Study of 18FET PET in Functional Pituitary Adenomas With Indeterminate MRI Findings (FET-PIT)

University Hospital, Lille

Status and phase: Begins enrollment this month; Phase 2

Conditions: Functional Pituitary Adenomas

Treatments: Drug: fluoroethyl-L tyrosine (18F)

Study type: Interventional

Funder types: Other

Identifiers

NCT07360548

2025_0205

Details and patient eligibility

About

Pituitary adenomas (PAs) are common benign tumors, but their potential for tumor aggression and hormone secretion make them serious tumors. In particular, patients with secreting tumors [prolactinomas (prolactin secretion), acromegaly (growth hormone), Cushing's disease (ACTH), thyrotropic adenomas (TSH)] have increased morbidity and mortality. They may be small and/or undetectable by magnetic resonance imaging (MRI), the current gold standard for morphological evaluation of pituitary lesions. The diagnosis of recurrence in a patient who has already undergone surgery also raises the problem of distinguishing between a lesion and postoperative remodeling. The detection of these tumors therefore represents a significant challenge in guiding therapeutic management.Nuclear medicine could solve this challenge, particularly radiopharmaceuticals (MRPs) used in PET (positron emission tomography) combined with CT scans. A few studies have evaluated MRPs in the context of APs, with those targeting amino acid metabolism proving to be the most promising, particularly carbon-11-labeled methionine (11C-MET). In retrospective studies only, 11C-MET PET has shown excellent performance in all situations where MRI fails (detection rate >80%), but the extremely short half-life of 11C requires heavy infrastructure, limiting its access in routine clinical practice.18Fluoroethyl-Tyrosine (18FET) is also a PET MRP targeting amino acid metabolism used in France in neuro-oncology with performance equivalent to 11C-MET, and which has the advantage of being available daily in all nuclear medicine centers.

The performance of 18FET in APs is almost unknown, with only two retrospective studies recently published, including 22 patients with Cushing's disease on the one hand and 17 patients with prolactinoma on the other: The detection rates were particularly interesting (82% and 100% respectively), but it is imperative to confirm these data prospectively and to evaluate the performance of this MRP in other functional types, which is therefore the purpose of this study.

Enrollment: 30 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Male and/or female
• Aged 18 years or older
• Suspected of having a functional pituitary adenoma (prolactinoma - Cushing's disease - acromegaly - thyrotropic adenoma), de novo or recurrence/persistence
• With indeterminate pituitary MRI
• Patient covered by social security
• Patient willing to comply with all study procedures and duration
• Patient eligible for surgery and/or radiotherapy in case of positive 18FET PET scan

Exclusion criteria

• Pregnancy
• Known hypersensitivity to radiopharmaceuticals
• Administrative reasons: inability to receive informed information, inability to participate in the entire study, lack of coverage by the social security system, refusal to sign the consent form
• Contraindication to surgery and radiotherapy in the case of positive 18FET PET
• Patients who are active alcohol users
• Patients suffering from liver disease or severe uncontrolled epilepsy
• Patients deprived of their liberty (guardianship, curatorship, etc.)

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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30 participants in 1 patient group

Patients

Experimental group

Description:

The investigative procedure used is 18FET PET, which will be the only difference from the usual care. The study data (clinical observations, laboratory results, imaging results) will be collected by the various study investigators during a consultation and/or via the Lille University Hospital computer server. Performance of the 18FET PET scan in the Nuclear Medicine Department. The experimental drug is \[18F\]Fluoroethyl-L-tyrosine, produced in accordance with Good Manufacturing Practices (GMP) guidelines and marketed under the name IASOglio by Curium PET France. The maximum activity for an adult is to 250 MBq. This activity must be administered by direct intravenous injection. Shelf life: 14 hours from the end of synthesis. After first use or after dilution, the product can be stored for up to 8 hours without exceeding the expiry date of 14 hours from the end of synthesis.

Treatment:

Drug: fluoroethyl-L tyrosine (18F)