FDA accepts Telix's Pixclara resubmission for recurrent or progressive glioma imaging

Telix Pharmaceuticals filed a resubmitted New Drug Application (NDA) to the US FDA for Pixclara (floretyrosine F 18), a positron emission tomography imaging agent targeting L-type amino acid transporters in glioma tissue, with the agency assigning a PDUFA goal date of September 11, 2026. The filing, accepted in April 2026, seeks approval for the characterization of recurrent or progressive glioma from treatment-related changes in both adult and pediatric patients — a diagnostic distinction that contrast-enhanced MRI alone cannot reliably resolve.

The NDA, originally submitted in August 2024 and resubmitted on March 13, 2026 following a Complete Response Letter in which the FDA requested additional confirmatory diagnostic performance data, covers the use of Pixclara as a PET imaging agent for glioma. The product holds both Orphan Drug and Fast Track designations from the FDA.

The clinical evidence package supporting the NDA draws on imaging data from routine clinical use, prospectively analyzed through a study registered as NCT07238322, which examined 18F-FET PET for the characterization of progressive or recurrent glioma from treatment-related changes. The source material does not explicitly identify this as the sole pivotal study, and the full trial package underpinning the filing has not been publicly disclosed. Telix has separately noted that Pixclara targets the same LAT1 and LAT2 membrane transport proteins as its therapeutic candidate TLX101-Tx (iodofalan I-131), currently under investigation in the IPAX-BrIGHT trial (NCT07100730) in recurrent glioblastoma — a distinct program that does not form part of the imaging NDA.

The diagnostic challenge at the centre of this filing is well established in neuro-oncology. Gliomas account for around 52% of all malignant brain and CNS tumors, according to the 2025 CBTRUS statistical report, while Telix states the US sees around 24,000 new cases annually . Following the standard Stupp protocol of surgical resection, concurrent radiotherapy, and temozolomide chemotherapy, recurrence occurs in nearly all glioblastoma patients, typically within 12 to 15 months of diagnosis. At that juncture, clinicians face a persistent problem: contrast-enhanced MRI, the current standard of care for post-treatment surveillance, cannot reliably distinguish true tumor recurrence from pseudoprogression or radiation necrosis. Pseudoprogression — treatment-induced MRI changes that mimic disease progression — occurs in roughly 20% to 30% of glioblastoma patients after chemoradiation.

Amino acid PET tracers including 18F-FET have been incorporated into international clinical guidelines — including NCCN Central Nervous System Cancer guidelines and joint guidance from EANM, EANO, SNMMI, and RANO published in Lancet Oncology in 2025 — but no such agent is currently FDA-approved in the United States. The Pixclara NDA represents the first attempt to bring an amino acid PET agent through US regulatory approval for this indication, and the FDA's issuance of a CRL in 2025 before accepting the resubmission reflects the agency's standards for diagnostic imaging agents, which require robust evidence of clinical utility in characterizing disease rather than simply detecting tracer uptake.

The filing arrives at a point of renewed activity in glioma drug development. Servier's vorasidenib received FDA approval in August 2024 for Grade 2 IDH-mutant glioma — the first targeted therapy for that subtype — creating a treatment landscape in which accurate imaging-based characterization of disease status becomes increasingly consequential for patient selection and response assessment. Pixclara, as a diagnostic tool rather than a therapeutic, would occupy a complementary role, and Telix has indicated it could serve as a patient selection instrument for LAT1-targeting therapies. Whether the resubmission addresses the FDA's earlier concerns sufficiently will become clearer when the agency reaches its September 2026 decision.

---

Spot something wrong? Report an issue with this article