64Cu-GRIP B in Patients With Acute Myocarditis

March 16, 2026 updated by: Javid Moslehi, MD

A Phase I PET Imaging Study of 64Cu-GRIP B, a Radiotracer Targeting Granzyme B, in Patients With Acute Myocarditis

The proposed patient study represents the first-ever acute myocarditis patient imaging study with 64Cu-GRIP B PET. The tracer is designed to detect extracellular granzyme B as it is secreted by activated cytotoxic T lymphocytes in the cardiomyocyte inflammatory microenvironment, highlighting areas of CD8 T cell activity leading to cardiomyocyte damage. Myocarditis is characterized pathologically by myocardial infiltration of T cells and macrophages with presence of cardiomyocyte death - the proposed tracer tests for both the accumulation of CD8 T cells and their cytotoxic activity, which will hopefully significantly improve diagnostic certainty. The study population is focused on patients with acute myocarditis to assess the specificity and sensitivity of 64Cu-GRIP B to detect myocarditis. In future studies, 64Cu-GRIP B PET may also serve as a biomarker to monitor early response to immunomodulatory therapies to treat acute myocarditis.

Each year at UCSF, the investigators encounter about 20 patients with acute myocarditis. These patients often present with non-specific cardiac symptoms with some evidence of cardiac injury (abnormal electrocardiogram or elevation in cardiac biomarkers such as troponin). Rarely is the diagnosis clear and often numerous additional clinical studies are necessary to rule out other common causes of cardiac injury like myocardial infarction. Patients identified with acute myocarditis by the investigators will receive standard clinical testing as appropriate and will also be consented to participate in a PET study with 64Cu-GRIP B. Over the course of this proposal, the investigators expect to enroll 10 patients who are being evaluated for acute myocarditis determined by current standard of care diagnostic modalities. The investigators will perform this feasibility assessment in parallel to the usual clinical care.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

10

Phase

  • Phase 1

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 Locations

  • United States
    • California
      • San Francisco, California, United States, 94143
        • University of California, San Francisco
        • Contact:
        • Principal Investigator:
          • Javid Moslehi, MD

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Participants must have histologically or cytologically confirmed myocarditis in accordance with the Dallas Criteria
  2. The subject is able and willing to comply with study procedures and provide signed and dated informed consent
  3. Age ≥18 years

  4. Demonstrates adequate organ function as defined below:

    Adequate bone marrow function:

    absolute neutrophil count ≥1,500/mcL platelets ≥100,000/mcL

    Adequate hepatic function:

    total bilirubin within normal institutional limits, unless elevated due to Gilbert's syndrome and direct bilirubin is within normal limits AST(SGOT) ≤3 X institutional upper limit of normal ALT(SGPT) ≤3 X institutional upper limit of normal

    Adequate renal function:

    creatinine ≤ 1.5 x within institutional upper limit of normal OR creatinine clearance GFR ≥ 60 mL/min/1.73 m2, calculated using the Cockcroft-Gault equation, unless data exists supporting safe use at lower kidney function values, no lower than 30 mL/min/1.73 m2

  5. Ability to understand and the willingness to sign a written informed consent document.
  6. Human immunodeficiency virus (HIV)-infected individuals on effective antiretroviral therapy with undetectable viral load within 6 months are eligible for this trial.
  7. For participants with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated.
  8. Individuals with a history of hepatitis C virus (HCV) infection must have been treated and cured. For individuals with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load.
  9. The effects of 64Cu-GRIP B on the developing human fetus are unknown. For this reason and because a diagnostic PET radiotracer that is used in this trial is known to be teratogenic, women of child-bearing potential and men must agree to use adequate contraception for the duration of study participation and for 2 weeks after last administration of study drug. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately.

Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 2 weeks after administration of study drug.

Exclusion Criteria:

  1. Has received systemic anticancer therapies within 3 weeks of first dose, radiation within 2 weeks, antibody therapy within 4 weeks. Concomitant administration of LHRH analogues for prostate cancer and somatostatin analogues for neuroendocrine tumors are allowed as per standard of care.
  2. Has not recovered from adverse events due to prior anti-cancer therapy to ≤ grade 1 or baseline (other than alopecia).
  3. Is currently receiving any other investigational agents.
  4. Has participated in a study of an investigational product and received study treatment or used an investigational device within 6 weeks of the first dose of study drug.
  5. Any other cardiac condition that may result in non-specific findings, including recent (within 6 months) Acute Coronary Syndrome or Type II NSTEMI. Participants with a recent viral infection, such as Influenza A, will also be excluded.
  6. Hypersensitivity to PET radiotracers or any of its excipients.
  7. Pregnant women are excluded from this study because 64Cu-GRIP B is a PET radiotracer with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to assessment of the mother with 64Cu-GRIP B, breastfeeding should be discontinued if the mother is treated with 64Cu-GRIP

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: Cohort A: participants with acute myocarditis (5 males, 5 females)
Participants will undergo whole body PET imaging 4 hours (+/- 1 hour) following 64Cu-GRIP B injections. 64Cu-GRIP B will be administered on an outpatient basis. It will be administered intravenously prior to PET imaging.
Drug: 64Cu-GRIP B is a radiolabeled peptide tracer, a copper-64 isotope bound to a peptide designed to target extracellular Granzyme B
The proposed patient study represents the first-ever acute myocarditis patient imaging study with 64Cu-GRIP B PET. The tracer is designed to detect extracellular granzyme B as it is secreted by activated cytotoxic T lymphocytes in the cardiomyocyte inflammatory microenvironment, highlighting areas of CD8 T cell activity leading to cardiomyocyte damage. This study is the first to evaluate the efficacy of 64Cu-GRIP B PET in detecting acute myocarditis. Notably, 64Cu-GRIP is currently being investigated in the setting of cancer in NCT05888532 and has been well tolerated.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
To assess the feasibility of detecting affected cardiac tissue in patients with acute myocarditis
Time Frame: From first dose administration through the safety follow-up at Day 70
• SUVmax of at least 1.5-fold above adjacent background at 4 hours post injection
From first dose administration through the safety follow-up at Day 70
To descriptively compare the number of areas of cardiac inflammation detected on ⁶⁴Cu-GRIP B PET imaging with those observed in a separate ⁶⁴Cu-GRIP B PET study of patients with cancer
Time Frame: From first dose administration through the safety follow-up at Day 70
• Compare the uptake in acute myocarditis cohort compared to the cohort from NCT05888532 that are undergoing the same PET imaging protocol but have no signs of myocarditis.
From first dose administration through the safety follow-up at Day 70

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Association Between 64Cu-GRIP B PET Uptake and Blood-Based Immune Parameters
Time Frame: From first dose administration through the safety follow-up at Day 70
Association between myocardial uptake of 64Cu-GRIP B measured by PET and blood-based immune biomarkers (e.g., circulating cytokine levels) in participants with acute myocarditis
From first dose administration through the safety follow-up at Day 70
Association Between 64Cu-GRIP B PET Uptake and Circulating Immune Cell Populations
Time Frame: From first dose administration through the safety follow-up at Day 70
Association between myocardial uptake of 64Cu-GRIP B measured by PET and circulating immune cell populations measured in peripheral blood in participants with acute myocarditis
From first dose administration through the safety follow-up at Day 70
Association Between 64Cu-GRIP B PET Uptake and Tissue-Based Immune Parameters
Time Frame: From first dose administration through the safety follow-up at Day 70
Association between myocardial uptake of 64Cu-GRIP B measured by PET and immune parameters measured in myocardial tissue samples in participants with acute myocarditis
From first dose administration through the safety follow-up at Day 70

Collaborators and Investigators

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

Sponsor

Javid Moslehi, MD

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.

General Publications

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 (Estimated)

August 1, 2026

Primary Completion (Estimated)

November 1, 2030

Study Completion (Estimated)

January 1, 2031

Study Registration Dates

First Submitted

March 11, 2026

First Submitted That Met QC Criteria

March 16, 2026

First Posted (Actual)

March 18, 2026

Study Record Updates

Last Update Posted (Actual)

March 18, 2026

Last Update Submitted That Met QC Criteria

March 16, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25-45647

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

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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