FDA Denies Approval of Brain Cancer Imaging Agent

The Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) to Telix Pharmaceuticals regarding the New Drug Application (NDA) for TLX101-CDx (Pixclara^®, ¹⁸F-floretyrosine) for the imaging of gliomas.

TLX101-CDx is an investigational positron emission tomography (PET) agent that targets the membrane transport proteins, LAT1 and LAT2. There is currently no FDA-approved targeted amino acid PET agent for brain cancer imaging available in the US. TLX101-CDx was previously granted Orphan Drug and Fast Track designations by the FDA.

In the CRL, the Agency noted that additional confirmatory clinical evidence would be required before a decision on approval can be made. No safety concerns were raised. 

In response, Dr Christian Behrenbruch, Telix Managing Director and Group CEO, said: “We have multiple go-forward pathways available to us, such as providing additional confirmatory data through several active clinical programs, including Company-led studies. Our immediate focus is understanding the FDA’s feedback and augmenting our submission with additional data to satisfy the Agency as soon as possible.”

In July 2024, the Company began an expanded access program (ClinicalTrials.gov Identifier: NCT06743100) that would enable the use of TLX101-CDx with PET for imaging progressive or recurrent glioma. 

Additionally, TLX101-CDx is being utilized as a companion diagnostic agent for TLX101 (4-L-[¹³¹I] iodo-phenylalanine, or ¹³¹I-IPA), an investigational LAT1-targeting glioblastoma therapy, in the phase 1/2 IPAX-2 (ClinicalTrials.gov Identifier: NCT05450744) and phase 2 IPAX-Linz studies.

Telix Pharmaceuticals will be requesting a hearing with the FDA on the CRL decision.

Read about particular CNS tumors such as Ependymoma

This article originally appeared on MPR