ClinicalTrials.gov record NCT05667493

An Extension Study to Assess Long-Term Safety of Eplontersen in Adults With Transthyretin-Mediated Amyloid Cardiomyopathy (ATTR-CM)

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Sep 17, 2026

An Open-Label Extension Study to Assess the Long-Term Safety of Eplontersen (ION-682884) in Patients With Transthyretin-Mediated Amyloid Cardiomyopathy (ATTR-CM)

About this page. This page shows the study's official ClinicalTrials.gov record ↗, with added help to make it easier to understand. We explain medical terms, highlight key details in plain language, and suggest questions you may want to ask the study team.

The record is periodically copied from ClinicalTrials.gov and may lag behind changes. AI summaries are checked by software, not a clinician.Read moreShow less

The official record is written by the study sponsor and published on ClinicalTrials.gov. It may not always reflect the latest changes. Before making any decisions, please confirm important information with the study team and your own healthcare team.

Where you see "AI summary", AI was used to create a plain-language explanation and software checked it against the source. It has not been reviewed by a clinician, so it may contain mistakes or leave out important details.

StatusEnrolling by invitationThe study enrols only people the study team invites, for example patients already at a particular clinic. It is not open to the public.

Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.

PhasePhase 3A later-stage study, usually with more participants, designed to give stronger evidence about how well a treatment works and how safe it is. It often compares the treatment with standard care or a placebo, and results may support an application for approval.

Age18 years old and older

SexAll

LocationArgentina, Australia, Austria, Belgium, Brazil, Canada, Czechia, Denmark, France, Germany, Greece, Israel, Italy, Japan, Poland, Portugal, Spain, Sweden, United Kingdom, United States

AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This open-label extension follows adults with transthyretin‑mediated amyloid cardiomyopathy (ATTR‑CM) who took part in an earlier eplontersen study or met related-study participation criteria. Participants receive subcutaneous eplontersen once every 4 weeks plus daily vitamin A for up to 36 months, or until eplontersen is approved and available at the site. The study’s main goal is to evaluate long-term safety and tolerability.

What it is studying. The study is testing the long-term safety and tolerability of extended, monthly dosing of eplontersen in people with ATTR-CM. It collects and tracks adverse events and serious adverse events, platelet counts, kidney function and urine protein, transthyretin (TTR) blood levels, and measures of walking ability and heart-failure quality of life over the treatment period.

What the researchers hope to learn. To gather long-term safety and tolerability data on eplontersen in people with ATTR-CM, including rates of adverse events, changes in platelet counts, kidney function, urine protein, transthyretin levels, walking distance, and heart‑failure quality of life measures.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

The purpose of this study is to evaluate the safety and tolerability of extended dosing with eplontersen in participants with ATTR-CM.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Drug: Eplontersen

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

Satisfactory completion of Treatment Period and the End of Treatment Visit of the Index Study (ION-682884-CS2) OR diagnosis of ATTR-CM and satisfactory participation on ISIS 420915- CS101 study as judged by the Investigator and Sponsor.
Investigator is willing to treat the participant with open-label eplontersen.
Willingness to adhere to vitamin A supplementation per protocol.

Exclusion criteria

Permanently discontinued study drug administration while participating in the Index Study (ION 682884-CS2) or IST (ISIS 420915-CS101 Study).
Have any new condition or worsening of an existing condition that in the opinion of the Investigator or Sponsor would make the participant unsuitable for enrolment, or which could interfere with the participant participating in or completing the study, including the need for treatment with medications disallowed in the Index Study.

Study description and what participation involves

The study's detailed description, as published on ClinicalTrials.gov.

Detailed description from the registry

This is a multicenter, open-label extension, Phase 3 study in up to approximately 1400 participants from the 682884-CS2 study. Eligible participants will receive eplontersen once every 4 weeks for up to 36 months or until after eplontersen is approved and available in the site's country, whichever occurs first. Participants will also receive daily supplemental doses of the recommended daily allowance (RDA) of vitamin A.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Participants receive open‑label eplontersen by subcutaneous injection once every 4 weeks for up to 36 months (or until 6 months after eplontersen is approved and available in the site's country). They must take a daily vitamin A supplement per protocol. The study includes regular safety monitoring with blood and urine tests (including platelet counts, kidney function, and urine protein), periodic physical assessments, a 6‑minute walk test, and heart‑failure/quality‑of‑life questionnaires. The registry does not provide a detailed visit schedule or exact timing of assessments beyond the up-to-36-month period.

How the study is structured. Phase 3, open-label extension where all enrolled participants receive monthly subcutaneous eplontersen and daily vitamin A. Single treatment group with no blinding or placebo. Participants are followed and monitored for up to 36 months (or until the drug is approved and available at the site).

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

The registry says participants are enrolled by invitation. Who decides who is invited, and how?
The listed sites are in Argentina, Australia, Austria, Belgium, Brazil, Canada, Czechia, Denmark, France, Germany, Greece, Israel, Italy, Japan, Poland, Portugal, Spain, Sweden, United Kingdom, United States. Is any of them reachable for me, and does the study help with travel?
Which of the eligibility criteria would need to be checked with tests before I could join?

More on wild-type ATTR amyloidosis

Clinical trials121 trials listed for wild-type ATTR amyloidosisEvery trial the registry lists for wild-type ATTR amyloidosis, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in wild-type ATTR amyloidosis researchLatest monthly update: September 2026. Includes: Frailty and support needs. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start: Nov 30, 2022
Primary completion: August 2029 (estimated)
Study completion: August 2029 (estimated)
Target enrollment: 1400 participants (estimated)
Last updated on registry: Apr 17, 2026
Data verified: Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor: Ionis Pharmaceuticals, Inc.
Collaborators: AstraZeneca

Participating sites (134)

Filter by country:

Mayo Clinic
Scottsdale, Arizona, 85259 · United States
Cedars-Sinai Medical Center
Beverly Hills, California, 90211 · United States
Altman Clinical and Translational Research Institute - Center for Clinical Research
La Jolla, California, 92037 · United States
University Of California San Francisco Urology Practice
San Francisco, California, 94143 · United States
Stanford University (Leland Stanford Junior University)
Stanford, California, 94305 · United States
University of Colorado Hospital - Anschutz Medical Campus
Aurora, Colorado, 80045 · United States
MedStar Washington Hospital Center
Washington D.C., District of Columbia, 20010 · United States
The George Washington Medical Faculty Associates - Foggy Bottom North Pavilion
Washington D.C., District of Columbia, 20037 · United States
Cleveland Clinic Florida
Weston, Florida, 33331 · United States
Piedmont Heart of Fayetteville
Atlanta, Georgia, 30309 · United States

Terms used on this page · explanations by MedicalUpdates.ai

Sponsor: The organisation or person that initiates the study and has authority over it. The sponsor may be a company, hospital, university, government agency or individual, and is not necessarily the organisation that funds the study.
open-label: No masking is used, so the assigned intervention is not deliberately hidden from participants or study staff.
study drug: A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
enrolment: The number of participants a study plans to include, or has included. 'Estimated' means the planned number; 'actual' means the number who joined.
Inclusion Criteria: The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion Criteria: The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.
open-label extension: A continuation study in which participants who completed an earlier study can keep receiving the treatment, usually with everyone knowing what they are given.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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