Radiopharm Theranostics Limited (RADX) reports RAD101 Phase 2b result

Rhea-AI Filing Summary

Radiopharm Theranostics Limited furnished a report on Form 6-K as a foreign private issuer, providing to the SEC an announcement it published on the Australian Securities Exchange.

The attached exhibit is titled "RAD101 interim Phase 2b data - 92% achieve primary endpoint," highlighting interim Phase 2b data for RAD101 where 92% achieved the primary endpoint. The company also states that this Form 6-K, including the exhibit, is furnished rather than filed for Exchange Act purposes and is not incorporated into other U.S. securities law filings unless specifically referenced.

Insights

Biotech clinical development analyst

Radiopharm furnishes RAD101 interim Phase 2b data showing 92% achieved the primary endpoint.

Radiopharm Theranostics Limited has furnished a Form 6-K that transmits to U.S. markets an Australian Securities Exchange announcement titled "RAD101 interim Phase 2b data - 92% achieve primary endpoint." This indicates that interim Phase 2b data for RAD101 show 92% achieving the primary endpoint, a key predefined measure of study success.

Phase 2b studies typically focus on confirming activity and refining dosing, so interim data reaching the primary endpoint for a high proportion of subjects can be an important development for a therapeutic program. However, the excerpt does not provide details such as sample size, safety profile, or duration of follow-up, which are needed to fully interpret the result.

The company clarifies that this information is being furnished, not deemed filed, and is not automatically incorporated into other U.S. securities law documents. Investors will likely look to the full Australian announcement dated December 15, 2025 and subsequent disclosures for more comprehensive efficacy and safety context around RAD101.

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 December 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 December 15, 2025 titled:

“RAD101 interim Phase 2b data - 92% achieve primary endpoint”

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.

1

EXHIBITS

Exhibit Number		Description
99.1		RAD101 interim Phase 2b data - 92% achieve primary endpoint

2

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: December 15, 2025	By:	/s/ Phillip Hains
		Phillip Hains
		Company Secretary

3

FAQ

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

Radiopharm Theranostics Limited furnished a Form 6-K to provide an announcement it published on the Australian Securities Exchange, attaching it as an exhibit for U.S. markets.

What is the key result mentioned for RAD101 in the exhibit to the Form 6-K for RADX?

The exhibit is titled "RAD101 interim Phase 2b data - 92% achieve primary endpoint," indicating that interim Phase 2b data for RAD101 show 92% achieving the primary endpoint.

When was the RAD101 interim Phase 2b announcement published for Radiopharm Theranostics (RADX)?

The company states that it published the announcement, referred to as the Public Notice, on the Australian Securities Exchange on December 15, 2025.

Does this Form 6-K for Radiopharm Theranostics (RADX) count as a filed document under the Exchange Act?

No. The company specifies that this report on Form 6-K, including the exhibit, shall not be deemed to be "filed" for purposes of the Securities Exchange Act of 1934.

Is the RAD101 interim Phase 2b information automatically incorporated into other SEC filings of Radiopharm Theranostics (RADX)?

No. The company explains that this Form 6-K and its exhibit are not incorporated by reference into any Securities Act filing unless expressly set forth by specific reference.

Who signed the Form 6-K on behalf of Radiopharm Theranostics (RADX)?

The report was signed on behalf of Radiopharm Theranostics Limited by Phillip Hains, who is identified as the Company Secretary, dated December 15, 2025.