Radiopharm’s New Phase 1 Imaging Trial Puts LRRC15-Targeted Radiotherapy in Focus

Radiopharm Theranostics Limited (AU:RAD) announced an update on their ongoing clinical study.

Radiopharm Theranostics Limited (AU:RAD) has announced a Phase 1, multicenter imaging study titled “A Phase 1, Multicenter Study of the Safety and Imaging of NTH-2403, a Lutetium-177 Radiolabeled Monoclonal Antibody Targeting the LRRC15 Epitope, in Participants With Locally Advanced or Metastatic Solid Tumors.” The study aims to test safety and imaging performance of LNTH-2403 in patients with advanced solid tumors, including colorectal, head and neck, non-small cell lung, and triple negative breast cancer. This early clinical work is important because it could validate a new way to both image and treat hard-to-treat cancers, supporting Radiopharm’s pipeline and its long-term value story if results are positive.

LNTH-2403 is an experimental drug that combines a targeted antibody with a radioactive component. It is designed to seek out a tumor marker called LRRC15 on cancer cells and cancer-supporting cells. Once bound, it can help doctors see tumors through imaging while also delivering a focused radiation dose to the cancer. The goal is to create a single product that helps find and potentially treat LRRC15-positive tumors more precisely than standard approaches.

This is an interventional Phase 1 study, meaning participants will actively receive the study drug. All patients are assigned to the same treatment group and receive a single dose of LNTH-2403, so there is no randomization or placebo group. The trial is open-label, so both doctors and patients know what treatment is given. The main purpose at this stage is diagnostic: to check if LNTH-2403 is safe to use and if it provides clear imaging in people with advanced solid tumors.

The study is listed as “Not Yet Recruiting,” indicating enrollment has not started. The initial submission to the registry was made on 26 November 2025, setting the formal start of regulatory tracking. The most recent update was filed on 20 January 2026, signaling that the sponsor is actively preparing the trial and refining details. Primary completion and final completion dates are not yet specified, but investors should assume that key safety and imaging readouts are still several years away from this first-in-human effort.

For investors, this update supports the long-term thesis around Radiopharm Theranostics as a player in radiopharmaceuticals and “theranostic” cancer care. Early-stage, single-arm imaging studies like this do not move revenue near term, but a clear path into LRRC15-positive tumors could boost sentiment if early data show strong targeting and clean safety. The collaboration with Lantheus Holdings adds credibility and may ease future commercialization or partnering if results are promising. In a competitive field that includes large-cap radiopharma and oncology players, this trial helps Radiopharm stay relevant in the race to bring next-generation targeted radiotherapies to market, though investors should weigh the high clinical risk and long timelines typical of Phase 1 oncology work.

The study is currently in the setup phase and remains active on the registry, with further details and ongoing updates available on the ClinicalTrials portal.

To learn more about AU:RAD’s potential, visit the Radiopharm Theranostics Limited drug pipeline page.