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acquisitionAnnounced · Jan 8, 2026BiopharmaceuticalsSource · CredibleArticle · Factual
Mersana Therapeutics
Day One Biopharma
Mersana Therapeutics · Day One Biopharma

Day One Biopharma acquires Mersana Therapeutics

David Najork
David Najork · Founding Software Engineer
Announced · Updated · 1 min read
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Deal value
$285M
Target
Mersana Therapeutics
Mersana Therapeutics
NASDAQ: MRSN · Cambridge, Massachusetts
Acquirer
Day One Biopharma
Day One Biopharma
Full Acquisition
Status
Pending

Day One Biopharma agreed to acquire Mersana Therapeutics. Reported deal value: $285M. Status: Pending. Sector: Biopharmaceuticals. Target headquarters context: Cambridge, Massachusetts, United States.

This page summarizes publicly available information about the transaction as of 2026-01-08. Figures and status may change as filings and press coverage update.

Day One Biopharmaceuticals has concluded its acquisition of Mersana Therapeutics after meeting all the tender offer conditions

Deal timeline

Announced
Jan 8, 2026 · pharmaceutical-technology.com
Additional milestones (proxy, vote, close) appear as filings and press updates are indexed.
Sector context

This transaction is classified in Biopharmaceuticals with a reported deal value of $285M. Figures and status may change as sources update.

Sources: pharmaceutical-technology.com · Primary article · FireStrike proprietary index