---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-23-086922"
form_type: "8-K"
ticker: "TCRX"
cik: "0001783328"
company_name: "TScan Therapeutics, Inc."
filed_at: "2023-03-31T23:59:59+00:00"
generated_at: "2026-06-17T08:11:01.304180+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# TScan CEO David Southwell steps down; Gavin MacBeath named acting CEO

## Summary
- David Southwell resigned as CEO, President, and Board member effective March 27, 2023; no disagreement with company.
- Gavin MacBeath, Ph.D., appointed acting CEO effective March 28, 2023; will continue as Chief Scientific and Operating Officer.
- Southwell receives 18 months salary continuation and COBRA; severance conditioned on release and compliance with restrictive covenants.
- Company reaffirms cash runway into Q2 2024 with $120M cash as of Dec 31, 2022; clinical programs on track.
- First patient dosed with TSC-101 on March 9, 2023; plans to provide preliminary safety/biomarker data by mid-year 2023.

## SEC filing metadata
- accession: 0001193125-23-086922
- form_type: 8-K
- ticker: TCRX
- cik: 0001783328
- company_name: TScan Therapeutics, Inc.
- filed_at: 2023-03-31T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 5.02, 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1783328/000119312523086922/0001193125-23-086922-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1783328/000119312523086922/d477438d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-23-086922
- JSON: https://secwatch.observer/filing/0001193125-23-086922.json
- Plain text: https://secwatch.observer/filing/0001193125-23-086922.txt

## Key facts
- Executive change
  David Southwell resigned as Chief Executive Officer and President at TScan Therapeutics, Inc..
  - Action: resigned
  - Role: Chief Executive Officer and President
  source text: On March 27, 2023, Mr. David Southwell stepped down from his roles as Chief Executive Officer and President of TScan Therapeutics, Inc. (the “Company”), and as a member of the Board of Directors of the Company (the “Board”), effective immediately.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1783328/000119312523086922/0001193125-23-086922-index.htm
- Executive change
  Gavin MacBeath was appointed as acting Chief Executive Officer at TScan Therapeutics, Inc..
  - Action: appointed
  - Role: acting Chief Executive Officer
  source text: On March 28, 2023, the Board appointed Gavin MacBeath, Ph.D., as acting Chief Executive Officer of the Company, effective as of March 28, 2023.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1783328/000119312523086922/0001193125-23-086922-index.htm

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