UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 or 15(d) of the

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): November 5, 2025

MOONLAKE IMMUNOTHERAPEUTICS

(Exact Name of Registrant as Specified in Its Charter)

Dorfstrasse 29

6300 Zug

Switzerland

(Address of principal executive offices and Zip Code)

41 415108022

(Registrant’s Telephone Number, Including Area Code)

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2 below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 1.01. Entry into a Material Definitive Agreement.

On November 5, 2025, MoonLake Immunotherapeutics (the “Company”) entered into an underwriting agreement (“Underwriting Agreement”) with Leerink Partners LLC as the underwriter named therein (the “Underwriter”), to issue and sell 7,142,857 Class A ordinary shares, par value $0.0001 per share (the “Shares”), at an offering price of $10.50 per share (the “Offering”).

The gross proceeds from the Offering are expected to be $75 million before deducting underwriting discounts and offering expenses.

The Shares described above were offered pursuant to a shelf registration statement on Form S-3 (File No. 333-274286), which became effective on September 11, 2023. A prospectus supplement dated November 5, 2025 relating to and describing the terms of the Offering was filed with the U.S. Securities and Exchange Commission on November 5, 2025. The Offering is expected to close on November 6, 2025, subject to the satisfaction of customary closing conditions.

In the Underwriting Agreement, the Company agreed to indemnify the Underwriter against certain liabilities, including liabilities under the Securities Act of 1933, as amended, or to contribute payments that the Underwriter may be required to make because of such liabilities.

A copy of the Underwriting Agreement is filed as Exhibit 1.1 and is incorporated herein by reference. The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to such exhibit.

Walkers (Cayman) LLP, Cayman counsel to the Company, has issued an opinion to the Company, dated November 5, 2025, regarding the validity of the issuance and sale of the Shares in the Offering. A copy of the opinion is filed herewith as Exhibit 5.1.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.