IPAX-1 Study of TLX101 Investigational Glioblastoma Therapy Published in Neuro-Oncology Advances

In This Article:

MELBOURNE, Australia, Sept. 4, 2024 /PRNewswire/ -- Telix Pharmaceuticals Limited (ASX: TLX, Telix, the Company) today announces that the Company's IPAX-1 Phase I study has been published in Neuro-Oncology Advances, confirming the safety and tolerability profile, and early efficacy of TLX101 therapy, in combination with external beam radiation therapy (EBRT) in recurrent glioblastoma (GBM), the most common and aggressive form of primary brain cancer.

(PRNewsfoto/Telix Pharmaceuticals Limited)
(PRNewsfoto/Telix Pharmaceuticals Limited)

TLX101 (4-L-[ 131I] iodo-phenylalanine, or 131I-IPA) is a systemically administered targeted radiation therapy that targets L-type amino acid transporter 1 (LAT1), which is typically over-expressed in GBM.

In the first peer-reviewed publication of the IPAX-1 study, Professor Josef Pichler and colleagues report that single or fractionated doses of TLX101 plus EBRT were associated with acceptable tolerability and specific tumour-targeting in patients with recurrent GBM. Authors explain that the study delivered encouraging preliminary efficacy data, demonstrating a median overall survival (OS) of 13 months from the initiation of treatment, or 23 months from initial diagnosis. Given that GBM has a median survival from initial diagnosis of 12-15 months, authors conclude that findings from the IPAX-1 study "support further investigation into the use of TLX101 plus EBRT, including its potential as a first line treatment".

Key findings of the IPAX-1 study, outlined in the paper, include:

  • All dosing regimens were well tolerated.

  • Organ-absorbed radiation doses in the red bone marrow (0.38 Gy) and kidney (1.28 Gy) confirmed no radiation-based toxicity.

  • Stable disease with MRI[1] assessment was observed in 4 of 9 patients at 3 months post-treatment (3-month follow-up, 1 patient did not reach protocol-mandated end of study), yielding a response rate of 44.4%.

  • At the 3-month follow-up, 6 patients demonstrated metabolic stable disease with 18F-FET PET imaging.

  • Median progression-free survival was 4.3 months (95% confidence interval, 3.3–4.5), while median OS was 13 months from the initiation of treatment (95% confidence interval, 7.1–27), or 23 months from initial diagnosis.

Metabolic tumour responses were determined using Telix's investigational PET[2] agent for glioma imaging, TLX101-CDx (Pixclara®[3]18F-floretyrosine or 18F-FET).

Professor Josef Pichler, Kepler University Hospital, Austria, Principal Investigator in the IPAX-1, IPAX-2 and IPAX-Linz studies, and lead author, commented, "A significant unmet need exists for well-tolerated and efficacious treatments for patients with glioblastoma. The results from this Phase I study demonstrate the favourable safety and tolerability profile and preliminary efficacy of TLX101 in combination with second-line EBRT, in patients with recurrent glioblastoma. Following treatment with TLX101 plus EBRT, stable disease was observed in 44% of patients at 3 months post-treatment and median progression-free survival was 4.3 months, with no confirmed radiation toxicity. The overall survival improvement trend seen in this patient population clearly warrants further investigation into the use of TLX101 plus EBRT, including its potential as a first-line treatment. These studies are now well advanced."