Radiopharm Theranostics (RADX) moves RV-01 trial to next dose cohort

Rhea-AI Filing Summary

Radiopharm Theranostics Ltd (RADX) reported a clinical milestone, dosing the first patient in the second cohort of its First-In-Human Phase 1/2a trial of RV-01 (177Lu-Betabart) in B7-H3 expressing solid tumors. Advancement to the second cohort at a 70 mCi dose followed a positive recommendation from the independent Safety and Monitoring Committee. RV-01, developed through a joint venture with MD Anderson Cancer Center, is a 177Lutetium-tagged monoclonal antibody targeting the B7-H3 immune checkpoint. The ongoing Phase 1/2a trial in the U.S. is a dose-escalation and expansion study designed to assess safety, biodistribution, pharmacokinetics, radiation dosimetry and preliminary anti-tumor activity, with a planned enrollment of 61 participants across multiple advanced solid tumor types.

Key Figures

Second cohort RV-01 dose: 70 mCi Planned trial enrollment: 61 participants Clinical trials in program: 1 Phase 2 and 5 Phase 1 trials +2 more

5 metrics

Second cohort RV-01 dose 70 mCi Dose level for the second cohort in the Phase 1/2a RV-01 trial

Planned trial enrollment 61 participants Target enrollment for the First-In-Human Phase 1/2a RV-01 study (NCT07189871)

Clinical trials in program 1 Phase 2 and 5 Phase 1 trials Stated composition of Radiopharm’s clinical program across solid tumor cancers

Trial identifier NCT07189871 Identifier for the First-In-Human Phase 1/2a RV-01 clinical trial

First patient dosed in second cohort 1 patient First patient dosed at 70 mCi in the second cohort of the RV-01 study

Key Terms

First-In-Human (FIH), radiopharmaceutical, biodistribution, radiation dosimetry, +2 more

6 terms

First-In-Human (FIH) medical

"its First-In-Human (FIH) Phase 1/2a clinical trial of RV-01"

The first-in-human (FIH) designation marks the first time a new drug, vaccine, medical device, or treatment is given to people rather than tested only in labs or animals. For investors, FIH is a major milestone because it moves a candidate from preclinical testing into human safety and early effectiveness evaluation—think of it as the prototype being driven on public roads, where results strongly influence future development costs, timelines, and commercial potential.

radiopharmaceutical medical

"the first radiopharmaceutical therapeutic developed in Company’s joint venture"

A radiopharmaceutical is a special type of medicine that contains a small amount of radioactive material, used primarily for medical imaging or treatment. It can be thought of as a tiny, targeted signal that helps doctors see inside the body or deliver therapy directly to affected areas. For investors, understanding radiopharmaceuticals is important because they represent a growing field within healthcare, driven by advancements in diagnostics and personalized treatments.

biodistribution medical

"designed to evaluate the safety, biodistribution, radiation dosimetry"

Biodistribution is the map of where a drug, vaccine, or diagnostic agent travels and accumulates inside the body after administration. Investors care because where a product ends up affects how well it works, what side effects it may cause, and whether regulators will approve it—similar to tracking dye in a plumbing system to find leaks or blockages; unexpected destinations can raise safety, cost, and market-adoption risks.

radiation dosimetry medical

"designed to evaluate the safety, biodistribution, radiation dosimetry"

Radiation dosimetry is the measurement and calculation of the amount of ionizing radiation absorbed by people, biological tissues, or materials. It matters to investors because accurate dosimetry determines safety, regulatory approval, product labeling and liability, and the effectiveness of medical treatments or industrial processes—much like measuring how long you can safely stay in the sun to avoid a burn, it helps companies manage risk, costs, and marketability.

castrate resistant prostate cancer medical

"who have a documented history of histopathologically confirmed castrate resistant prostate cancer"

triple negative breast cancer medical

"endometrial cancer, triple negative breast cancer, or esophageal squamous cell carcinoma"

Triple negative breast cancer is a type of breast cancer that lacks three common markers used to identify and target the disease, making it more challenging to treat. It tends to grow and spread more quickly than other forms, which can lead to more aggressive outcomes. Its complexity can impact medical research and treatment developments, influencing investor interest in healthcare companies working on new therapies.

FAQ

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

Radiopharm Theranostics announced it has dosed the first patient in the second cohort of its First-In-Human Phase 1/2a clinical trial of RV-01 (177Lu-Betabart) in B7-H3 expressing solid tumors, following a positive Safety and Monitoring Committee recommendation to proceed.

What dose level of RV-01 is Radiopharm (RADX) testing in the second cohort?

The second cohort of the RV-01 Phase 1/2a trial is being treated at a 70 mCi dose of RV-01. Advancement to this dose level followed a positive recommendation from the independent Safety and Monitoring Committee overseeing the study.

What is RV-01 in Radiopharm Theranostics’ (RADX) pipeline?

RV-01 is a 177Lutetium-conjugated monoclonal antibody targeting B7-H3, an immune checkpoint molecule overexpressed in several tumor types. It is the first radiopharmaceutical therapeutic developed by Radiopharm’s joint venture with The University of Texas MD Anderson Cancer Center.

What is the goal and size of the RV-01 Phase 1/2a trial by RADX?

The First-In-Human Phase 1/2a trial aims to evaluate safety, biodistribution, pharmacokinetics, radiation dosimetry and preliminary anti-tumor activity of RV-01 and to determine a recommended dose. The study plans to enroll 61 participants with various advanced solid tumor cancers.

Which cancer types are included in the Radiopharm (RADX) RV-01 trial?

Eligible participants include patients with histopathologically confirmed castrate resistant prostate, colorectal, non-small cell and small cell lung, head and neck squamous cell, ovarian, cervical, endometrial, triple negative breast cancer, or esophageal squamous cell carcinoma.

What broader clinical pipeline does Radiopharm Theranostics (RADX) report?

Radiopharm describes a clinical program including one Phase 2 and five Phase 1 trials across a variety of solid tumor cancers, leveraging peptides, small molecules and monoclonal antibodies for diagnostic and therapeutic radiopharmaceutical applications.

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Form 6-K: How Foreign Companies Report to the SEC →

Available on EDGAR 08/26/2026 - 08:00 AM Accepted by SEC EDGAR 08/26/2026 - 08:00 AM Learn about SEC filing dates

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 August 2026

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 ☐

RADIOPHARM THERANOSTICS LIMITED

EXPLANATORY NOTE

Radiopharm Theranostics Limited (the “Company”) published one announcement (the “Public Notice”) to the Australian Securities Exchange on August 26, 2026 titled:

“RAD Doses First Patient in Second Cohort of BetaBart (RV-01)”

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

This Form 6-K, including the exhibits hereto, is incorporated by reference into the registration statement of the Company on Form F-3 (File No. 333-292178) and forms part thereof to the extent not superseded by documents or reports subsequently filed by the Company under the Securities Act of 1933 or the Securities Exchange Act of 1934.

1

EXHIBITS

Exhibit Number		Description
99.1		RAD Doses First Patient in Second Cohort of BetaBart (RV-01)

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: August 26, 2026	By:	/s/ Amritha Sushil
		Amritha Sushil
		Company Secretary

3

Exhibit 99.1 

ASX ANNOUNCEMENT August 26, 2026

Radiopharm Theranostics Doses First Patient in Second Cohort of Phase 1/2a Clinical Trial of BetaBart (RV-01) in B7-H3 Expressing Solid Tumors

Doses first patient at 70 mCi dose of RV-01, the first radiopharmaceutical therapeutic developed in Company’s joint venture with MD Anderson Cancer Center

Sydney, Australia – 26 August 2026 – Radiopharm Theranostics (ASX: RAD, Nasdaq: RADX, “Radiopharm” or the “Company”), a clinical-stage biopharmaceutical company focused on developing innovative oncology radiopharmaceuticals for areas of high unmet medical need, today announced that it has dosed the first patient in the second cohort of its First-In-Human (FIH) Phase 1/2a clinical trial of RV-01 (177Lu-Betabart) in patients with B7-H3 expressing tumors. This follows a positive recommendation from the Safety and Monitoring Committee (SMC), an independent multidisciplinary committee, to advance to the 70 mCi dose of RV-01.

RV-01 is a 177Lutetium-tagged engineered monoclonal antibody, designed with a strong affinity for the 4Ig isoform of B7-H3. B7-H3 is an immune checkpoint molecule that is overexpressed across several tumor types and has emerged as a compelling target for antibody-based cancer immunotherapy. Multiple preclinical studies with RV-01 have shown tumor shrinkage and prolonged survival in animals treated with the radiotherapeutic agent.

The Phase 1/2a clinical trial is a dose escalation and expansion trial designed to evaluate the safety, biodistribution, radiation dosimetry and preliminary anti-tumor activity of RV-01 in B7-H3 expressing tumors. The trial will determine the recommended dose of RV-01 to move forward in future studies. The Phase 1/2a study is currently being conducted at clinical centers across the U.S.

“Dosing the first patient in the second dose cohort of our Phase 1/2a RV-01 study marks an important clinical and operational milestone for Radiopharm and reflects the continued advancement of this first therapeutic radiopharmaceutical program from our joint venture with MD Anderson Cancer Center,” said Riccardo Canevari, CEO and Managing Director of Radiopharm Theranostics. “The recommendation to proceed to the 70 mCi dose level provides an important early indication of the program’s progression through dose escalation and reinforces our confidence in RV-01’s development pathway.”

“B7-H3 remains one of the most compelling targets in oncology due to its broad expression across multiple solid tumor types, and we believe RV-01 has the potential to emerge as a differentiated therapeutic approach for patients with significant unmet needs. We remain focused on enrolling patients in the current cohort and look forward to reporting initial clinical data later this year,” commented Dimitris Voliotis, M.D., Chief Medical Officer of Radiopharm Theranostics.

Radiopharm Theranostics Limited
Suite 1, Level 3, 62 Lygon Street, Carlton South VIC 3053 Australia
ABN: 57 647 877 889

ASX ANNOUNCEMENT August 26, 2026

About RV-01

RV-01 is the first radiopharmaceutical therapeutic agent developed by Radiopharm Ventures, the Joint Venture formed between Radiopharm Theranostics and The University of Texas MD Anderson Cancer Center. RV-01 is a 177Lutetium-conjugated therapeutic that targets B7-H3, an immune checkpoint molecule that is overexpressed in several tumor types. Multiple preclinical studies with RV-01 have shown tumor shrinkage and prolonged survival in animals treated with the radiotherapeutic agent.

About the Phase 1/2a Clinical Trial

The FIH Phase 1/2a study (NCT07189871) is designed to establish the safety profile, biodistribution, pharmacokinetics, and radiation dosimetry of 177Lu-Betabart (RV-01). The study aims to enroll 61 eligible participants who have a documented history of histopathologically confirmed castrate resistant prostate cancer, colorectal cancer, non-small cell lung cancer, small cell lung cancer, head and neck squamous cell cancer, ovarian cancer, cervical cancer, endometrial cancer, triple negative breast cancer, or esophageal squamous cell carcinoma.

About Radiopharm Theranostics

Radiopharm Theranostics is a clinical stage radiotherapeutics company developing a world-class platform of innovative radiopharmaceutical products for diagnostic and therapeutic applications in areas of high unmet medical need. Radiopharm is listed on ASX (RAD) and on NASDAQ (RADX). The company has a pipeline of distinct and highly differentiated platform technologies spanning peptides, small molecules and monoclonal antibodies for use in cancer. The clinical program includes one Phase 2 and five Phase 1 trials in a variety of solid tumor cancers including lung, breast, prostate and brain. Learn more at radiopharmtheranostics.com.

Authorized on behalf of the Radiopharm Theranostics Board of Directors by Executive Chairman Paul Hopper.

For more information:

Investors:

Riccardo Canevari

CEO & Managing Director
P: +1 862 309 0293
E: rc@radiopharmtheranostics.com

Anne Marie Fields

Precision AQ (formerly Stern IR)

E: annemarie.fields@precisionaq.com

Media:

Matt Wright
NWR Communications
P: +61 451 896 420
E: matt@nwrcommunications.com.au

Follow Radiopharm Theranostics:

Website – https://radiopharmtheranostics.com/
X – https://x.com/TeamRadiopharm
LinkedIn – https://www.linkedin.com/company/radiopharm-theranostics/
InvestorHub – https://investorhub.radiopharmtheranostics.com/

Radiopharm Theranostics Limited
Suite 1, Level 3, 62 Lygon Street, Carlton South VIC 3053 Australia
ABN: 57 647 877 889

Filing Exhibits & Attachments

1 document

Press Releases

• EX-99.1 RAD DOSES FIRST PATIENT IN SECOND COHORT OF BETABART (RV-01) 13.1 KB