Merus N.V., a public company with limited liability incorporated under Dutch law (the “Company”); and

Stichting Continuïteit Merus, a foundation incorporated under Dutch law (the “Foundation”).

The objects of the Foundation are to promote and protect the interests of the Company, of the business connected with it and of its stakeholders from time to time and to repress possible influences which could threaten the strategy, continuity, independence and/or identity of the Company or its business to such an extent that this could be considered to be damaging to the aforementioned interests.

For that purpose, the Company and the Foundation have entered into the Call Option Agreement, pursuant to which the Foundation may exercise the Call Option and acquire Preferred Shares.

Parent and Purchaser desire that Purchaser acquires the Company on the terms and subject to the conditions set forth in the Transaction Agreement.

The Company Board has, among other matters, unanimously (a) determined that, on the terms and subject to the conditions set forth in the Transaction Agreement, the Transaction Agreement, the Offer, the Back-End Transactions and the other Transactions to be consummated by the Company are in the best interests of the Company and the sustainable success of its business, having considered the interests of its shareholders, employees and other relevant stakeholders, (b) duly authorized and approved the execution and delivery of the Transaction Agreement, and the performance by the Company of its obligations under the Transaction Agreement and the consummation by the Company of the Offer, the Back-End Transactions and the other Transactions to be consummated by the Company, (c) resolved, subject to the relevant terms and conditions of the Transaction Agreement, to support the Offer and the other Transactions, to recommend acceptance of the Offer by the Company’s shareholders and to recommend that the Company’s shareholders vote for approval and adoption of the matters contemplated by the Transaction Agreement to be proposed to the Company’s general meeting, and (d) resolved that the Company shall pursue the Transactions on the terms, and subject to the provisions, of the Transaction Agreement.

The Foundation believes that the Transactions do not constitute a threat to the interests of the Company, its businesses or its stakeholders and wishes to enter into this Agreement in support of the Transactions.

DEFINITIONS AND INTERPRETATION

Definitions

Interpretation

Terms that are defined in the singular have a corresponding meaning in the plural and vice versa.

The terms “written” and “in writing” include by use of electronic means of communication.

No provision of this Agreement shall be interpreted adversely against a Party solely because that Party was responsible for drafting that particular provision.

Although this Agreement has been drafted in the English language, this Agreement pertains to Dutch legal concepts. Any consequence of the use of English words and expressions in this Agreement under any law other than Dutch law shall be disregarded.

The words “include”, “included” and “including” are used to indicate that the matters listed are not a complete enumeration of all matters covered.

The titles and headings in this Agreement are for construction purposes as well as for reference. No Party may derive any rights from such titles and headings.

CALL OPTION ARRANGEMENTS

The Company and the Foundation each irrevocably and unconditionally agree, as an inducement to Parent’s and Purchaser’s willingness to enter into the Transaction Agreement, in furtherance of the Company’s interest in pursuing the Transactions and, given the Company Board’s resolutions described in recital D. of this Agreement, consistent with the purpose of the Foundation, that:

during the term of the Transaction Agreement the Foundation shall not and cannot exercise the Call Option;

the Call Option Agreement, including the Call Option, shall terminate without any further action by either Party being required subject only to, and with effect from, the occurrence of the Closing; and

the Foundation and its board members will, as soon as reasonably practicable following the Closing, take all actions necessary to effect the dissolution (ontbinding) and liquidation (vereffening) of the Foundation.

The Company and the Foundation each confirm that:

the Foundation has not exercised the Call Option at any time prior to the execution of the Transaction Agreement;

other than the Call Option Agreement, there are no agreements or arrangements in place between the Company and the Foundation; and

other than regular payments of remuneration to directors of the Foundation, no amounts are, or will become, due or payable by the Company or any of its subsidiaries to any board member of the Foundation.

MISCELLANEOUS PROVISIONS

Third-party stipulation

Corporate effect

No implied waiver

Nothing shall be construed as a waiver under this Agreement unless a document to that effect has been signed by the Parties and approved in writing by the Parent.

The failure of a Party to exercise or enforce any right under this Agreement shall not constitute a waiver of the right to exercise or enforce such right in the future.

Amendment

Invalidity

In the event that a provision of this Agreement is null and void or unenforceable (either in whole or in part):

the remainder of this Agreement shall continue to be effective to the extent that, given the substance and purpose of this Agreement, such remainder is not inextricably related to the null and void or unenforceable provision; and

the Parties shall make every effort to reach agreement on a new provision which differs as little as possible from the null and void or unenforceable provision, taking into account the substance and purpose of this Agreement.

No rescission or nullification

No transfer, assignment or encumbrance

Term and termination

Counterparts

GOVERNING LAW AND JURISDICTION

This Agreement shall be governed by and construed in accordance with the laws of the Netherlands.

The Parties agree that any dispute in connection with this Agreement or any agreement resulting therefrom shall be submitted to the exclusive jurisdiction of the competent court in Amsterdam, the Netherlands.

/s/ Sven (Bill) Ante Lundberg

/s/ G. Reijnen

/s/ R. van Leen