Radiopharm Theranostics Hits 90% Concordance in Brain Metastases Imaging Trial

Promising Interim Results in Brain Metastases Imaging

Radiopharm Theranostics has announced encouraging second interim data from its Phase 2b clinical trial of RAD 101, a novel imaging agent designed to improve diagnosis of brain metastases. The trial, conducted in the U.S. with 30 planned patients, has so far dosed 20 individuals. Impressively, 90% of these patients showed concordance between RAD 101 PET imaging and conventional MRI scans, the study’s primary endpoint.

This high level of agreement suggests RAD 101 could offer a reliable alternative or complement to MRI, which, while the current standard, has known limitations in distinguishing recurrent tumors from treatment effects such as radiation necrosis. The ability to more accurately identify active brain metastases is critical for timely and appropriate treatment decisions.

Encouraging Sensitivity and Specificity Trends

Beyond concordance, early data from five patients with six-month follow-up and biopsy results indicate positive trends in sensitivity and specificity, key measures of a diagnostic test’s accuracy. Sensitivity reflects the test’s ability to correctly identify patients with disease, while specificity measures its ability to exclude those without. These encouraging signals, though preliminary, bolster confidence in RAD 101’s potential clinical utility.

RAD 101 works by targeting fatty acid synthase (FASN), an enzyme overexpressed in many solid tumors, including brain metastases. This novel mechanism may allow RAD 101 to detect metabolic activity in tumors that MRI alone might miss or misinterpret, offering a more nuanced picture of disease status.

Regulatory Momentum and Next Steps

The U.S. Food and Drug Administration has granted RAD 101 Fast Track designation, recognising the urgent need for improved diagnostic tools in neuro-oncology. This status can accelerate the development and review process, potentially bringing RAD 101 to clinicians and patients sooner.

Radiopharm Theranostics plans to complete the full 30-patient Phase 2b study by June 2026, with final data expected to inform the design of a pivotal trial. The company’s leadership expresses growing confidence that RAD 101 could fill a significant diagnostic gap, supporting more accurate and timely treatment decisions for patients with brain metastases.

With brain metastases affecting over 300,000 patients annually in the U.S. alone, and incidence rising due to improved systemic therapies, the need for better imaging solutions is acute. RAD 101’s progress thus far positions Radiopharm Theranostics as a notable player in this challenging field.