secwatch.observer — SEC 8-K summary
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Issuer:     Day One Biopharmaceuticals, Inc. (—)
CIK:        0001845337
Form:       8-K
Filed at:   2026-01-06T23:59:59+00:00
Accession:  0001104659-26-001127
Event type: m_and_a
Sentiment:  neutral
Materiality: 0.90
Item codes: 1.01, 2.01, 7.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

Day One completes acquisition of Mersana for $25/share cash plus CVRs up to $30.25
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- Acquisition closed Jan 6, 2026; Mersana becomes wholly owned subsidiary of Day One.
- Tender offer saw 60.57% of Mersana shares tendered; total cash consideration ~$128.8M.
- Each Mersana share received $25 cash plus one non-tradable CVR with potential milestone payments up to $30.25/share.
- CVR milestones include FDA breakthrough designation and sales thresholds for emiltatug-ledadotin (Emi-Le).
- Mersana common stock to be delisted from Nasdaq effective Jan 6, 2026.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1845337/000110465926001127/0001104659-26-001127-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1845337/000110465926001127/tm261757d1_8k.htm
  HTML page:      https://secwatch.observer/filing/0001104659-26-001127

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer