---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-21-276762"
form_type: "8-K"
ticker: "SYBX"
cik: "0001527599"
company_name: "SYNLOGIC, INC."
filed_at: "2021-09-20T23:59:59+00:00"
generated_at: "2026-06-29T02:36:58.374912+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Synlogic reports positive PKU data: SYNB1618 reduces Phe, SYNB1934 shows 2x activity

## Summary
- SYNB1618 showed 20% reduction in fasting plasma Phe after 14 days at 1e12 dose in Phase 2 SynPheny-1 interim analysis.
- SYNB1934 demonstrated two-fold higher activity than SYNB1618 in head-to-head Phase 1 study based on biomarkers of Phe metabolism.
- Safety profile consistent with prior studies: no serious AEs, no drug-related discontinuations; AEs mild-moderate GI.
- Company plans to complete Phase 2 SynPheny-1 with SYNB1934 arm and prepare Phase 3 program for most promising strain in 2022.
- Shares trade on Nasdaq under SYBX; data support Synthetic Biotic platform for metabolic diseases.

## SEC filing metadata
- accession: 0001193125-21-276762
- form_type: 8-K
- ticker: SYBX
- cik: 0001527599
- company_name: SYNLOGIC, INC.
- filed_at: 2021-09-20T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1527599/000119312521276762/0001193125-21-276762-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1527599/000119312521276762/d234976d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-21-276762
- JSON: https://secwatch.observer/filing/0001193125-21-276762.json
- Plain text: https://secwatch.observer/filing/0001193125-21-276762.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.