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): May 16, 2018

ImmunoGen, Inc.

(Exact name of registrant as specified in its charter)

830 Winter Street, Waltham, MA 02451

(Address of principal executive offices)  (Zip Code)

Registrant’s telephone number, including area code: (781) 895-0600

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 (see General Instruction A.2. below):

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

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

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

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

Indicate by check mark whether the registrant is a 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 o

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. o

Item 8.01                                           Other Events.

On May 16, 2018, ImmunoGen, Inc. (“ImmunoGen”) issued a press release announcing positive findings from the FORWARD II trial of mirvetuximab soravtansine combination regimens with Avastin® (bevacizumab) and carboplatin. ImmunoGen also announced that on May 17, 2018 at 8:00 a.m. ET, it will host an investor conference call to discuss new data from the FORWARD II trial. A copy of such press release is being filed as Exhibit 99.1 to this report and is incorporated herein by reference. A copy of the investor presentation to be used on the investor conference call is being furnished as Exhibit 99.2 to this report.

Item 9.01                                           Financial Statements and Exhibits.

(d) Exhibits

The information set forth in Exhibit 99.2 shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liability of that section, and shall not be incorporated by reference into any registration statement or other document filed under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

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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.

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