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Completed

NCT Number: NCT04818671

Evaluating the Long-Term Safety and Tolerability of Efgartigimod PH20 SC Administered Subcutaneously 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).

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Key information

Conditions

Generalized Myasthenia Gravis Autoimmune Diseases Autoimmune Diseases of the Nervous System Immune System Diseases Myasthenia Gravis Neoplasms Neoplasms by Site Nervous System Diseases Nervous System Neoplasms Neurodegenerative Diseases Neuromuscular Diseases Neuromuscular Junction Diseases Paraneoplastic Syndromes Paraneoplastic Syndromes, Nervous System

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Investigator site 5 - BE0320007, Ghent, Belgium

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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.

  • 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
  • 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

Treatment and study plan

efgartigimod PH20 SC

Biological

Subcutaneous injection with efgartigimod PH20 SC

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. Percent Change in Total IgG Levels From Baseline

    Time frame: Up to week 4 of the first cycle

    IgG: immunoglobulin G

  3. 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.

  4. Efgartigimod Serum Concentrations

    Time frame: Up to week 4 of the first cycle

  5. Incidence of ADAs Against Efgartigimod Over Time

    Time frame: Up to 3.5 years

    ADA: Anti-drug antibodies.

  6. Incidence of NAbs Against Efgartigimod Over Time

    Time frame: Up to 3.5 years

    NAbs: neutralizing antibodies

  7. Incidence of Antibodies Against rHuPH20 Over Time

    Time frame: Up to 3.5 years

  8. Incidence of NAbs Against rHuPH20 Over Time

    Time frame: Up to 3.5 years

    NAbs: neutralizing antibodies

  9. 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.

  10. 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.

  11. 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

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

    Time frame: Up to 3.5 years

Sponsors and collaborators

Lead sponsor

argenx

Industry

Registry information

Official study 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

Acronym: ADAPTSC+

Important dates

Study start
2021
Primary completion
2024
Study completion
2024
First posted
Mar 26, 2021
Registry last updated
Jan 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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