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): February 12, 2025

Onconetix, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (513) 620-4101

(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:

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 February 12, 2025, Onconetix, Inc. (the “Company”) issued a promissory note to Keystone Capital Partners, LLC (the “Investor”) with original issue discount of $17,647.06, in an aggregate principal amount of $117,647.06 (the “Note”). The Note is due and payable upon the earlier of (i) the Company’s receipt of sufficient proceeds from its Equity Line of Credit with the Investor and (ii) November 12, 2025, subject to mandatory prepayment in the event that the Company raises sufficient additional capital through other securities offerings. The note is subordinate to the Company’s existing debt obligations to Veru Inc.

The foregoing description of the Note does not purport to be complete and is qualified in its entirety by the terms of the Note, which is attached hereto as Exhibit 10.1 and is incorporated herein by reference.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

The information contained in Item 1.01 of this Current Report on Form 8-K is hereby incorporated by reference into this Item 2.03.

Item 4.01. Changes in Registrant’s Certifying Accountant

Effective February 13, 2025, the Audit Committee of the Company’s Board of Directors (the “Audit Committee”) authorized the appointment of MaloneBailey LLP (“MaloneBailey”) as the Company’s new independent registered public accounting firm for the fiscal year ended December 31, 2024, and MaloneBailey was appointed as the Company’s independent registered public accounting firm. During the Company’s two most recent fiscal years ended December 31, 2024 and 2023, and the subsequent interim period through February 13, 2025, neither the Company nor anyone acting on behalf of the Company had consulted MaloneBailey regarding either: (i) the application of accounting principles to a specified transaction, either completed or proposed, or the type of audit opinion that might be rendered on the Company’s financial statements, nor did MaloneBailey provide a written report or oral advice to the Company that MaloneBailey concluded was an important factor considered by the Company in reaching a decision as to the accounting, auditing or financial reporting issues; or (ii) any matter that was either the subject of a “disagreement” (as defined in Item 304(a)(1)(iv) of Regulation S-K and the related instructions) or a “reportable event” (as described in Item 304(a)(1)(v) of Regulation S-K).

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

On February 18, 2025, Christian Brühlmann resigned from his position as Chief Strategy Officer of the Company. Mr. Brühlmann will remain in his position as Chief Business Officer of Proteomedix AG.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits.

SIGNATURE

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