Telix Pharmaceuticals [ASX:TLX]
Seeing Brain Cancer to Target It

For neuro-oncologists, understanding what is happening inside the brain is essential to determining the next course of care. Yet imaging is only one part of the challenge. Delivering treatment directly to malignant tissue is also difficult, particularly when the blood-brain barrier blocks many therapeutic substances from entering brain tissue.

Telix Pharmaceuticalsls [ASX:TLX] is addressing both challenges through molecularly targeted radiopharmaceuticals. Its neuro-oncology program uses the biological characteristics of brain tumors to develop diagnostic imaging agents and investigate targeted radiation therapies.

At the center of this work are L-type amino acid transporters, particularly LAT1 and LAT2. These proteins help cells take up amino acids and are found in several cancers. The company develops small molecules that interact with these transporters to explore how radioactive isotopes can reach tumor tissue for imaging or treatment.

By linking tumor imaging with research into targeted radiation therapy, Telix is pursuing two related goals, identifying cancer activity and investigating ways to treat it.

Bringing Clarity to Glioma Imaging

The first major clinical application is Pixclara (floretyrosine F 18), Telix’s amino acid positron emission tomography (PET) imaging drug for glioma.

Following treatment, conventional scans can struggle to distinguish a growing tumor from treatment-related changes. Pixclara provides additional information by using an F-18-labeled amino acid compound that targets LAT1 and LAT2 transport proteins. PET imaging shows where the compound travels in the body, helping clinicians assess metabolic activity associated with suspected recurrent or progressive glioma.

In September 2026, the US Food and Drug Administration approved Pixclara for use alongside other diagnostic tests to differentiate recurrent or progressive glioma from treatment-related changes in adults and children aged one month or older. The approval marked the first FDA authorization of an FET-PET imaging drug for glioma. Commercial availability began in October, with the first patients receiving Pixclara at medical centers in Indianapolis and Cleveland.

Pixclara does not provide a definitive answer on its own. A positive PET finding does not independently confirm tumor progression, and a negative result cannot exclude it. Clinicians must interpret the images alongside MRI findings, the patient’s clinical history and other available evidence. By adding information to an otherwise uncertain picture, Pixclara can help specialists decide whether further investigation or intervention is needed.

The imaging technology also supports Telix’s research into targeted treatments, where it helps researchers select patients and assess tumor response.

Taking Radiation Across the Blood-Brain Barrier

The biological mechanism behind Pixclara is also central to Telix’s investigational treatment program.

The blood-brain barrier protects the central nervous system by controlling the movement of substances from the bloodstream into brain tissue. While essential to normal physiology, it creates a significant challenge when treating malignant tumors.

Telix connects molecular imaging with targeted radiopharmaceutical development, using amino acid transport mechanisms to investigate how brain tumors can be identified and treated more precisely.

The compound carries iodine-131, a therapeutic radioisotope that emits beta radiation. The aim is to carry radiation to cancer tissue, damage tumor cells and limit exposure to surrounding areas. Unlike external-beam radiation, which is delivered from outside the body, the investigational agent is administered systemically. Its targeting characteristics are intended to influence where the radioactive compound accumulates.

TLX101-Tx remains under clinical investigation. Further studies must establish whether it improves patient outcomes, as well as determine the right dose and recognize its safety. Nevertheless, the research extends Telix’s molecular-targeting strategy beyond imaging. The company is applying related biological principles to two different objectives: characterizing tumor activity and delivering therapeutic radiation.

In April 2026, Telix began dosing patients in IPAX-BrIGHT, its pivotal Phase 3 trial evaluating TLX101-Tx in recurrent glioblastoma. The first patient received treatment at Austin Health in Melbourne under the supervision of Professor Hui Gan.

The global, multicenter, open-label trial compares TLX101-Tx combined with lomustine chemotherapy against lomustine alone in patients whose glioblastoma has returned after initial treatment. The trial is an important step because recurrent glioblastoma presents substantial treatment challenges, and available therapies have limited effectiveness for many patients.

Rather than evaluating TLX101-Tx in isolation, the study examines whether adding targeted radiopharmaceutical therapy to an established chemotherapy regimen can improve outcomes.

Telix is also incorporating its FET-PET imaging technology into the study for patient selection and assessment of metabolic tumor response. The imaging program has a role beyond diagnosis, helping researchers study how patients respond to the investigational treatment.

Earlier studies, including IPAX-1 and the investigator-initiated IPAX-Linz trial, provided preliminary safety and survival data in patients with recurrent glioblastoma. Those results supported further investigation but do not establish that TLX101-Tx offers a benefit over standard care. The comparative Phase 3 trial is intended to provide more conclusive evidence.

Telix is also evaluating TLX101-Tx in newly diagnosed glioblastoma through IPAX-2, a Phase 1 study involving the investigational therapy alongside standard postoperative treatment.

In May 2026, the company reported completion of enrollment across three dose-escalation cohorts involving 12 patients at sites in Australia, Austria and the Netherlands. No dose-limiting toxicities had been observed at the doses evaluated when the milestone was announced. The study is examining tolerability and appropriate dosing for potential further development in the first-line setting.

Together, IPAX-BrIGHT and IPAX-2 examine TLX101-Tx at different stages of glioblastoma. Both studies build on Telix’s effort to use targeted radiopharmaceuticals to deliver radiation to cancer tissue.

Exploring the Potential of Alpha Therapy

Telix is extending its research beyond beta-emitting radiopharmaceuticals through TLX102-Tx, an investigational compound incorporating astatine-211.

Like TLX101-Tx, TLX102 uses a small-molecule targeting approach associated with amino acid transport mechanisms. The key difference lies in its radioactive payload.

Astatine-211 emits alpha particles that release substantial energy over a relatively short distance. This allows researchers to explore whether alpha radiation can deliver concentrated energy to targeted cells while limiting exposure to surrounding tissue.

Telix is investigating whether these properties could offer a different treatment option for difficult-to-treat cancers, including brain tumors. The program remains at an earlier stage than TLX101-Tx, and its potential benefits have not yet been established in clinical studies of brain cancer.

Its significance within the portfolio is the ability to investigate varied radiation types using different radioactive isotopes while drawing on related targeting chemistry.

Building Radiopharmaceutical Capability in Australia

Developing targeted radiopharmaceuticals requires more than identifying a promising compound. Radioisotope handling, specialized manufacturing and close coordination with clinical teams are essential to translating research into patient care.

Telix has developed an operational presence in Australia that connects these requirements.

The IPAX-BrIGHT trial’s first patient treatment in Melbourne and the involvement of Australian centers in IPAX-2 highlight the region’s role in advancing Telix’s neuro-oncology clinical programs.

In July 2026, Telix opened its North Melbourne radiopharmaceutical facility, bringing radiochemistry laboratories, clinical manufacturing, patient dose administration and imaging capabilities together at one site.

The facility supports collaboration between research, production and clinical teams, addressing some of the practical requirements involved in developing radiopharmaceutical treatments. For a field in which radioactive compounds have specific production, handling and administration requirements, this infrastructure is an important part of clinical development.

Telix’s neuro-oncology program has reached two distinct stages. Pixclara has entered clinical use following US regulatory approval, while TLX101-Tx is undergoing pivotal investigation, and TLX102-Tx represents a further research direction.

The distinction between these stages matters. Diagnostic approval does not establish the effectiveness of an investigational therapy, and clinical development does not guarantee eventual authorization.

What connects the programs is a strategy built around the molecular behavior of brain tumors.

When a post-treatment scan raises questions about whether glioma has returned, targeted imaging can provide additional evidence to guide clinical assessment. Telix is simultaneously investigating whether related targeting mechanisms can deliver therapeutic radiation to cancer tissue.

From its Australian research and manufacturing base, the company is advancing both applications through clinical development, connecting more precise brain cancer imaging with the longer-term goal of treating tumors through targeted radiopharmaceuticals.