Evaluating the Long-Term Safety and Tolerability of Efgartigimod PH20 SC Administered Subcutaneously in Patients With Generalized Myasthenia Gravis (ADAPTSC+)

January 20, 2026 updated by: argenx

A Long-Term, Single-Arm, Open-label, Multicenter Phase 3 Study to Evaluate the Safety and Tolerability of Multiple Subcutaneous Injections of Efgartigimod PH20 SC in Patients With Generalized Myasthenia Gravis

The purpose of this study is to evaluate the long-term safety and tolerability of efgartigimod PH20 SC 1000 mg, and the clinical efficacy, PD, pharmacokinetics (PK), immunogenicity, impact on the quality of life (QoL) of the participants, treatment satisfaction, and administration method preference, and the feasibility of self- and caregiver-supported administration of the SC injection.

Treatment duration: 3-week treatment periods, repeated as needed with at least 28 days in between treatment periods

Health measurements: total levels of immunoglobulin G (IgG), Acetylcholine receptor binding autoantibodies (AChR-Ab) levels, Myasthenia Gravis Activities of Daly Living (MG-ADL).

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.

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.
184

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 3

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

  • Belgium
      • Ghent, Belgium, 9000
        • Investigator site 5 - BE0320007
  • Czechia
      • Brno, Czechia, 625 00
        • Investigator site 24 - CZ4200005
  • Georgia
      • Tbilisi, Georgia, 0112
        • Investigator Site 2 - GEO9950002
      • Tbilisi, Georgia, 0114
        • Investigator Site 1 - GEO9950001
      • Tbilisi, Georgia, 0114
        • Investigator Site 3 - GEO9950003
    • K'alak'i T'bilisi
      • Tbilisi, K'alak'i T'bilisi, Georgia, 0160
        • Investigator Site 32 - GEO9950004
      • Tbilisi, K'alak'i T'bilisi, Georgia, 016
        • Investigator Site 33 - GEO9950016
  • Germany
      • Berlin, Germany, 10117
        • Investigator Site 25 - DE490006
      • Münster, Germany, 48149
        • Investigator Site 26 - DE490009
  • Hungary
      • Budapest, Hungary, 1082
        • Investigator site 10 - HU0360013
      • Budapest, Hungary, 1204
        • Investigator site 9 - HU0360012
  • Italy
      • Milan, Italy, 20133
        • Investigator site 11 - IT0390003
      • Napoli, Italy, 80138
        • Investigator Site 34 - IT0390007
      • Roma, Italy, 00189
        • Investigator Site 35 - IT0390008
  • Japan
      • Osaka, Japan, 565-0871
        • Investigator site 14 - JP0810007
      • Sapporo, Japan, 060 8542
        • Investigator Site 27 - JP0810008
      • Sendai, Japan, 983-8520
        • Investigator site 13 - JP0810005
      • Tokyo, Japan, 160-0023
        • Investigator site 15 - JP0810009
    • Chiba-Shi
      • Chiba, Chiba-Shi, Japan, 260-8677
        • Investigator site 12 - JP0810002
    • Hokkaido
      • Sapporo, Hokkaido, Japan, 063-0005
        • Investigator Site 36 - JP0810055
    • Iwate
      • Hanamaki, Iwate, Japan, 025-0082
        • Investigator site 8 - JP0810004
    • Tokyo
      • Ōta-ku, Tokyo, Japan, 143-8541
        • Investigator Site 28- JP0810059
  • Netherlands
      • Leiden, Netherlands, 2333
        • Investigator site 16 - NL0310001
  • Poland
      • Gdansk, Poland, 80-952
        • Investigator site 17 - PL0480001
      • Katowice, Poland, 40-123
        • Investigator site 19 - PL0480007
      • Krakow, Poland, 31-426
        • Investigator site 22 - PL0480065
      • Krakow, Poland, 31-505
        • Investigator site 18 - PL0480005
      • Lublin, Poland, 20-093
        • Investigator site 20 - PL0480018
      • Warsaw, Poland, 02-097
        • Investigator site 21 - PL0480022
  • Russia
      • Novosibirsk, Russia, 630087
        • Investigator Site 29- RU0070002
      • Saint Petersburg, Russia, 194354
        • Investigator Site 30 - RU0070014
  • Spain
      • Barcelona, Spain, 08035
        • Investigator Site 37 - ES0340021
      • Barcelona, Spain, 08041
        • Investigator Site 31 - ES0340038
      • Valencia, Spain, 46026
        • Investigator site 23 - ES0340039
  • United States
    • California
      • Carlsbad, California, United States, 92011
        • Investigator site 6 - US0010032
      • Palo Alto, California, United States, 94304
        • Investigator Site 47 - US0010021
    • Florida
      • Boca Raton, Florida, United States, 33428
        • Investigator Site 45 - US0010108
      • Port Charlotte, Florida, United States, 33952
        • Investigator site 4 - US0010110
      • Tampa, Florida, United States, 41076
        • Investigator Site 39 - US0010006
    • Kansas
      • Kansas City, Kansas, United States, 66160
        • Investigator Site 41 - US0010015
    • New York
      • Amherst, New York, United States, 14226
        • Investigator Site 46 - US0010111
    • North Carolina
      • Chapel Hill, North Carolina, United States, 27514
        • Investigator Site 38 - US0010003
      • Durham, North Carolina, United States, 27710
        • Investigator Site 44 - US0010077
    • Ohio
      • Cleveland, Ohio, United States, 44195
        • Investigator Site 42 - US0010019
    • Tennessee
      • Cordova, Tennessee, United States, 38018
        • Investigator site 7 - US0010008
    • Texas
      • Austin, Texas, United States, 78759
        • Investigator Site 43 - US0010066
      • San Antonio, Texas, United States, 78229
        • Investigator Site 40 - US0010009

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. Must be capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.
  2. Previously participated in antecedent studies ARGX-113-2001 or ARGX-113-1705 and are eligible for roll over.

  3. Contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies and:

    • Women of Child bearing potential (WOCBP) must have a negative urine pregnancy test at baseline before investigational medicinal product (IMP) can be administered.

Exclusion Criteria:

  1. The participant was discontinued early from studies ARGX-113-2001 or ARGX-113-1705, unless the reason for discontinuation from study ARGX-113-1705 was to roll over into study ARGX-113-2002.

    a. Participants who, in the investigator's judgment, are not benefiting from efgartigimod IV in study ARGX-113-1705 Part B are not eligible for roll over into ARGX-113-2002.

  2. Are pregnant or lactating, or intend to become pregnant during the study or within 90 days after the last dose of investigational medicinal product (IMP)

  3. Has any of the following medical conditions:

    1. Clinically significant uncontrolled chronic bacterial, viral, or fungal infection at roll-over
    2. Any other known autoimmune disease that, in the opinion of the investigator, would interfere with accurate assessment of clinical symptoms of myasthenia gravis or put the participant at undue risk

    3. History of malignancy unless deemed cured by adequate treatment with no evidence of reoccurrence for ≥3 years before the first administration of investigational medicinal product (IMP).

      Participants with the following cancers can be included at any time:

      • adequately treated basal cell or squamous cell skin cancer
      • carcinoma in situ of the cervix
      • carcinoma in situ of the breast
      • incidental histological findings of prostate cancer (TNM classification of malignant tumors stage T1a or T1b)
    4. Clinical evidence of other significant serious diseases, or the participant has had a recent major surgery, or who have any other condition that, in the opinion of the investigator, could confound the results of the study or put the participant at undue risk
  4. Received a live-attenuated vaccine within 28 days prior to study entry or plan to receive a live-attenuated vaccine during the study
  5. A known hypersensitivity reaction to efgartigimod, rHuPH20, or any of its excipients

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 PH20 SC
Patients receiving efgartigimod PH20 subcutaneous (SC) treatment
Biological: efgartigimod PH20 SC
Subcutaneous injection with efgartigimod PH20 SC

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 AEs, SAEs and AESIs
Time Frame: Up to 3.5 years
Adverse events, Serious Adverse event and Adverse events of special interest. Adverse events in the 'Infections and infestations' SOC were defined as AESIs because efgartigimod causes a transient reduction in total IgG levels.
Up to 3.5 years

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
MG-ADL Total Score Changes From Baseline
Time Frame: Up to week 4 of the first cycle
The Myasthenia Gravis Activities of Daily Living (MG-ADL) is an 8-item patient-reported scale that assesses MG symptoms and their effects on daily activities. It evaluates a participant's capacity to perform different activities in their daily life. The total score ranges from 0 to 24 with higher scores indicating more impairment.
Up to week 4 of the first cycle
Percent Change in Total IgG Levels From Baseline
Time Frame: Up to week 4 of the first cycle
IgG: immunoglobulin G
Up to week 4 of the first cycle
Percent Change in AChR-Ab From Baseline in AChR-Ab Seropositive Participants
Time Frame: Up to week 4 of the first cycle
AchR-Ab: anti-acetylcholine receptor antibodies.
Up to week 4 of the first cycle
Efgartigimod Serum Concentrations
Time Frame: Up to week 4 of the first cycle
Up to week 4 of the first cycle
Incidence of ADAs Against Efgartigimod Over Time
Time Frame: Up to 3.5 years
ADA: Anti-drug antibodies.
Up to 3.5 years
Incidence of NAbs Against Efgartigimod Over Time
Time Frame: Up to 3.5 years
NAbs: neutralizing antibodies
Up to 3.5 years
Incidence of Antibodies Against rHuPH20 Over Time
Time Frame: Up to 3.5 years
Up to 3.5 years
Incidence of NAbs Against rHuPH20 Over Time
Time Frame: Up to 3.5 years
NAbs: neutralizing antibodies
Up to 3.5 years
Changes in Total MG-QoL15r From Baseline
Time Frame: Up to week 4 of the first cycle
Myasthenia Gravis Quality of Life 15 item scale revised (MG-QoL 15r) scores range from 0 to 30 with a higher score representing more severe symptoms.
Up to week 4 of the first cycle
Changes in EQ-5D-5L VAS Score From Baseline
Time Frame: Up to week 4 of the first cycle
EuroQoL 5 Dimensions 5-Level (EQ-5D-5L) visual analog scale (VAS) scores range from 0 to 100 with a higher score representing better health.
Up to week 4 of the first cycle
Percent of Participants or Caregivers by Number of Training Visits Needed to be Competent to Start Self- or Caregiver-Supported Administration
Time Frame: Up to 3.5 years
Up to 3.5 years
Percent of Self- or Caregiver-supported Study Drug Administration Among All Study Treatment Visits at Home
Time Frame: Up to 3.5 years
Up to 3.5 years

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

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.
April 26, 2021

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.
December 31, 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.
December 31, 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).
March 11, 2021

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 25, 2021

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 26, 2021

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.
January 22, 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.
January 20, 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.
January 1, 2026

More Information

Terms related to this study

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-113-2002

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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