# EDGAR Filing Document

**Accession Number:** 0001442836
**File Stem:** 0001104659-26-004556
**Filing Date:** 2026-1
**Character Count:** 2964
**Document Hash:** b4745b6e4bbcd23fa396689b26515ca3
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-004556.hdr.sgml**: 20260116

**ACCESSION NUMBER**: 0001104659-26-004556

**CONFORMED SUBMISSION TYPE**: 15-12G

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260116

**DATE AS OF CHANGE**: 20260116

**EFFECTIVENESS DATE**: 20260116

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Mersana Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001442836
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 15-12G
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38129
- **FILM NUMBER:** 26539649

**BUSINESS ADDRESS:**
- **STREET 1:** 840 MEMORIAL DRIVE
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 617-498-0020

**MAIL ADDRESS:**
- **STREET 1:** 840 MEMORIAL DRIVE
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MERSANA THERAPEUTICS INC
- **DATE OF NAME CHANGE:** 20080813

**UNITED STATES<br>SECURITIES AND EXCHANGE COMMISSION** **<br>WASHINGTON, D.C. 20549**

**FORM 15**

**CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION** 

**UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934**

**OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13 AND 15(d) OF THE**

**SECURITIES EXCHANGE ACT OF 1934.**

**Commission File Number: 001-38129**

**Mersana Therapeutics, Inc.**

(Exact name of registrant as specified in its charter)

**840 Memorial Drive**

**Cambridge, Massachusetts 02139**

**Telephone: (617) 498-0020 <br>(Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)**

**Common Stock, par value $0.0001 per share<br>(Title of each class of securities covered by this Form)**

**None<br>(Titles of all other classes of securities for which a duty to file reports under Section 13(a) or 15(d) remains)**

Please place an X in the box(es) to designate the appropriate rule provision(s) relied upon to terminate or suspend the duty to file reports:

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| | |
|:---|:---|
| Rule 12g-4(a)(l) | ⌧ |
| Rule 12g-4(a)(2) | ◻ |
| Rule 12h-3(b)(l)(i) | ⌧ |
| Rule 12h-3(b)(l)(ii) | ◻ |
| Rule 15d-6 | ◻ |
| Rule 15d-22(b) | ◻ |

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Approximate number of holders of record as of the certification or notice date: One (1) holder.

Pursuant to the requirements of the Securities Exchange Act of 1934, Mersana Therapeutics, Inc. has caused this certification/notice to be signed on its behalf by the undersigned duly authorized person.

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| | | |
|:---|:---|:---|
|  | **Mersana Therapeutics, Inc.** | **Mersana Therapeutics, Inc.** |
|  | By: | /s/ Charles N. York II |
|  | Name: Charles N. York II, M.B.A. | Name: Charles N. York II, M.B.A. |
|  | Title: Chief Executive Officer | Title: Chief Executive Officer |
| Date: January 16, 2026 |  |  |

---