Radiopharm Theranostics (ASX: RAD) has announced that patient enrollment has commenced for the third cohort of its ongoing Phase 1 dose-escalation trial evaluating 177Lu-RAD204, a radiolabeled single-domain antibody targeting PD-L1 in advanced solid tumours.
The company confirmed that the Data Safety Monitoring Committee has approved progression to a higher 90 mCi dose of lutetium-177, following the completion of the first two dosing cohorts. Patients in these cohorts demonstrated tumour uptake and a favourable safety profile, supporting continued escalation.
“This represents a major milestone for Radiopharm,” said CEO and Managing Director Riccardo Canevari. “With enrollment now complete for the second cohort, we can proceed to dose patients at 90 mCi as approved by the safety committee. We’re particularly encouraged by the initial tumour uptake data and safety results, and we look forward to collecting more data as we advance.”
The open-label Phase 1 study, titled 'Phase 0/1 Study of the Safety and Tolerability of 177Lu-RAD204, a Lutetium-177 Radiolabelled Single Domain Antibody Against Programmed Cell Death Ligand-1 in Patients with Metastatic Solid Tumours', is designed to evaluate safety, tolerability, biodistribution, radiation dosimetry, and preliminary anti-tumour activity.
The basket trial includes patients with non-small cell and small cell lung cancers (NSCLC, SCLC), triple-negative breast cancer (TNBC), cutaneous melanoma, head and neck squamous cell carcinoma (HNSCC), and endometrial cancer. These are conditions where PD-L1 is often overexpressed and therapeutic options are limited.
177Lu-RAD204 builds on previously published Phase 1 imaging data using 99mTc-RAD204 in NSCLC, which demonstrated favourable dosimetry and tumour targeting. By combining PD-L1-specific targeting with therapeutic radioisotopes, the therapy aims to overcome resistance mechanisms that limit the efficacy of current checkpoint inhibitors and other standard-of-care treatments.
Radiopharm said its goal is to establish 177Lu-RAD204 as a novel radiopharmaceutical therapy for patients with PD-L1-positive advanced cancers who have few remaining treatment options.
The company’s broader clinical program now includes five ongoing studies, one Phase 2 and four Phase 1 trials, across a pipeline spanning peptides, small molecules, and monoclonal antibodies in oncology.
“Radiopharm is executing to plan across its pipeline,” said Mr Canevari. “We believe our targeted radiotherapeutic approach has the potential to deliver meaningful benefit for patients who currently have limited options.”