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 Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
10
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.
University of California, San Francisco
San Francisco, California, United States
To assess the feasibility of detecting affected cardiac tissue in patients with acute myocarditis
• SUVmax of at least 1.5-fold above adjacent background at 4 hours post injection
Time frame: 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
• 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.
Time frame: From first dose administration through the safety follow-up at Day 70
Association Between 64Cu-GRIP B PET Uptake and Blood-Based Immune Parameters
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
Time frame: From first dose administration through the safety follow-up at Day 70
Association Between 64Cu-GRIP B PET Uptake and Circulating Immune Cell Populations
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
Time frame: From first dose administration through the safety follow-up at Day 70
Association Between 64Cu-GRIP B PET Uptake and Tissue-Based Immune Parameters
Association between myocardial uptake of 64Cu-GRIP B measured by PET and immune parameters measured in myocardial tissue samples in participants with acute myocarditis
Time frame: From first dose administration through the safety follow-up at Day 70
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