FDA Accepts NDA for Imaging Agent TLX101-Px in Brain Cancer

The FDA has accepted a resubmitted new drug application for TLX101-Px (Pixclara), to be used as an imaging agent for patients with brain cancer, according to a press release from Telix.¹

FDA Sets TLX101-Px Approval Date

A Prescription Drug User Fee Act date of September 11, 2026, has been assigned.

TLX101-Px is an investigational PET imaging agent, which the press release noted the potential approval would fill an unmet need in the treatment of glioma for both pediatric and adult patients.

“There remains a critical unmet need in improving our ability to image residual glioma after treatment,” Thomas Hope, MD, vice chair, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), said in the press release. “We have worked with Telix for the last 3 years to help leverage our clinical data to help make FET-PET[9] available to patients in the US.”

Previous FDA Actions for TLX101-Px

In March, a resubmitted NDA was provided to the FDA, after a complete response letter was issued by the agency in April 2025.^2,3 The FDA had requested additional confirmatory evidence regarding the diagnostic performance of TLX101-Px.

Additionally, orphan drug designation was given in October 2020 to the imaging agent, followed by fast track designation in April 2024.^4,5

TLX101-Px Trial Updates

Data from the phase 1 IPAX-2 trial (NCT05450744) is supporting these regulatory decisions.⁶ Additionally, TLX101-Px is showing potential for being utilized as a patient selection and response assessment tool for TLX101-Tx, which is a LAT1-targeting therapy candidate. This is being assessed in the phase 3 IPAX BrIGHT trial (NCT07100730).⁷

In the IPAX-2 open-label, single-arm, parallel-group, multicenter trial, an estimated 12 patients were to be enrolled and assessed to determine the safety of ascending radioactive dose level of TLX-101 that were given intravenously in combination with the standard of care to patients who were newly diagnosed with glioblastoma. The primary end point was incidence rate and the grade of dose limiting toxicities, and safety and tolerability of the recommended phase 2 dose.

The study design showed an interventional model with a 3+3 ascending dose for patients with neoplastic disease, glioblastoma, or glioblastoma multiforme. The intervention arm was 131 I-IPA and given as an injection/solution intravenously. The study arm was TLX101 plus standard of care therapy.

Patients were eligible for treatment if they had prior surgery for glioblastoma, but no systemic therapy or radiation; have a Karnofsky Performance Status of 70 or more; planned to begin chemoradiation therapy 3 to 6 weeks after surgical resection with Stupp regimen; have adequate organ function at screening; or have at least 6 slides without staining or a tissue block available from a previous biopsy or surgery.

Patients were excluded from treatment if they could undergo a contrast-enhanced MRI; could be treated with tumor-treating fields prior to progression; have a history or evidence of delayed-type hypersensitivity-dependent chronic infection, like tuberculosis, or a systemic fungal or parasitic infection; have a known history of allergy of temozolomide, have haemostaseologic conduction that would preclude catheterization or invasive procedures, or have a previous phenylketonuria diagnosis.

In the IPAX BrIGHT trial, an estimated 50 patients are to be enrolled into the prospective, controlled, open-label pivotal study of iodofalan solution for injection plus lomustine vs lomustine alone in patients with radiographically confirmed recurrent glioblastoma at first recurrence. The primary end point was safety and tolerability, and dose optimization. Secondary end points were TLX-Tx concentration in the blood, radiation dosimetry, and TLX-Tx concentration in the urine.

Patients were enrolled if they had previously confirmed neuropathological diagnosis of the glioblastoma, radiographic evidence of first recurrence of progressive glioblastoma via RANO 2.0, or increased 18F FET PET following co-registration with MRI. Patients were excluded if they had prior course with external beam radiation to the brain the past 3 months, treatment with bevacizumab (Avastin) within the previous 6 weeks, or known contraindications to imaging tracer or any product of contrast media and MRI contraindications.

References

1. FDA accepts NDA for TLX101-Px (Pixclara®). News release. Telix. April 10, 2026. Accessed April 10, 2026. https://tinyurl.com/mrykd99c
2. Telix resubmits NDA to U.S. FDA for TLX101-Px (Pixclara) brain cancer imaging candidate. Telix Pharmaceuticals. March 16, 2026. Accessed April 10, 2026. https://tinyurl.com/43sts63h
3. Telix provides regulatory update on TLX101-CDx. News release. Telix Pharmaceuticals. April 28, 2025. Accessed April 10, 2026. https://tinyurl.com/4nf5fesa
4. Telix granted FDA orphan drug designation for glioma imaging agent. News release. Telix Pharmaceuticals. October 6, 2020. Accessed April 10, 2026. https://tinyurl.com/muhzdf2x
5. TLX101-CDx (Pixclara) granted FDA fast track designation. News release. Telix Pharmaceuticals. April 15, 2024. Accessed April 10, 2026. https://tinyurl.com/2fu33ryy
6. 131I-TLX-101 for treatment of newly diagnosed glioblastoma (IPAX-2) (IPAX-2). ClinicalTrials.gov. Updated January 21, 2026. Accessed April 10, 2026. https://tinyurl.com/mwjftba5
7. 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://tinyurl.com/bdcvurr3