Safety and Efficacy Questions Loom as RAD 402 Enters Human Testing
Radiopharm Theranostics has initiated dosing in its Phase 1 clinical trial of RAD 402, a novel radiolabelled antibody targeting KLK3 in advanced prostate cancer. Early data from the trial’s initial dose levels are expected in the second half of 2026.
- First patient dosed in Phase 1 trial of RAD 402
- RAD 402 targets KLK3 with Terbium 161 radiolabel
- Trial aims to establish safety, tolerability, and dosing
- Preclinical studies show strong tumour targeting and minimal off-target effects
- Data from first two dose levels expected in 2H 2026
A Milestone in Prostate Cancer Radiotherapy
Radiopharm Theranostics (ASX:RAD) has reached a significant clinical milestone by dosing the first patient in its Phase 1 trial of RAD 402, a next-generation radiopharmaceutical designed to treat advanced prostate cancer. This trial marks the company’s first-in-human evaluation of a monoclonal antibody that selectively targets the KLK3 protein, a well-known marker highly expressed in prostate cancer cells.
RAD 402 is radiolabelled with Terbium 161, a radionuclide that offers dual emission properties, potentially enhancing the therapeutic effect while limiting damage to healthy tissue. The Phase 1 study will primarily assess the safety and tolerability of RAD 402, alongside its distribution throughout the body and preliminary signs of clinical activity. The trial’s dose escalation design aims to identify the maximum tolerated dose and recommend an optimal dose for subsequent phases.
Innovative Approach Backed by Preclinical Promise
Preclinical data have been encouraging, with mouse xenograft models demonstrating strong tumour targeting by RAD 402 and minimal uptake in bone marrow or other off-target sites. This selective targeting is crucial in reducing potential side effects often associated with radiotherapies. Additionally, the compound’s hepatic clearance profile aligns with expectations for monoclonal antibodies, suggesting manageable metabolism and elimination.
CEO Riccardo Canevari highlighted the importance of this advancement, noting that RAD 402’s differentiated mechanism could offer a meaningful new option for patients with limited treatment alternatives. He also acknowledged the support of partners TerThera and Cyclotek, who provide the critical supply and radiolabelling of Terbium 161, underscoring the collaborative effort behind this development.
Looking Ahead: Data and Development
The company anticipates sharing data from the first two dose levels in the second half of 2026, which will provide early insights into RAD 402’s clinical profile. While these initial results will focus on safety and dosing, they will set the stage for further clinical evaluation and potential expansion into Phase 2 trials.
Radiopharm Theranostics maintains a broad clinical pipeline, with multiple trials underway targeting various solid tumours including lung, breast, and brain metastases. The progress of RAD 402 adds to this momentum, positioning the company as a notable player in the evolving field of oncology radiopharmaceuticals.
Bottom Line?
As Radiopharm advances RAD 402 through early clinical testing, the coming months will be critical in validating its promise and shaping its future in prostate cancer treatment.
Questions in the middle?
- Will RAD 402 demonstrate a favourable safety profile at higher dose levels?
- How will RAD 402’s efficacy compare to existing prostate cancer radiotherapies?
- What are the timelines and plans for Phase 2 expansion based on upcoming data?
