Open Label Extension of Efgartigimod in Adults With Post-COVID-19 POTS (POTS)

October 8, 2025 updated by: argenx

Open-Label Extension Study to Evaluate the Long-term Safety and Efficacy of Efgartigimod in Adult Patients With Post-COVID-19 Postural Orthostatic Tachycardia Syndrome (PC-POTS) Who Completed Study ARGX-113-2104

The OLE study aims to investigate the safety, efficacy, pharmacodynamics (PD), pharmacokinetics (PK), and immunogenicity of efgartigimod in participants with post-COVID-19 postural orthostatic.

Study Overview

Status

Status

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

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

Study ARGX-113-2105 is a long-term, single-arm, open-label, multicenter extension of the ARGX-113-2104 study, designed to evaluate the long-term safety of efgartigimod IV in adult patients with PC-POTS. Participants will be enrolled from both active and placebo arms of the ARGX-113-2104 study and will receive efgartigimod IV 10 mg/kg in the extension study without knowledge of their prior treatment arm. To be eligible to enroll in this study, participants must have completed the 24-week treatment period of the ARGX-113-2104 study and must not have permanently discontinued the IMP in that study.

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.
33

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

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • California
      • La Jolla, California, United States, 92037
        • UC Sand Diego Sulpizio Cardiovascular Center
      • Palo Alto, California, United States, 94304
        • Standford Movement Disorder Center
    • Illinois
      • Glenview, Illinois, United States, 60026
        • North Shore University HealthSystem
    • Maryland
      • Baltimore, Maryland, United States, 21205
        • Johns Hopkins University
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
        • Brigham and Women's Hospital
    • Ohio
      • Cleveland, Ohio, United States, 44106
        • University Hospitals, Neurology Clinical Trials
    • Texas
      • Fort Worth, Texas, United States, 76104
        • Apex Trials Group
      • Rosharon, Texas, United States, 77583
        • Pioneer Clinical Research
    • Utah
      • West Valley City, Utah, United States, 84119
        • Metrodora Institute

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. The participant has completed the ARGX-113-2104 study without permanent discontinuation of IMP and agrees to directly roll over into the extension study without discontinuation of IMP.
  2. The participant signs the informed consent form, and can comply with OLE study (ARGX-113-2105) protocol requirements.
  3. The participant agrees to use contraceptives consistent with local regulations regarding the methods of contraception for those participating in clinical studies. Contraceptive requirements are provided.
  4. Female participants of childbearing potential must have a negative urine pregnancy test at baseline before receiving IMP.

Exclusion Criteria:

  1. The participant has a clinically significant condition, based on the judgement of the Study Investigator, eg, laboratory abnormalities, 12-lead ECG readings, concomitant medical disease(s), etc., which may place them at undue risk or confound interpretation of study data.
  2. The participant intends to become pregnant or start breastfeeding during 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: Efgartigimod
Receive efgartigimod IV 10mg/kg infusions during a treatment period of 48 weeks
Drug: Efgartigimod
Participants will receive efgartigimod IV 10 mg/kg open label, respectively.

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
Number of Participants With TEAEs, TESAEs and TEAESIs
Time Frame: From the first dose of study drug (Day 1) up to 60 days post last dose of study drug, up to 383 days
An adverse event (AE) was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug. A serious adverse event (SAE) was any untoward medical occurrence that at any dose resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or any other medically important event. An adverse event of special interest (AESI) was an AE of scientific and medical concern specific to the sponsor's product or program. Treatment-emergent adverse events (TEAEs) were defined as AEs with onset on or after the first administration of study drug up to and including 60 days after the last study drug administration.
From the first dose of study drug (Day 1) up to 60 days post last dose of study drug, up to 383 days

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
Change From Baseline to Weeks 24 and 48 in the COMPASS 31 (2-week Recall Version)
Time Frame: Baseline (Day 1) and Weeks 24 and 48
Composite Autonomic Symptom Score (COMPASS) 31 modified version (2-week recall) is a self-rated questionnaire to evaluate the severity and distribution of autonomic symptoms in various autonomic nerve disorders. It consists of 31 questions in 6 weighted domains (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal {GI}-mixed upper and diarrhea, bladder, and pupillomotor). A weighted total score of 0 (mild) to 100 (severe) was determined by adding a maximum raw score for each domain. Higher scores indicated a more severe degree of autonomic symptoms.
Baseline (Day 1) and Weeks 24 and 48
Change From Baseline to Weeks 24 and 48 in the MaPS
Time Frame: Baseline (Day 1) and Weeks 24 and 48
The Malmö POTS Symptom Score (MaPS) score is a dedicated POTS symptom scoring questionnaire. The score consists of 12 questions that assess symptom burden related (tachycardia, palpitations, dizziness, presyncope) and unrelated to orthostatic intolerance (GI symptoms, insomnia, concentration difficulties). Participants graded their symptoms for the past 7 days using a numerical rating scale ranging from 0 (no symptoms) to 10 (very pronounced symptoms). The total score was calculated by summing up the items/individual items and range was 0 to 120 points, with higher scores indicating more severe symptoms.
Baseline (Day 1) and Weeks 24 and 48
Percentage of Participants With Improved PGI-S at Weeks 24 and 48
Time Frame: Baseline (Day 1) and Weeks 24 and 48
The Patient Global Impression-Severity (PGI-S) is a participant-rated, single-item scale to assess the severity of a health condition. The scale was used to assess the severity of symptoms over the past week (1-week recall) and overall experience of symptoms over the past 2 weeks (2-week recall). Both were rated on a 4-point type Likert scale, with scores ranging from 1 (none), 2 (mild), 3 (moderate), and 4 (severe). Higher scores indicate greater symptom severity. An "improved PGI-S" was defined by a change from baseline of -3, -2 and -1.
Baseline (Day 1) and Weeks 24 and 48
Percentage of Participants With Improved PGI-C at Weeks 24 and 48
Time Frame: Baseline (Day 1) and Weeks 24 and 48
The Patient Global Impression-Change (PGIC) is a single-item scale to capture the participant's perception of an overall change in their symptoms from start of study drug. It was rated on a 7-point Likert scale, with scores ranging from 1 (much better), 2 (somewhat better), 3 (a little better), 4 (no change), 5 (a little worse), 6 (somewhat worse), and 7 (much worse). Higher PGI-C scores signify worse outcome. An "improved PGI-C" was defined by a change from baseline of 1, 2 and 3.
Baseline (Day 1) and Weeks 24 and 48
Change From Baseline to Weeks 24 and 48 in the PROMIS Fatigue Short Form 8a
Time Frame: Baseline (Day 1) and Weeks 24 and 48
The Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue Short Form 8a assesses the impact and perceived fatigue during the last 7 days. This validated 8-question scale has 5 response options, with scores ranging from 1 (not at all) to 5 (very much). Total scores ranged from 8 to 40; higher scores indicated higher fatigue levels and were converted to a T-score with a mean of 50 and standard deviation of 10. A decrease in T-score (negative change from baseline) indicated improvement in fatigue.
Baseline (Day 1) and Weeks 24 and 48
Change From Baseline to Weeks 24 and 48 in the PROMIS Cognitive Function Short Form 6a
Time Frame: Baseline (Day 1) and Weeks 24 and 48
PROMIS Cognitive Function Short Form 6a assesses the frequency of cognitive difficulties experienced in the past 7 days. The questionnaire comprises 6 questions on subjective cognitive difficulties regarding a participant's concentration, memory, language, mental acuity, and perceived changes in cognitive functioning. The participant marks their response on a 5-point Likert scale (1: never and 5: very often). Scores ranged from 6 to 30; higher scores indicated worse perceived cognitive functioning and were converted to a T-score with a mean of 50 and standard deviation of 10. An increase in T-score (positive change from baseline) indicated better cognitive function.
Baseline (Day 1) and Weeks 24 and 48
Percent Change From Baseline in Total IgG Levels at Weeks 24 and 48
Time Frame: Baseline (Day 1) and Weeks 24 and 48
Blood samples for immunoglobulin G (IgG) analysis were collected at specified time points. Total IgG concentrations were quantified using validated methods at a central laboratory.
Baseline (Day 1) and Weeks 24 and 48
Serum Concentration of Efgartigimod
Time Frame: Pre-dose at Baseline (Day 1) and Weeks 1, 4, 12 and 24
Serum samples were collected at specified timepoints to determine the concentration of efgartigimod.
Pre-dose at Baseline (Day 1) and Weeks 1, 4, 12 and 24
Number of Participants With ADAs Against Efgartigimod
Time Frame: From the first dose of study drug (Day 1) up to Week 48
Blood samples were collected at specified timepoints to assess anti-drug antibodies (ADAs) against efgartigimod. ADA incidence reported here was defined as total number of participants with treatment-induced and treatment-boosted ADA. Treatment-induced ADA was defined as a baseline negative sample and at least 1 positive post-baseline sample. Treatment-boosted ADA was defined as a baseline positive sample and the titer value increased 4-fold or more compared to baseline.
From the first dose of study drug (Day 1) up to Week 48

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.
argenx

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
IQVIA Pty Ltd

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.
June 20, 2023

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.
August 15, 2024

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.
August 15, 2024

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).
June 22, 2023

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.
June 22, 2023

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.
June 26, 2023

Study Record Updates

Last Update Posted (Estimated)

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.
October 23, 2025

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.
October 8, 2025

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.
October 1, 2025

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.
  • ARGX-113-2105

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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.

No

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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