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Evuzamitide in PET/CT to Measure Potential Therapeutic Response in ATTR

A Follow-Up Study to Monitor Therapeutic Response in Transthyretin Cardiac Amyloidosis Using Amyloid Reactive Peptide 124I-evuzamitide (AT01) PET/CT

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05635045
Enrollment
10
Registered
2022-12-02
Start date
2022-07-08
Completion date
2024-06-12
Last updated
2025-07-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Transthyretin Amyloidosis

Keywords

124I-evuzamitide, Positron Emission Tomography (PET), ATTR-CM

Brief summary

This was a single center, prospective cohort study that is evaluating the ability of 124I-evuzamitide PET scanning to detect potential therapeutic changes in subjects under treatment for ATTR after one year had elapsed since their original 124I-evuzamitide PET scan. Ten previously scanned subjects re-consented to undergo another 124I-evuzamitide PET scan. Demographic, clinical and phenotypic data were collected to characterize potential changes since their previous scans.

Detailed description

Transthyretin cardiac amyloidosis (ATTR-CA) causes progressive heart disease that is often overlooked. It harms the heart muscle because the unstable, unfurled amyloid proteins fold up into large pieces that get caught in between layers of heart tissue, causing amyloid deposits. The earlier it is detected, the better for the patient. There is a need to improve the early diagnosis of this disease because echocardiography (sonograms of the heart) and cardiac MRI are not useful enough for this. There is an X-ray of the heart using a compound called PYP that can detect amyloid deposits earlier than ultrasound images or clinical signs, but it's not clear how early it does so. Also, it can't detect amyloid deposits outside the heart, which causes lots of pain and suffering in people with this disease. In the first phase of this study the radiation compound, evuzamitide, was shown to detect amyloidosis in the heart of selected subjects. So, the investigators used it to detect potential therapeutic changes in 10 subjects undergoing treatment for Transthyretin Amyloidosis. Changes in the uptake of evuzamitide were compared between subjects treated on stabilizer only, subjects treated on silencer only and subjects treated with two different combinations of stabilizer plus silencer

Interventions

DRUGI 124-Evuzamitide

Amyloid reactive protein used as imaging agent in whole body SPECT-CT imaging

Sponsors

Attralus, Inc.
CollaboratorINDUSTRY
Columbia University
Lead SponsorOTHER

Study design

Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
DIAGNOSTIC
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
50 Years to 105 Years
Healthy volunteers
Yes

Inclusion criteria

1. 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. 2. Were enrolled in the initial pilot using 124I-Evuzamitide, on ATTR stabilizer and/or silencer therapy. Able to understand and sign the informed consent document after the nature of the study has been fully explained. 3. TTR genotype shown to be either Val122Ile or wild type.

Exclusion criteria

Overall Inclusion Criteria: 1. 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. 2. Were enrolled in the initial pilot using 124I-Evuzamitide, on ATTR stabilizer and/or silencer therapy. Able to understand and sign the informed consent document after the nature of the study has been fully explained. 3. TTR genotype shown to be either Val122Ile or wild type. The presence of any of the following excludes eligibility for enrollment in this study: 1. Primary amyloidosis (AL) or secondary amyloidosis (AA). 2. Active malignancy or non-amyloid disease with expected survival of less than 1 year. 3. Heart failure, in the opinion of the investigator, primarily caused by something other than amyloidosis. 4. Ventricular assist device. 5. Impairment from stroke, injury or other medical disorder that precludes participation in the study. 6. Disabling dementia or other mental or behavioral disease. 7. Enrollment in a clinical trial not approved for co-enrollment. 8. Continuous intravenous inotropic therapy. 9. Inability or unwillingness to comply with the study requirements. 10. Chronic kidney disease requiring hemodialysis or peritoneal dialysis. 11. Patients taking heparin, or heparin derivatives (e.g. low molecular weight heparins) for anticoagulation. 12. Other reason that would make the subject inappropriate for entry into this study.

Design outcomes

Primary

MeasureTime frameDescription
Median of Uptake of Evuzamitide as Measured by Volume of Interest in MillilitersUp to one month after imagingVolumes of interest (VOIs) were manually traced on PET emission images fused with CT images to define the left ventricular (LV) and right ventricular (RV) contours, including cavity blood pool. Blood pool activity concentration was measured in a 10-mm-diameter left atrial spherical VOI. For 124I-evuzamitide, we used a threshold of mean + 2 standard deviations of blood pool activity concentration.
Median of Change in Evuzamitide Uptake as Measured by Percentage Change in Injected Dose (%ID)Up to one month after imagingMedian percentage change in injected dose (%ID), calculated as VOI mean activity concentration x VOI volume/injected activity.
Median of Uptake of Evuzamitide as Measured by Cardiac Amyloid Activity (CAA) in GramsUp to one month after imagingCardiac amyloid activity (CAA) in grams is measured as VOI mean standardized uptake value times VOI volume. Standardized uptake value was defined as mean or maximal VOI activity concentration/(injected activity/bodyweight), while target-to-background ratio was considered VOI mean activity concentration/blood pool mean activity concentration. VOI volume was manually traced on PET emission images fused with CT images.

Countries

United States

Participant flow

Participants by arm

ArmCount
Stabilizer Only
Subjects treated with tafamidis selected to re-scan to determine the change over time in Evuzamitide uptake
4
Silencer Only
Subjects treated with vutrisiran selected to re-scan to determine the change over time in Evuzamitide uptake
1
Stabilizer and Silencer (Tafamidis + Patisiran)
Subjects treated with tafamidis and patisiran selected to re-scan to determine the change over time in Evuzamitide uptake
3
Stabilizer and Silencer (Vutrisiran + Diflunisal)
Subjects treated with vutrisiran and diflunisal selected to re-scan to determine the change over time in Evuzamitide uptake
2
Total10

Withdrawals & dropouts

PeriodReasonFG000FG001FG002FG003
Overall Studymeasurements were not usable due material error in imaging agent supplied0010

Baseline characteristics

CharacteristicStabilizer OnlySilencer OnlyStabilizer and Silencer (Tafamidis + Patisiran)Stabilizer and Silencer (Vutrisiran + Diflunisal)Total
Age, Continuous68.75 years65 years75 years60 years67.77 years
Ethnicity (NIH/OMB)
Hispanic or Latino
1 Participants0 Participants0 Participants0 Participants1 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
3 Participants1 Participants3 Participants2 Participants9 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants0 Participants0 Participants
PYP Scan result
PYP Score 0 - no uptake
0 Participants0 Participants0 Participants0 Participants0 Participants
PYP Scan result
PYP Score 1 - less uptake than bone
1 Participants1 Participants0 Participants0 Participants2 Participants
PYP Scan result
PYP Score 2 - as much uptake as bone
0 Participants0 Participants0 Participants1 Participants1 Participants
PYP Scan result
PYP Score 2 or 3 - indeterminate whether uptake is equal to or greater than bone
0 Participants0 Participants1 Participants0 Participants1 Participants
PYP Scan result
PYP Score 3 - more uptake than bone
3 Participants0 Participants2 Participants1 Participants6 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Asian
0 Participants0 Participants0 Participants1 Participants1 Participants
Race (NIH/OMB)
Black or African American
1 Participants1 Participants0 Participants0 Participants2 Participants
Race (NIH/OMB)
More than one race
0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
White
3 Participants0 Participants3 Participants1 Participants7 Participants
Sex: Female, Male
Female
0 Participants0 Participants0 Participants0 Participants0 Participants
Sex: Female, Male
Male
4 Participants1 Participants3 Participants2 Participants10 Participants
TTR Genotype
Asp38Glu
0 Participants0 Participants0 Participants1 Participants1 Participants
TTR Genotype
Thr60Ile
0 Participants1 Participants0 Participants0 Participants1 Participants
TTR Genotype
V122i
2 Participants0 Participants0 Participants0 Participants2 Participants
TTR Genotype
Val30Met
0 Participants0 Participants0 Participants1 Participants1 Participants
TTR Genotype
Wild-Type
2 Participants0 Participants3 Participants0 Participants5 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
EG003
affected / at risk
deaths
Total, all-cause mortality
0 / 40 / 10 / 30 / 2
other
Total, other adverse events
0 / 40 / 11 / 30 / 2
serious
Total, serious adverse events
0 / 40 / 10 / 30 / 2

Outcome results

Primary

Median of Change in Evuzamitide Uptake as Measured by Percentage Change in Injected Dose (%ID)

Median percentage change in injected dose (%ID), calculated as VOI mean activity concentration x VOI volume/injected activity.

Time frame: Up to one month after imaging

Population: 1 subject was scanned but their measurements were not usable due material error in imaging agent supplied.

ArmMeasureValue (MEDIAN)
Stabilizer OnlyMedian of Change in Evuzamitide Uptake as Measured by Percentage Change in Injected Dose (%ID)0.2 percent change
Silencer OnlyMedian of Change in Evuzamitide Uptake as Measured by Percentage Change in Injected Dose (%ID)0.8 percent change
Stabilizer and Silencer (Tafamidis + Patisiran)Median of Change in Evuzamitide Uptake as Measured by Percentage Change in Injected Dose (%ID)1.3 percent change
Stabilizer and Silencer (Vutrisiran + Diflunisal)Median of Change in Evuzamitide Uptake as Measured by Percentage Change in Injected Dose (%ID)0.3 percent change
Primary

Median of Uptake of Evuzamitide as Measured by Cardiac Amyloid Activity (CAA) in Grams

Cardiac amyloid activity (CAA) in grams is measured as VOI mean standardized uptake value times VOI volume. Standardized uptake value was defined as mean or maximal VOI activity concentration/(injected activity/bodyweight), while target-to-background ratio was considered VOI mean activity concentration/blood pool mean activity concentration. VOI volume was manually traced on PET emission images fused with CT images.

Time frame: Up to one month after imaging

Population: 1 subject was scanned but their measurements were not usable due material error in imaging agent supplied.

ArmMeasureValue (MEDIAN)
Stabilizer OnlyMedian of Uptake of Evuzamitide as Measured by Cardiac Amyloid Activity (CAA) in Grams180.2 grams
Silencer OnlyMedian of Uptake of Evuzamitide as Measured by Cardiac Amyloid Activity (CAA) in Grams852.8 grams
Stabilizer and Silencer (Tafamidis + Patisiran)Median of Uptake of Evuzamitide as Measured by Cardiac Amyloid Activity (CAA) in Grams952.5 grams
Stabilizer and Silencer (Vutrisiran + Diflunisal)Median of Uptake of Evuzamitide as Measured by Cardiac Amyloid Activity (CAA) in Grams155.4 grams
Primary

Median of Uptake of Evuzamitide as Measured by Volume of Interest in Milliliters

Volumes of interest (VOIs) were manually traced on PET emission images fused with CT images to define the left ventricular (LV) and right ventricular (RV) contours, including cavity blood pool. Blood pool activity concentration was measured in a 10-mm-diameter left atrial spherical VOI. For 124I-evuzamitide, we used a threshold of mean + 2 standard deviations of blood pool activity concentration.

Time frame: Up to one month after imaging

Population: 1 subject was scanned but their measurements were not usable due material error in imaging agent supplied.

ArmMeasureValue (MEDIAN)
Stabilizer OnlyMedian of Uptake of Evuzamitide as Measured by Volume of Interest in Milliliters78.7 mL
Silencer OnlyMedian of Uptake of Evuzamitide as Measured by Volume of Interest in Milliliters253.6 mL
Stabilizer and Silencer (Tafamidis + Patisiran)Median of Uptake of Evuzamitide as Measured by Volume of Interest in Milliliters177.2 mL
Stabilizer and Silencer (Vutrisiran + Diflunisal)Median of Uptake of Evuzamitide as Measured by Volume of Interest in Milliliters39.6 mL

Source: ClinicalTrials.gov · Data processed: Feb 5, 2026