Evuzamitide as SPECT/CT Imaging Agent for Diagnosis of Transthyretin Amyloidosis

This is a single center, prospective cohort study that is evaluating the ability of 124I-evuzamitide PET scanning to: (1) identify extra-cardiac amyloid deposits in patients with ATTRwt-CA and the Val122Ile variant; (2) to detect cardiac TTR amyloidosis in subjects with heart failure, increased wall thickness but only grade 1 Tc99PYP scans who are not currently diagnosed with ATTR-CA; and (3) to detect cardiac ATTR in allele carriers of TTR variants (Phe64Leu, late onset Val30Met) that are associated with cardiac amyloidosis but have PYP scans not diagnostic of ATTR-CM. If 124I-evuzamitide PET scanning is shown to be valuable in any of these three cohorts, it would address critical unmet needs regarding the diagnosis and extent of disease in ATTR-CM.Consented eligible patients will undergo a single 124I-evuzamitide PET scan. Clinically available demographic, clinical and phenotypic data that is collected as part of routine clinical care will be used to characterize the type, severity, and stage of ATTR-CM.

Inclusion Criteria:Must have given written informed consent (signed and dated) and any authorizations required by local law and be able to comply with all study requirements.New York Heart Association (NYHA) class I-IIIAble to understand and sign the informed consent document after the nature of the study has been fully explained.Cohort 1: Subjects with grade 1 Tc99-PYP scans who have clinical features suggestive of ATTR-CM or have grade 1 Tc99-PYP scans but endomyocardial biopsy evidence of TTR cardiac amyloidosis.Heart failure with a preserved ejection fraction (EF>40%)Grade 1 Tc99-PYP scan performed for clinical suspicion of ATTR-CMNo evidence of monoclonal proteins by assessment of serum kappa and lambda free light chain ratio and immunofixation of serum and urine.Left ventricular septal OR inferolateral wall thickness ≥12 mm.Cohort 2: Subjects with TTR variant such as Phe64Leu, late onset Val30Met, etc.) that are associated with cardiac amyloidosis but have PYP scans not diagnostic of ATTR-CMTc99-PYP scan performed for clinical suspicion of ATTR-CM that is not diagnostic of ATTR-CMNo evidence of monoclonal proteins by assessment of serum kappa and lambda free light chain ratio and immunofixation of serum and urine.Left ventricular septal OR inferolateral wall thickness ≥12 mm with echocardiographic features of ATTR-CM (low tissue doppler velocities, preserved apical strain, elevated E/E') or CMR features of an infiltrative cardiomyopathy (increased wall thickness with delayed enhancement or difficulty nulling of the myocardium)Cohort 3: Subjects with ATTR-CM from either ATTRwt or Val122Ile variant who have biopsy proven evidence of extra-cardiac TTR amyloidosis or clinical suspicion of extracardiac disease, including but not limited to peripheral neuropathy, carpal tunnel syndrome, spinal stenosis.ATTR-CM defined by the followingAmyloid deposits in cardiac or non-cardiac tissue confirmed by Congo Red (or equivalent) staining OR technetium scintigraphy with 99m Tc-pyrophosphate with Grade 2 or 3 cardiac uptake in the absence of abnormal light chains ratio,End-diastolic interventricular septum thickness of > 12 mm on previous echocardiogramTTR genotype shown to be either Val122Ile or wild type.Exclusion Criteria:Primary amyloidosis (AL) or secondary amyloidosis (AA).Active malignancy or non-amyloid disease with expected survival of less than 1 year.Heart failure, in the opinion of the investigator, primarily caused by something other than amyloidosis.Ventricular assist device.Impairment from stroke, injury or other medical disorder that precludes participation in the study.Disabling dementia or other mental or behavioral disease.Enrollment in a clinical trial not approved for co-enrollment.Continuous intravenous inotropic therapy.Inability or unwillingness to comply with the study requirements.Chronic kidney disease requiring hemodialysis or peritoneal dialysis.Patients taking heparin, or heparin derivatives (e.g. low molecular weight heparins) for anticoagulation.Other reason that would make the subject inappropriate for entry into this study.Pregnancy or current lactational feeding of infants.