FDA Accepts NDA for TLX101-Px Imaging Agent in Recurrent/Progressive Glioma

The FDA has accepted a resubmitted new drug application (NDA) seeking the approval of TLX101-Px (Pixclara; Floretyrosine F 18; [¹⁸F-FET]), an investigational PET agent for the characterization of recurrent or progressive glioma for treatment-related changes in adult and pediatric patients.¹

The FDA has assigned a Prescription Drug User Fee Act goal date of September 11, 2026.

Notably, neuroimaging of glioma with ¹⁸F-FET is recommended in several international guidelines. For instance, the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology for the management of central nervous system cancers recommend the consideration of amino acid PET tracers, including ¹⁸F-FET, for the following uses in primary and secondary brain tumors:²

• Identifying tumor extent
• Planning diagnostic biopsy
• Planning radiotherapy to improve visualization of tumor margins
• Differentiating tumor progression and treatment-related changes per RANO/EANO/SNMMI guidelines

“Distinguishing tumor progression from treatment-related change remains one of the most challenging aspects of glioma care,” Patrick Wen, MD, the E. Antonio Chiocca, MD, PhD, Family Endowed Chair in Neuro-Oncology at Mass General Brigham Cancer Institute in Boston, Massachusetts, stated in a news release.¹ “PET imaging with ¹⁸F-FET is an important tool in clinical practice worldwide, and the FDA’s acceptance of this application is a meaningful step toward broader access for patients and clinicians in the US.”

What is the regulatory history of TLX101-Px?

Previously, in October 2020, the FDA granted orphan drug designation to TLX101-Px as a diagnostic agent for the management of glioma.³ The agent has also received fast track designation from the FDA.¹

“There remains a critical unmet need in improving our ability to image residual glioma after treatment," Thomas Hope, MD, vice chair of the Department of Radiology and Biomedical Imaging at the University of California, San Francisco, added in the news release. “We have worked with Telix for the last 3 years to help leverage our clinical data to help make FET-PETavailable to patients in the US.”

What is the mechanism of action of TLX101-Px, and how might it be used in clinical practice in the future?

TLX101-Px, a PET imaging candidate, targets the membrane transport proteins LAT1 and LAT2. Notably, this allows for the potential use of TLX101-Px as a tool for patient selection and assessing response to the investigational LAT1-targeting agent TLX101-Tx (iodofalan ¹³¹I), which is under investigation in the phase 3 IPAX-BrIGHT trial (NCT07100730) in patients with recurrent glioblastoma.

IPAX-BrIGHT is enrolling patients at least 18 years of age with IDH wild-type glioblastoma per WHO 2021 classification who have radiographic evidence of first recurrence or progressive glioma per RANO 2.0 criteria following first-line treatment with biopsy or maximal safe resection and standard radiotherapy or chemotherapy.⁴ Patients must have increased ¹⁸F-FET PET tracer uptake within or in the vicinity of their tumor per amino acid–based molecular imaging. Patients will receive TLX101-Tx alone or in combination with lomustine (Gleostine). The primary outcomes include safety and tolerability, as well as dose optimization. Secondary outcomes include TLX101-Tx concentration levels in the blood and urine, as well as radiation dosimetry.

“The FDA’s acceptance of our NDA resubmission is an important milestone for Telix,” Kevin Richardson, chief executive officer of Telix Precision Medicine, added in the news release. “We appreciate the FDA’s constructive engagement and look forward to working closely with the Agency to urgently obtain approval and then bring this product to market for the benefit of patients.”

References

1. FDA accepts NDA for TLX101-Px (Pixclara). News release. Telix. April 10, 2026. Accessed April 10, 2026. https://telixpharma.com/news-views/fda-accepts-nda-for-tlx101-px-pixclara/
2. NCCN. Clinical Practice Guidelines in Oncology. Central nervous system cancers, version 3.2025. Accessed April 10, 2026. https://www.nccn.org/professionals/physician_gls/pdf/cns.pdf
3. 18F-FET, a PET tracer. FDA. Accessed April 10, 2026. https://www.accessdata.fda.gov/scripts/opdlisting/oopd/detailedIndex.cfm?cfgridkey=767920
4. Study of TLX101-Tx plus standard of care (SoC) versus SoC alone for the treatment of patients with recurrent glioblastoma (IPAX BrIGHT). ClinicalTrials.gov. Updated March 12, 2026. Accessed April 10, 2026. https://clinicaltrials.gov/study/NCT07100730