Plan Discretionary; Extraordinary Compensation. In accepting the Option, Participant acknowledges, understands and agrees that:

Discretionary Award, Extraordinary Benefit. Awards under the Plan are granted to employees of the Company and the Affiliates in the Committee’s sole discretion. The Award described in this Grant Agreement is a one-time benefit and does not create any contractual or other right to receive other Awards under the Plan or other benefits in lieu thereof. Future grants, if any, will be at the sole discretion of the Committee. The Grantee’s participation in the Plan is voluntary. This Award (and each other Award, if any, granted under the Plan) constitutes an extraordinary item of compensation and is not part of the Grantee’s normal or expected compensation for purposes of calculating any severance, retirement, or other benefit rights (unless otherwise expressly provided in an applicable benefit plan).

Extraordinary Item of Compensation. The Employee expressly recognizes and acknowledges that the Employee’s participation in the Plan is a result of the discretionary and unilateral decision of ​, as well as the Employee’s free and voluntary decision to participate in the Plan in accordance with the terms and conditions of the Plan, the Agreement and this Addendum. As such, the Employee acknowledges and agrees that ​, in its sole discretion, may amend and/or discontinue the Employee’s participation in the Plan at any time and without any liability. The value of the Award is an extraordinary item of compensation outside the scope of the Employee’s employment contract, if any. The Award is not part of the Employee’s regular or expected compensation for purposes of calculating any severance, resignation, redundancy, end of service payments, bonuses, long‑service awards, pension or retirement benefits, or any similar payments, which are the exclusive obligations of ​‑Mexico.

Discretionary Plan; Employment. The Plan is discretionary in nature and may be suspended or terminated by the Company at any time. With respect to the Plan, # each grant of Stock Units is a one-time benefit which does not create any contractual or other right to receive

Discretionary Nature of Plan. The Plan is discretionary and may be amended, cancelled or terminated by the Company at any time, in its discretion. The grant of the Restricted Stock in this Award does not create any contractual right or other right to receive any Restricted Stock or other Awards in the future. Future Awards, if any, will be at the sole discretion of the Company. Any amendment, modification, or termination of the Plan shall not constitute a change or impairment of the terms and conditions of the Grantee’s employment with the Company.

A Nonqualified Discretionary Profit-Sharing Contribution in an amount equal to the Participant's Excess Compensation multiplied by the percentage (if any) used under the Qualified Plan to determine the Participant's Discretionary Profit-Sharing Contribution.

"Fiduciary" means any person who # exercises any discretionary authority or discretionary control respecting management of the Plan or exercises any authority or control respecting management or disposition of its assets, # renders investment advice for a fee or other compensation, direct or indirect, with respect to any monies or other property of the Plan or has any authority or resp onsibility to do so, or # has any discretionary authority or discretionary responsibility in the administration of t he Plan.

“Bonus Compensation” means the portion of an Eligible Employee’s Compensation derived from regular incentive programs sponsored by the Company, including the corporate annual bonus and the field management bonus (but excluding spot bonuses, ad hoc bonuses, and other discretionary and non-discretionary bonuses that are not part of a regular incentive program). Bonus Compensation for a Plan Year shall refer to amounts earned with respect to such Plan Year, even if paid after the end of the Plan Year.

Discretionary Adjustments. Upon the occurrence or in anticipation of any corporate event or transaction involving the Company (including, without limitation, any merger, reorganization, recapitalization, combination or exchange of shares, or any transaction described in [Section 4(B)], the Committee may, in its sole discretion, provide # that Awards will be settled in cash rather than Stock, # that Awards will become immediately vested and non-forfeitable and exercisable (in whole or in part) and will expire after a designated period of time to the extent not then exercised, # that Awards will be assumed by another party to a transaction or otherwise be equitably converted or substituted in connection with such transaction, # that outstanding Awards may be settled by payment in cash or cash equivalents equal to the excess of the fair market value of the underlying Stock, as of a specified date associated with the transaction (or the per-shares transaction price), over the exercise or base price of the Award, # that performance targets and performance periods for Performance Awards will be modified, or # any combination of the foregoing. The Committee’s determination need not be uniform and may be different for different Participants whether or not such Participants are similarly situated. Any discretionary adjustments made pursuant to this [Section 4(C)] shall be subject to the provisions of [Section 15(B)].

Discretionary Termination. Regeneron, in its sole discretion, may terminate this Agreement in its entirety effective as of any time after the ​ of the Effective Date upon delivery of at least ​ days’ prior written notice to CytomX.