---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-23-002041"
form_type: "8-K"
ticker: "CCCC"
cik: "0001662579"
company_name: "C4 Therapeutics, Inc."
filed_at: "2023-02-02T23:59:59+00:00"
generated_at: "2026-06-20T02:27:59.875476+00:00"
event_type: "leadership"
sentiment: "negative"
materiality_score: 0.55
calibrated_materiality_score: 0.55
confidence: "high"
source: SEC EDGAR
---

# C4 Therapeutics CMO Adam Crystal resigns; Hagop Youssoufian named interim CMO

## Summary
- Adam S. Crystal, M.D., Ph.D., resigns as CMO effective Feb 24, 2023 to pursue a head of R&D opportunity elsewhere.
- Crystal will provide transitional consulting services on an as-needed basis until Sep 1, 2023.
- Hagop Youssoufian, M.D., appointed interim CMO effective Feb 24, 2023; permanent search underway.

## SEC filing metadata
- accession: 0001628280-23-002041
- form_type: 8-K
- ticker: CCCC
- cik: 0001662579
- company_name: C4 Therapeutics, Inc.
- filed_at: 2023-02-02T23:59:59+00:00
- event_type: leadership
- sentiment: negative
- materiality_score: 0.55
- calibrated_materiality_score: 0.55
- confidence: high
- sec_items: 5.02, 7.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1662579/000162828023002041/0001628280-23-002041-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1662579/000162828023002041/cccc-20230130.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-23-002041
- JSON: https://secwatch.observer/filing/0001628280-23-002041.json
- Plain text: https://secwatch.observer/filing/0001628280-23-002041.txt

## Key facts
- Executive change
  Adam S. Crystal resigned as Chief Medical Officer at C4 Therapeutics, Inc..
  - Action: resigned
  - Role: Chief Medical Officer
  source text: On January 30, 2023, Adam S. Crystal, M.D., Ph.D., informed us of his intent to resign from his position as the Chief Medical Officer of C4 Therapeutics, Inc.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1662579/000162828023002041/0001628280-23-002041-index.htm

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