6-K
Radiopharm Theranostics Ltd (RADX)
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 April 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 ☐
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 April 8, 2026 titled:
“RAD202 Phase 1 HEAT Trial Advances to Dose Level 3”
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 <br><br>Number | Description |
|---|---|
| 99.1 | RAD202 Phase 1 HEAT Trial Advances to Dose Level 3 |
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: April 8, 2026 | By: | /s/ Phillip Hains |
| Phillip Hains | ||
| Company Secretary |
3
Exhibit99.1
| ASX ANNOUNCEMENT<br><br><br>April 8, 2026 |
|---|
RadiopharmTheranostics advances to Cohort 3 in 177Lu-RAD202 Phase 1 Dose Escalating Clinical Trial
| ● | Receives Positive Recommendation from Data Safety and MonitoringCommittee (DSMC) to progress Phase 1 to the next dose level of 130mCi in patients with HER2+ advanced solid tumors |
|---|
Sydney, Australia – 8 April 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 received a positive recommendation from the Data Safety and Monitoring Committee (DSMC) to advance its clinical-stage radiotherapeutic asset, 177Lu-RAD202 (RAD202), to the next dose level of 130mCi in the Phase 1 ‘HEAT’ clinical trial in patients with Human Epidermal Growth Factor Receptor 2 (HER2)-positive advanced solid tumors^1^. The DSMC is a multidisciplinary committee that conducts detailed reviews of study data, discusses potential safety events and provides recommendations regarding trial continuation.
“We are encouraged by the rapid progress of the Phase 1 ‘HEAT’ trial of RAD202, as it underscores the favorable safety profile, allowing us to accelerate the dose escalation from Cohort 2 to Cohort 3.” said Riccardo Canevari, CEO and Managing Director of Radiopharm Theranostics. “Considering the current progress and the strong execution, we remain on track to complete the Phase 1 dose escalation by the end of 2026.”
The Phase 1 ‘HEAT’ study is currently being conducted at clinical centers across Australia. The announcement of the previous dose level in this study of 75mCi was released on 1 October 2025.
About 177Lu-RAD202:
RAD202 is a proprietary single-domain monoclonal antibody (sdAb) that targets the Human Epidermal Growth Factor Receptor 2 (HER2)-positive expression in advanced solid tumors. HER2 is overexpressed in breast cancer and several other solid tumors and represents a validated target in oncology. In a previous diagnostic study of ten HER2-positive breast cancer patients, RAD202 demonstrated clinical proof-of-concept and had positive safety and biodistribution.
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.
| ^1^ | clinicaltrials.gov/study/NCT06824155 |
|---|
Radiopharm TheranosticsLimitedSuite 1, Level 3, 62 Lygon Street, Carlton South VIC 3053 AustraliaABN: 57 647 877 889
| ASX ANNOUNCEMENT<br><br><br>April 8, 2026 |
|---|
Authorized on behalf of the RadiopharmTheranostics 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 TheranosticsLimitedSuite 1, Level 3, 62 Lygon Street, Carlton South VIC 3053 AustraliaABN: 57 647 877 889