Initial Statement of Beneficial Ownership (3)

FORM 3	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0104 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^*

Arbuckle Stuart A

2. Date of Event Requiring Statement (MM/DD/YYYY) 1/23/2018

3. Issuer Name and Ticker or Trading Symbol

IMMUNOGEN INC [IMGN]

(Last) (First) (Middle)

C/O VERTEX PHARMACEUTICALS INCORPORATED, 50 NORTHERN AVE

4. Relationship of Reporting Person(s) to Issuer (Check all applicable)

__ X __ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)

(Street)

BOSTON, MA 02210

(City) (State) (Zip)

5. If Amendment, Date Original Filed (MM/DD/YYYY)

6. Individual or Joint/Group Filing (Check Applicable Line)

_ X _ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

*Table II - Derivative Securities Beneficially Owned ( e.g.* , puts, calls, warrants, options, convertible securities)**
1. Title of Derivate Security (Instr. 4)	2. Date Exercisable and Expiration Date (MM/DD/YYYY)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivate Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security		6. Nature of Indirect Beneficial Ownership (Instr. 5)
Deferred Share Unit	4/1/2018 ⁽²⁾ ⁽³⁾	⁽²⁾	Common Stock ⁽²⁾	6500	$0 ⁽¹⁾	D
Stock Option (right to buy)	3/1/2018 ⁽⁴⁾	1/23/2028	Common Stock	4167	$8.20	D

Explanation of Responses:
(1)	The deferred share units were issued pursuant to the Issuer's Compensation Policy for Non-Employee Directors and are convertible into Common Stock on a one-to-one basis
(2)	The vested deferred share units are to be settled 100% in shares of the Common Stock of the Company upon the reporting person's retirement from the Board of Directors.
(3)	The deferred share units vest ratably over a three year period in quarterly increments beginning on April 1, 2018, contingent upon the individual remaining a director as of each vesting date.
(4)	Exercisable as to 2,084 shares commencing on March 1, 2018 and 2,083 shares commencing on June 1, 2018, contingent upon the individual remaining a director as of each vesting date.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Arbuckle Stuart A C/O VERTEX PHARMACEUTICALS INCORPORATED 50 NORTHERN AVE BOSTON, MA 02210	X

Signatures
/s/ Craig Barrows, attorney in fact		1/24/2018
^** Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.