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

NCT04818671 | Completed Phase 3 Results DMC FDA Drug

• 1 other identifier: ARGX-113-2002
• Study Type: interventional
• Target: 184
• Locations: 12 countries
• Sites: 47

Brief 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 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).

Conditions

Generalized Myasthenia Gravis

Outcome Measures

Primary Outcomes (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.

  Up to 3.5 years

Secondary Outcomes (12)

• MG-ADL Total Score Changes From Baseline

  Up to week 4 of the first cycle

• Percent Change in Total IgG Levels From Baseline

  Up to week 4 of the first cycle

• Percent Change in AChR-Ab From Baseline in AChR-Ab Seropositive Participants

  Up to week 4 of the first cycle

• Efgartigimod Serum Concentrations

  Up to week 4 of the first cycle

• Incidence of ADAs Against Efgartigimod Over Time

  Up to 3.5 years

Study Arms (1)

efgartigimod PH20 SC

EXPERIMENTAL

Patients receiving efgartigimod PH20 subcutaneous (SC) treatment

Biological: efgartigimod PH20 SC

Interventions

efgartigimod PH20 SC BIOLOGICAL

Subcutaneous injection with efgartigimod PH20 SC

efgartigimod PH20 SC

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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

Sponsors & Collaborators

• argenx: lead

Study Sites (47)

Investigator site 6 - US0010032

Carlsbad, California, 92011, United States

Location

Investigator Site 47 - US0010021

Palo Alto, California, 94304, United States

Location

Investigator Site 45 - US0010108

Boca Raton, Florida, 33428, United States

Location

Investigator site 4 - US0010110

Port Charlotte, Florida, 33952, United States

Location

Investigator Site 39 - US0010006

Tampa, Florida, 41076, United States

Location

Investigator Site 41 - US0010015

Kansas City, Kansas, 66160, United States

Location

Investigator Site 46 - US0010111

Amherst, New York, 14226, United States

Location

Investigator Site 38 - US0010003

Chapel Hill, North Carolina, 27514, United States

Location

Investigator Site 44 - US0010077

Durham, North Carolina, 27710, United States

Location

Investigator Site 42 - US0010019

Cleveland, Ohio, 44195, United States

Location

Investigator site 7 - US0010008

Cordova, Tennessee, 38018, United States

Location

Investigator Site 43 - US0010066

Austin, Texas, 78759, United States

Location

Investigator Site 40 - US0010009

San Antonio, Texas, 78229, United States

Location

Investigator site 5 - BE0320007

Ghent, 9000, Belgium

Location

Investigator site 24 - CZ4200005

Brno, 625 00, Czechia

Location

Investigator Site 32 - GEO9950004

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

Location

Investigator Site 33 - GEO9950016

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

Location

Investigator site 2 - GEO9950002

Tbilisi, 0112, Georgia

Location

Investigator Site 1 - GEO9950001

Tbilisi, 0114, Georgia

Location

Investigator site 3 - GEO9950003

Tbilisi, 0114, Georgia

Location

Investigator Site 25 - DE490006

Berlin, 10117, Germany

Location

Investigator Site 26 - DE490009

Münster, 48149, Germany

Location

Investigator site 10 - HU0360013

Budapest, 1082, Hungary

Location

Investigator site 9 - HU0360012

Budapest, 1204, Hungary

Location

Investigator site 11 - IT0390003

Milan, 20133, Italy

Location

Investigator Site 34 - IT0390007

Naples, 80138, Italy

Location

Investigator Site 35 - IT0390008

Roma, 00189, Italy

Location

Investigator site 12 - JP0810002

Chiba, Chiba-Shi, 260-8677, Japan

Location

Investigator Site 36 - JP0810055

Sapporo, Hokkaido, 063-0005, Japan

Location

Investigator site 8 - JP0810004

Hanamaki, Iwate, 025-0082, Japan

Location

Investigator Site 28- JP0810059

Ōta-ku, Tokyo, 143-8541, Japan

Location

Investigator site 14 - JP0810007

Osaka, 565-0871, Japan

Location

Investigator Site 27 - JP0810008

Sapporo, 060 8542, Japan

Location

Investigator site 13 - JP0810005

Sendai, 983-8520, Japan

Location

Investigator site 15 - JP0810009

Tokyo, 160-0023, Japan

Location

Investigator site 16 - NL0310001

Leiden, 2333, Netherlands

Location

Investigator site 17 - PL0480001

Gdansk, 80-952, Poland

Location

Investigator site 19 - PL0480007

Katowice, 40-123, Poland

Location

Investigator site 22 - PL0480065

Krakow, 31-426, Poland

Location

Investigator site 18 - PL0480005

Krakow, 31-505, Poland

Location

Investigator site 20 - PL0480018

Lublin, 20-093, Poland

Location

Investigator site 21 - PL0480022

Warsaw, 02-097, Poland

Location

Investigator Site 29- RU0070002

Novosibirsk, 630087, Russia

Location

Investigator Site 30 - RU0070014

Saint Petersburg, 194354, Russia

Location

Investigator Site 37 - ES0340021

Barcelona, 08035, Spain

Location

Investigator Site 31 - ES0340038

Barcelona, 08041, Spain

Location

Investigator site 23 - ES0340039

Valencia, 46026, Spain

Location

MeSH Terms

Conditions

Myasthenia Gravis

Condition Hierarchy (Ancestors)

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

Results Point of Contact

• Title: Regulatory Manager
• Organization: argenx BV

regulatory@argenx.com

+32 93103400

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 11, 2021
• First Posted: March 26, 2021
• Study Start: April 26, 2021
• Primary Completion: December 31, 2024
• Study Completion: December 31, 2024
• Last Updated: January 22, 2026
• Results First Posted: January 22, 2026

Record last verified: 2026-01

Locations

BE (1); CZ (1); GE (5); ES (3); JP (8); NL (1); US (13); PL (6); IT (3); HU (2); DE (2); RU (2)