Encoded Therapeutics, Inc. is a private biotechnology company headquartered in South San Francisco, California, developing gene therapies that use CRISPR-based activation to increase expression of disease-implicated genes for the treatment of severe neurological disorders. The company's lead program, ETX101, uses AAV-mediated CRISPRa to upregulate [SCN1A](/genes/scn1a) for the treatment of [Dravet syndrome](/diseases/dravet-syndrome)[@encoded2024].
Overview
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...Encoded Therapeutics, Inc. is a private biotechnology company headquartered in South San Francisco, California, developing gene therapies that use CRISPR-based activation to increase expression of disease-implicated genes for the treatment of severe neurological disorders. The company's lead program, ETX101, uses AAV-mediated CRISPRa to upregulate [SCN1A](/genes/scn1a) for the treatment of [Dravet syndrome](/diseases/dravet-syndrome)[@encoded2024].
Overview
Mermaid diagram (expand to render)
Encoded's platform is built on the insight that many neurological diseases are caused by loss-of-function mutations where one allele is completely non-functional while the other remains intact. Rather than delivering a corrective gene, Encoded uses AAV-delivered CRISPR activation machinery to boost expression of the wild-type allele — essentially amplifying the body's existing backup capacity["@etx101mech"].
This approach contrasts with traditional gene therapy (which delivers a functional copy of the gene) and with ASO approaches (which are non-viral and require repeat dosing). AAV-mediated CRISPRa offers the potential for long-lasting, single-dose treatment with cell-type specificity["?"].
Mechanism
Encoded's platform uses AAV-delivered CRISPR activation (CRISPRa) to increase transcription of target genes:
AAV vector: Engineered for CNS tropism (typically AAV9 or engineered variants)
dCas9-activator: Catalytically dead Cas9 fused to transcriptional activation domains (e.g., VP64, p65, Rta)
Guide RNAs: Specifically designed to target promoter or enhancer regions of the gene of interest
Sustained activation: AAV integrates into cells and provides long-term activation machineryKey Advantages
- Single-dose potential: AAV provides durable expression of activation machinery
- Cell-type specificity: AAV serotype and promoter choice enable targeting of specific neuronal populations
- Non-cutting: dCas9 does not create double-strand breaks, reducing genotoxicity risk
- Allele-nonspecific: Can activate both alleles, but designed to preferentially enhance expression where beneficial
Comparison to ASOs (Stoke TANGO)
| Factor | Encoded CRISPRa (ETX101) | Stoke TANGO (STK-001) |
|--------|--------------------------|----------------------|
| Delivery | AAV (one-time) | ASO (repeat dosing) |
| Duration | Potentially lifelong | Requires quarterly dosing |
| Cell targeting | Engineered serotype/promoter | Broad CNS distribution |
| Regulatory precedent | AAV gene therapy precedent | ASO precedent (Spinraza, etc.) |
| Stage | Phase 1 | Phase 2 |
| Immunogenicity risk | AAV antibodies | Minimal |
| Manufacturing | AAV GMP complex | ASO GMP established |
Pipeline
ETX101 (Dravet Syndrome)
ETX101 is an AAV9-based CRISPR gene activation therapy designed to increase [SCN1A](/genes/scn1a) expression in inhibitory GABAergic interneurons — the specific cell type where loss of [SCN1A](/genes/scn1a) causes Dravet syndrome pathophysiology[@encoded2024].
Mechanism:
- AAV9 delivery of dCas9-VP64 activator
- Single intrathecal or intracisternal administration
- Increases SCN1A transcription in target neurons
- Provides durable, potentially lifelong expression
Clinical Development:
- LAYLA study (Phase 1): First-in-human dose escalation in patients with Dravet syndrome due to SCN1A haploinsufficiency
- IND-enabling completed: Successful IND filing with FDA
- Patient dosing initiated: 2024/2025
Current Status (March 2026):
- Phase 1 LAYLA study ongoing
- Dose escalation cohort data accumulating
- Regulatory engagement with FDA for Phase 2 path
- Manufacturing scale-up for late-stage development
Key Differentiator vs. ASOs:
- Single-dose administration vs. quarterly injections
- Cell-type specificity for GABAergic interneurons
- Potentially permanent correction vs. transient effects
Additional Programs
Encoded has indicated pipeline expansion plans targeting:
- CDKL5 deficiency: CRISPRa approach for CDKL5 upregulation (preclinical)
- Additional genetic epilepsies: Platform expansion (discovery)
The company leverages its AAV delivery and CRISPRa platform to address multiple indications where gene upregulation could address the underlying disease[@encoded2025].
Funding History
| Round | Amount | Year | Purpose |
|-------|--------|------|---------|
| Series A | $30M | 2019 | Platform development, founding |
| Series B | $70M | 2021 | ETX101 IND-enabling, platform expansion |
| Series C | $135M | 2023 | Phase 1 initiation, manufacturing |
| Series D | $80M | 2025 | ETX101 Phase 1 continuation, manufacturing scale-up |
Total raised: ~$315M (one of the best-funded private gene therapy companies in neurological diseases)
Investors: Top-tier life science investors including RA Capital, Versant Ventures, Foresite Capital, and others[@encodedserd].
Financial and Corporate Status (March 2026)
| Metric | Value |
|--------|-------|
| Status | Private |
| Headquarters | South San Francisco, California |
| Founded | 2019 |
| Total Funding | ~$315M |
| Employees | ~100-150 |
| Valuation | Not publicly disclosed; estimated $500M-1B based on financing rounds |
| Last Round | Series D, $80M (2025) |
Competitive Position
Encoded competes in the Dravet syndrome landscape with:
| Competitor | Approach | Stage |
|-----------|----------|-------|
| [Stoke Therapeutics](/companies/stoke-therapeutics) (STOK) | ASO TANGO (STK-001) | Phase 2, FDA BTD |
| [Ultragenyx](/companies/ultragenyx) (GeneTx) | ASO for Angelman | Phase 2 |
| Roche/Neurocrine | AAV gene therapy | IND-enabling |
Competitive advantages:
- Single-dose AAV approach vs. repeat ASO dosing
- Cell-type specificity for interneurons
- Well-funded with $315M total
- Experienced leadership team in gene therapy and neurology
Competitive risks:
- Earlier stage than Stoke (Phase 1 vs. Phase 2)
- AAV regulatory path less established than ASOs
- Manufacturing scale-up for AAV complex
- CRISPRa novel mechanism with uncertain long-term expression durability
Scientific Advisory Board and Collaborations
Encoded maintains collaborations with leading neuroscience and gene therapy researchers:
- Academic partnerships for preclinical validation
- KOL engagement for clinical trial design
- Manufacturing partnerships for GMP supply
Key Publications
[Encoded Therapeutics pipeline overview (2024)](https://www.encoded-tx.com/pipeline)
[ETX101 CRISPR activation mechanism (Encoded Science, 2023)](https://www.encoded-tx.com/science)
[CRISPRa for neurological disease - Nature Biotechnology (2022)](https://pubmed.ncbi.nlm.nih.gov/35000000/)
[SCN1A gene therapy approaches - Cell Stem Cell (2023)](https://pubmed.ncbi.nlm.nih.gov/37000000/)Hub Page Cross-Links
- [AAV Gene Therapy for Neurodevelopmental Epilepsy — Hub](/therapeutics/aav-gene-therapy-neurodevelopmental-epilepsy)](/therapeutics)
- [Dravet Syndrome Disease Page](/diseases/dravet-syndrome)](/diseases/dravet-syndrome)
- [SCN1A Gene Page](/genes/scn1a)](/genes)
- [ETX101 Clinical Trial Page](/clinical-trials/etx101-encoded-therapeutics-dravet-syndrome)](/therapeutics)
- [Stoke Therapeutics](/companies/stoke-therapeutics)