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Generalized Myasthenia GravisPhase 3ADAPTSC+NCT04818671

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

A Phase 3 study testing efgartigimod PH20 SC in people with Generalized Myasthenia Gravis, run by argenx at 47 sites in 12 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

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… Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Generalized Myasthenia Gravis
What is being tested?
efgartigimod PH20 SC
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
184 participants
Where
47 sitesin 12 countries
Study dates
26 Apr 2021to 31 Dec 2024
Phase
Phase 3
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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.
  • Previously participated in antecedent studies ARGX-113-2001 or ARGX-113-1705 and are eligible for roll over.
  • 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.

Who cannot join

  • 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.
  • 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.
  • 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)
  • Has any of the following medical conditions:
  • Clinically significant uncontrolled chronic bacterial, viral, or fungal infection at roll-over
  • 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
Show all 15Show fewer
  • 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)
  • 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
  • Received a live-attenuated vaccine within 28 days prior to study entry or plan to receive a live-attenuated vaccine during the study
  • A known hypersensitivity reaction to efgartigimod, rHuPH20, or any of its excipients

Trial locations and contacts

47 sites in 12 countries.

47 sites in 12 countries

United States13 sites

  • Investigator Site 46 - US0010111

    Amherst, New York, 14226

  • Investigator Site 43 - US0010066

    Austin, Texas, 78759

  • Investigator Site 45 - US0010108

    Boca Raton, Florida, 33428

  • Investigator site 6 - US0010032

    Carlsbad, California, 92011

  • Investigator Site 38 - US0010003

    Chapel Hill, North Carolina, 27514

  • Investigator Site 42 - US0010019

    Cleveland, Ohio, 44195

  • Investigator site 7 - US0010008

    Cordova, Tennessee, 38018

  • Investigator Site 44 - US0010077

    Durham, North Carolina, 27710

  • Investigator Site 41 - US0010015

    Kansas City, Kansas, 66160

  • Investigator Site 47 - US0010021

    Palo Alto, California, 94304

  • Investigator site 4 - US0010110

    Port Charlotte, Florida, 33952

  • Investigator Site 40 - US0010009

    San Antonio, Texas, 78229

  • Investigator Site 39 - US0010006

    Tampa, Florida, 41076

Other trials in United States

Japan8 sites

  • Investigator site 12 - JP0810002

    Chiba, Chiba-Shi, 260-8677

  • Investigator site 8 - JP0810004

    Hanamaki, Iwate, 025-0082

  • Investigator site 14 - JP0810007

    Osaka, 565-0871

  • Investigator Site 28- JP0810059

    Ōta-ku, Tokyo, 143-8541

  • Investigator Site 36 - JP0810055

    Sapporo, Hokkaido, 063-0005

  • Investigator Site 27 - JP0810008

    Sapporo, 060 8542

  • Investigator site 13 - JP0810005

    Sendai, 983-8520

  • Investigator site 15 - JP0810009

    Tokyo, 160-0023

Other trials in Japan

Poland6 sites

  • Investigator site 17 - PL0480001

    Gdansk, 80-952

  • Investigator site 19 - PL0480007

    Katowice, 40-123

  • Investigator site 22 - PL0480065

    Krakow, 31-426

  • Investigator site 18 - PL0480005

    Krakow, 31-505

  • Investigator site 20 - PL0480018

    Lublin, 20-093

  • Investigator site 21 - PL0480022

    Warsaw, 02-097

Other trials in Poland

Georgia5 sites

  • Investigator Site 32 - GEO9950004

    Tbilisi, K'alak'i T'bilisi, 0160

  • Investigator Site 33 - GEO9950016

    Tbilisi, K'alak'i T'bilisi, 016

  • Investigator site 2 - GEO9950002

    Tbilisi, 0112

  • Investigator Site 1 - GEO9950001

    Tbilisi, 0114

  • Investigator site 3 - GEO9950003

    Tbilisi, 0114

Other trials in Georgia

Italy3 sites

  • Investigator site 11 - IT0390003

    Milan, 20133

  • Investigator Site 34 - IT0390007

    Naples, 80138

  • Investigator Site 35 - IT0390008

    Roma, 00189

Other trials in Italy

Spain3 sites

  • Investigator Site 37 - ES0340021

    Barcelona, 08035

  • Investigator Site 31 - ES0340038

    Barcelona, 08041

  • Investigator site 23 - ES0340039

    Valencia, 46026

Other trials in Spain

Germany2 sites

  • Investigator Site 25 - DE490006

    Berlin, 10117

  • Investigator Site 26 - DE490009

    Münster, 48149

Other trials in Germany

Hungary2 sites

  • Investigator site 10 - HU0360013

    Budapest, 1082

  • Investigator site 9 - HU0360012

    Budapest, 1204

Other trials in Hungary

Russia2 sites

  • Investigator Site 29- RU0070002

    Novosibirsk, 630087

  • Investigator Site 30 - RU0070014

    Saint Petersburg, 194354

Other trials in Russia

Belgium1 site

  • Investigator site 5 - BE0320007

    Ghent, 9000

Other trials in Belgium

Czechia1 site

  • Investigator site 24 - CZ4200005

    Brno, 625 00

Other trials in Czechia

Netherlands1 site

  • Investigator site 16 - NL0310001

    Leiden, 2333

Other trials in Netherlands

About this study

Official title: 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).

Being tested
efgartigimod PH20 SC
Medical subject headings
Myasthenia Gravis

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • efgartigimod PH20 SCBiological

    Subcutaneous injection with efgartigimod PH20 SC

Study groups in NCT04818671
Study groupRoleWhat they receive
efgartigimod PH20 SCExperimentalPatients receiving efgartigimod PH20 subcutaneous (SC) treatment
Receives: Biological: efgartigimod PH20 SC

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Number of AEs, SAEs and AESIs

    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.

    Measured: Up to 3.5 years

Secondary outcomes (12)

  1. MG-ADL Total Score Changes From Baseline

    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.

    Measured: Up to week 4 of the first cycle

  2. Percent Change in Total IgG Levels From Baseline

    IgG: immunoglobulin G

    Measured: Up to week 4 of the first cycle

  3. Percent Change in AChR-Ab From Baseline in AChR-Ab Seropositive Participants

    AchR-Ab: anti-acetylcholine receptor antibodies.

    Measured: Up to week 4 of the first cycle

  4. Efgartigimod Serum Concentrations

    Measured: Up to week 4 of the first cycle

  5. Incidence of ADAs Against Efgartigimod Over Time

    ADA: Anti-drug antibodies.

    Measured: Up to 3.5 years

  6. Incidence of NAbs Against Efgartigimod Over Time

    NAbs: neutralizing antibodies

    Measured: Up to 3.5 years

  7. Incidence of Antibodies Against rHuPH20 Over Time

    Measured: Up to 3.5 years

  8. Incidence of NAbs Against rHuPH20 Over Time

    NAbs: neutralizing antibodies

    Measured: Up to 3.5 years

  9. Changes in Total MG-QoL15r From Baseline

    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.

    Measured: Up to week 4 of the first cycle

  10. Changes in EQ-5D-5L VAS Score From Baseline

    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.

    Measured: Up to week 4 of the first cycle

  11. Percent of Participants or Caregivers by Number of Training Visits Needed to be Competent to Start Self- or Caregiver-Supported Administration

    Measured: Up to 3.5 years

  12. Percent of Self- or Caregiver-supported Study Drug Administration Among All Study Treatment Visits at Home

    Measured: Up to 3.5 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted26 Mar 2021
  2. Study start26 Apr 2021
  3. Primary completion31 Dec 2024
  4. Study completion31 Dec 2024

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
184 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04818671
Sponsor's protocol ID
ARGX-113-2002
Acronym
ADAPTSC+
Status last verified
Jan 2026
First submitted
11 Mar 2021
Last updated
22 Jan 2026
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Undecided

Publications

  • Meisel A, Antozzi C, Bhavaraju-Sanka R, De Bleecker JL, Huang WY, Jimenez RH, Verhamme FM, Jiang M, Liu L, Korobko D, Kostera-Pruszczyk A, Utsugisawa K, Verschuuren JJGM, Vu T, Wiendl H, Howard JF Jr. Long-term safety, tolerability, and efficacy of subcutaneous efgartigimod PH20 in generalized myasthenia gravis: final results from a phase 3 open-label extension study (ADAPT-SC+). Front Neurol. 2026 Aug 21;17:1876344. doi: 10.3389/fneur.2026.1876344. eCollection 2026.

    PubMed 42699831

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing efgartigimod PH20 SC in people with Generalized Myasthenia Gravis, run by argenx at 47 sites in 12 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 22 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 47 sites in United States, Japan, Poland, Georgia, Italy and 7 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 22 Jan 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of AEs, SAEs and AESIs (time frame: Up to 3.5 years). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04818671, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jan 2026.

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