UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 11, 2020

MERSANA THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Delaware	001-38129	04-3562403
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

840 Memorial Drive Cambridge, MA 02139
Cambridge, MA	02139
(Address of principal executive offices)	(Zip Code)

(Registrant’s telephone number, including area code): (617) 498-0020

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $0.0001 par value	MRSN	The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company x

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. x

Item 1.01 Entry into a Material Definitive Agreement.

On March 11, 2020, Mersana Therapeutics, Inc. (the “Company”), entered into a Seventh Lease Extension and Modification Agreement (the “Extension Agreement”) to the Lease (the “Lease”) with Rivertech Associates II LLC (the “Lessor”), which covers certain laboratory and office space at 840 Memorial Drive, Cambridge, MA 02139 (the “Premises”). The Extension Agreement, effective as of March 10, 2020, extended the Lease to March 31, 2026, and requires the Lessor to provide certain improvements to the mechanical systems at the Premises.

The foregoing description of the Amendment is qualified in its entirety by the full text of the Extension Agreement, a copy of which will be filed as an exhibit to the Company’s Quarterly Report on From 10-Q for the quarter ending March 31, 2020.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MERSANA THERAPEUTICS, INC.
By:	/s/ Brian DeSchuytner
	Brian DeSchuytner Senior Vice President, Finance & Product Strategy

Date: March 13, 2020