Inclusion Criteria:

• Understands the study procedures and can give signed informed consent (as specified in Section 10.1.3), which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.
• Male or female ≥18 years of age.
• Is suspected of having cardiac amyloidosis and is willing to undergo a diagnostic evaluation for cardiac amyloidosis (e.g., echocardiography, CMR, bone avid tracer cardiac SPECT, extracardiac or endomyocardial biopsy, etc.). Participants can be enrolled before or during their diagnostic evaluation for cardiac amyloidosis.
• Able to undergo PET/CT imaging as part of the study, including ability to lie supine for approximately 1 hour.
• For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods that result in a failure rate of <1% per year during the treatment period and for at least 30 days after administration of I-124 evuzamitide.
  • A woman is considered of childbearing potential if she is postmenarchal, has not reached a postmenopausal state (≥ 12 months of amenorrhea with no identified cause other than menopause), and has not undergone surgical sterilization (removal of ovaries and/or uterus). The definition of childbearing potential may be adapted for alignment with local guidelines or requirements.
  • Examples of contraceptive methods with a failure rate of < 1% per year include bilateral tubal ligation, male sterilization, established and proper use of hormonal contraceptives that inhibit ovulation, hormone-releasing intrauterine devices, and copper intrauterine devices.
    • Contraception methods that do not result in a failure rate of < 1% per year such as cap, diaphragm, or sponge with spermicide, or male or female condom with or without spermicide, are not acceptable.
    • The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the participant. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or postovulation methods) and withdrawal are not acceptable methods of contraception.
• For men: agreement to remain abstinent or use contraceptive measures and agreement to refrain from donating sperm, as defined below:
  • With female partners of childbearing potential, men must remain abstinent or use a condom plus an additional contraceptive method that together result in a failure rate of < 1% per year during the treatment period and for at least 120 days (30 days plus a 90-day spermatogenesis cycle) after the last dose of study intervention. Men must refrain from donating sperm during this same period.

Exclusion Criteria:

• Established diagnosis of cardiac amyloidosis.
• Established diagnosis of systemic amyloidosis (e.g., renal AL or ATTR peripheral neuropathy) without known cardiac involvement. Participants who are amyloid positive only with carpal tunnel tissue or laminectomy are allowed as long as they do not have other known organ involvement.
• Receiving therapy with an approved treatment (e.g., tafamadis) or in a clinical trial for treatment for ATTR cardiac amyloidosis at time of enrollment. For AL and ATTR: Patients may enter the screening period of a clinical trial for treatment after the ICF is signed and participant is enrolled in this trial but may not receive an experimental therapy until after the Day 30 safety follow-up visit in this trial.
• Is pregnant or breast-feeding.
• Is mentally or legally incapacitated, has significant emotional problems at the time of the study, or has a history of psychosis.
• Has a known allergy to potassium iodide.
• Receiving hemodialysis or peritoneal dialysis.
• eGFR less than 15ml/min/1.73m2.
• Myocardial infarction within three (3) months of screening.
• Has severe claustrophobia or any medical condition that would prevent completion of the imaging protocol.
• Has any illness that, in the opinion of the investigator, might confound the results of the study or pose additional risk to the participant.
• Has received heparin or heparin analogs (e.g., enoxaparin, dalteparin, fondaparinux) within seven (7) days prior to I-124 evuzamitide administration.
• Known uncorrected thyroid disorders (other than mild elevation of thyroid stimulating hormone with normal T4).

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 9/30/2024. Questions regarding updates should be directed to the study team contact.