secwatch.observer — SEC 8-K summary
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Issuer:     C4 Therapeutics, Inc. (CCCC)
CIK:        0001662579
Form:       8-K
Filed at:   2026-09-25T11:04:25+00:00
Accession:  0001628280-26-063497
Event type: other_material
Sentiment:  positive
Materiality: 0.50
Item codes: 7.01, 8.01, 9.01
LLM model:  deepseek-v4.1-flash:cloud@v2

C4 Therapeutics cemsidomide biomarker data positive; 75 µg elranatamab combo declared safe, Phase 1b advances
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- Phase 1 cemsidomide + dexamethasone in 62 heavily pre-treated RRMM patients showed coordinated CD8+ T-cell activation and NK-cell reprogramming at the 75 µg and 100 µg doses.
- Phase 1b cemsidomide + elranatamab (ELREXFIO): first two patients showed CD8+ effector memory T-cell expansion (elevated HLA-DR) with no rise in exhaustion markers PD-1, TIM-3, LAG3.
- Safety data review committee declared the 75 µg cemsidomide dose with elranatamab safe after the first six-patient cohort; trial advancing to a 100 µg escalation cohort and a 75 µg expansion cohort.
- Data from all Phase 1b cohorts evaluated are expected in mid-2027; results presented at the 23rd International Myeloma Society Annual Meeting on September 25, 2026.
- CMO Len Reyno said the data reinforce a strategy to establish cemsidomide as a backbone therapy in multiple myeloma for immune-based combinations.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1662579/000162828026063497/0001628280-26-063497-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1662579/000162828026063497/cccc-20260925.htm
  HTML page:      https://secwatch.observer/filing/0001628280-26-063497

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