IPAX-Linz Study Shows Promising Results for TLX101 Glioma Therapy

Telix Pharmaceuticals Limited has announced promising preliminary outcomes from its Phase 2 IPAX-Linz study, which investigates TLX101 (131I-iodofalan) as a treatment for recurrent high-grade glioma, a severe form of brain cancer. The trial, held in Melbourne, Australia, and Indianapolis, was initiated by investigators and focuses on evaluating the safety, tolerability, and early efficacy of TLX101 in conjunction with external beam radiation therapy (EBRT). The trial's participants included patients experiencing their first or second recurrence of high-grade gliomas, such as glioblastoma.

The study's findings indicate that TLX101 treatment is well tolerated, with no serious adverse events reported. The efficacy data reveals a median overall survival (OS) of 12.4 months from the start of TLX101 treatment, or 32.2 months from initial diagnosis. These results align with previous findings from the IPAX-1 study, which documented a median OS of 13 months from treatment initiation with TLX101, or 23 months from the initial diagnosis. For comparison, patients with recurrent glioblastoma treated solely with EBRT have a median survival of 9.9 months.

The IPAX-Linz trial included eight patients who received adaptive dosing of TLX101 intravenously, with administered activity levels reaching up to 4 GBq prior to, and up to 2 GBq following, second-line EBRT. The study's inclusion criteria required patients to have glioblastoma with evidence of first or second recurrence after standard radiochemotherapy, and at least six months since their initial EBRT. Participants also underwent molecular imaging with Telix's investigational PET agent for glioma, TLX101-CDx, to identify increased amino acid uptake. Notably, surgery for relapsed tumors was permitted, and five of the eight patients had MGMT unmethylated tumors, which are often associated with particularly poor prognoses.

Professor Josef Pichler of Kepler University Hospital in Austria, serving as the Principal Investigator for the IPAX-Linz, IPAX-1, and IPAX-2 studies, noted the results' significance. According to Pichler, TLX101 treatment was well tolerated even at higher doses than used in previous trials, and the efficacy observed in the IPAX-1 study was reaffirmed despite the challenging prognostic factors. These initial findings suggest that TLX101 holds substantial promise for improving outcomes in patients with high-grade glioma and supports the potential for higher therapeutic doses in future controlled studies.

Dr. David Cade, Chief Medical Officer at Telix, expressed optimism about the findings, emphasizing the new options they present for patients with typically poor outcomes. Dr. Cade acknowledged the efforts of Dr. Pichler and his team, highlighting the significance of the study's more advanced and complex patient cohort, which reflects a real-world patient population.

The preliminary results from the IPAX-Linz study will be presented at the Nuclear Medicine and Neurooncology Symposium in Vienna, Austria, in May 2025. Meanwhile, Telix continues to explore TLX101's potential in both front-line and recurrent settings. The company is also progressing with IPAX-2, a Phase 1/2 trial for front-line glioblastoma treatment in combination with standard care and employing TLX101-CDx as a diagnostic tool.

Telix aims to begin a registration-enabling study for TLX101 in recurrent glioblastoma at Australian sites in the second half of 2025, pending ethics approval. Following a successful pre-IND meeting with the U.S. Food and Drug Administration (FDA) in late 2024, Telix plans to submit an IND application in early 2025, with the intention to start the study at U.S. sites later that year.

TLX101 (131I-iodofalan) is a targeted radiation therapy that focuses on the L-type amino acid transporter 1 (LAT1), commonly over-expressed in glioblastoma. This therapy adopts a small molecule approach to traverse the blood-brain barrier, which typically restricts many therapeutic agents from entering the brain. TLX101 has received orphan drug designation in both the U.S. and Europe for glioma treatment, though it has not yet acquired marketing authorization in any jurisdiction.

Telix Pharmaceuticals Limited, headquartered in Melbourne, Australia, is a biopharmaceutical company committed to developing and commercializing therapeutic and diagnostic radiopharmaceuticals. The company operates globally, with branches in countries including the United States, Brazil, Canada, and Japan. Telix is advancing a wide range of clinical and commercial products to address unmet medical needs in oncology and rare diseases.