SEC Form SC TO-T filed by Cidara Therapeutics Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1)

OF THE SECURITIES EXCHANGE ACT OF 1934

CIDARA THERAPEUTICS, INC.

(Name of Subject Company (Issuer))

CAYMUS PURCHASER, INC.

(Offeror)

A Wholly Owned Subsidiary of

MERCK SHARP & DOHME LLC

(Parent of Offeror)

A Wholly Owned Subsidiary of

MERCK & CO., INC.

(Parent of Offeror)

(Names of Filing Persons (identifying status as offeror, issuer or other person))

Common Stock, par value $0.0001 per share

Series A Convertible Voting Preferred Stock, par value $0.0001 per share

(Title of Class of Securities)

171757206

(CUSIP Number of Class of Securities)

Kelly E.W. Grez

Corporate Secretary, Merck & Co., Inc.

126 East Lincoln Avenue Rahway, NJ 07065

(908) 740-4000

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

Copies to:

Saee Muzumdar

Sebastian L. Fain

Gibson, Dunn & Crutcher LLP

200 Park Avenue

New York, NY 10166

(212) 351-4035

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

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:

Items 1 through 9 and Item 11.

This Tender Offer Statement on Schedule TO (the “Schedule TO”) relates to the offer by Caymus Purchaser, Inc., a Delaware corporation and a wholly owned indirect subsidiary of Merck Sharp & Dohme LLC, a New Jersey limited liability company, to acquire (i) all of the outstanding shares of common stock, par value $0.0001 per share (the “Common Shares”) of Cidara Therapeutics, Inc., a Delaware corporation (“Cidara”), for $221.50 per Common Share, and (ii) all of the outstanding shares of Series A Convertible Voting Preferred Stock, par value $0.0001 per share (the “Series A Shares”) of Cidara for $15,505.00 per Series A Share, in each case, in cash, without interest, subject to any applicable withholding of taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated December 5, 2025 (as it may be amended or supplemented from time to time, the “Offer to Purchase”), and in the related Letter of Transmittal (as it may be amended or supplemented from time to time, the “Letter of Transmittal”) and in the related Notice of Guaranteed Delivery (as it may be amended or supplemented from time to time, the “Notice of Guaranteed Delivery” and, together with the Offer to Purchase and the Letter of Transmittal, the “Offer”), copies of which are attached hereto as Exhibits (a)(1)(i), (a)(1)(ii) and (a)(1)(iii), respectively.

The information set forth in the Offer to Purchase, including all schedules thereto, is hereby expressly incorporated herein by reference in response to all of the items of this Schedule TO, except as otherwise set forth below.

Not applicable.

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SIGNATURES

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

Date: December 5, 2025

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