On Thursday, Telix Pharmaceuticals Limited (NASDAQ:TLX) received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) for the Biologics License Application (BLA) for TLX250-CDx (Zircaix, 89Zr-DFO girentuximab), an investigational PET2 agent for the diagnosis and characterization of renal masses as clear cell renal cell carcinoma (ccRCC).
The CRL identifies deficiencies relating to the Chemistry, Manufacturing, and Controls (CMC) package.
The FDA has requested additional data to establish comparability between the drug product used in the ZIRCON Phase 3 clinical trial and the scaled-up manufacturing process intended for commercial use.
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Additionally, the FDA has documented notices of deficiency (Form 483) issued to two third-party manufacturing and supply chain partners that will require remediation prior to resubmission.
The company will request a Type A meeting with the FDA to address the deficiencies and determine an appropriate timeframe for resubmission.
TLX250-CDx has a Breakthrough Therapy designation and Priority Review status.
The CRL does not impact Telix's stated revenue guidance for 2025.
The company intends to continue to provide patient access to TLX250-CDx through the FDA-approved expanded access program (EAP), subject to consultation with the FDA.
“Telix believes these concerns are readily addressable and submission remediation will begin immediately,” the company said in an exchange filing.
Reuters noted that if the drug is approved, it would be the first PET scan-based drug specifically designed for kidney cancer in the U.S.
William Blair wrote, “While the delay (assuming an early 2027 launch) negatively affected our fair value by only 2.5%, this second CRL will likely influence investors' sentiment on Telix management's regulatory
execution and its ability to navigate the complex CMC and logistics of the radiopharmaceutical industry.”
Analyst Andy Hsieh sees the Zircaix franchise as a key growth lever for Telix, helping diversify beyond its core PSMA PET imaging business amid pricing pressure and ahead of Gozellix's expected pass-through status on October 1.
Without Zircaix, William Blair expects investor attention to remain squarely on its Illuccix and Gozellix's commercial performance.
In July 2024, the FDA did not accept the BLA filing for TLX250-CDx after identifying a filing issue in the CMC package. The specific filing concern relates to demonstrating adequate sterility assurance during the dispensing of TLX250-CDx in the radiopharmacy production environment.
Price Action: TLX stock is down 13.18% at $10.51 at the last check on Thursday.
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