Radiopharm Theranostics (RAD) Study Update summary

Study background and rationale

• Fatty acid synthase is crucial for brain metastasis survival, enabling cancer cells to thrive in a lipid-deprived brain environment by synthesizing their own fats.

• Brain metastases mainly originate from lung, breast, and melanoma, accounting for about 90% of cases.

• Differentiating between tumor recurrence and treatment effects post-stereotactic radiosurgery is challenging with MRI alone.

• The study targets patients with equivocal MRI findings after radiosurgery, aiming to improve diagnostic accuracy.

• PET imaging with RAD-101 offers a functional assessment, potentially addressing unmet clinical needs in brain metastasis management.

Study design and progress

• The ongoing first-in-class Phase IIb study is recruiting in the U.S., focusing on patients with ambiguous MRI results post-radiosurgery.

• The Phase 2b trial is a U.S. multi-center, open-label, single-arm study with 30 participants.

• Phase IIa at Imperial College London included 22 patients, showing high tracer uptake in all intracranial disease regardless of tumor origin.

• Interim analysis from the current Phase IIb study is positive, with a high degree of correlation between PET findings and clinical outcomes; 92% of evaluable patients achieved concordance with MRI, meeting the primary endpoint.

• The trial has reached 50% patient enrollment and received FDA Fast Track Designation.

Key findings and clinical implications

• High PET SUV (>2) correlates with shorter overall survival, while MRI often fails to provide prognostic information.

• PET imaging can distinguish viable tumor from radiation necrosis, guiding treatment decisions and potentially preventing unnecessary interventions.

• PET detected tumor progression earlier than MRI in some cases, suggesting earlier intervention could improve outcomes.

• PET scans showed true negatives in cases with only necrosis, supporting its specificity.

• Combining PET with MRI enhances diagnostic accuracy, especially in challenging regions like the cerebellum.