Cardiac Amyloid Detection by PET/CT Imaging of Iodine (124I) Evuzamitide (124I-p5+14): A Phase 1/2 Study

Jonathan S Wall; Emily B Martin; Ronald Lands; Radhakrishnan Ramchandren; Alan Stuckey; R Eric Heidel; Bryan Whittle; Dustin Powell; Tina Richey; Angela D Williams; James S Foster; Spencer Guthrie; Stephen J Kennel

doi:10.1016/j.jcmg.2023.08.009

Cardiac Amyloid Detection by PET/CT Imaging of Iodine (¹²⁴I) Evuzamitide (¹²⁴I-p5+14): A Phase 1/2 Study

JACC Cardiovasc Imaging. 2023 Nov;16(11):1433-1448. doi: 10.1016/j.jcmg.2023.08.009.

Affiliations

¹ Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA. Electronic address: jwall@utmck.edu.
² Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA.
³ University Cancer Specialists, University of Tennessee Medical Center, Knoxville, Tennessee, USA.
⁴ Department of Surgery, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA.
⁵ Department of Radiology, University of Tennessee Medical Center, Knoxville, Tennessee, USA.
⁶ Hendersonville Radiologic Consultants, Hendersonville, North Carolina, USA.
⁷ Attralus, Inc, San Francisco, California, USA.

PMID: 37940323
DOI: 10.1016/j.jcmg.2023.08.009

Abstract

Background: The noninvasive detection of cardiac amyloid, as well as deposits in other vital organs, is critical for early diagnosis and quantitative disease monitoring. Positron emission tomography is an intrinsically quantitative imaging modality suitable for high-resolution amyloid detection.

Objectives: This study sought to evaluate the safety and efficacy of a novel amyloid-reactive peptide, designated p5+14, labeled with iodine-124 (¹²⁴I), in patients with diverse types of systemic amyloidosis.

Methods: In a single-site, open label phase 1/2 study (NCT03678259), the safety, biodistribution, and sensitivity of a single intravenous infusion of ¹²⁴I-evuzamitide was assessed in patients with systemic amyloidosis (n = 50), asymptomatic transthyretin sequence variant carriers (n = 2), and healthy volunteers (n = 5). Subjects were administered 1.4 ± 0.2 mg of ¹²⁴I-evuzamitide (71.5 ± 12.4 MBq) and positron emission tomography/x-ray computed tomography images acquired at 5.2 hours (Q25-Q75: 4.9-5.4 hours) postinfusion. Images were assessed visually and semi-quantitatively for positive uptake of radiotracer in the heart and other major organs.

Results: Uptake of ¹²⁴I-evuzamitide in the heart and other abdominothoracic organs was consistent with the patient's clinical presentation and the type of amyloidosis. The patient- and cardiac-associated sensitivity for imaging and clinical observations was 93.6% (95% CI: 82.8%-97.8%) and 96.2% (95% CI: 81.8%-99.8%), respectively. Semi-quantitative uptake of the radiotracer correlated significantly with serum N-terminal pro-B-type natriuretic peptide measurements in patients with light chain-associated amyloidosis. Cardiac uptake was not observed in any healthy volunteers. The agent was well tolerated, with 1 drug-related adverse event and no deaths.

Conclusions: ¹²⁴I-evuzamitide is an amyloid-binding radiotracer capable of detecting cardiac amyloid in patients with high sensitivity.

Keywords: (124)I-p5+14; PET/CT imaging; cardiac amyloidosis; iodine ((124)I) evuzamitide; systemic amyloidosis.

Publication types

Clinical Trial, Phase II
Clinical Trial, Phase I
Research Support, U.S. Gov't, P.H.S.
Research Support, N.I.H., Extramural

MeSH terms

Amyloid
Amyloidosis* / diagnostic imaging
Humans
Immunoglobulin Light-chain Amyloidosis*
Iodine Radioisotopes
Positron Emission Tomography Computed Tomography
Predictive Value of Tests
Tissue Distribution

Substances

Iodine-124
Amyloid
Iodine Radioisotopes