The FDA has granted priority review to TLX101-CDx (18F-floretyrosine; 18F-FET; Pixclara), a PET imaging agent developed by Telix Pharmaceuticals Limited, for use in progressive or recurrent glioma. This decision accelerates the potential availability of a new tool for characterizing brain tumors in both pediatric and adult patients.
The new drug application (NDA) for TLX101-CDx, submitted in August 2024, seeks approval for the agent's use in distinguishing recurrent or progressive glioma from treatment-related changes. The FDA has set a Prescription Drug User Fee Act (PDUFA) date of April 26, 2025, for its decision.
Addressing Unmet Needs in Glioma Imaging
According to Telix Pharmaceuticals, FDA approval of TLX101-CDx would align brain cancer imaging in the United States with more advanced standards of care already in use internationally. Kevin Richardson, chief executive officer at Telix Precision Medicine, emphasized the critical need for improved brain cancer imaging and the company's commitment to delivering precision medicine solutions.
Currently, distinguishing between true tumor progression and pseudo-progression (treatment-induced changes) can be challenging using standard MRI, potentially leading to inappropriate treatment decisions. TLX101-CDx offers a potential solution by providing a more accurate assessment of tumor activity.
Mechanism of Action and Companion Diagnostic Potential
TLX101-CDx is designed to target the membrane transport proteins LAT1 and LAT2, which are often overexpressed in glioma cells. This dual-targeting function may allow for the use of TLX101-CDx as a companion diagnostic for TLX101 (131I-iodofalan, or 131I-IPA), a novel anti-glioblastoma therapy also under development by Telix.
Ongoing Clinical Trials
Telix is currently evaluating TLX101 in combination with other therapies in two clinical trials:
- IPAX-2 (NCT05450744): This phase 1 trial is assessing the safety of ascending doses of TLX101 plus standard-of-care therapy in patients with newly diagnosed glioblastoma. The primary endpoints are dose-limiting toxicities and the safety and tolerability of TLX101. The trial is being conducted at multiple sites across Australia, New Zealand, and Europe.
- IPAX-Linz: This phase 2 trial is evaluating TLX101 plus external beam radiotherapy in patients with recurrent high-grade gliomas, including glioblastoma multiforme. The trial aims to assess the benefit of TLX101 in the second-line or refractory setting, with a targeted recruitment of 10 patients.
The FDA previously granted fast track designation to TLX101-CDx in April 2024, underscoring the agency's recognition of its potential to address an unmet medical need in patients with progressive or recurrent glioma.
