**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Olivier F. Clerc, Brigham and Women's Hospital, Boston MA USA

**Main Body of the Abstract**
Background: Diagnosis of hereditary cardiac amyloidosis remains challenging. 124I-evuzamitide (124I-p5+14, AT-01), a novel pan-amyloid radiotracer, accurately detects cardiac involvement in light-chain and wild-type transthyretin amyloidosis. However, its ability to detect cardiac involvement in rare forms of amyloidosis has not been well studied.
Objectives: To compare myocardial uptake of 124I-evuzamitide in rare forms of amyloidosis with or without cardiac involvement and in controls.
Methods: We included 20 participants: 7 with hereditary amyloidosis (2 AApoAI, 1 AApoAIV, 1 ATTRv p.L78H, 2 ATTRv p.T80A, 1 ATTRv p.V142I), 1 with localized pulmonary light-chain amyloidosis and 12 controls without amyloidosis. All participants underwent positron emission tomography/computed tomography (PET/CT) 5 hours after injection of 124I-evuzamitide (median administered activity 0.97 mCi). We assessed all scans visually and measured myocardial radiotracer activity above blood pool as left ventricular percent injected dose (LV %ID = [mean activity concentration / injected activity] x activity volume).
Results: All participants with hereditary amyloidosis had myocardial uptake on visual assessment, but the participant with localized amyloidosis and controls had no myocardial uptake. Median LV %ID was 1.6197 (IQR 0.6783-2.1057) in hereditary amyloidosis, 0.0001 in localized amyloidosis, and 0.0027 (IQR 0.0007-0.0093) in controls (overall p<0.001). For both AApoAI participants, echocardiogram and magnetic resonance imaging (MRI) showed no signs of cardiac involvement, but PET/CT demonstrated myocardial 124I-evuzamitide uptake (Figure).
Conclusions: 124I-evuzamitide PET/CT can detect cardiac involvement in multiple types of hereditary amyloidosis, even when the echocardiogram and MRI are negative. Furthermore, 124I-evuzamitide PET/CT appropriately shows very low, non-myocardial uptake in localized amyloidosis and in controls.



**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Olivier F. Clerc, Brigham and Women's Hospital, Boston MA USA

**Main Body of the Abstract**
**Background:** Diagnosis of hereditary cardiac amyloidosis remains challenging. 124I-evuzamitide (124I-p5+14, AT-01), a novel pan-amyloid radiotracer, accurately detects cardiac involvement in light-chain and wild-type transthyretin amyloidosis. However, its ability to detect cardiac involvement in rare forms of amyloidosis has not been well studied.
**Objectives:** To compare myocardial uptake of 124I-evuzamitide in rare forms of amyloidosis with or without cardiac involvement and in controls.
**Methods:** We included 20 participants: 7 with hereditary amyloidosis (2 AApoAI, 1 AApoAIV, 1 ATTRv p.L78H, 2 ATTRv p.T80A, 1 ATTRv p.V142I), 1 with localized pulmonary light-chain amyloidosis and 12 controls without amyloidosis. All participants underwent positron emission tomography/computed tomography (PET/CT) 5 hours after injection of 124I-evuzamitide (median administered activity 0.97 mCi). We assessed all scans visually and measured myocardial radiotracer activity above blood pool as left ventricular percent injected dose (LV %ID = [mean activity concentration / injected activity] x activity volume).
**Results:** All participants with hereditary amyloidosis had myocardial uptake on visual assessment, but the participant with localized amyloidosis and controls had no myocardial uptake. Median LV %ID was 1.6197 (IQR 0.6783-2.1057) in hereditary amyloidosis, 0.0001 in localized amyloidosis, and 0.0027 (IQR 0.0007-0.0093) in controls (overall p<0.001). For both AApoAI participants, echocardiogram and magnetic resonance imaging (MRI) showed no signs of cardiac involvement, but PET/CT demonstrated myocardial 124I-evuzamitide uptake (Figure).
**Conclusions:** 124I-evuzamitide PET/CT can detect cardiac involvement in multiple types of hereditary amyloidosis, even when the echocardiogram and MRI are negative. Furthermore, 124I-evuzamitide PET/CT appropriately shows very low, non-myocardial uptake in localized amyloidosis and in controls.



Cardiac Involvement in Rare Forms of Amyloidosis Assessed Using 124I-Evuzamitide PET/CT PB141 (#536)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.