New PET/CT Tracer Shows High Accuracy for Cardiac Amyloidosis

Iodine-124 evuzamitide positron emission tomography/computed tomography (PET/CT) showed high sensitivity and specificity for cardiac amyloidosis in a prospective multicenter study published in JAMA.

The phase 3, open-label, single-group REVEAL study enrolled 195 adults undergoing evaluation for suspected cardiac amyloidosis at 18 US centers. Of these, 170 received the tracer and underwent PET/CT, forming the intent-to-image population. The image-evaluable population included 169 participants with interpretable imaging and sufficient clinical information for expert adjudication. PET/CT readers were blinded to clinical data, and amyloidosis specialists adjudicated diagnoses without access to the investigational scans.

The tracer had 94% sensitivity and 86% specificity. Positive predictive value was 85%, and negative predictive value was 94%. Among 76 participants classified as having cardiac amyloidosis by the adjudication committee, 54 had transthyretin amyloidosis, 21 had light-chain amyloidosis, and 1 had an indeterminate subtype. PET/CT findings were positive in 52 of 54 participants with transthyretin amyloidosis and 20 of 21 with light-chain amyloidosis.

Participants received approximately 1 mCi of iodine-124 evuzamitide intravenously, followed by imaging 3 to 5 hours later. Potassium iodide, 130 mg, was administered orally for 3 days beginning at least 30 minutes before the tracer injection. The study compared PET/CT findings with an expert-adjudicated clinical reference standard rather than with alternative diagnostic strategies. The reference standard was complex and limited to clinical information obtained during a 60-day follow-up period, and the light-chain amyloidosis subgroup was small.

Current noninvasive bone-avid tracer approaches primarily address transthyretin cardiac amyloidosis under defined conditions and have limitations for light-chain and other forms of amyloidosis. Because iodine-124 evuzamitide targets structural components associated with multiple amyloid types, it could broaden noninvasive evaluation. However, the limitations of the reference standard and the small light-chain subgroup warrant caution when interpreting the findings’ clinical applicability.

Source: Dorbala S, et al. Iodine-124 evuzamitide positron emission tomography/computed tomography for diagnosing cardiac amyloidosis: the REVEAL nonrandomized clinical trial. JAMA. Published online August 30, 2026.