First-in-human Evaluation of [18F]CETO

Studies of 18F-CETO as a Tracer for Adrenal PET Diagnostics

Purpose of this clinical phase 1 trial was to determine if para-chloro-2-[18F]fluoroethyletomidate positron emission computed tomography ([18F]CETO-positron emission computed tomography(PET)/computed tomography(CT)) can be used in diagnostics of adrenal tumors and if the biochemical/pharmacological states conditions in humans with various illnesses, compared to healthy humans, such as the radio tracer is suitable?

After receiving oral and written information about the study and its potential risks, all participants provided written informed consent. All participants underwent a screening visit 1-28 days before their [18F]CETO PET/CT. At the screening visit their medical history was obtained, including besides information of previous disease(s) and medication, also a clinical examination, WHO performance status, height, weight, pulse rate and blood pressure, blood chemistry and haematology.

Right before the PET/CT investigation a baseline assessment was performed including:

• A physical examination according to Modified Early Warning Score (MEWS)
• 12-lead electrocardiogram (ECG)
• Any concomitant medications was recorded
• Medical history - occurrence of any new symptoms and events since the screening visit
• Hematology (International Normalized Ratio (INR) in patients with antiocoagulant treatment).
• Pregnancy test in women.
• Assessment of injection site monitored by visual inspection (rash and phlebitis)

Participants received on average 0,76 mikrograms (range 0,1-1.37 mikrograms) of administered mass of CETO in conjunction to the PET/CT investigation.

Potential adverse events were monitored closely during, and after the administration of [18F]CETO, with access to emergency medicine resources.

Each participant remained for observation at least 3 hours after administration of [18F]CETO and the following assessments were performed:

• Blood withdrawn for additional post-scan chemical analysis.
• Assessment of injection site monitored by visual inspection (rash and phlebitis).
• MEWS

The ten first participants were evaluated for serious adverse events/adverse events (SAE/AEs) the day after (approximately 24 hours after) performing the [18F]CETO PET due to the short half-life of the radionuclide used, fluorine- 18 (T1/2= 109.5 min). Safety reporting was assessed by use of clinical Adverse Events and Common Toxicity Criteria (CTC), laboratory and non-laboratory toxicities.

Inclusion Criteria:

• Patients diagnosed with adrenal incidentalomas with an concurrent overproduction of aldosterone or cortisol or no concurrent hormone production, or patients diagnosed with adrenocortical carcinoma
• For healthy volunteers inclusion criteria included no known diseases, no ongoing medication and no known adrenal anomalies.

Exclusion Criteria for patients and healthy volunteers:

• pregnancy, age below 18, claustrophobia