Completed enrolment in Phase 2b clinical trial of imaging agent RAD 101 in patients with recurrent brain metastases following earlier announcement of interim data demonstrating concordance with MRI (the primary endpoint) in 90% of evaluable subjects (18/20)

Presented initial Phase 0/1 data for RAD 202 at the American Association for Cancer Research demonstrating encouraging tumor uptake and a favorable safety profile in the lowest dose cohort

Received positive recommendation from Data and Safety Monitoring Committee (DSMC) to advance RAD 202 to the next dose level

Initiated two First-In-Human (FIH) clinical trials for radiotherapeutic assets RV-01 in various tumor types and RAD 402 in advanced prostate cancer

SYDNEY, April 23, 2026 (GLOBE NEWSWIRE) -- 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 financial results for the quarter ended March 31, 2026, and provided a corporate update.

"We entered 2026 with strong momentum and continue to execute across our differentiated therapeutics and diagnostics pipeline," said Riccardo Canevari, CEO and Managing Director of Radiopharm Theranostics. "The Phase 2b interim results for RAD 101, demonstrating 90% concordance with MRI in recurrent brain metastases, further validate the potential of our imaging platform and strengthen our confidence as we prepare for the next stages of development. In parallel, initial first-in-human data from RAD 202 showing meaningful tumor uptake and a favorable safety profile underscore the breadth of our therapeutic opportunities."

"Importantly, the initiation of two additional Phase 1 trials—RV-01 through our Radiopharm Ventures collaboration and RAD 402 in advanced prostate cancer—reflects the growing productivity of our platform and our disciplined approach to pipeline expansion. With multiple clinical milestones ahead, we are well positioned to build long-term value as we advance innovative radiopharmaceuticals for patients with high unmet needs," concluded Mr. Canevari.

Program and Business Updates

18F-RAD101 – Small molecule targeting fatty acid synthase radiolabelled with Fluorine-18

RAD 101 is being evaluated in a single-arm U.S. Phase 2b clinical trial for the diagnostic performance of the molecule in 30 individuals with confirmed recurrent brain metastases from solid tumors of different origins. RAD 101 has received U.S. Food and Drug Administration (FDA) Fast Track Designation to expedite the review process and help bring the novel imaging small molecule to the over 300,000 patients diagnosed annually in the U.S. with cerebral metastases.

In April 2026, the Company dosing the final patient in the Phase 2b imaging trial of RAD 101. Radiopharm Theranostics has signed a supply agreement with Siemens Healthineers, who will radiolabel and distribute RAD101 with Fluorine-18 (¹⁸F).
In March 2026, Radiopharm Theranostics reported interim data from twenty patients in the Phase 2b trial of RAD 101, with 90% of evaluable patients achieving concordance with MRI imaging, the primary endpoint.
These promising interim data are in line with the Phase 2a results and, if confirmed, will trigger the preparation of a multi-center, multi-country Phase 3 registrational trial.

177Lu-RAD202 – Nanobody targeting HER2 radiolabelled with Lutetium 177

The Company continues to evaluate RAD 202 in the Phase 0/1 ‘HEAT' clinical trial in patients with Human Epidermal Growth Factor Receptor 2 (HER2)-positive advanced solid tumors. HER2 is overexpressed in breast cancer and several other solid tumors and represents a validated target in oncology. RAD 202 has demonstrated clinical proof-of-concept with positive safety and biodistribution.

In April 2026, Radiopharm presented data from the Phase 0/1 at the American Association for Cancer Research 2026, which demonstrated meaningful tumor uptake of RAD 202, was generally well tolerated, included no dose-limiting toxicities, and organ-level absorbed radiation doses within the expected and clinically acceptable ranges.
Radiopharm Theranostics received a positive recommendation from the Data Safety and Monitoring Committee to advance RAD 202 to the next dose level of 130mCi in the Phase 1 ‘HEAT' clinical trial.
The Company expects to complete enrolment in the higher dose Cohort 3 and to have data from both the second and third cohorts in mid-2026.

177Lu-RAD204 – Nanobody targeting PD-L1 radiolabelled with Lutetium 177

RAD 204 is continuing to be evaluated in a Phase 1 study in PD-L1-driven cancers, including Non-Small Cell Lung Cancer (NSCLC), Small-Cell Lung Cancer (SCLC), Triple-negative Breast Cancer (TNBC), Cutaneous Melanoma, head and neck squamous cell carcinoma (HNSCC) and Endometrial Cancer. Previous Phase 1 imaging data of 16 NSCLC patients treated with RAD 204 demonstrated that the diagnostic compound is safe and is associated with acceptable dosimetry.

The Company completed enrolment of the second Cohort of the Phase 1 study of RAD 204 and can proceed with dosing patients in the third Cohort with an updated dose of 90mCi of Lu177 as approved by the Data and Safety Monitoring Committee.
Two out of three patients in the 30mCi cohort exhibited stable disease for 5.5 months in metastatic NSCLC, compared to historical data of 3.5 months PFS with standard of care (SOC).
Initial data from the first two cohorts show tumor uptake in the PD-L1-positive lesions, in line with published results of the previously conducted imaging study.
RAD 204's safety profile is reassuring and there have been no drug-related adverse events reported.
Data from the third cohort of patients at 90mCi in the Phase 1 study of RAD 204 are expected mid-2026.

Lu177-RV 01 – monoclonal antibody targeting 4Ig isoform of B7H3 radiolabelled with Lutetium 177

RV 01 (Betabart) is a monoclonal antibody targeting the 4Ig isoform of B7H3, an immune checkpoint protein that is highly expressed in tumors and not in healthy tissue. In multiple preclinical studies, RV-01 has shown tumor shrinkage and prolonged survival. This is the first radiopharmaceutical therapeutic developed by Radiopharm Ventures, a joint venture between Radiopharm Theranostics and the MD Anderson Cancer Center.

In February 2026, the first patient was dosed in the First-In-Human (FIH) Phase 1/2a clinical trial, which is designed to establish the safety profile, biodistribution, pharmacokinetics, and radiation dosimetry of RV-01 in various tumor types. The trial will also determine the recommended dose of RV-01 for future studies.
In January 2026, the Company increased its ownership in Radiopharm Ventures from 75% to 87.5% as the joint venture continues to show promising progress in its cancer therapeutic pipeline, including the advancement of its leading B7H3 candidate and other preclinical assets.

Tb161-RAD 402 – Monoclonal antibody targeting KLK3 radiolabelled with Terbium 161

RAD 402 is a monoclonal antibody targeting Kallikrein Related Peptidase 3 (KLK3) radiolabelled with the radionuclide 161Tb for the treatment of prostate cancer. In preclinical studies, RAD 402 in mouse xenografts showed strong tumor targeting, limited bone and marrow uptake, and a hepatic excretion profile consistent with expectations for a monoclonal antibody.

In March 2026, the first patient was dosed in the First-In-Human (FIH) Phase 1 clinical trial of RAD 402, designed to evaluate the safety, tolerability, whole-body distribution, and preliminary clinical activity of RAD 402 in patients with advanced prostate cancer. The dose escalation Phase 1 study is designed to determine the Maximum Tolerated Dose and recommended Phase 2 dose for expansion.

Ga68-RAD301 – Peptide targeting αvB-integrin radiolabeled with Gallium 68

RAD 301 is being evaluated in a Phase 1 imaging trial in patients with Pancreatic Ductal Adenocarcinoma (PDAC). The αvB-integrin is a cellular marker for tumor invasion and metastatic growth, which correlates with decreased survival in several carcinomas, particularly pancreatic. RAD 301 has previously received Orphan Drug Designation (ODD) from the FDA and data from the Phase 1 trial is supportive of the Company's decision to move to a Phase 2 imaging trial in patients with loco-regional pancreatic cancer.

Enrolment in the Phase 1 imaging trial in metastatic pancreatic cancer continues, having dosed 8 patients out of 9, with last patient expected mid-2026.
Initial data from the first six patients demonstrated confirmed safety and significant uptake in the AvB6 positive lesions.

Financial Update

Closing cash at the end of the quarter was $19.2 million, decreasing from $34.5 million at the end of the prior quarter.

Net cash outflows from operating activities during the period was $14.9 million with direct Research and Development expenditure and staff costs accounting for 95% of the operating activities.

In compliance with Listing Rule 4.7C, payments to related parties and their associates, as detailed in item 6.1 of Appendix 4C, encompass remuneration for director fees to executive and non-executive directors, conducted in the ordinary course of business at commercial rates, excluding reimbursements for out-of-pocket expenses.

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, and brain metastases. 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

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Radiopharm Theranostics Reports Business Update