A Phase 3 interventional study of Floretyrosine F 18 ([18F]FET) in Brain Metastasis, Radiation Necrosis and Pseudoprogression, sponsored by Telix Pharmaceuticals (Innovations) Pty Limited. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-12.
Sponsored by Telix Pharmaceuticals (Innovations) Pty Limited (part of Telix Pharmaceuticals Limited) · Phase 3, Interventional, and Diagnostic
This Phase 3 study will evaluate whether [18F]Floretyrosine ([18F]FET) PET imaging can help distinguish active brain tumor growth from treatment-related changes in patients with brain metastases who have unclear MRI findings after treatment. The study has two parts. Part 1 will identify the lowest effective dose of [18F]FET PET that provides reliable imaging results. Part 2 will evaluate the accuracy of [18F]FET PET, using the optimized dose, for distinguishing tumor progression from treatment-related changes. Study results will be compared with information from follow-up imaging, clinical assessments, and, when available, tissue samples obtained during routine clinical care. The goal is to determine whether [18F]FET PET can improve diagnostic accuracy and support clinical decision-making for patients with brain metastases.
2,441 studies on the registry are indexed under Brain Neoplasms; 541 are open to participants now.
This study's planned enrollment of 381 is above the median of 40 across 1,832 interventional studies indexed under Brain Neoplasms.
Browse Brain Neoplasms studies →Telix Pharmaceuticals (Innovations) Pty Limited is the lead sponsor of 22 studies on the registry; 9 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Brain metastases
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Floretyrosine F 18 ([18F]FET)
Floretyrosine F 18 (\[18F\]FET) is an investigational amino acid positron emission tomography (PET) radiopharmaceutical administered as a single intravenous injection for diagnostic imaging. Participants in Part 1 receive 740 MBq (±10%) of \[18F\]FET to evaluate dose optimization through comparison of reconstructed reduced-dose and full-dose PET images. Participants in Part 2 receive \[18F\]FET at the optimized dose identified in Part 1 to evaluate its diagnostic performance for differentiating tumor progression from treatment-related changes in brain metastases with equivocal MRI findings following therapy
Patient-Level Mean Dice Similarity Coefficient for Lesion Spatial Agreement Between Reduced-Dose and Full-Dose [18F]FET PET Images
The patient-level mean Dice Similarity Coefficient (DSC), derived from all evaluable lesions, will be used to assess lesion spatial agreement between each reduced-dose \[18F\]FET PET dataset and the full-dose reference scan. The DSC results will be used to identify the lowest \[18F\]FET dose demonstrating non-inferior lesion spatial agreement.
Time frame: From Day 1 through Day 2 (±1 day) follow-up
Sensitivity of [18F]FET PET for Distinguishing Tumor Progression From Treatment-Related Changes Compared With CSOT
Sensitivity will be assessed for \[18F\]FET PET at the optimized dose for distinguishing tumor progression from treatment-related changes, using the Composite Standard of Truth (CSOT) as the reference standard.
Time frame: From baseline Day 1 through CSOT determination (approximately 2-3 months).
Number of Participants With Adverse Events Following Administration of 740 MBq [18F]FET
The incidence and severity of adverse events and other safety findings will be assessed following administration of 740 MBq (±10%) \[18F\]FET PET
Time frame: From Day 1 through Day 2 (±1 day) follow-up
Inter-Reader Agreement for [18F]FET PET Classification at the Optimized Dose
Inter-reader agreement will be assessed for interpretation of \[18F\]FET PET images obtained at the optimized dose.
Time frame: Baseline Day 1 through completion of image interpretation following CSOT determination (approximately 2-3 months
Lesion-Level Sensitivity of [18F]FET PET for Distinguishing Tumor Progression From Treatment-Related Changes
Sensitivity will be assessed at the lesion level for distinguishing tumor progression from treatment-related changes
Time frame: From baseline Day 1 through CSOT determination, approximately 2-3 months
Sensitivity of [18F]FET PET Compared With Histopathologic Confirmation
Sensitivity of \[18F\]FET PET will be assessed using histopathologic confirmation as the reference in participants with available histopathology.
Time frame: From baseline Day 1 through histopathologic confirmation, approximately 2-3 months
Positive Predictive Value of [18F]FET PET for Tumor Progression Compared With CSOT
Positive predictive value will be assessed for \[18F\]FET PET classification of tumor progression using the Composite Standard of Truth (CSOT) as the reference standard
Time frame: From baseline Day 1 through CSOT determination, approximately 2-3 months
Negative Predictive Value of [18F]FET PET for Tumor Progression Compared With CSOT
Negative predictive value will be assessed for \[18F\]FET PET classification of tumor progression using the Composite Standard of Truth (CSOT) as the reference standard.
Time frame: From baseline Day 1 through CSOT determination, approximately 2-3 months
Maximum Standardized Uptake Value (SUVmax) of [18F]FET PET Lesions
SUVmax will be measured for evaluable lesions on \[18F\]FET PET.
Time frame: Baseline Day 1 imaging assessment
Mean Standardized Uptake Value (SUVmean) of [18F]FET PET Lesions
SUVmean will be measured for evaluable lesions on \[18F\]FET PET.
Time frame: Baseline Day 1 imaging assessment
Maximum Tumor-to-Brain Ratio (TBRmax) of [18F]FET PET Lesions
TBRmax will be measured for evaluable lesions on \[18F\]FET PET.
Time frame: Baseline Day 1 imaging assessment
Mean Tumor-to-Brain Ratio (TBRmean) of [18F]FET PET Lesions
TBRmean will be measured for evaluable lesions on \[18F\]FET PET.
Time frame: Baseline Day 1 imaging assessment
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) at the Optimized Dose
Safety and tolerability at the optimized dose will be assessed by the number of participants experiencing treatment-emergent adverse events (TEAEs), including serious adverse events (SAEs), adverse events leading to treatment discontinuation, and treatment-related adverse events, as applicable. Adverse events will be assessed and graded according to the protocol-specified safety assessment criteria.
Time frame: From Day 1 administration through study completion, approximately 5-6 months
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Dec 2026; primary completion for Apr 2028, 16 months later.
Of 56 phase 3 interventional studies under Brain Neoplasms, half reached primary completion within 81 months of starting (the median), counting those still running; a quarter within 48 and three quarters within 269. This study's planned 16 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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Telix Pharmaceuticals (Innovations) Pty Limited →