FET PET/CT Imaging To Localize Pituitary Adenomas In Cushing Disease

18Fluoro-O-(2) Fluoroethyl-L-tyrosine (FET) PET For Localization Of Pituitary Adenomas In Patients With Cushing Disease

The purpose of this research is to evaluate the performance [sensitivity, specificity, accuracy] of FET PET/CT imaging to detect ACTH-secreting pituitary adenoma, using operative findings and histopathology as truth standard.

Study Overview

• Status: Recruiting
• Conditions: Pituitary Adenoma; Cushing Disease
• Intervention / Treatment: Drug: Fluoro-O-(2) fluoroethyl-L-tyrosine (FET) PET

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Early Phase 1

Contacts and Locations

• Study Contact: Name: Brent Gessner, MBA; Phone Number: 507-284-2950; Email: Gessner.Brent@mayo.edu

Study Locations

• United States
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Recruiting
      • Mayo Clinic in Rochester
      • Principal Investigator: Derek Johnson, MD
      • Contact: Brent Gessner; Phone Number: 507-284-2950

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Patients must meet ALL criteria listed below for entry:

• Biochemically diagnosed ACTH-dependent Cushing disease.
• No previous pituitary surgery.
• Planned to undergo pituitary surgery for localization/resection of adenoma.
• No contraindications for PET/CT.
• Recent (within 3 months) pituitary MR, or pending pituitary MR to be performed as close as possible to FET PET/CT.
• Age ≥ 18 years.
• Ability to provide informed consent.

Exclusion Criteria:

• Pregnant as determined by a pregnancy test as per institutional guidelines for individuals of child-bearing potential
• Declining to use effective contraceptive methods during the study (for individuals of child-bearing potential)
• Need for emergent surgery that would be delayed by participation
• Bacterial, viral, or fungal infections requiring systemic therapy
• Serious co-morbidities and serious nonmalignant disease (e.g., hydronephrosis, kidney failure, liver failure, systemic or local inflammatory or autoimmune diseases or other conditions) that in the opinion of the investigator could compromise patient safety and/or protocol objectives
• Known diagnosis of autoimmune disorders
• Patients receiving any other investigational agent within the past 28 days
• Breastfeeding. Note: nursing parents are allowed if the potential participant commits to pumping breast milk and discarding it from injection to ≥ 24 hours from the time of the FET injection.
• Known hypersensitivity to any excipients used in FET

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: (ACTH)-dependent Cushing disease; Patients with adrenocorticotropic hormone (ACTH)-dependent Cushing disease who may be considered candidates for surgical treatment	Drug: Fluoro-O-(2) fluoroethyl-L-tyrosine (FET) PET; Patients will receive intravenous administration of radiolabeled FET (5mCi ±10%) administered 20 minutes (±10minutes) prior to the initiation of the attenuation correction CT followed by the PET acquisition encompassing the participant's head/neck, centered on the pituitary gland.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sensitivity of FET PET results in comparison to histopathology	Percentage of cases where surgical findings and pathology are in agreement with [18F]FET-PET/MRI imaging	Baseline
Specificity of FET PET results in comparison to histopathology		Baseline
Accuracy of FET PET results in comparison to histopathology		Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Agreement of FET detection of ACTH-secreting pituitary with pituitary protocol MR	Percentage of cases where pituitary protocol MR results are in agreement with FET-PET imaging	Baseline

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Investigators: Principal Investigator: Derek Johnson, MD, Mayo Clinic

Publications and helpful links

Helpful Links

• Mayo Clinic Clinical Trials

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): April 1, 2028
• Study Completion (Estimated): July 1, 2028

Study Registration Dates

• First Submitted: March 4, 2026
• First Submitted That Met QC Criteria: March 4, 2026
• First Posted (Actual): March 10, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Endocrine System Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neoplasms by Site; Neoplasms; Endocrine Gland Neoplasms; Nervous System Neoplasms; Central Nervous System Neoplasms; Hypothalamic Diseases; Hypothalamic Neoplasms; Supratentorial Neoplasms; Brain Neoplasms; Hyperpituitarism; Pituitary Diseases; Pituitary Neoplasms; Pituitary ACTH Hypersecretion; 2-phenyl-6-(2'-(4'-(ethoxycarbonyl)thiazolyl))thiazolo(3,2-b)(1,2,4)triazole
• Other Study ID Numbers: 22-006092

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No