UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE TO

Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1)
of the Securities Exchange Act of 1934

CHECKMATE PHARMACEUTICALS, INC.

(Name of Subject Company)

SCANDINAVIAN ACQUISITION SUB, INC.

(Offeror)

REGENERON PHARMACEUTICALS, INC.

(Parent of Offeror)
(Names of Filing Persons)

Common stock, par value $0.0001 per share

(Title of Class of Securities)

162818108

(CUSIP Number of Class of Securities)

Joseph J. LaRosa, Esq.
Regeneron Pharmaceuticals, Inc.
Executive Vice President, General Counsel and Secretary
777 Old Saw Mill River Road
Tarrytown, New York 10591-6707
(914) 847-7000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications on Behalf of Filing Persons)

With a copy to:

Andrew R. Brownstein, Esq.
Victor Goldfeld, Esq.
John L. Robinson, Esq.
Wachtell, Lipton, Rosen & Katz
51 West 52nd Street
New York, NY 10019
(212) 403-1000

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Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

Amount Previously Paid: N/A	Filing Party: N/A
Form or Registration No.: N/A	Date Filed: N/A

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Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

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third-party tender offer subject to Rule 14d-1.

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issuer tender offer subject to Rule 13e-4.

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going-private transaction subject to Rule 13e-3.

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amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer:   ☐

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

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Rule 13e-4(i) (Cross-Border Issuer Tender Offer)

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Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)

This Tender Offer Statement on Schedule TO (this “Schedule TO”) relates to the tender offer by Scandinavian Acquisition Sub, Inc., a Delaware corporation (“Purchaser”) and a wholly owned subsidiary of Regeneron Pharmaceuticals, Inc., a New York corporation (“Regeneron”), for all of the outstanding shares of common stock, par value $0.0001 per share (“Shares”), of Checkmate Pharmaceuticals, Inc., a Delaware corporation (“Checkmate”), at a price of $10.50 per share, to be paid to the seller in cash, without interest, and subject to reduction for any applicable withholding taxes, upon the terms and conditions set forth in the offer to purchase, dated May 2, 2022 (the “Offer to Purchase”), a copy of which is attached as Exhibit (a)(1)(A), and in the related letter of transmittal (the “Letter of Transmittal”), a copy of which is attached as Exhibit (a)(1)(B), which, as each may be amended or supplemented from time to time, collectively constitute the “Offer.”

All the information set forth in the Offer to Purchase, including Schedule I thereto, is incorporated by reference herein in response to Items 1 through 9 and Item 11 of this Schedule TO, and is supplemented by the information specifically provided in this Schedule TO.

Item 1.   Summary Term Sheet.

Regulation M-A Item 1001

The information set forth in the Offer to Purchase under the caption SUMMARY TERM SHEET is incorporated herein by reference.

Item 2.   Subject Company Information.

Regulation M-A Item 1002

(a)   Name and Address.   The name, address, and telephone number of the subject company’s principal executive offices are as follows:

Checkmate Pharmaceuticals, Inc.
245 Main Street, 2nd Floor
Cambridge, MA 02142
(617) 682-3625

(b)-(c)   Securities; Trading Market and Price.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

INTRODUCTION

THE TENDER OFFER — Section 6 (“Price Range of Shares; Dividends”)

Item 3.   Identity and Background of Filing Person.

Regulation M-A Item 1003

(a)-(c)   Name and Address; Business and Background of Entities; and Business and Background of Natural Persons.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 8 (“Certain Information Concerning Regeneron and Purchaser”)

SCHEDULE I — Information Relating to Regeneron and Purchaser

Item 4.   Terms of the Transaction.

Regulation M-A Item 1004

(a)   Material Terms.   The information set forth in the Offer to Purchase is incorporated herein by reference.

Item 5.   Past Contacts, Transactions, Negotiations and Agreements.

Regulation M-A Item 1005

(a)   Transactions.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 10 (“Background of the Offer; Past Contacts or Negotiations with Checkmate”)

(b)   Significant Corporate Events.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 10 (“Background of the Offer; Past Contacts or Negotiations with Checkmate”)

THE TENDER OFFER — Section 11 (“The Merger Agreement; Other Agreements”)

THE TENDER OFFER — Section 12 (“Purpose of the Offer; Plans for Checkmate”)

Item 6.   Purposes of the Transaction and Plans or Proposals.

Regulation M-A Item 1006

(a)   Purposes.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

THE TENDER OFFER — Section 12 (“Purpose of the Offer; Plans for Checkmate”)

(c) (1)-(7)   Plans.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 9 (“Source and Amount of Funds”)

THE TENDER OFFER — Section 10 (“Background of the Offer; Past Contacts or Negotiations with Checkmate”)

THE TENDER OFFER — Section 11 (“The Merger Agreement; Other Agreements”)

THE TENDER OFFER — Section 12 (“Purpose of the Offer; Plans for Checkmate”)

THE TENDER OFFER — Section 13 (“Certain Effects of the Offer”)

THE TENDER OFFER — Section 14 (“Dividends and Distributions”)

Item 7.   Source and Amount of Funds or Other Consideration.

Regulation M-A Item 1007

(a)   Source of Funds.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 9 (“Source and Amount of Funds”)

THE TENDER OFFER — Section 10 (“Background of the Offer; Past Contacts or Negotiations with Checkmate”)

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(b)   Conditions.   The Offer is not subject to a financing condition.

(d)   Borrowed Funds.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 9 (“Source and Amount of Funds”)

THE TENDER OFFER — Section 10 (“Background of the Offer; Past Contacts or Negotiations with Checkmate”)

THE TENDER OFFER — Section 11 (“The Merger Agreement; Other Agreements”)

THE TENDER OFFER — Section 15 (“Conditions of the Offer”)

Item 8.   Interest in Securities of the Subject Company.

Regulation M-A Item 1008

(a)   Securities Ownership.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

THE TENDER OFFER — Section 8 (“Certain Information Concerning Regeneron and Purchaser”)

THE TENDER OFFER — Section 11 (“The Merger Agreement; Other Agreements”)

THE TENDER OFFER — Section 12 (“Purpose of the Offer; Plans for Checkmate”)

SCHEDULE I — Information Relating to Regeneron and Purchaser

(b)   Securities Transactions.   None.

Item 9.   Persons/Assets Retained, Employed, Compensated or Used.

Regulation M-A Item 1009

(a)   Solicitations or Recommendations.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 3 (“Procedures for Accepting the Offer and Tendering Shares”)

THE TENDER OFFER — Section 10 (“Background of the Offer; Past Contacts or Negotiations with Checkmate”)

THE TENDER OFFER — Section 18 (“Fees and Expenses”)

Item 10.   Financial Statements.

Regulation M-A Item 1010

(a)   Financial Information.   Not Applicable.

(b)   Pro Forma Information.   Not Applicable.

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Item 11.   Additional Information.

Regulation M-A Item 1011

(a)   Agreements, Regulatory Requirements and Legal Proceedings.   The information set forth in the Offer to Purchase under the following captions is incorporated herein by reference:

SUMMARY TERM SHEET

THE TENDER OFFER — Section 10 (“Background of the Offer; Past Contacts or Negotiations with Checkmate”)

THE TENDER OFFER — Section 11 (“The Merger Agreement; Other Agreements”)

THE TENDER OFFER — Section 12 (“Purpose of the Offer; Plans for Checkmate”)

THE TENDER OFFER — Section 13 (“Certain Effects of the Offer”)

THE TENDER OFFER — Section 16 (“Certain Legal Matters; Regulatory Approvals”)

(c)   Other Material Information.   The information set forth in the Offer to Purchase and the Letter of Transmittal is incorporated herein by reference.

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Item 12.   Exhibits.

Regulation M-A Item 1016

Exhibit No.	Description
(a)(1)(A)*	Offer to Purchase, dated as of May 2, 2022.
(a)(1)(B)*	Letter of Transmittal.
(a)(1)(C)*	Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.
(a)(1)(D)*	Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.
(a)(1)(E)*	Summary Advertisement as published in The New York Times on May 2, 2022
(a)(1)(F)	Joint Press Release issued by Regeneron Pharmaceuticals, Inc. and Checkmate Pharmaceuticals, Inc. on April 19, 2022 (incorporated by reference to Exhibit 99.1 to the Schedule TO-C filed by Regeneron Pharmaceuticals, Inc. with the U.S. Securities and Exchange Commission on April 19, 2022).
(a)(1)(G)	Social Media Posts from April 19, 2022 (incorporated by reference to Exhibit 99.2 to the Schedule TO-C filed by Regeneron Pharmaceuticals, Inc. with the U.S. Securities and Exchange Commission on April 19, 2022).
(d)(1)	Agreement and Plan of Merger among Checkmate Pharmaceuticals, Inc., Regeneron Pharmaceuticals, Inc., and Scandinavian Acquisition Sub, Inc., dated as of April 18, 2022 (incorporated by reference to Exhibit 2.1 to the Form 8-K filed by Checkmate Pharmaceuticals, Inc. with the U.S. Securities and Exchange Commission on April 19, 2022).
(d)(2)*	Confidentiality Agreement dated as of March 22, 2022, between Checkmate Pharmaceuticals, Inc. and Regeneron Pharmaceuticals, Inc.
(d)(3)	Tender and Support Agreement, dated as of April 18, 2022, by and among Regeneron Pharmaceuticals, Inc., Scandinavian Acquisition Sub, Inc. and certain Stockholders of Checkmate Pharmaceuticals, Inc. (incorporated by reference to Exhibit 99.1 to the Form 8-K filed by Checkmate Pharmaceuticals, Inc. with the U.S. Securities and Exchange Commission on April 19, 2022).
(d)(4)*	Exclusivity Agreement, dated as of March 22, 2022, by and between Regeneron Pharmaceuticals, Inc. and Checkmate Pharmaceuticals, Inc.
(g)	None.
(h)	None.
107*	Filing fee table.

*

Filed herewith.

Item 13.   Information Required by Schedule 13E-3.

Not applicable.

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SIGNATURES

After due inquiry and to the best of their knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: May 2, 2022

SCANDINAVIAN ACQUISITION SUB, INC.

By:

/s/ Nouhad Husseini

Name:

Nouhad Husseini

Title:

Managing Director

REGENERON PHARMACEUTICALS, INC.

By:

/s/ Joseph J. LaRosa

Name:

Joseph J. LaRosa

Title:

Executive Vice President,
General Counsel and Secretary