An Extension Study of Donidalorsen (IONIS-PKK-LRx) in Participants With Hereditary Angioedema

April 17, 2026 updated by: Ionis Pharmaceuticals, Inc.

An Open-Label Extension Study of ISIS 721744 in Patients With Hereditary Angioedema

The purpose of this study was to evaluate the safety and efficacy of extended dosing of donidalorsen administered subcutaneously (SC), with alternative dosing and/or dose frequency with donidalorsen in participants with hereditary angioedema (HAE).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This was an open-label extension study of donidalorsen in 20 participants with HAE. The length of participation in the study was approximately 68 weeks, which included an up to 4-week qualification period, a 52-week treatment period, and a 12-week post-treatment period. Following the Week 53 treatment period visit, participants received donidalorsen in an extended treatment period for up to an additional 156 weeks. Participants taking part in the extended treatment period entered the 12-week post-treatment period after completion of, or early termination from, the extended treatment period.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Expanded Access

Expanded Access

A way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the U.S. Food and Drug Administration (FDA). Also called compassionate use. There are different expanded access types.
Available

Available

  • Available: Expanded access is currently available for this investigational treatment, and patients who are not participants in the clinical study may be able to gain access to the drug, biologic, or medical device being studied.
  • No longer available: Expanded access was available for this intervention previously but is not currently available and will not be available in the future.
  • Temporarily not available: Expanded access is not currently available for this intervention but is expected to be available in the future.
  • Approved for marketing: The intervention has been approved by the U.S. Food and Drug Administration for use by the public.
 outside the clinical trial. See expanded access record.

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Netherlands
      • Amsterdam, Netherlands, 1105 AZ
        • Ionis Investigative Site
  • United States
    • Arizona
      • Scottsdale, Arizona, United States, 85251
        • Ionis Investigative Site
    • California
      • Santa Monica, California, United States, 90404
        • Ionis Investigative Site
    • Minnesota
      • Plymouth, Minnesota, United States, 55446
        • Ionis Investigative Site
    • Ohio
      • Cincinnati, Ohio, United States, 45231
        • Ionis Investigative Site
    • Pennsylvania
      • Hershey, Pennsylvania, United States, 17033
        • Ionis Investigative Site
    • Texas
      • Dallas, Texas, United States, 75231
        • Ionis Investigative Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Satisfactory completion of ISIS 721744-CS2 (index study) through Week 17 with an acceptable safety and tolerability profile, per Sponsor and Investigator judgement
  2. Able and willing to participate in a 64-week study
  3. Females must be non-pregnant, non-lactating and either surgically sterile or post-menopausal
  4. Males must be surgically sterile or abstinent* or if engaged in sexual relations with a female of child-bearing potential, participant is utilizing an acceptable contraceptive method
  5. Participants must have access to, and the ability to use, ≥ 1 acute medication(s) (e.g., plasma-derived or recombinant C1- inhibitor (C1-INH) concentrate or a bradykinin-2 [BK-2] antagonist) to treat angioedema attacks

Exclusion Criteria:

1. Have any new condition or worsening of an existing condition or change or anticipated change in medication, which in the opinion of the Investigator would make the participant unsuitable for enrollment, or could interfere with the participant participating in or completing the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: HAE-1/HAE-2
Participants with hereditary angioedema Type I/Type II (HAE-1/HAE-2) who received placebo or donidalorsen, 80 milligrams (mg), SC once every 4 weeks, in the previous study ISIS 721744-CS2 (NCT04030598), received donidalorsen, 80 mg, SC once every 4 weeks, from Week 1 to Week 13 (Fixed Dosing Period). Starting From Week 17 (Flexible Dosing Period), participants had 3 different dosing options as: 80 mg every 4 weeks, 80 mg every 8 weeks for participants who were attack-free for ≥12 weeks, 100 mg every 4 weeks for participants who were not attack-free for ≥12 weeks up to Week 53 based on the investigator and sponsor medical monitor recommendation. Participants continued flexible dosing from Week 53 for up to approximately 209 weeks.
Drug: Donidalorsen
Donidalorsen administered SC
Other Names:
  • ISIS 721744
  • IONIS-PKK-LRx
Experimental: HAE-nC1-INH
Participants with hereditary angioedema with normal C1-inhibitor (HAE-nC1-INH) who received donidalorsen, 80 mg, SC, once every 4 weeks, in the previous study ISIS 721744-CS2 (NCT04030598), continued to receive donidalorsen, 80 mg, SC once every 4 weeks, from Week 1 to Week 13 (Fixed Dosing Period). Starting From Week 17 (Flexible Dosing Period), participants had 2 different dosing options as: 80 mg every 4 weeks, and 100 mg every 4 weeks for participants who were not attack-free for ≥12 weeks up to Week 53 based on the investigator and sponsor medical monitor recommendation. Participants continued flexible dosing from Week 53 for up to approximately 209 weeks.
Drug: Donidalorsen
Donidalorsen administered SC
Other Names:
  • ISIS 721744
  • IONIS-PKK-LRx

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Percentage of Participants With Treatment-emergent Adverse Events (TEAEs)
Time Frame: Up to Week 221
An adverse event (AE) was defined as any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not the AE is considered related to the medicinal (investigational) product. TEAEs were defined as those AEs that either started or worsened in severity on or after the date/time of first administration of study drug in this OLE Study. TEAEs included both serious and non-serious TEAEs.
Up to Week 221
Percentage of Participants With Clinically Meaningful Changes in Clinical Laboratory Assessments
Time Frame: Up to Week 221
Clinical laboratory tests including clinical chemistry, hematology, coagulation, complement, inflammatory, urinalysis were performed. The percentage of participants with clinically meaningful changes were reported. Clinical meaningfulness was determined by the investigator.
Up to Week 221
Percentage of Participants With Clinically Meaningful Changes in Vital Signs
Time Frame: Up to Week 221
Vital sign measurements including heart rate, respiratory rate, body temperature, systolic and diastolic blood pressure and pulse pressure were assessed. Percentage of participants with clinically meaningful changes in the vital signs were reported. Clinically meaningfulness was determined by the investigator.
Up to Week 221
Percentage of Participants With Clinically Meaningful Changes in Electrocardiograms (ECGs) Parameters
Time Frame: Up to Week 221
The ECG parameters included ventricular rate, PR interval, QRS duration, QTc, QT corrected using the Fridericia's formula (QTcF), QT corrected using the Bazett's formula (QTcB), and overall interpretation. Percentage of participants with clinically meaningful changes in the ECG parameters were reported. Clinical meaningfulness was determined by the investigator.
Up to Week 221
Percentage of Participants Who Received At Least One Concomitant Medication
Time Frame: Up to Week 221
Concomitant medications include medications that participants were exposed to on or after the first dose of ISIS 721744 in the OLE study. Percentage of participants who received at least one concomitant medication were reported.
Up to Week 221

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Percent Change From Baseline in Time-normalized HAE Attack (Per 4 Weeks) Rate
Time Frame: Up to Week 221
HAE attack rate was calculated for each participant as the number of HAE attacks occurring during the respective period divided by the number of days the participant contributed to this period multiplied by 28 days. An HAE attack was defined as an event with signs or symptoms consistent with an attack in at least 1 of the locations: peripheral angioedema (cutaneous swelling involving an extremity, the face, neck, torso, and/or genitourinary region), abdominal angioedema (abdominal pain, with or without abdominal distention, nausea, vomiting, or diarrhea), laryngeal angioedema (stridor, dyspnea, difficulty speaking, difficulty swallowing, throat tightening, or swelling of the tongue, palate, uvula, or larynx). A negative change from baseline in HAE attacks indicates an improvement in HAE attacks.
Up to Week 221
Percentage of Participants Who Used On-demand Medications
Time Frame: Up to Week 221
The most commonly used on-demand medications during the On-Treatment Period were C1 esterase inhibitors (human) and icatibant, which were allowed per-protocol for treatment of acute attacks.
Up to Week 221

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ionis Pharmaceuticals, Inc.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 31, 2020

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 24, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 24, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 11, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 11, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 13, 2020

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ISIS 721744-CS3
  • 2020-000197-14 (EudraCT Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Ionis may share anonymized individual participant data, aggregated clinical data, and other types of data that support the results in this study. Data requests from qualified researchers will be considered once all three of the following criteria are met: (1) 12 months from marketing approval of the study drug in both the United States and European Union; (2) 18 months from conclusion of the study; and (3) 6 months from publication of study article. Access would be via a secure environment and is contingent upon approval of a research proposal and entry into an appropriate data use agreement. Requests to access data can be submitted via the website https://vivli.org/ourmember/ionis/.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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