FDA Approves PET Imaging Agent for Brain Cancer Based on UCSF Data
UC San Francisco study data was instrumental in today’s approval by the Food and Drug Administration (FDA) of a PET imaging agent that helps physicians evaluate gliomas, a form of brain cancer.
The approval of floretyrosine F 18 (18F-FET) was supported by prospective clinical trial data generated at UCSF through a multi-year study. The agent addresses a persistent challenge in caring for people with gliomas: determining whether changes seen on conventional imaging represent tumor growth or changes caused by treatment.
“Molecular imaging is an incredibly powerful tool for characterizing disease in ways conventional imaging sometimes cannot,” said study sponsor Thomas Hope, MD, director of Molecular Therapy in UCSF’s Department of Radiology and Biomedical Imaging.
Gliomas are the most common primary tumors of the central nervous system, with approximately 24,000 people diagnosed in the U.S. each year. They can infiltrate surrounding brain tissue, making them particularly difficult to evaluate and treat.
“Patients and their families can face tremendous uncertainty when an MRI changes and we can’t confidently determine why,” said UCSF Health neuro-oncologist Nancy Ann Oberheim Bush, MD. “Having better non-invasive tools to characterize what is happening in the brain can help us make more informed treatment decisions and give patients clearer answers about their disease.”
From academia to industry
The FDA approval grew out of a UCSF clinical trial that evaluated 18F-FET PET in patients with brain tumors. UCSF subsequently made data from the trial available to Telix Pharmaceuticals. Javier Villanueva-Meyer, MD, was the lead neuroradiologist for the trial.
UCSF and Telix collaborated to help translate that academic research into a product that could meet FDA requirements.
“It’s an exciting example of how academic research and industry can work together to move a promising diagnostic tool from a clinical study toward broader patient care,” said Hope.
Contrast-enhanced MRI is the standard imaging method used to assess gliomas, but it cannot always reliably distinguish active tumor from changes in the brain caused by radiation, chemotherapy, or other treatments. The two can look similar on an MRI.
In many other cancers, physicians can investigate an uncertain imaging finding with a biopsy or blood-based test. Repeatedly sampling brain tissue, however, is often impractical or unsafe.
18F-FET PET offers another way to characterize suspicious tissue. The imaging agent mimics an amino acid and is taken up more readily by glioma cells than by surrounding normal tissue and many treatment-related changes. PET imaging can then reveal areas of increased uptake.
The additional information may help physicians define tumor boundaries, assess response to therapy, and detect recurrent disease, helping guide decisions about a patient’s care.
Building on UCSF strengths
The work draws on UCSF’s longstanding strengths in translational molecular imaging and radiopharmaceutical development.
Unlike conventional medications, PET imaging agents contain short-lived radioactive isotopes that require specialized production and handling. UCSF has expertise and infrastructure spanning radiopharmaceutical production, imaging, clinical trials, and patient care, enabling researchers and clinicians to study promising molecular imaging agents and move them toward clinical practice.
That translational model previously helped UCSF researchers advance prostate-specific membrane antigen, or PSMA, PET imaging for prostate cancer. UCSF investigators played a leading role in clinical studies that helped establish PSMA PET as a more sensitive method for detecting prostate cancer and supported its adoption into patient care.
The 18F-FET work extends that approach to glioma, bringing together radiology, nuclear medicine, neuro-oncology, radiopharmaceutical production, and industry.
“For patients with brain tumors, better imaging isn’t simply about producing a clearer picture,” Hope said. “It’s about giving clinicians better information to decide what to do next. Developing tools that can reduce uncertainty and help us more precisely direct care is exactly what translational molecular imaging should do.”
UCSF is pursuing the regulatory steps needed to produce 18F-FET locally through its radiopharmaceutical facility, added Hope.
The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. UCSF Health, which serves as UCSF's primary academic medical center, includes top-ranked specialty hospitals and other clinical programs, and has affiliations throughout the Bay Area. UCSF School of Medicine also has a regional campus in Fresno. Learn more at ucsf.edu, or see our Fact Sheet.