EXPLANATORY NOTE
ImmunoGen, Inc. (the Company) is filing this post-effective amendment to deregister certain of the securities originally registered pursuant to the Registration Statement on Form S-8 (File No. 333-200432), filed with the Securities and Exchange Commission on November 21, 2014 by the Company (the Registration Statement) with respect to shares of the Companys common stock, par value $0.01 per share (Common Stock), thereby registered for issuance under the Companys 2006 Employee, Director and Consultant Equity Incentive Plan, as amended (the 2006 Plan). An aggregate of 5,501,602 shares of Common Stock were registered for issuance under the 2006 Plan pursuant to the Registration Statement.
On December 9, 2016, the Companys shareholders approved the Companys 2016 Employee, Director and Consultant Equity Incentive Plan (the 2016 Plan), which replaced the 2006 Plan. Following the approval of the 2016 Plan, no future awards were allowed to be made under the 2006 Plan after December 9, 2016. As of the close of business on December 9, 2016, 1,169,987 shares of Common Stock were reserved and available for issuance under future awards under the 2006 Plan. Accordingly, 1,169,987 shares registered under the Registration Statement were deregistered pursuant to Post-Effective Amendment No. 1 to the Registration Statement filed on August 4, 2017 (Amendment No. 1).
An additional 1,594,909 shares of Common Stock registered under the Registration Statement were added to the shares reserved for issuance under the 2016 Plan as a result of the forfeiture, cancellation or termination (other than by exercise) of previously made grants under the 2006 Plan during the period between December 9, 2016 and May 31, 2017 underlying grants made under the 2006 Plan. Accordingly, an additional 1,594,909 shares registered under the Registration Statement were deregistered pursuant to Amendment No. 1.
On June 20, 2018, the Companys shareholders approved the Companys 2018 Employee, Director and Consultant Equity Incentive Plan (the 2018 Plan), which replaced the 2016 Plan. The maximum number of shares of Common Stock reserved and available for issuance under the 2018 Plan includes the number of shares underlying any grants previously made under the 2006 Plan that are forfeited, canceled or terminated (other than by exercise) on or after June 20, 2018. An additional 2,736,706 shares registered under the Registration Statement (the First Carried Forward Shares) have been included in the shares reserved for issuance under the 2018 Plan as a result of the forfeiture, cancellation or termination (other than by exercise) of previously made grants under the 2006 Plan during the period between June 20, 2018 and November 30, 2019, which are hereby deregistered.
Contemporaneously with the filing of this Post-Effective Amendment No. 2 to the Registration Statement, the Company is filing a Registration Statement on Form S-8 to register the First Carried Forward Shares for issuance pursuant to the 2018 Plan.
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