[6-K] Radiopharm Theranostics Ltd Current Report (Foreign Issuer)

Rhea-AI Filing Summary

Radiopharm Theranostics (RADX) furnished a Form 6-K noting it published an Australian Securities Exchange announcement titled “RAD starts enrollment of 3rd Cohort of Phase 1 177Lu-RAD204” on November 12, 2025. The announcement is attached as Exhibit 99.1.

The company states the submission is furnished, not filed, under the Exchange Act and is not incorporated by reference into Securities Act filings unless expressly 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 November 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 one announcement (the “Public Notice”) to the Australian Securities Exchange on November 12, 2025 titled:

“RAD starts enrollment of 3rd Cohort of Phase 1 177Lu-RAD204”

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		RAD starts enrollment of 3rd Cohort of Phase 1 177Lu-RAD204

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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: November 12, 2025	By:	/s/ Phillip Hains
		Phillip Hains
		Company Secretary

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FAQ

What did Radiopharm Theranostics (RADX) report in this Form 6-K?

It furnished an ASX announcement titled “RAD starts enrollment of 3rd Cohort of Phase 1 177Lu-RAD204,” attached as Exhibit 99.1.

When was the ASX announcement referenced by RADX published?

The ASX announcement was published on November 12, 2025.

What is the exhibit included with the RADX 6-K filing?

The filing includes Exhibit 99.1: “RAD starts enrollment of 3rd Cohort of Phase 1 177Lu-RAD204.”

Is the RADX 6-K deemed filed or incorporated by reference?

It is furnished, not filed, and is not incorporated by reference unless specifically referenced.

What clinical program is mentioned in the RADX 6-K?

The title references Phase 1 177Lu-RAD204 and the start of enrollment for the 3rd cohort.