FDA Approves TLX101-Px for Glioma Imaging

The FDA has approved TLX101-Px (Pixclara; floretyrosine F 18 [¹⁸F-FET]), a radioactive amino acid FET-PET imaging agent, to differentiate treatment-related changes from recurrent or progressive glioma, in combination with other diagnostic strategies, in adult and pediatric patients at least 1 month of age.¹

“Having an FDA-approved FET-PET product with high diagnostic accuracy will make a significant, positive difference to the [treatment] of patients with gliomas,” Patrick Wen, MD, the E. Antonio Chiocca, MD, PhD, Family Endowed Chair in Neuro-Oncology at Mass General Brigham Cancer Institute, stated in a news release. “This is a very positive step forward for brain cancer imaging and treatment planning.”

According to the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology for central nervous system cancers, amino acid PET tracers, including 18F-FET, may be used for identifying tumor extent, planning diagnostic biopsy, planning radiotherapy to improve visualization of tumor margins, and differentiating tumor progression from treatment-related changes per RANO, EANO, and SNMMI guidelines.² The NCCN Guidelines note that the most clinically established radiolabeled amino acid tracers used in the evaluation of primary and secondary brain tumors include 11C-methyl-L-methionine, ¹⁸F-FET, and 3,4-dihydroxy-6-¹⁸F-fluoro-L-phenylalanine, and that reported sensitivities and specificities for these applications often approach or exceed 90% across multiple uses. The neuroimaging of glioma with ¹⁸F-FET is also recommended in several international guidelines.

“The approval of Pixclara will advance glioma care by enabling more precise monitoring, complementing the role of MRI,” Kelly Sitkin, president and chief executive officer of the American Brain Tumor Association, added in the news release.¹ “We welcome the FDA’s decision, which provides a pathway to access this technology in the United States [US] and helps address a critical unmet need in brain cancer diagnostics.”

What is the mechanism of action of TLX101-Px?

TLX101-Px is an intravenous PET imaging agent that includes a small molecule targeting compound that is labeled with the diagnostic radioisotope fluorine-18. After being administered into the bloodstream, TLX101-Px targets the membrane transport proteins L-type amino acid transporters 1 and 2 (LAT1 and LAT2). Once TLX101-Px is bound to LAT1 and LAT2, its energy emissions can be detected via PET scan.

“[The] FDA approval of [TLX101-Px] will enable broad access in the US to FET-PET imaging, which is already recognized in international clinical practice guidelines,” Kevin Richardson, chief executive officer of Telix Precision Medicine, the developer of TLX101-Px, added in the news release. “As the first FDA-approved PET imaging drug for glioma, Pixclara will provide physicians in the US with more certainty in their diagnoses and greater confidence in their treatment planning for patients.”

What is the safety profile of TLX101-Px?

Among 382 patients with glioma in whom the safety of TLX101-Px was evaluated, 371 adult patients received at least 1 dose of the agent at a mean activity level of 204 ± 18 MBq (5.5 ± 0.47 mCi). The remaining 11 patients, who were pediatric patients, received at least 1 dose of the agent at a mean activity level of 155 ± 53.5 MBq (4.2 ± 1.4 mCi).

Patients had a mean age of 57 years (range, 5-86). Most patients were male (59%). Enrolled races included White (26%) Asian (6%), Black or African American (< 1%), and other or unreported (67%). Enrolled ethnicities included Hispanic/Latino (3%), non-Hispanic/Latino (96%), and unknown or unreported (< 1%).

The only adverse effect (AE) that occurred in at least 0.5% of patients receiving TLX101-Px was headache (0.5%). Other AEs that occurred in less than 0.5% of patients included nausea, injection site reaction, fatigue, and malaise. Overall, the investigators deemed the safety profile of TLX101-Px to be consistent across adult and pediatric patients.

Notably, in August 2026, an investigational new drug application was cleared by the FDA to investigate TLX101-Px in a phase 3 registrational trial for the diagnosis of patients with brain metastases.

References

1. FDA approves Telix’s brain cancer imaging drug Pixclara. News release. Telix. September 14, 2026. Accessed September 14, 2026. https://telixpharma.com/news-views/fda-approves-telixs-brain-cancer-imaging-drug-pixclara/#_ftn1
2. NCCN. Clinical Practice Guidelines in Oncology. Central nervous system cancers, version 3.2026. August 17, 2026. Accessed September 14, 2026. https://www.nccn.org/professionals/physician_gls/pdf/cns.pdf