity and may improve cognitive function in AD[4].
As detailed above, SPN-820 is an AMPA modulator with potential cognitive benefits.
| Company | Candidate | Stage | Notes |
|---|---|---|---|
| Taked | Various | Preclinical | Japanese CNS pipeline |
| Mitsubishi Tanabe | MT-381 | Discovery | AMPA modulator |
| Approach | Companies | Stage | Promise |
|---|---|---|---|
| GABA-A PAMs | Sage, Biohaven, Cerevel | Phase 1-2 | High (proven safety) |
| AMPA Modulators | Supernus, Takeda | Phase 2 | Moderate-High |
| Glutamate Transporters | AstraZeneca, Daiichi | Discovery | Moderate |
| NMDA Antagonists | Forest/AbbVie, Relmada | Approved/Phase 3 | Moderate |
| EAAT Enhancers | Multiple academic | Preclinical | Moderate |
Successful therapies would:
Forss, M. et al. GABA-A receptor modulation in Alzheimer's disease. 2023. ↩︎
Liu, J. et al. Glutamate transporter dysfunction in Alzheimer's disease. 2022. ↩︎ ↩︎
Green, A.R. et al. NMDA receptor antagonists for neuroprotection in AD. 2018. ↩︎ ↩︎
Ward, B.A. et al. AMPA receptor modulators for cognitive enhancement. 2019. ↩︎