Onconetix (ONCO) adds counsel legal opinion in S-1 Amendment

Rhea-AI Filing Summary

Onconetix, Inc. filed Amendment No. 1 to its Form S-1 registration statement, mainly to add a new legal opinion as Exhibit 5.1 from Ellenoff Grossman & Schole LLP regarding the legality of the securities being registered. The amendment is described as an exhibit-only filing, with the remainder of the registration statement unchanged and omitted from this document.

The filing states that the proposed sale of securities may occur from time to time after the registration statement becomes effective. It also lists extensive corporate, financing, equity plan, and commercial agreements as exhibits and is signed on behalf of Onconetix by Chief Executive Officer David A. White and other directors and officers.

Key Figures

Registration Number: 333-295376

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Registration Number 333-295376 Form S-1 Amendment No. 1 for Onconetix, Inc.

Key Terms

Registration Statement, Emerging growth company, Equity Incentive Plan, Forbearance Agreement, +2 more

6 terms

Registration Statement regulatory

"Onconetix, Inc. is filing this Amendment No. 1 ... to its Registration Statement on Form S-1"

A registration statement is a formal document that companies file with a government agency to offer new shares of stock to the public. It provides essential information about the company's finances, operations, and risks, helping investors make informed decisions. Think of it as a detailed product description that ensures transparency and trust before buying into a company.

Emerging growth company regulatory

"See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company”"

An emerging growth company is a recently public or smaller public firm that qualifies for temporary, lighter regulatory and disclosure rules to reduce the cost and effort of being public. For investors, it means the company may provide less historical financial detail and face fewer reporting requirements than larger firms, so it can grow more quickly but also carries higher uncertainty—like buying a promising early-stage product with fewer user reviews.

Equity Incentive Plan financial

"2019 Equity Incentive Plan. 2022 Equity Incentive Plan."

An equity incentive plan is a program that gives employees, executives or directors the right to receive company stock or options to buy stock as part of their pay. Think of it as offering slices of future company profit to motivate people to boost long‑term performance; for investors it matters because it can align employee goals with shareholder value but also increases the number of shares outstanding, which can dilute existing ownership.

Forbearance Agreement financial

"Forbearance Agreement, dated April 24, 2024, by and between the Company and Veru Inc."

A forbearance agreement is a temporary deal between a borrower and a lender where the lender agrees to delay or reduce payments instead of declaring a default; think of it as a pause button on a loan while both sides work out a longer-term fix. It matters to investors because it affects a company’s short-term cash flow and the likelihood of loan losses or restructuring, which can change credit risk and share value.

Registration Rights Agreement financial

"Form of Registration Rights Agreement dated as of October 2, 2024 relating to the resale"

A registration rights agreement is a contract that gives investors the option to have their ownership stakes officially registered with the government, making it easier to sell their shares later. This agreement matters because it provides investors with a clearer path to cash out their investments if they choose, offering more liquidity and confidence in their ability to sell their holdings when desired.

Power of Attorney legal

"Power of Attorney Pursuant to Power of Attorney By: /s/ David A. White"

A power of attorney is a legal document that allows one person to make decisions and act on behalf of another person, often in financial or legal matters. It’s like giving someone a trusted helper or agent the authority to handle important tasks if you are unable to do so yourself. This matters to investors because it can impact how their assets are managed or transferred if they become unable to oversee their affairs.

S-1 Filings Explained: Reading an IPO Registration →

As filed with the Securities and Exchange Commission on May 7, 2026 

Registration No. 333-295376

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Amendment No. 1

to

FORM S-1

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

Onconetix, Inc.

(Exact Name of Registrant as Specified in its Charter)

Delaware		2834		83-2262816
(State or other jurisdiction of incorporation or organization)		(Primary Standard Industrial Classification Code Number)		(I.R.S. Employer Identification No.)

201 E. Fifth Street, Suite 1900
Cincinnati, Ohio 45202
Telephone: (513) 620-4101
(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

David A. White
Chief Executive Officer

201 E. Fifth Street, Suite 1900
Cincinnati, Ohio 45202
Telephone: (513) 620-4101
(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

with copies to:

Barry I. Grossman, Esq.
Jessica Yuan, Esq.
Ellenoff Grossman & Schole LLP
1345 Avenue of the Americas
New York, NY 10105
Phone: (212) 370-1300
Fax: (212) 370-7889

Approximate date of commencement of proposed sale to the public: From time to time after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer		☐		Accelerated filer		☐
Non-accelerated filer		☒		Smaller reporting company		☒
				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 7(a)(2)(B) of the Securities Act. ☐

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

Onconetix, Inc. is filing this Amendment No. 1 (this “Amendment”) to its Registration Statement on Form S-1 (File No. 333-295376) (the “Registration Statement”) as an exhibit-only filing to file Exhibit 5.1. Accordingly, this Amendment consists only of the facing page, this explanatory note, Item 16(a) of Part II of the Registration Statement, the signature page to the Registration Statement and the filed exhibit. The remainder of the Registration Statement is unchanged and has been omitted.

PART II
INFORMATION NOT REQUIRED IN PROSPECTUS

Item 16. Exhibits and Financial Statement Schedules. 

				Incorporated by Reference
Exhibit No.		Description		Form		Exhibit		Filing Date
2.1		Share Exchange Agreement, dated February 11, 2026, by and among Onconetix, Inc., Realbotix, LLC, Realbotix Corp, and Simulacra Corporation.†		8-K		2.1		February 12, 2026
3.1		Amended and Restated Certificate of Incorporation filed with Delaware Secretary of State dated February 23, 2022.		8-K		3.1		February 24, 2022
3.2		Certificate of Amendment to the Company’s Second Amended and Restated Certificate of Incorporation dated April 21, 2023		8-K		3.1		April 24, 2023
3.3		Certificate of Amendment to the Company’s Second Amended and Restated Certificate of Incorporation dated December 15, 2023.		8-K		3.1		December 21, 2023
3.4		Fourth Amended and Restated Bylaws of the Company dated December 1 2023		8-K		3.2		December 21, 2023
3.5		Certificate of Amendment to the Amended and Restated Certificate of Incorporation, as amended, of Onconetix, Inc. dated September 24, 2024.		8-K		3.1		September 24, 2024
3.6		Form of Certificate of Amendment to the Amended and Restated Certificate of Incorporation, as amended, of Onconetix, Inc., dated June 11, 2025		8-K		3.1		June 11, 2025
3.7		Certificate of Amendment to the Amended and Restated Certificate of Incorporation, as amended, of Onconetix, Inc. dated March 25, 2026		8-K		3.1		March 27, 2026
4.1		Specimen Common Stock Certificate.		S-1		4.1		October 8, 2021
4.2		Description of Registered Securities.		10-K		4.2		April 11, 2024
4.3		Form of Inducement PIO.		8-K		4.1		July 11, 2024
4.4		Form of Warrant.(Series C)		8-K		4.1		October 3, 2024
4.5		Form of Warrant.(Series D)		8-K		4.1		September 26, 2025
4.6		Form of Warrant.(Series E)		8-K		4.1		October 3, 2025
4.7		Certification of Designation of Series C Preferred Stock.		8-K		3.1		October 3, 2024
4.8		Certification of Designation of Series D Preferred Stock.		8-K		3.1		September 26, 2025
4.9		Certification of Designation of Series E Preferred Stock.		8-K		3.1		October 3, 2025
5.1**		Opinion of Ellenoff Grossman & Schole LLP as to the legality of the securities being registered.
10.1		2019 Equity Incentive Plan.		S-1		10.1		October 8, 2021
10.2		2022 Equity Incentive Plan.		S-1/A		10.2		January 6, 2022
10.3		2019 Equity Incentive Plan Form of Stock Option Grant Agreement.		S-1		10.3		October 8, 2021
10.4		2022 Equity Incentive Plan Form of Incentive Stock Option Agreement (Employee).		S-1/A		10.4		January 6, 2022
10.5		2022 Equity Incentive Plan Form of Nonstatutory Stock Option Agreement (Consultant).		S-1/A		10.5		January 6, 2022
10.6		2022 Equity Incentive Plan Form of Nonstatutory Stock Option Agreement (Non-Employee Director).		S-1/A		10.6		January 6, 2022
10.7		2022 Equity Incentive Plan Form of Nonstatutory Stock Option Agreement (Employee).		S-1/A		10.7		January 6, 2022
10.8		Lease Agreement, dated as of April 29, 2021, between the Registrant and Regus Management Group, LLC.		S-1		10.11		October 8, 2021
10.9		General Release of Claims, dated October 5, 2023, by and between Jon Garfield and the Company.		8-K		99.1		October 10, 2023
10.10		Release, dated January 10, 2024, by and between the Company and Dr. Neil Campbell.		8-K		99.1		January 12, 2024
10.11		Form of Indemnification Agreement for Directors and Officers.		8-K		10.3		October 10, 2023

II-1

10.12		Form of Amendment, dated October 5, 2023, to Asset Purchase Agreement, dated June 13, 2023, by and among WraSer, Xspire, Legacy-Xspire Holdings, LLC, and the Company.		10-Q		10.14		October 20, 2023
10.13†#		Exclusive Distribution Agreement, dated September 20, 2023, between the Company and Cardinal Health 105, LLC.		10-Q		10.6		November 17, 2023
10.14		Form of Lock-Up Agreement, dated December 15, 2023, by and among the Company and certain stockholders of Proteomedix.		8-K		10.1		December 21, 2023
10.15		Form of Non-Competition and Non-Solicitation Agreement, dated December 15, 2023, by and among the Company and certain stockholders of Proteomedix.		8-K		10.2		December 21, 2023
10.16		Form of Stockholder Support Agreement, dated December 15, 2023, by and among the Company, Proteomedix, and certain stockholders of Proteomedix		8-K		10.3		December 21, 2023
10.17		Form of Subscription Agreement, dated December 15, 2023, by and among the Company, Proteomedix, and the PMX Investor.		8-K		10.4		December 21, 2023
10.18		Separation Agreement, dated January 17, 2024, between the Company and Erin Henderson.		8-K		10.1		January 19, 2024
10.19		Consulting Agreement, dated January 17, 2024, between the Company and The Aetos Group.		8-K		10.2		January 19, 2024
10.20		Debenture, dated January 23, 2024 issued to the PMX Investor		8-K		10.1		January 29, 2024
10.21		Consulting Agreement, dated January 4, 2024, by and between the Company and Thomas Meier.		8-K		10.1		February 12, 2024
10.22		License Agreement, dated March 27, 2023, between Proteomedix and Laboratory Corporation of America Holdings.		10-K		10.55		April 11, 2024
10.23		Forbearance Agreement, dated April 24, 2024, by and between the Company and Veru Inc.		8-K		10.1		April 26, 2024
10.24		Master Research Services Agreement, dated October 1, 2022, by and between Proteomedix AG and Immunovia, AB		S-1/A		10.60		June 25, 2024
10.25		Collaboration Agreement, dated July 19, 2021, by and between Proteomedix AG and New Horizon Health Limited		S-1/A		10.61		June 25, 2024
10.26		Amendment No. 1, dated June 26, 2023, to Collaboration Agreement, dated July 19, 2021, by and between Proteomedix AG and New Horizon Health Limited		S-1/A		10.62		June 25, 2024
10.27		Release Agreement, dated June 10, 2024, between the Company and Bruce Harmon.		8-K		99.1		June 13, 2024
10.28		Consulting Agreement, dated June 10, 2024, between the Company and Karina Fedasz.		8-K/A		10.1		June 14, 2024
10.29		Form of Inducement Letter		8-K		10.1		July 11, 2024
10.30		Amended and Restated Forbearance Agreement between the Company and Veru, dated September 19, 2024		8-K		10.1		September 20, 2024
10.31		Form of Securities Purchase Agreement dated October 2, 2024 relating to the sale of the Series C Preferred Stock and Warrants		8-K		10.1		October 3, 2024
10.32		Form of Registration Rights Agreement dated as of October 2, 2024 relating to the resale of the shares of Common Stock underlying the Series C Preferred Stock and Warrants		8-K		10.2		October 3, 2024
10.33		ELOC Purchase Agreement dated October 2, 2024		S-1		10.45		December 11, 2024
10.34		ELOC Registration Rights Agreement dated October 2, 2024		S-1		10.46		December 11, 2024
10.35		Waiver and Amendment No. 1 to Forbearance Agreement, dated November 26, 2024, between the Company and Veru		8-K		10.1		December 3, 2024
10.36		Settlement Agreement and Release, dated September 22, 2025, by and between the Company and Veru, Inc.		8-K		10.3		September 26, 2025
10.37		Form of Termination Agreement effective as of September 24, 2025, by and between the Company and Ocuvex Therapeutics, Inc.		8-K		10.4		September 26, 2025
10.38		Note, dated February 12, 2025		8-K		10.1		February 18, 2025
10.39		Consulting Agreement, dated February 28, 2025, between the Company and James Sapirstein		8-K		99.1		February 28, 2025
10.40		Note, dated May 16, 2025		8-K		10.1		May 22, 2025

II-2

10.41		Note, dated June 5, 2025		8-K		10.1		June 11, 2025
10.42		Form of Company Support Agreement, dated July 16, 2025, by and among Parent, the Company and certain Company stockholders.		8-K		10.2		July 16, 2025
10.43		Form of Conversion Price Reduction Consent		8-K		10.3		July 16, 2025
10.44		Promissory Note, dated August 6, 2025, by and between Keystone Capital Partners, LLC and the Company		8-K		10.1		August 12, 2025
10.45		Amended and Restated Promissory Note, dated August 7, 2025, by and between Veru, Inc. and the Company		8-K		10.2		August 12, 2025
10.46		Promissory Note, dated August 28, 2025, by and between Keystone Capital Partners, LLC and the Company		8-K		10.1		September 4, 2025
10.47		Promissory Note, dated August 28, 2025, by and between KCP Fund I, LLC and the Company		8-K		10.2		September 4, 2025
10.48		Second Amended and Restated Promissory Note, dated August 28, 2025, by and between Veru, Inc. and the Company		8-K		10.3		September 4, 2025
10.49		Waiver, dated August 28, 2025, by and between Veru, Inc. and the Company		8-K		10.4		September 4, 2025
10.50		License Agreement, dated September 17, 2025, by and between Immunovia AB and Proteomedix AG		8-K		10.1		September 22, 2025
10.51		Form of Securities Purchase Agreement dated September 22, 2025 relating to the sale of the Series D Preferred Stock and Warrants		8-K		10.1		September 26, 2025
10.52		Form of Registration Rights Agreement dated as of September 22, 2025 relating to the resale of the shares of Common Stock underlying the Series D Preferred Stock and Warrants		8-K		10.2		September 26, 2025
10.53		Form of Securities Purchase Agreement dated October 1, 2025 relating to the sale of the Series E Preferred Stock and Warrants		8-K		10.1		October 3, 2025
10.54		Form of Registration Rights Agreement dated as of October 1, 2025 relating to the resale of the shares of Common Stock underlying the Series E Preferred Stock and Warrants		8-K		10.2		October 3, 2025
10.55		First Amendment to License Agreement between Proteomedix AG and Laboratory Corporation of America Holdings, dated December 6, 2025#		8-K		10.1		December 10, 2025
10.56#		Employment Agreement, dated March 18, 2026, between the Company and Mr. David White#		8-K		10.1		March 25, 2026
21		List of Subsidiaries.		10-K		21		March 13, 2026
23.1*		Consent of MaloneBailey LLP
23.2**		Consent of Ellenoff Grossman & Schole (included as part of Exhibit 5.1 hereto).
24*		Power of Attorney
107*		Filing Fee Table.		S-1		107		April 28, 2026

* Previously filed.

** Filed herewith.

† Certain of the exhibits and schedules to this Exhibit have been omitted in accordance with Regulation S-K Item 601(a)(5). The Company agrees to furnish a copy of all omitted exhibits and schedules to the SEC upon its request.

# Certain portions of this exhibit (indicated by “[*]” have been omitted pursuant to Item 601(b)(10)(iv) of Regulation S-K as we have determined they (1) are not material and (2) are the type that the Company treats as private or confidential. The Registrant hereby agrees to furnish a copy of any omitted portion to the SEC upon request.

II-3

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cincinnati, Ohio, on May 7, 2026.

	ONCONETIX, INC.
	By:	/s/ David A. White
	Name:	David A. White
	Title:	Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

Signature		Title		Date
/s/ David A. White		Chief Executive Officer		May 7, 2026
David A. White		(Principal Executive Officer)
*		Interim Chief Financial Officer		May 7, 2026
Karina M. Fedasz		(Principal Financial and Accounting Officer)
*		Chairman of the Board and Director		May 7, 2026
Sammy Dorf
*		Director		May 7, 2026
Sarah Romano
*		Director		May 7, 2026
Josh Epstein

Pursuant to Power of Attorney

By:	/s/ David A. White
	David A. White
	Attorney-in-Fact

II-4

FAQ

What is Onconetix (ONCO) filing in this S-1 amendment?

Onconetix filed Amendment No. 1 to its Form S-1 as an exhibit-only update. The amendment primarily adds a legal opinion (Exhibit 5.1) on the validity of the securities being registered, while leaving the substantive disclosure in the original registration statement unchanged.

What is the main purpose of Onconetix’s Amendment No. 1 to the S-1?

The amendment’s main purpose is to file Exhibit 5.1, a legal opinion from Ellenoff Grossman & Schole LLP. This opinion addresses the legality of the securities covered by the registration statement, which is a standard requirement for Securities Act registration statements.

When can Onconetix (ONCO) begin selling securities under this registration?

The document states the proposed sale to the public may occur from time to time after the registration statement becomes effective. Effectiveness is determined under Section 8(a) of the Securities Act, either by a further amendment or by action of the Securities and Exchange Commission.

Who signed Onconetix’s S-1 Amendment No. 1 and in what roles?

The amendment is signed on behalf of Onconetix by Chief Executive Officer David A. White. Signatures also appear for the interim Chief Financial Officer, who serves as principal financial and accounting officer, and several directors, with White additionally acting as attorney-in-fact under a power of attorney.

Which law firm provided the legal opinion in Onconetix’s S-1 amendment?

Ellenoff Grossman & Schole LLP provided the legal opinion filed as Exhibit 5.1. The firm’s opinion addresses the legality of the securities being registered, and its consent appears as Exhibit 23.2, included as part of the same opinion exhibit in the amendment.

What types of agreements are listed as exhibits in the Onconetix S-1 amendment?

The exhibit index lists a wide range of agreements, including equity incentive plans, warrant forms, preferred stock designations, license and collaboration agreements, forbearance and settlement agreements with Veru Inc., securities purchase agreements, notes, consulting agreements, and various corporate governance documents.