X0206 3 2020-06-01 1 0000855654 ImmunoGen, Inc. IMGN 0001814150 Coen Stacy Ann 830 WINTER STREET WALTHAM MA 02451 0 1 0 0 Chief Business Officer Exhibit 24.1 - Power of Attorney No securities are beneficially owned. David G. Foster - attorney in fact 2020-06-04