Radiopharm Agrees FDA Design for RAD101 Trial

The company reached agreement with the FDA on a pivotal Phase 3 study of its brain metastases imaging agent, RAD101.

Updated on Nov. 4, 2026 in Cancer

Bold vector editorial illustration of a single glass vial with amber liquid inside a lead shielding block on a laboratory bench, set against generous negative space. — Radiopharm Theranostics reached agreement with the FDA on the design of a pivotal Phase 3 trial of its RAD101 brain metastases imaging agent, which plans to enrol 280 patients. AI Illustration. Upload story photo >

Radiopharm Theranostics reached agreement with the FDA on the design of a pivotal Phase 3 trial evaluating RAD101 in patients with indeterminate brain metastases following radiotherapy. The company plans to enrol 280 patients.

Why it matters

Distinguishing active tumour recurrence from radiation necrosis or pseudoprogression after radiotherapy remains a clinical challenge, and an imaging agent that can do so could help clarify treatment decisions for patients with brain metastases.

A Phase 2b trial showed 93% concordance between MRI and PET scans of brain metastases in patients with suspected recurrence, while the planned Phase 3 study will enrol 280 patients. Whether RAD101 PET will match the reference standard for sensitivity and specificity remains to be determined.

The players

Radiopharm Theranostics

Radiopharm Theranostics is a company developing radiopharmaceutical diagnostic and therapeutic agents, including RAD101.

Siemens Healthineers

Siemens Healthineers is a German medical technology company that supplies imaging equipment and is supplying clinical material for the RAD101 trial.

U.S. Food and Drug Administration

The U.S. Food and Drug Administration is the federal agency that regulates drugs and medical imaging agents and reviewed the design of the RAD101 trial.

The details

RAD101 is a small molecule radiolabelled with Fluorine-18 that selectively binds to fatty acid synthase, an enzyme overexpressed in brain metastases from solid tumours. The trial will use co-primary endpoints of sensitivity and specificity measured against a defined reference standard, and it is being conducted as a multi-centre study with a clinical supply provided under a partnership with Siemens Healthineers.

April: Radiopharm signed a supply agreement with Siemens Healthineers.

Big Picture

RAD101 was previously granted FDA fast track designation to address the unmet need for imaging that separates tumour recurrence from radiation necrosis after brain metastasis treatment. The FDA's agreement on the pivotal trial design moves the agent further along that pathway.

If approved, a PET imaging agent that distinguishes recurrent brain tumours from treatment effects could help clinicians decide on follow-up care for patients after radiotherapy. Patients should discuss any imaging questions with their oncology team, as the trial results are not yet available.

The takeaway

Clearer imaging after brain radiotherapy could help patients and clinicians tell active cancer apart from treatment-related changes, but the Phase 3 results will determine whether RAD101 delivers that benefit.