Exhibit 10.1

 

SUMMARY OF ANNUAL EXECUTIVE BONUS PROGRAM

ImmunoGen does not have a formal incentive or bonus plan for executives.  The
Compensation Committee of the our Board of Directors does, however, annually
establish key performance criteria, based upon the corporate goals and
objectives, to be met by the Company, and may also establish individual
objectives for our executives.  The Compensation Committee evaluates the
Company’s and the individual’s actual performance against those criteria and,
where applicable, individual objectives, in its determination of whether cash
incentive or bonus payments should be made to our executives.  Key performance
criteria may include any or all of the following: (i) our actual financial
performance against our plan for the applicable fiscal year; (ii) meeting
certain research and development milestones, including internal product
development advancement; and (iii) meeting key targets associated with its
collaborations with third parties, including support of partner programs and
business development.

Each executive is eligible to receive a target bonus expressed as a percentage
of his or her annual base salary which, once set, remains at that level for each
subsequent year unless specifically changed by the Compensation Committee.  The
actual bonus amount for each executive is determined based on both the Company’s
actual performance against its key performance criteria and, if applicable, the
executive’s level of accomplishment against his or her predetermined individual
performance goals and objectives.  When evaluating the performance of individual
executives, the Compensation Committee also considers factors such as changes in
business conditions and other relevant external circumstances.  At the
discretion of the Compensation Committee, bonuses in excess of the calculated
result may be made for exceptional performance or other similar reasons.

The Compensation Committee may set a threshold percentage of Company achievement
against its key performance criteria below which bonuses based on Company
performance will not be payable.  Assuming the threshold percentage has been
achieved, the portion of the executives’ target bonuses tied to Company
performance is earned on a pro-rata basis up to achievement of 100% of the
Company objectives.  Additional Company performance objectives may also be set
by the Compensation Committee that, if achieved, could result in bonus payments
in excess of 100% of the portion of an executive’s target bonus based on Company
performance.  Where applicable, the individual objectives portion of the
executives’ target bonuses may be earned irrespective of whether the threshold
for payment of the Company performance bonuses has been achieved or the extent
to which the bonuses based on Company performance are payable.

--------------------------------------------------------------------------------