^68Ga-grazytracer PET for In Vivo Visualization of Immune Cell Effector Functions

November 7, 2026 updated by: Peking University Third Hospital

In Vivo Visualization of Immune Cell Effector Functions Using ^68Ga-grazytracer PET: An Exploratory Study of Cancer and Autoimmune Diseases

This is a prospective, single-center, exploratory clinical study designed to evaluate the feasibility, safety, and clinical utility of ^68Ga-grazytracer positron emission tomography (PET) for noninvasive in vivo visualization of immune cell effector function in patients with cancer and autoimmune diseases. ^68Ga-grazytracer is a granzyme B (GZMB)-targeted PET radiotracer developed to visualize cytotoxic immune activation.

Approximately 60-80 adult participants will be enrolled in two study cohorts: (1) patients with malignant tumors who are scheduled to receive systemic anticancer therapy, including immune checkpoint inhibitors, CAR-T cell therapy, chemotherapy, radiotherapy, targeted therapy, or combination therapy; and (2) patients with autoimmune diseases, including systemic lupus erythematosus, systemic sclerosis, and immune myocarditis, who are receiving or planning to receive immunomodulatory treatment.

Participants will undergo ^68Ga-grazytracer PET/CT imaging before treatment initiation and again during the predefined treatment period. Imaging findings, including tracer uptake and semiquantitative parameters (e.g., SUVmax and target-to-background ratio), will be analyzed together with clinical outcomes, laboratory findings, disease activity assessments, and follow-up data.

The primary objectives are to evaluate the safety and tolerability of ^68Ga-grazytracer PET imaging and to investigate the association between GZMB-targeted PET imaging and treatment response in patients with cancer, disease activity and organ involvement in autoimmune diseases, and therapeutic response to immunomodulatory treatment. This study aims to provide preliminary evidence supporting the use of ^68Ga-grazytracer PET as a molecular imaging biomarker for noninvasive assessment of immune effector function in cancer and autoimmune diseases.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background Granzyme B (GZMB) is a key effector molecule released by activated cytotoxic T lymphocytes and natural killer cells during immune responses. GZMB-mediated cytotoxic activity plays an important role in antitumor immunity and is also involved in tissue injury, immune remodeling, and therapeutic responses in autoimmune diseases. Therefore, noninvasive visualization of GZMB activity may provide a direct assessment of immune effector function in vivo.

^68Ga-grazytracer is a GZMB-targeted PET radiotracer developed for molecular imaging of immune effector activity. Previous preclinical and early clinical studies have demonstrated the feasibility of this tracer for monitoring immune responses and predicting treatment outcomes in patients receiving immunotherapy. However, its clinical value across different disease settings has not been systematically evaluated.

Objectives This study aims to investigate the clinical utility of ^68Ga-grazytracer PET for evaluating immune cell effector function in patients with cancer and autoimmune diseases. The specific objectives are:To evaluate the association between ^68Ga-grazytracer PET findings and treatment response in patients receiving cancer immunotherapy.To investigate the relationship between tracer uptake and disease activity, organ involvement, and therapeutic response in patients with autoimmune diseases.To evaluate the safety, tolerability, and imaging feasibility of ^68Ga-grazytracer PET.

Study Design This is a prospective, single-center, exploratory clinical study conducted at Peking University Third Hospital. Approximately 60-80 adult participants will be enrolled in two cohorts:a cancer cohort including patients with malignant tumors receiving systemic anticancer therapy; and an autoimmune disease cohort including patients with systemic lupus erythematosus, systemic sclerosis, or immune myocarditis receiving immunomodulatory therapy.

Participants will undergo ^68Ga-grazytracer PET/CT imaging before treatment initiation and again during the predefined treatment period. PET imaging findings will be analyzed together with clinical outcomes, laboratory biomarkers, disease activity assessments, and follow-up data to evaluate the relationship between GZMB-targeted imaging and immune responses.

Outcome Assessment Imaging analyses will include visual assessment and semiquantitative parameters such as maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR). The study will evaluate the relationship between PET imaging findings and treatment response, disease activity, organ involvement, and clinical outcomes. Safety assessments will include monitoring of tracer-related adverse events and overall tolerability.

Significance This study is expected to provide preliminary evidence supporting the use of ^68Ga-grazytracer PET as a noninvasive molecular imaging biomarker for immune cell effector function. The results may facilitate treatment response assessment in cancer immunotherapy and improve evaluation of disease activity and immune modulation in autoimmune diseases, thereby providing a foundation for future multicenter validation studies.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Beijing Municipality
      • Beijing, Beijing Municipality, China, 100191

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

**Inclusion Criteria:**

  • Age ≥18 years, regardless of sex.
  • Ability to understand the study objectives and provide written informed consent.
  • Cancer cohort:
  • Patients with a confirmed diagnosis of malignancy who are scheduled to receive systemic anticancer treatment.
  • Patients who have not previously received immunotherapy.
  • Autoimmune disease cohort:
  • Patients with a confirmed diagnosis of an autoimmune disease, such as systemic sclerosis or systemic lupus erythematosus, with evidence of immune-mediated inflammation.
  • Patients who are scheduled to receive or are currently receiving immunomodulatory therapy.

**Exclusion Criteria:**

  • Pregnant or breastfeeding women.
  • Patients with severe cardiac, hepatic, renal, or other major organ dysfunction who are considered unsuitable for study participation by the investigator.
  • Patients unable to tolerate PET/CT imaging or complete the required follow-up assessments.
  • Patients with any other condition that, in the investigator's judgment, makes them unsuitable for participation in the study.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: ^68Ga-grazytracer PET Imaging

All enrolled participants will undergo ^68Ga-grazytracer PET/CT imaging according to the study protocol for noninvasive assessment of immune cell effector function. Participants include patients with cancer and autoimmune diseases. PET/CT imaging will be performed before treatment initiation and during the predefined treatment period according to the study protocol. Imaging findings will be correlated with clinical characteristics, treatment response, and disease activity.
Diagnostic test: ^68Ga-grazytracer PET/CT

Participants will undergo whole-body ^68Ga-grazytracer PET/CT imaging following intravenous administration of ^68Ga-grazytracer according to the study protocol. PET/CT imaging will be performed before treatment initiation and during the predefined treatment period to noninvasively assess granzyme B expression and immune cell effector function in vivo. Imaging findings will be analyzed in conjunction with clinical characteristics, treatment response, disease activity, and other study assessments.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Incidence of Adverse Events Related to ⁶⁸Ga-grazytracer PET/CT Imaging
Time Frame: From tracer administration through completion of PET/CT imaging (approximately 2 hours).

The number and percentage of participants experiencing adverse events (AEs) related to ⁶⁸Ga-grazytracer administration or PET/CT imaging will be assessed. Adverse events will be evaluated according to their occurrence, severity (CTCAE grade), and relationship to the imaging procedure, including serious adverse events (SAEs).
From tracer administration through completion of PET/CT imaging (approximately 2 hours).
Change in Maximum Standardized Uptake Value (SUVmax) on ⁶⁸Ga-grazytracer PET
Time Frame: Baseline and during the predefined treatment period (up to 6 months).

The maximum standardized uptake value (SUVmax) will be measured in predefined target lesions or affected tissues using ⁶⁸Ga-grazytracer PET imaging. Changes in SUVmax from baseline to follow-up will be assessed to characterize granzyme B-related immune activity during treatment.
Baseline and during the predefined treatment period (up to 6 months).
Change in Target-to-Background Ratio (TBR) on ⁶⁸Ga-grazytracer PET
Time Frame: Baseline and during the predefined treatment period (up to 6 months).

The target-to-background ratio (TBR) will be calculated for predefined target lesions or affected tissues using ⁶⁸Ga-grazytracer PET imaging, with a predefined reference region such as the blood pool or liver. Changes in TBR from baseline to follow-up will be assessed to characterize relative tracer uptake during treatment. TBR is a dimensionless ratio.
Baseline and during the predefined treatment period (up to 6 months).

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Area Under the ROC Curve (AUC) of ⁶⁸Ga-grazytracer PET SUVmax for Predicting Tumor Treatment Response
Time Frame: Up to 6 months

The discriminative performance of ⁶⁸Ga-grazytracer PET maximum standardized uptake value (SUVmax) for distinguishing treatment responders from non-responders will be evaluated in the cancer cohort using receiver operating characteristic (ROC) curve analysis. Tumor response will be assessed according to RECIST 1.1 or iRECIST criteria, with responders defined as complete response (CR) or partial response (PR), and non-responders as stable disease (SD) or progressive disease (PD). The area under the ROC curve (AUC), a dimensionless measure ranging from 0 to 1, will be reported with its 95% confidence interval.
Up to 6 months

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Peking University Third Hospital

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 6, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 7, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 13, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 7, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB00006761-M20260118

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

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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