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ClosedPublished 6 Jan 2026

Day One /
Mersana

Day One adds Mersana Therapeutics to its clinical pipeline

Buy side: Day One
Buy sideDay One
Target: Mersana
TargetMersana
Day One Biopharmaceuticals, Inc. · 6 Jan 2026Source
See the source
Buy side: Day One
Buy sideDay One
Target: Mersana
TargetMersana
01 / BuyerDay One
02 / TargetMersana
Source for the buyer and target: Day One Biopharmaceuticals, Inc.

For the buyer and target.

“Promptly following the Expiration Date and Purchaser’s acceptance for payment of the Shares pursuant to the Offer, Day One and Purchaser consummated the Merger pursuant to the terms of the Merger Agreement and without any action by the stockholders of Mersana in accordance with Section 251(h) of the DGCL.”

Published 6 Jan 2026

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01

What happened

Day One Biopharmaceuticals, Inc. completed its acquisition of Mersana Therapeutics, Inc. The transaction provides for $25 per share in cash, plus a non-tradable CVR per share with potential milestone payments of up to $30.25 per CVR. [01]

Mersana became a direct wholly owned subsidiary of Day One following a statutory merger on Jan. 6, 2026. The acquisition adds Emi-Le, a clinical-stage antibody drug conjugate targeting B7-H4, to Day One’s pipeline. [01]

02

The source

Everything on this page comes from the source below, quoted word for word.

01
Source · Day One Biopharmaceuticals, Inc.

Day One adds Mersana Therapeutics to its clinical pipeline

This document is the source for the companies, stage, figure and people on this page.

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03

Timeline

Every date the source states, in order, each with the words it comes from. Anything marked ahead is a target the source gives, not something that has happened.

  1. Also stated

    “Mersana became a direct wholly owned subsidiary of Day One following a statutory merger on Jan. 6, 2026”

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  2. Published by Day One Biopharmaceuticals, Inc.

    The source this page is built from.

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