Trial · NCT04818671

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

NCT04818671, Phase 3, Completed, argenx; results first posted 2026-01-22

3 sourcestrials-2026-11-12-0.4.0

Cite this record

ConductScience Library. Evaluating the Long-Term Safety and Tolerability of Efgartigimod PH20 SC Administered Subcutaneously in Patients With Generalized Myasthenia Gravis. Trials, record NCT04818671. Release trials-2026-11-12-0.4.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT04818671

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Evaluating the Long-Term Safety and Tolerability of Efgartigimod PH20 SC Administered Subcutaneously in Patients With Generalized Myasthenia Gravis
NCT number: NCT04818671
Status: Completed
Phases: Phase 3
Enrollment: 184 participants, actual
Lead sponsor: argenx
Conditions: Generalized Myasthenia Gravis
Interventions: efgartigimod PH20 SC
First posted: 2021-03-26
Last updated: 2026-01-22
Results first posted: 2026-01-22

Source ClinicalTrials.gov

Registered outcomes13

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Number of AEs, SAEs and AESIs	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	MG-ADL Total Score Changes From Baseline	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.
Secondary	Percent Change in Total IgG Levels From Baseline	Up to week 4 of the first cycle	IgG: immunoglobulin G
Secondary	Percent Change in AChR-Ab From Baseline in AChR-Ab Seropositive Participants	Up to week 4 of the first cycle	AchR-Ab: anti-acetylcholine receptor antibodies.
Secondary	Efgartigimod Serum Concentrations	Up to week 4 of the first cycle
Secondary	Incidence of ADAs Against Efgartigimod Over Time	Up to 3.5 years	ADA: Anti-drug antibodies.
Secondary	Incidence of NAbs Against Efgartigimod Over Time	Up to 3.5 years	NAbs: neutralizing antibodies
Secondary	Incidence of Antibodies Against rHuPH20 Over Time	Up to 3.5 years
Secondary	Incidence of NAbs Against rHuPH20 Over Time	Up to 3.5 years	NAbs: neutralizing antibodies
Secondary	Changes in Total MG-QoL15r From Baseline	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.

1 to 10 of 13Source ClinicalTrials.gov

See all 13 registered outcomes

Outcomes13

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Number of AEs, SAEs and AESIs	Up to 3.5 years	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study	events	NUMBER
SECONDARY	MG-ADL Total Score Changes From Baseline	Up to week 4 of the first cycle	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. Only participants with an assessment at baseline and the respective weeks of first cycle are reported in each row.	score on a scale	MEAN
SECONDARY	Percent Change in Total IgG Levels From Baseline	Up to week 4 of the first cycle	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. Only participants with an assessment at baseline and week 4 of the first cycle are reported.	Percent change	MEAN
SECONDARY	Percent Change in AChR-Ab From Baseline in AChR-Ab Seropositive Participants	Up to week 4 of the first cycle	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. Only participants with an assessment at baseline and week 4 of the first cycle are reported.	Percent change	MEAN
SECONDARY	Efgartigimod Serum Concentrations	Up to week 4 of the first cycle	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. Only participants with an assessment at baseline and week 4 of the first cycle are reported.	ng/mL	MEAN
SECONDARY	Incidence of ADAs Against Efgartigimod Over Time	Up to 3.5 years	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. The number analyzed is the total number of ADA evaluable participants.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Incidence of NAbs Against Efgartigimod Over Time	Up to 3.5 years	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. The number analyzed is the total number of NAb-evaluable participants.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Incidence of Antibodies Against rHuPH20 Over Time	Up to 3.5 years	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. The number analyzed is the total number of rHuPH20 Ab evaluable participants.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Incidence of NAbs Against rHuPH20 Over Time	Up to 3.5 years	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. The number analyzed is the total number of rHuPH20 NAb-evaluable participants.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Changes in Total MG-QoL15r From Baseline	Up to week 4 of the first cycle	Safety analysis set: all participants who were exposed to efgartigimod PH20 SC in this study. Only participants with an assessment at baseline and the respective weeks of first cycle are reported in each row.	score on a scale	MEAN

1 to 10 of 13Source ClinicalTrials.gov

See all 13 outcomes

Results by group33

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Category	Value	Spread	Units
Number of AEs, SAEs and AESIs	Efgartigimod PH20 SC	Number of AEs	3325		events
Number of AEs, SAEs and AESIs	Efgartigimod PH20 SC	Number of SAEs	107		events
Number of AEs, SAEs and AESIs	Efgartigimod PH20 SC	Number of AESIs	420		events
MG-ADL Total Score Changes From Baseline	Efgartigimod PH20 SC	Cycle 1, Week 1	-2.2	Standard Error 0.20	score on a scale
MG-ADL Total Score Changes From Baseline	Efgartigimod PH20 SC	Cycle 1, Week 2	-3.4	Standard Error 0.21	score on a scale
MG-ADL Total Score Changes From Baseline	Efgartigimod PH20 SC	Cycle 1, Week 3	-3.9	Standard Error 0.22	score on a scale
MG-ADL Total Score Changes From Baseline	Efgartigimod PH20 SC	Cycle 1, Week 4	-4.0	Standard Error 0.23	score on a scale
Percent Change in Total IgG Levels From Baseline	Efgartigimod PH20 SC		-62.6	Standard Error 0.93	Percent change
Percent Change in AChR-Ab From Baseline in AChR-Ab Seropositive Participants	Efgartigimod PH20 SC		-57.6	Standard Error 2.29	Percent change
Efgartigimod Serum Concentrations	Efgartigimod PH20 SC		21693	Standard Deviation 8242	ng/mL

1 to 10 of 33Source ClinicalTrials.gov

See all 33 results by group

Participant flow3

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Efgartigimod PH20 SC	180
Overall Study	COMPLETED	Efgartigimod PH20 SC	138
Overall Study	NOT COMPLETED	Efgartigimod PH20 SC	42

Source ClinicalTrials.gov

Adverse events99

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Anaemia	Blood and lymphatic system disorders	Efgartigimod PH20 SC	18	180
other	Iron deficiency anaemia	Blood and lymphatic system disorders	Efgartigimod PH20 SC	13	180
other	Cataract	Eye disorders	Efgartigimod PH20 SC	9	180
other	Abdominal pain upper	Gastrointestinal disorders	Efgartigimod PH20 SC	11	180
other	Diarrhoea	Gastrointestinal disorders	Efgartigimod PH20 SC	32	180
other	Nausea	Gastrointestinal disorders	Efgartigimod PH20 SC	16	180
other	Fatigue	General disorders	Efgartigimod PH20 SC	10	180
other	Influenza like illness	General disorders	Efgartigimod PH20 SC	14	180
other	Injection site bruising	General disorders	Efgartigimod PH20 SC	24	180
other	Injection site erythema	General disorders	Efgartigimod PH20 SC	55	180

1 to 10 of 99Source ClinicalTrials.gov

See all 99 adverse events

Adverse event totals3

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Efgartigimod PH20 SC	5	180
Total, other adverse events	Efgartigimod PH20 SC	167	180
Total, serious adverse events	Efgartigimod PH20 SC	55	180

Source ClinicalTrials.gov

Papers1

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as
42699831	DERIVED

Source PubMed

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons0

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

None in this release.

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Source

Release: trials-2026-11-12-0.4.0
Release manifest SHA-256: 0f4a8d8c48aee2a7573ae0fa94ecbeab70c1adbe449bbc95c424bc7d3e97b9d4
Registry capture: 2026-11-12
Results copy, AACT: 2026-03-23
NIH clinical studies file: 2026-11-13

Source ClinicalTrials.gov

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNone stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

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