Synaptic Therapeutics

Overview

Synaptic Therapeutics is a clinical-stage biotechnology company focused on developing novel therapeutics that protect and restore synaptic function in neurodegenerative diseases. Founded in 2021 and headquartered in Cambridge, Massachusetts, the company's mission is to address synaptic loss, the strongest pathological correlate of cognitive decline in Alzheimer's disease["@synaptic"].

Overview

Synaptic Therapeutics is a clinical-stage biotechnology company focused on developing novel therapeutics that protect and restore synaptic function in neurodegenerative diseases. Founded in 2021 and headquartered in Cambridge, Massachusetts, the company's mission is to address synaptic loss, the strongest pathological correlate of cognitive decline in Alzheimer's disease["@synaptic"].

The company's lead program, ST-101, is a first-in-class small molecule that targets the sigma-2 receptor to protect synapses from amyloid-beta toxicity. Unlike amyloid-targeting antibodies that aim to reduce amyloid burden, ST-101 directly protects the synaptic connections that are essential for memory and cognition.

Pipeline Overview

| Program | Target/Mechanism | Indication | Phase | Status |
|---------|-----------------|------------|-------|--------|
| ST-101 | Sigma-2 receptor agonist | Alzheimer's disease | Phase 1 | Active (2024) |
| ST-202 | Sigma-2 receptor agonist | Parkinson's disease | Preclinical | Research |
| ST-303 | Synaptic stabilizer | Dementia with Lewy Bodies | Discovery | Research |

Technology Platform

Sigma-2 Receptor Targeting

Synaptic Therapeutics focuses on the sigma-2 receptor:

Receptor Function:

• Located on endoplasmic reticulum and lysosomes
• Regulates synaptic protein homeostasis
• Controls autophagy and cellular stress responses
• Protects against apoptosis

• Direct synaptic protection
• Independent of amyloid reduction
• Preserves dendritic spine integrity
• Maintains neuronal connectivity

Synaptic Protection Mechanism

ST-101 protects synapses through multiple pathways:

• Blocks amyloid-beta induced synapse damage
• Maintains dendritic spine density
• Preserves postsynaptic structures

• Activates stress protective pathways
• Improves protein homeostasis
• Reduces apoptotic signaling

• Maintains neurotransmitter release
• Preserves synaptic plasticity
• Protects against excitotoxicity

Lead Program: ST-101

Clinical Development

Phase 1 Study (2024):

ST-101 entered Phase 1 clinical trials in 2024, evaluating:

• Safety and tolerability in healthy volunteers
• Single and multiple ascending doses
• Pharmacokinetics and target engagement
• Biomarker assessments in cerebrospinal fluid

• Expected to begin in 2025
• Patients with early Alzheimer's disease
• Cognitive and biomarker endpoints

Differentiation from Amyloid Therapies

ST-101 represents a novel approach:

| Feature | ST-101 | Anti-Amyloid Antibodies |
|---------|--------|------------------------|
| Target | Sigma-2 receptor | Amyloid-beta |
| Mechanism | Synaptic protection | Amyloid reduction |
| Approach | Downstream | Upstream |
| Stage | Phase 1 | Approved |

Science and Research

Synaptic Loss in Alzheimer's Disease

Synaptic loss is the key correlate of cognitive decline:

• Occurs early in disease progression
• Correlates strongly with memory deficits
• Present before significant amyloid burden
• Continues throughout disease progression
• Current therapies do not directly address it

Sigma-2 Receptor Biology

The sigma-2 receptor is a unique target:

• Not directly involved in amyloid production
• Modulates synaptic homeostasis
• Protects against multiple toxic insults
• Oral bioavailability possible

Preclinical Data

ST-101 has demonstrated:

• Protection against amyloid-induced synapse loss in vitro
• Improved cognitive function in AD mouse models
• Good brain penetration
• Favorable safety profile
• Synaptic density preservation

Corporate Information

Headquarters: Cambridge, Massachusetts, USA

Founded: 2021

Funding:

• Seed: $5 million (2021)
• Series A: $40 million (2023)
• Series B: $60 million (2025)

• Atlas Venture
• Google Ventures (GV)
• OrbiMed
• Alexandria Venture Investments

• Dr. Sarah W. - CEO and Co-founder
• Dr. James M. - CSO and Co-founder
• Dr. Patricia L. - CMO

Recent Developments (2024-2025)

• 2025: Series B financing completed ($60 million)
• 2024: ST-101 entered Phase 1 clinical trials
• 2024: IND clearance received from FDA
• 2023: Positive preclinical data published

Competitive Landscape

| Company | Program | Mechanism | Stage |
|---------|---------|-----------|-------|
| Synaptic Therapeutics | ST-101 | Sigma-2 agonist | Phase 1 |
| Cognition/Novartis | CT1812 | Sigma-2 antagonist | Phase 2 |
| Vigil Neuroscience | VIG-106 | TREM2 agonist | Phase 1 |
| Lyterian | LYT-100 | NLRP3 inhibitor | Phase 1b/2a |

Cross-References

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• Synaptic Dysfunction
• Sigma-2 Receptor
• [Amyloid](/mechanisms/amyloid-aggregation) Cascade Hypothesis
• Synaptic Plasticity Deficits
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/genes/ar)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

References