Type	Name	Date
Underwriting agreement	Underwriting Agreement	05/05/2023
Underwriting agreement	Underwriting Agreement	12/03/2021
Indenture	Indenture, by and between the Registrant and Wilmington Trust, National Association, as Trustee	06/20/2016

Type	Name	Date
Exchange agreement	Exchange Agreement, by and among ImmunoGen, Inc. and RA Capital Healthcare Fund, L.P	05/02/2023

Type	Name	Date
Other	Letter Agreement between the Registrant and Charles Q. Morris	09/30/2014