---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-25-043290"
form_type: "8-K"
ticker: "CCCC"
cik: "0001662579"
company_name: "C4 Therapeutics, Inc."
filed_at: "2025-10-01T23:59:59+00:00"
generated_at: "2026-05-17T05:06:13.513872+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# C4 Therapeutics Enters Clinical Trial Collaboration with Pfizer for Multiple Myeloma Drug Combination

## Summary
- C4 Therapeutics and Pfizer signed a clinical trial collaboration and supply agreement for elranatamab and cemsidomide.
- Pfizer will supply elranatamab (ELREXFIO) at no cost for a Phase 1b trial in relapsed/refractory multiple myeloma.
- The Phase 1b trial will evaluate cemsidomide, dexamethasone, and elranatamab as second-line or later therapy.
- Trial expected to start in Q2 2026; C4 Therapeutics sponsors and conducts the trial.
- C4 Therapeutics CEO noted potential to improve outcomes and combine with a growing standard-of-care bispecific.

## SEC filing metadata
- accession: 0001628280-25-043290
- form_type: 8-K
- ticker: CCCC
- cik: 0001662579
- company_name: C4 Therapeutics, Inc.
- filed_at: 2025-10-01T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1662579/000162828025043290/0001628280-25-043290-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1662579/000162828025043290/cccc-20251001.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-25-043290
- JSON: https://secwatch.observer/filing/0001628280-25-043290.json
- Plain text: https://secwatch.observer/filing/0001628280-25-043290.txt

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