Diagnostic Validity of [18F]GP1 PET for Diagnosing Acute Deep Vein Thrombosis

August 19, 2025 updated by: Dae Hyuk Moon

A Phase 2, Open-label, Non-randomized, Single Center Study to Assess Diagnostic Validity of [18F]GP1 Positron Emission Tomography/Computed Tomography for Acute Deep Vein Thrombosis of the Lower Extremities in Symptomatic Patients

The first-in-human study of [18F]GP1 positron emission tomography/computed tomography (PET/CT) showed that [18F]GP1 is safe and promising novel PET tracer for imaging acute venous thromboembolism with favorable biodistribution and pharmacokinetics in patients. The goal of this phase 2 study is to evaluate whether [18F]GP1 PET/CT is sensitive and specific for the diagnosis of acute deep vein thrombosis in the appropriate patient population and clinical setting. This study will provide preliminary evidence of efficacy and expand the safety database in a larger group of patients who were suspected of having acute deep vein thrombosis. This study will further optimize image acquisition techniques, and develop methods and criteria by which [18F]GP1 PET/CT will be evaluated. Other critical questions about [18F]GP1 biodistribution including [18F]GP1 uptake in pulmonary and systemic arteries will be evaluated.

Study Overview

Detailed Description

This study is an open label, non-randomized, single center, intervention study. An estimated 63 symptomatic subjects with a pretest score of deep vein thrombosis likely (Wells score ≥ 2) or a positive D-dimer test will receive [18F]GP1 PET/CT to evaluate the diagnostic validity of [18F]GP1 PET/CT for detecting deep vein thrombosis foci in lower extremities.

The study comprises 3 periods: screening, treatment, and follow-up. The screening period starts with the patient's signature on the informed consent form and ends with assignment to treatment that is inclusion of the subject for treatment. The treatment period starts with baseline measurements, and ends with the last measurement/procedure on the day of intravenous injection of 250 MBq of [18F]GP1. The follow-up period contains the end-of-study interview. Key measurement is the PET/CT image acquisition about 120 minutes after the single injection of [18F]GP1 This study includes venous ultrasonography of deep vein thrombosis as a valid reference standard. [18F]GP1 PET/CT will be assessed qualitatively and quantitatively by three experienced readers.

This study will be monitored regularly by a clinical research associate from the sponsor or a designated contract research organization. Data quality and study integrity will be assessed. The investigator will document the items that are required to evaluate the study in the subject files. Data required according to this protocol are to be recorded on the case report forms provided by the sponsor as soon as possible.

Study Type

Interventional

Enrollment (Actual)

52

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

19 years to 79 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • A subject will be enrolled if he/she meets all of the following inclusion criteria.

    • Subject is aged between 19 and 79 years and male or female of any race/ethnicity.
    • Patient has a first episode of clinically suspected acute deep vein thrombosis of the lower extremity within 14 days prior to the planned [18F]GP1 PET/CT.
    • The pretest probability for deep vein thrombosis is likely by two-level Wells score (≥ 2), or the D-dimer test is positive.
    • Subject underwent or is scheduled to undergo venous ultrasonography within 7 days of [18F]GP1 PET/CT:
    • Patient has Eastern Cooperative Oncology Group performance status of 0-2 at time of screening.

Exclusion Criteria:

  • A subject is to be excluded from the study if he/she does not fulfill the inclusion criteria or display any of the following criteria.

    • Subject or subject's legally acceptable representative does not provide written informed consent.
    • Subject has a previous history of objectively diagnosed deep vein thrombosis or pulmonary embolism.
    • Subject has symptoms of acute deep vein thrombosis lasting for longer than 4 weeks at time of screening.
    • Subject is suspected to have pulmonary embolism with shock or hypotension
    • Subject had pretreatment with glycoprotein IIb/IIIa inhibitors within 15 days before the administration of [18F]GP1.
    • Anticancer chemotherapy is scheduled to be given to subject before or within 24 hours after administration of [18F]GP1.
    • Female subject is pregnant or nursing. Exclusion of the possibility of pregnancy is made by one of the following: 1) woman is physiologically post-menopausal (cessation of menses for more than 2 years), or 2) woman is surgically sterile (has had a documented bilateral oophorectomy and/or documented hysterectomy). If the woman is of childbearing potential, a urine pregnancy test performed within 24 hours immediately prior to administration of [18F]GP1 has to be negative and the women is advised to apply contraceptive measures during her participation in this study.
    • Subject has concurrent severe and/or uncontrolled and/or unstable medical disease other than cancer (e.g. congestive heart failure, acute myocardial infarction, severe pulmonary disease, chronic renal or hepatic disease) which could compromise participation in the study in the judgment of the investigator.
    • Subject is a relative of the investigator, student of the investigator or otherwise dependent.
    • Subject has been involved in another investigative clinical study involving administration of an investigational drug from preceding 4 weeks prior to the study enrollment or within 24 hours after administration of [18F]GP1.
    • Subject has been previously included in this study.
    • Subject has any other condition or personal circumstances that, in the judgment of the investigator, might make collection of complete data difficult or impossible.
    • Additive-related precautions: This investigational product contains sodium bisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Deep vein thrombosis
Subjects with Deep vein thrombosis will receive a single IV injection of [18F] GP1
A radioactive dose of 250 MBq of the study drug with a total quantity of ≤ 10 µg will be administered as slow intravenous bolus injection over up to 60 seconds. PET/CT examinations will be performed at 120 ± 15 min after the administration of [18F]GP1.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sensitivity and specificity of qualitative [18F]GP1 PET/CT interpretation for the diagnosis of patients with acute proximal deep vein thrombosis
Time Frame: within 7 days of [18F]GP1 PET/CT
Sensitivity = (the number of [18F]GP1 PET/CT-positive patients divided by the number of ultrasonography-positive patients) x 100; specificity = (the number of [18F]GP1 PET/CT-negative patients divided by the number of ultrasonography-negative patients) x 100.
within 7 days of [18F]GP1 PET/CT

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Area under the receiver operating characteristic curve, sensitivity and specificity of quantitative [18F]GP1 PET/CT interpretation for the diagnosis of patients with acute proximal deep vein thrombosis
Time Frame: Within 7 days of [18F]GP1 PET/CT
Area under the receiver operating characteristic curve. Sensitivity = (the number of [18F]GP1 PET/CT-positive patients divided by the number of ultrasonography-positive patients) x 100; specificity = (the number of [18F]GP1 PET/CT-negative patients divided by the number of ultrasonography-negative patients) x 100.
Within 7 days of [18F]GP1 PET/CT
Positive and negative percent agreement between qualitative [18F]GP1 PET/CT and ultrasonography interpretation for the diagnosis of patients with acute distal deep vein thrombosis
Time Frame: Within 7 days of [18F]GP1 PET/CT
Positive percent agreement = (the number of [18F]GP1 PET/CT-positive patients divided by the number of ultrasonography-positive patients) x 100; negative percent agreement = (the number of [18F]GP1 PET/CT-negative patients divided by the number of ultrasonography-negative patients) x 100
Within 7 days of [18F]GP1 PET/CT
Positive and negative percent agreement between quantitative [18F]GP1 PET/CT and ultrasonography interpretation for the diagnosis of patients with acute distal deep vein thrombosis
Time Frame: Within 7 days of [18F]GP1 PET/CT
Positive percent agreement = (the number of [18F]GP1 PET/CT-positive patients divided by the number of ultrasonography-positive patients) x 100; negative percent agreement = (the number of [18F]GP1 PET/CT-negative patients divided by the number of ultrasonography-negative patients) x 100
Within 7 days of [18F]GP1 PET/CT
Intra- and inter-reader variability of qualitative [18F]GP1 PET/CT interpretation for the assessment of acute proximal and distal deep vein thrombosis
Time Frame: Within 1 day of [18F]GP1 PET/CT
kappa statistic
Within 1 day of [18F]GP1 PET/CT
Detection rate of pulmonary embolism with [18F]GP1 PET/CT
Time Frame: Within 1 day of [18F]GP1 PET/CT
The number of [18F]GP1 PET/CT-positive patients divided by the number of ultrasonography-positive patients) x 100; negative percent agreement = (the number of all patients who underwent [18F]GP1 PET/CT
Within 1 day of [18F]GP1 PET/CT
Percent fraction of unmetabolized [18F]GP1 in plasma
Time Frame: Within 1 day of [18F]GP1 PET/CT
Percentage
Within 1 day of [18F]GP1 PET/CT
Incidence of treatment emergent adverse events
Time Frame: From the administration of [18F]GP1 to one day after [18F]GP1 PET/CT
Number of participants with treatment emergent adverse events graded by the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0)
From the administration of [18F]GP1 to one day after [18F]GP1 PET/CT
Blood pressure
Time Frame: Pre-treatment and three hours after the administration of [18F]GP1
mmHg
Pre-treatment and three hours after the administration of [18F]GP1
Heart rate
Time Frame: Pre-treatment and three hours after the administration of [18F]GP1
beats/minute
Pre-treatment and three hours after the administration of [18F]GP1
Body temperature
Time Frame: Pre-treatment and three hours after the administration of [18F]GP1
Celsius
Pre-treatment and three hours after the administration of [18F]GP1
Physical examination
Time Frame: Pre-treatment and three hours after the administration of [18F]GP1
The limited physical examination will comprise: general appearance, skin, neck, lungs, heart, abdomen, and a limited neurological examination (mental status, motor strength and sensor perception).
Pre-treatment and three hours after the administration of [18F]GP1
Blood tests for safety
Time Frame: Pre-treatment and three hours after the administration of [18F]GP1
The clinical laboratory safety parameters to be assessed are as follows: glutamate pyruvate transaminase, glutamate-oxaloacetate transaminase, alkaline phosphatase, total bilirubin, creatinine, potassium, sodium, total protein, blood urea nitrogen, albumin.
Pre-treatment and three hours after the administration of [18F]GP1

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: Dae Hyuk Moon, MD, Asan Medical Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 13, 2020

Primary Completion (Actual)

August 13, 2025

Study Completion (Actual)

August 13, 2025

Study Registration Dates

First Submitted

November 4, 2019

First Submitted That Met QC Criteria

November 5, 2019

First Posted (Actual)

November 7, 2019

Study Record Updates

Last Update Posted (Actual)

August 24, 2025

Last Update Submitted That Met QC Criteria

August 19, 2025

Last Verified

August 1, 2025

More Information

Terms related to this study

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

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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