Commitments and Contingencies	9 Months Ended
Sep. 30, 2025
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Note 10 — Commitments and Contingencies *Office Lease* Proteomedix leases office and lab space in Zurich Switzerland. On April 1, 2024, the original lease was amended to add additional office and laboratory space. The lease amendment was accounted for as a separate lease, resulting in an additional right-of-use asset and lease liability of approximately $88,000. In May 2025, Proteomedix entered into a lease amendment to reduce its leased premises. Effective June 30, 2025, the Company terminated the April 2024 lease amendment, which included office space and laboratory space. Additionally, a partial termination of a prior lease amendment further reduced the office space. As of September 30, 2025, the remaining leases resulted in a right-of-use asset and lease liability of approximately $6,155. Lease payments for the remainder of the year ending December 31, 2025, are approximately $6,155. The impact of these leases is considered immaterial to the Company’s condensed consolidated financial statements. *Litigation* From time to time, the Company may be subject to various legal proceedings and claims that arise in the ordinary course of its business activities. As of September 30, 2025, the Company is not a party to any material legal proceedings and is not aware of any pending or threatened claims. *Termination of Ocuvex Merger Agreement* On July 16, 2025, the Company entered into an Agreement and Plan of Merger with (i) Onconetix Merger Sub, Inc., a Delaware corporation and a direct, wholly owned subsidiary of the Company, and (ii) Ocuvex Therapeutics, Inc., a Delaware corporation (“Ocuvex”, and such agreement, the “Merger Agreement”). Pursuant to the Merger Agreement, Merger Sub will merge with and into Ocuvex, with Ocuvex surviving the merger as a direct, wholly owned subsidiary of the Company (the “Merger”). Effective September 24, 2025, pursuant to the terms of the Merger Agreement, the Company and Ocuvex entered into a Termination and Release Agreement (the “Termination Agreement”) pursuant to which they agreed to terminate the Merger Agreement and the transactions contemplated thereby. The Termination Agreement also provides for a mutual release of claims among the Company, Ocuvex and their affiliates and in consideration of the foregoing, the Company agreed to pay to Ocuvex, an amount equal to $302,343.55 (the “Termination Payment”), which represents all amounts payable by the Company to Ocuvex pursuant to the terms of the Merger Agreement. As of September 24, 2025, Ocuvex confirmed receipt of the Termination Payment, and as a result the Merger Agreement is of no further force and effect. *Registration Rights Agreements* In connection with private placements consummated in April 2022 and August 2022, the Company entered into Registration Rights Agreements with the purchasers. Upon the occurrence of any Event (as defined in each Registration Rights Agreement), which, among others, prohibits the purchasers from reselling the securities for more than ten consecutive calendar days or more than an aggregate of fifteen calendar days during any 12-month period, and should the registration statement cease to remain continuously effective, the Company would be obligated to pay to each purchaser, on each monthly anniversary of each such Event, an amount in cash, as partial liquidated damages and not as a penalty, equal to the product of 2.0% multiplied by the aggregate subscription amount paid by such purchaser in the private placements. As of September 30, 2025 and December 31, 2024, and as a result of the consummation of the remaining warrants associated with the April 2022 and August 2022 private placements, the Company has no further obligations pertaining to the Registration Rights Agreements. *Indemnification* In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. To date, the Company has not been required to defend any action related to its indemnification obligations. However, during the third quarter of 2023, the Company received a claim from its former CEO and a former accounting employee requesting advancement of certain expenses. The Company recorded approximately $209,000 in related expenses during the year ended December 31, 2023, of which approximately $159,000 was paid through reduction of the outstanding related party receivable due from the former CEO. The Company recorded a related accrual of approximately $50,000, which was included in accrued expenses at December 31, 2023, and which was paid during 2024, and accordingly there is no related accrual as of September 30, 2025. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is not estimable at this time.

Commitments and Contingencies

9 Months Ended

Sep. 30, 2025

Commitments and Contingencies [Abstract]

Note 10 — Commitments and Contingencies

Office Lease

Proteomedix leases office and lab space in Zurich Switzerland. On April 1, 2024, the original lease was amended to add additional office and laboratory space. The lease amendment was accounted for as a separate lease, resulting in an additional right-of-use asset and lease liability of approximately $88,000.

In May 2025, Proteomedix entered into a lease amendment to reduce its leased premises. Effective June 30, 2025, the Company terminated the April 2024 lease amendment, which included office space and laboratory space. Additionally, a partial termination of a prior lease amendment further reduced the office space.

As of September 30, 2025, the remaining leases resulted in a right-of-use asset and lease liability of approximately $6,155. Lease payments for the remainder of the year ending December 31, 2025, are approximately $6,155. The impact of these leases is considered immaterial to the Company’s condensed consolidated financial statements.

Litigation

From time to time, the Company may be subject to various legal proceedings and claims that arise in the ordinary course of its business activities. As of September 30, 2025, the Company is not a party to any material legal proceedings and is not aware of any pending or threatened claims.

Termination of Ocuvex Merger Agreement

On July 16, 2025, the Company entered into an Agreement and Plan of Merger with (i) Onconetix Merger Sub, Inc., a Delaware corporation and a direct, wholly owned subsidiary of the Company, and (ii) Ocuvex Therapeutics, Inc., a Delaware corporation (“Ocuvex”, and such agreement, the “Merger Agreement”). Pursuant to the Merger Agreement, Merger Sub will merge with and into Ocuvex, with Ocuvex surviving the merger as a direct, wholly owned subsidiary of the Company (the “Merger”).

Effective September 24, 2025, pursuant to the terms of the Merger Agreement, the Company and Ocuvex entered into a Termination and Release Agreement (the “Termination Agreement”) pursuant to which they agreed to terminate the Merger Agreement and the transactions contemplated thereby. The Termination Agreement also provides for a mutual release of claims among the Company, Ocuvex and their affiliates and in consideration of the foregoing, the Company agreed to pay to Ocuvex, an amount equal to $302,343.55 (the “Termination Payment”), which represents all amounts payable by the Company to Ocuvex pursuant to the terms of the Merger Agreement.

As of September 24, 2025, Ocuvex confirmed receipt of the Termination Payment, and as a result the Merger Agreement is of no further force and effect.

Registration Rights Agreements

In connection with private placements consummated in April 2022 and August 2022, the Company entered into Registration Rights Agreements with the purchasers. Upon the occurrence of any Event (as defined in each Registration Rights Agreement), which, among others, prohibits the purchasers from reselling the securities for more than ten consecutive calendar days or more than an aggregate of fifteen calendar days during any 12-month period, and should the registration statement cease to remain continuously effective, the Company would be obligated to pay to each purchaser, on each monthly anniversary of each such Event, an amount in cash, as partial liquidated damages and not as a penalty, equal to the product of 2.0% multiplied by the aggregate subscription amount paid by such purchaser in the private placements. As of September 30, 2025 and December 31, 2024, and as a result of the consummation of the remaining warrants associated with the April 2022 and August 2022 private placements, the Company has no further obligations pertaining to the Registration Rights Agreements.

Indemnification

In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. To date, the Company has not been required to defend any action related to its indemnification obligations. However, during the third quarter of 2023, the Company received a claim from its former CEO and a former accounting employee requesting advancement of certain expenses. The Company recorded approximately $209,000 in related expenses during the year ended December 31, 2023, of which approximately $159,000 was paid through reduction of the outstanding related party receivable due from the former CEO. The Company recorded a related accrual of approximately $50,000, which was included in accrued expenses at December 31, 2023, and which was paid during 2024, and accordingly there is no related accrual as of September 30, 2025. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is not estimable at this time.