Theranostics (RADX) files Form 6-K with ASX Appendix 4C report

Rhea-AI Filing Summary

Theranostics Limited submitted a Form 6-K as a foreign private issuer for October 2025. The filing primarily serves to furnish investors with a copy of the company’s announcement to the Australian Securities Exchange titled “Quarterly Activities/Appendix 4C Cash Flow Report,” dated October 28, 2025.

The ASX announcement is attached as Exhibit 99.1. The company clarifies that this Form 6-K, including the exhibit, is furnished rather than filed for U.S. securities law purposes and will only be incorporated into other U.S. securities filings if specifically referenced.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the Month of October 2025

Commission File Number: 001-41621

RADIOPHARM THERANOSTICS LIMITED

(Name of Registrant)

Level 3, 62 Lygon Street, Carlton South, Victoria, 3053, Australia

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒       Form 40-F ☐

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes ☐       No ☒

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82-

RADIOPHARM THERANOSTICS LIMITED

EXPLANATORY NOTE

Radiopharm Theranostics Limited (the “Company”) published an announcement (the “Public Notice”) to the Australian Securities Exchange on October 28, 2025 titled:

“Quarterly Activities/Appendix 4C Cash Flow Report”  

A copy of the Public Notice is attached as an exhibit to this report on Form 6-K.

This report on Form 6-K (including the exhibit hereto) shall not be deemed to be “filed” for purposes of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) and shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing.

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EXHIBITS

Exhibit Number		Description
99.1		Quarterly Activities/Appendix 4C Cash Flow Report

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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, thereunto duly authorized.

	RADIOPHARM THERANOSTICS LIMITED
Date: October 28, 2025	By:	/s/ Phillip Hains
		Phillip Hains
		Company Secretary

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FAQ

What does Theranostics Limited (RADX) report in this Form 6-K?

Theranostics Limited uses this Form 6-K to furnish its “Quarterly Activities/Appendix 4C Cash Flow Report” announcement made to the Australian Securities Exchange. The ASX announcement is attached as Exhibit 99.1 and provides the detailed quarterly activity and cash flow information.

What exhibit is attached to Theranostics Limited’s (RADX) October 2025 Form 6-K?

The Form 6-K includes a single exhibit, numbered 99.1, titled “Quarterly Activities/Appendix 4C Cash Flow Report.” This exhibit is the full announcement that Theranostics Limited released to the Australian Securities Exchange on October 28, 2025.

Is Theranostics Limited’s (RADX) Quarterly Activities/Appendix 4C report considered filed with the SEC?

The company states the Form 6-K, including the Quarterly Activities/Appendix 4C exhibit, is furnished rather than filed under the Exchange Act. It will only be treated as filed or incorporated into other U.S. securities documents if explicitly referenced in a future filing.

Why did Theranostics Limited (RADX) furnish its ASX Quarterly Activities report to the SEC?

As a foreign private issuer, Theranostics Limited furnishes important home-market disclosures to the SEC for U.S. investors. This Form 6-K transmits its ASX “Quarterly Activities/Appendix 4C Cash Flow Report” so U.S. markets can access the same quarterly activity and cash flow information.

Who signed Theranostics Limited’s (RADX) October 2025 Form 6-K?

The Form 6-K was signed on behalf of Theranostics Limited by Phillip Hains, the Company Secretary. His signature confirms that the company has duly authorized the submission of this report and the attached Quarterly Activities/Appendix 4C exhibit to the SEC.