---
schema_version: "secwatch.filing_event.v1"
accession: "0001558370-23-015840"
form_type: "8-K"
ticker: "ACRS"
cik: "0001557746"
company_name: "Aclaris Therapeutics, Inc."
filed_at: "2023-09-18T23:59:59+00:00"
generated_at: "2026-06-10T14:44:32.743110+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Aclaris reports positive Phase 1 MAD data for ATI-2138; advances to Phase 2a in ulcerative colitis

## Summary
- ATI-2138 well tolerated in 60-subject MAD trial; no serious adverse events; mild headache and diarrhea only events in >1 subject.
- Dose-proportional PK and near-maximal inhibition of ITK and JAK3 biomarkers achieved at 30 mg total daily dose.
- Company to start Phase 2a proof-of-concept in ulcerative colitis in early 2024; evaluating second PoC in another T-cell mediated disease.
- CEO highlights KINect discovery engine; upcoming Phase 2 data for zunsemetinib (RA) and ATI-1777 (atopic dermatitis) expected late 2023.

## SEC filing metadata
- accession: 0001558370-23-015840
- form_type: 8-K
- ticker: ACRS
- cik: 0001557746
- company_name: Aclaris Therapeutics, Inc.
- filed_at: 2023-09-18T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1557746/000155837023015840/0001558370-23-015840-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1557746/000155837023015840/acrs-20230918x8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001558370-23-015840
- JSON: https://secwatch.observer/filing/0001558370-23-015840.json
- Plain text: https://secwatch.observer/filing/0001558370-23-015840.txt

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