FET-PET Agent Approved for Glioma Imaging

The FDA has approved floretyrosine F18 (Pixclara, Telix Pharmaceuticals), an intravenous PET imaging agent, for differentiating recurrent or progressive glioma from treatment-related change, in conjunction with other diagnostic evaluations, in adults and children aged 1 month or older.Floretyrosine F18 is the first floretyrosine PET (FET-PET) agent approved in the US for glioma, Telix said in a press release.It combines the amino acid derivative floretyrosine with the radioisotope fluorine-18. Floretyrosine is taken up by amino acid transporters that are overexpressed in gliomas, with the radioisotope then detected by PET.In its latest central nervous system cancer guidelines, the National Comprehensive Cancer Network said FET-PET and other amino acid PET options enhance diagnostic performance when combined with MRI “by improving lesion characterization, particularly in cases where conventional imaging is equivocal.” FET-PET is already used in Europe for gliomas. FDA declined Telix’s original approval application in April 2025 because it “did not provide substantial evidence of effectiveness,” according to the agency’s complete response letter. The company worked with FDA and resubmitted the application in March 2026. The approval is based on two studies with a total of 381 patients aged 5-85 years, according to the label for floretyrosine F18.In both studies, three readers used FET-PET to determine whether imaging changes were due to disease or treatment. Their judgements were compared against those of experts using MRI and histopathologic, surgical, and clinical reports to make the call. The FET-PET readers agreed with the expert panels that changes were due to disease 66%-83% of the time. They agreed that changes were due to treatment 48%-64% of the time. Headache was the most common adverse event, occurring in 0.5% of patients. Reactions in fewer patients included nausea, fatigue, malaise, and injection-site reaction.Telix is also seeking a floretyrosine F18 indication to diagnose brain metastases.M. Alexander Otto is a physician assistant and award-winning journalist. He is also an MIT science journalism fellow. Email: aotto@medscape.net