Evaluating the Pharmacodynamic Noninferiority of Efgartigimod PH20 SC Administered Subcutaneously as Compared to Efgartigimod Administered Intravenously in Patients With Generalized Myasthenia Gravis (ADAPTsc)

• ClinicalTrials.gov Identifier: NCT04735432
• Recruitment Status: Completed
• First Posted: February 3, 2021
• Results First Posted: February 28, 2023
• Last Update Posted: February 28, 2023
• Sponsor: argenx
• Information provided by (Responsible Party): argenx

• Study Type: Interventional
• Study Design: Allocation: Randomized; Intervention Model: Parallel Assignment; Masking: None (Open Label); Primary Purpose: Treatment
• Condition: Generalized Myasthenia Gravis
• Interventions: Biological: efgartigimod PH20 SC; Biological: efgartigimod IV
• Enrollment: 110

Participant Flow

Recruitment Details

Participant's evaluation of eligibility was performed at screening and confirmed at randomization visit 1. The overall study duration per subject was approximately 12 weeks spanning the study periods - 2 weeks for screening, 3 weeks for treatment, and 7 weeks for follow-up.

Pre-assignment Details

153 patients were screened, 111 patients were randomized 1:1 to receive efgartigimod PH20 SC 1000 mg (55) or efgartigimod IV 10 mg/kg (56) once weekly for 4 administrations (4 doses on days 1, 8, 15, and 22). 110 patients started in the study (received treatment) as one participant randomized to the efgartigimod IV arm did not receive treatment due to an AE. 55 patients received study treatment in each treatment arm.

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description	Patients receiving efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with 1000 mg efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Period Title: Overall Study
Started	55	55
Completed	52	55
Not Completed	3	0
Reason Not Completed
Other - due to personal reason	1	0
Adverse Event	2	0

Baseline Characteristics

Arm/Group Title		Efgartigimod PH20 SC	Efgartigimod IV	Total
Arm/Group Description		Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod	Total of all reporting groups
Overall Number of Baseline Participants		55	55	110
Baseline Analysis Population Description		ITT analysis set: All randomized participants who were exposed to the IMP. mITT analysis set: All randomized participants with a value for total IgG levels at baseline and at least 1 postbaseline time point. Safety analysis set: All randomized participants who were exposed to IMP. PK analysis set: A subset of the safety analysis set with at least 1 post dose PK measurement.
Age, Categorical; Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	55 participants	55 participants	110 participants
	<=18 years	0 0.0%	0 0.0%	0 0.0%
	Between 18 and 65 years	43 78.2%	37 67.3%	80 72.7%
	>=65 years	12 21.8%	18 32.7%	30 27.3%
Age, Continuous; Median (Full Range); Unit of measure: Years
	Number Analyzed	55 participants	55 participants	110 participants
		53.0; (19 to 84)	59.0; (24 to 83)	53.5; (19 to 84)
Sex: Female, Male; Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	55 participants	55 participants	110 participants
	Female	31 56.4%	34 61.8%	65 59.1%
	Male	24 43.6%	21 38.2%	45 40.9%
Race (NIH/OMB); Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	55 participants	55 participants	110 participants
	American Indian or Alaska Native	0 0.0%	0 0.0%	0 0.0%
	Asian	4 7.3%	4 7.3%	8 7.3%
	Native Hawaiian or Other Pacific Islander	0 0.0%	0 0.0%	0 0.0%
	Black or African American	0 0.0%	0 0.0%	0 0.0%
	White	50 90.9%	51 92.7%	101 91.8%
	More than one race	1 1.8%	0 0.0%	1 0.9%
	Unknown or Not Reported	0 0.0%	0 0.0%	0 0.0%

Outcome Measures

1. Primary Outcome

Title	Percent Change From Baseline in Total IgG Levels at Day 29 (mITT Analysis Set)
Description	ANCOVA Analysis of Percent Change From Baseline in Total IgG Level at Day 29 (ie, 7 days after the fourth IV or SC administration).
Time Frame	From week 0 to week 4

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	50	52
Least Squares Mean (95% Confidence Interval); Unit of Measure: percent
	-66.4; (-68.91 to -63.86)	-62.2; (-64.67 to -59.72)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Efgartigimod PH20 SC, Efgartigimod IV
	Comments	The primary endpoint was analyzed using an ANCOVA model with treatment as a factor and total IgG levels at baseline as a covariate. The NI evaluation was based on a percent reduction from baseline in total IgG levels at day 29 (week 4) using an NI margin of 10%. Only the results for mITT analysis set are entered.
	Type of Statistical Test	Non-Inferiority
	Comments	This was a phase 3, multicenter, randomized, open-label, parallel-group, 12-week study to evaluate the noninferiority of the pharmacodynamic effect of efgartigimod PH20 SC 1000 mg compared with efgartigimod IV 10 mg/kg in patients with generalized myasthenia gravis.
Statistical Test of Hypothesis	P-Value	< 0.0001
	Comments	[Not Specified]
	Method	ANCOVA
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS mean difference
	Estimated Value	-4.2
	Confidence Interval	(2-Sided) 95%; -7.73 to -0.66
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 1.782
	Estimation Comments	[Not Specified]

2. Secondary Outcome

Title	Percent Change From Baseline in Total IgG Levels Over Time (mITT Analysis Set)
Description	Total IgG level percent change from baseline over time for the overall population.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

mITT Analysis Set: All randomized participants with a value for total IgG levels at baseline and at least 1 postbaseline timepoint.

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Mean (Standard Error); Unit of Measure: percent
Week 1	-40.1 (1.45)	-39.6 (1.51)
Week 2	-56.9 (1.57)	-55.1 (1.85)
Week 3	-62.2 (1.41)	-59 (2)
Week 4	-64.7 (1.95)	-62.3 (1.24)
Week 5	-57.4 (1.7)	-49.9 (2.17)
Week 6	-44 (2.52)	-38.9 (2.24)
Week 7	-31.2 (4.67)	-25.3 (2.78)
Week 8	-8.9 (8.65)	-14.6 (3.13)
Week 10	7.8 (7.78)	-3.1 (3.82)

3. Secondary Outcome

Title	Percent Change From Baseline in AChR-Ab Levels Over Time in AChR- Ab Positive Patients (mITT Analysis Set)
Description	Percent reduction from baseline in AChR-Ab levels over time in AChR-Ab positive patients measured in mITT Analysis Set. Descriptive statistics have been used for this secondary end point.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	45	46
Mean (Standard Error); Unit of Measure: percent
Week 1	-42.5 (1.5)	-43.7 (1.55)
Week 2	-57.4 (1.39)	-55.1 (1.52)
Week 3	-61.8 (1.6)	-59.2 (1.66)
Week 4	-62.2 (1.76)	-59.6 (1.74)
Week 5	-55.3 (1.52)	-47.2 (2.98)
Week 6	-40.4 (3.13)	-29.9 (4.61)
Week 7	-26.7 (4.76)	-15.8 (5.63)
Week 8	-14.5 (7.82)	-7.1 (6.02)
Week 10	13.5 (23.16)	10.3 (7.85)

4. Secondary Outcome

Title	Percent Change From Baseline in IgG Subtype Levels Over Time (mITT Analysis Set)
Description	Median (IQR) Percent Change From Baseline for the IgG Subtypes (IgG1, IgG2, IgG3, and IgG4) in the Overall Population. The highest number of patients among all weeks for the analysis is chosen for each arm. Descriptive statistics have been used for this secondary end point.
Time Frame	Baseline to week 10

Outcome Measure Data

Analysis Population Description

mITT Analysis Set: All randomized participants with a value for total IgG levels at baseline and at least 1 postbaseline timepoint.

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Median (Inter-Quartile Range); Unit of Measure: Percent change
Percent change from baseline at week 4 IgG1	-71; (-79.3 to -56.6)	-68.4; (-73 to -61.5)
Percent change from baseline at week 4 IgG2	-65.6; (-72.2 to -58.1)	-64.5; (-73 to -57.4)
Percent change from baseline at week 4 IgG3	-69.6; (-78.3 to -58.4)	-64.7; (-76.9 to -59.5)
Percent change from baseline at week 4 IgG4	-56.4; (-64.4 to -37.2)	-55.5; (-64.2 to -42.1)

5. Secondary Outcome

Title	AUEC of the Percent Change From Baseline in Total IgG Level (mITT Analysis Set)
Description	AUEC of the percent reduction from baseline total IgG per dosing interval (days 1-8, days 8-15, days 15-22, and days 22-29), days 1-29, days 1-57 and over the entire study (days 1-71). The highest number of patients among all weeks for the analysis is chosen for each arm. Descriptive statistics have been used for this secondary end point.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Mean (Standard Error); Unit of Measure: percent days
Days 1-8 (baseline-week 1)	-138.9 (5.48)	-139.1 (5.67)
Days 8-15 (week 1-week 2)	-341.9 (9.9)	-328.3 (10.98)
Days 15-22 (week 2-week 3)	-416.0 (12.06)	-399.8 (14.46)
Days 22-29 (week 3-week 4)	-447.3 (9.24)	-427.0 (9.76)
Days 1-29 (baseline-week 4)	-1332.5 (30.78)	-1311.6 (26.35)
Days 1-57 (baseline-week 8)	-2515.9 (96.98)	-2387.6 (77.61)
Days 1-71 (baseline-week 10)	-2562.9 (171.86)	-2500.3 (116.10)

6. Secondary Outcome

Title	Еfgartigimod IV and PH20 SC Serum Pharmacokinetic Parameter Ctrough
Description	Evaluation of observed predose concentration (Ctrough) (after all doses for the IV and SC treatment arms). The analysis will present data from Week 1 to Week 4. Descriptive statistics have been used for this secondary end point.
Time Frame	From Week 1 to Week 4.

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	49	51
Mean (Standard Deviation); Unit of Measure: μg/mL
Ctrough week 1	18.3 (8.05)	16.4 (33.0)
Ctrough week 2	21.4 (8.36)	14.0 (6.92)
Ctrough week 3	22.5 (9.61)	15.2 (8.05)
Ctrough week 4	22.0 (8.12)	14.9 (6.43)

7. Secondary Outcome

Title	Efgartigimod IV Serum Pharmacokinetic Parameter Cmax
Description	Evaluation of maximum observed concentration (Cmax) (after all doses for the IV treatment arm). The analysis will present data from Baseline to Week 3. Descriptive statistics have been used for this secondary end point.
Time Frame	From Baseline to Week 3

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod IV
Arm/Group Description:	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	54
Mean (Standard Deviation); Unit of Measure: μg/mL
Cmax Baseline	199 (62.8)
Cmax week 1	215 (63.0)
Cmax week 2	211 (75.0)
Cmax week 3	206 (59.5)

8. Secondary Outcome

Title	Incidence of ADA Against Efgartigimod (Safety Analysis Set)
Description	Incidence of antidrug antibodies (ADA) against Efgartigimod in the overall population. ADA analysis is performed with a validated ELISA in a 3-tiered approach (ADA screening analysis, confirmatory analysis and a titration assay). Descriptive statistics have been used for this secondary end point.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Measure Type: Number; Unit of Measure: Percent of patients
	34.5	20.0

9. Secondary Outcome

Title	Incidence of Antibodies Against rHuPH20 in the SC Treatment Arm (Safety Analysis Set)
Description	Incidence of antibodies against rHuPH20 in the Efgartigimod PH20 SC Arm. antibody analysis is performed with a validated ELISA in a 3-tiered approach (screening analysis, confirmatory analysis and a titration assay) Descriptive statistics have been used for this secondary end point.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC
Overall Number of Participants Analyzed	55
Measure Type: Number; Unit of Measure: Percent of patients
	5.5

10. Secondary Outcome

Title	Incidence and Severity of AEs and SAEs (Safety Analysis Set)
Description	Evaluation of incidence and severity of treatment-emergent adverse events (TEAEs) and incidence of serious AEs (SAEs). Descriptive statistics have been used for this secondary end point.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Measure Type: Number; Unit of Measure: Percent of patients
≥1 AE	67.3	50.9
≥1 SAE	14.5	7.3
≥1 Grade 3 or higher AE	16.4	7.3
≥1 AESI	18.2	16.4
≥1 Injection site reaction (localized)	38.2	1.8
≥1 Infusion- or injection-related reaction	25.5	3.6
≥1 Fatal AE	0	0
≥1 Treatment-related AE according to PI	43.6	21.8
≥1 Procedure-related AE according to PI	25.5	3.6
≥1 Treatment-related SAE	0	0
≥1 AE for which the IMP was interrupted	1.8	0
≥1 AE for which the IMP was discontinued	3.6	0

11. Secondary Outcome

Title	MG-ADL Responders (ITT Analysis Set)
Description	Evaluation of number and percentage of Myasthenia Gravis Activities of Daily Living (MG-ADL) responders in the overall population. The 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, including talking, chewing, swallowing, breathing, brushing their teeth, combing their hair, or getting up from a chair. The MG-ADL also assesses double vision and eyelid droop. It is a discrete quantitative variable in which the 8 items are rated by the participant on a scale of 0 to 3. The total score can range from 0 to 24, with higher total scores indicating more impairment. A participant was considered a MG-ADL responder if he/she showed a reduction of at least 2 points from baseline on the MG-ADL score for at least 4 consecutive weeks. Descriptive statistics have been used for this secondary end point.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Measure Type: Number; Unit of Measure: percent
	69.1	69.1

12. Secondary Outcome

Title	QMG Responders (ITT Analysis Set)
Description	Evaluation of number and percentage of Quantitative Myasthenia Gravis (QMG) responders in the overall population (ITT Analysis Set). Descriptive statistics have been used for this secondary end point. One subject in the EFG IV arm had no post-baseline QMG assessment and thus was excluded from the denominator.
Time Frame	From Baseline to Week 10

Outcome Measure Data

Analysis Population Description

One patient from Efgartigimod IV didn't have any post-baseline QMG assessment.

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	54
Measure Type: Number; Unit of Measure: percent
	65.5	51.9

13. Secondary Outcome

Title	Change From Baseline in MG-ADL Total Score Over Time (ITT Analysis Set)
Description	Evaluation of MG-ADL Total Score Change from baseline over time for the overall population (ITT Analysis Set). Descriptive statistics have been used for this secondary end point. The 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, including talking, chewing, swallowing, breathing, brushing their teeth, combing their hair, or getting up from a chair. The MG-ADL also assesses double vision and eyelid droop. It is a discrete quantitative variable in which the 8 items are rated by the participant on a scale of 0 to 3. The total score can range from 0 to 24, with higher total scores indicating more impairment. A participant was considered a MG-ADL responder if he/she showed a reduction of at least 2 points from baseline on the MG-ADL score for at least 4 consecutive weeks.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Mean (Standard Error); Unit of Measure: Total score on a scale
Week 1	-2.2 (0.33)	-2.0 (0.30)
Week 2	-3.6 (0.40)	-3.2 (0.35)
Week 3	-4.7 (0.36)	-4.3 (0.33)
Week 4	-5.1 (0.38)	-4.7 (0.37)
Week 5	-4.9 (0.36)	-4.3 (0.41)
Week 6	-4.2 (0.35)	-3.7 (0.44)
Week 7	-3.9 (0.35)	-3.6 (0.44)
Week 8	-3.3 (0.34)	-2.9 (0.4)
Week 10	-2.2 (0.44)	-2.1 (0.43)

14. Secondary Outcome

Title	Change From Baseline in QMG Score Over Time (ITT Analysis Set)
Description	Evaluation of QMG Total Score change from baseline over time for the overall population (ITT Analysis Set). The QMG (Quantitative Myasthenia Gravis) quantifies disease severity based on impairments of body function and structures as defined by the International Classification of Functioning, Disability and Health. The QMG consists of 13 items that assess ocular, bulbar, and limb function. Six of the 13 items are timed endurance tests measured in seconds. Each item has a possible score from 0 to 3. The total possible score is 39, where higher total scores indicate more severe impairments. It is based on qualitative testing of specific muscle groups to assess limb function. Descriptive statistics have been used for this secondary end point. A participant was considered a QMG responder if he/she showed a reduction of at least 3 points from baseline on the QMG score for at least 4 consecutive weeks.
Time Frame	From baseline to week 10

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Efgartigimod PH20 SC	Efgartigimod IV
Arm/Group Description:	Patients receiving 1000 mg efgartigimod PH20 subcutaneous (SC) treatment. efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC	Patients receiving 10 mg/kg efgartigimod intravenous (IV) treatment. efgartigimod IV: Intravenous infusion of efgartigimod
Overall Number of Participants Analyzed	55	55
Mean (Standard Error); Unit of Measure: Total score
Week 1	-3 (0.48)	-2 (0.44)
Week 2	-4.3 (0.58)	-3.4 (0.44)
Week 3	-5.7 (0.61)	-4.5 (0.5)
Week 4	-6.1 (0.62)	-5.2 (0.52)
Week 5	-5.9 (0.61)	-5 (0.57)
Week 6	-5.2 (0.6)	-5 (0.61)
Week 7	-3.9 (0.61)	-4.1 (0.55)
Week 8	-3.7 (0.66)	-3.3 (0.53)
Week 10	-2.3 (0.6)	-2.8 (0.53)

Adverse Events

Time Frame	up to 12 weeks (throughout the treatment period)
Adverse Event Reporting Description	AEs will be reported by the participant (or, when appropriate, by a caregiver, surrogate, legally authorized representative). The investigator are responsible for detecting, documenting, and recording events that meet the definition of an AE or SAE and remain responsible for following up AEs that are serious, considered related to the study intervention or study procedures, or that caused the participant to discontinue the study intervention.
Arm/Group Title	Efgartigimod PH20 SC		Efgartigimod IV
Arm/Group Description	Patients receiving efgartigimod PH20 subcutaneous (SC) treatment efgartigimod PH20 SC: Subcutaneous injection with efgartigimod PH20 SC		Patients receiving efgartigimod intravenous (IV) treatment efgartigimod IV: Intravenous infusion of efgartigimod
All-Cause Mortality
	Efgartigimod PH20 SC		Efgartigimod IV
	Affected / at Risk (%)		Affected / at Risk (%)
Total	0/55 (0.00%)		0/55 (0.00%)
Serious Adverse Events
	Efgartigimod PH20 SC		Efgartigimod IV
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	8/55 (14.55%)		4/55 (7.27%)
Cardiac disorders
Cardiac failure congestive † 1	0/55 (0.00%)	0	1/55 (1.82%)	1
General disorders
Chest pain † 1	0/55 (0.00%)	0	1/55 (1.82%)	1
Infections and infestations
Cellulitis † 1	1/55 (1.82%)	1	0/55 (0.00%)	0
Injury, poisoning and procedural complications
Humerus fracture † 1	1/55 (1.82%)	1	0/55 (0.00%)	0
Nervous system disorders
Myasthenia gravis † 1	5/55 (9.09%)	5	1/55 (1.82%)	1
Optic neuritis † 1	1/55 (1.82%)	1	0/55 (0.00%)	0
Syncope † 1	1/55 (1.82%)	1	0/55 (0.00%)	0
Reproductive system and breast disorders
Testicular cyst † 1	0/55 (0.00%)	0	1/55 (1.82%)	1
Respiratory, thoracic and mediastinal disorders
Dyspnoea † 1	1/55 (1.82%)	1	1/55 (1.82%)	1
1 Term from vocabulary, MedDRA 24.1; † Indicates events were collected by systematic assessment
Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events	5%
	Efgartigimod PH20 SC		Efgartigimod IV
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	37/55 (67.27%)		23/55 (41.82%)
Gastrointestinal disorders
Diarrhoea † 1	1/55 (1.82%)	5	3/55 (5.45%)	3
General disorders
Fatigue † 1	2/55 (3.64%)	2	3/55 (5.45%)	3
Injection site bruising † 1	4/55 (7.27%)	4	0/55 (0.00%)	0
Injection site erythema † 1	7/55 (12.73%)	7	0/55 (0.00%)	0
Injection site pain † 1	3/55 (5.45%)	3	0/55 (0.00%)	0
Injection site pruritus † 1	5/55 (9.09%)	5	0/55 (0.00%)	0
Injection site rash † 1	8/55 (14.55%)	14	0/55 (0.00%)	0
Infections and infestations
Urinary tract infection † 1	1/55 (1.82%)	1	3/55 (5.45%)	3
Injury, poisoning and procedural complications
Contusion † 1	0/55 (0.00%)	0	3/55 (5.45%)	3
Fall † 1	1/55 (1.82%)	1	3/55 (5.45%)	3
Nervous system disorders
Headache † 1	7/55 (12.73%)	10	7/55 (12.73%)	11
Myasthenia gravis † 1	6/55 (10.91%)	8	1/55 (1.82%)	2
1 Term from vocabulary, MedDRA 24.1; † Indicates events were collected by systematic assessment

Limitations and Caveats

None reported.

More Information

Certain Agreements

All Principal Investigators ARE employed by the organization sponsoring the study.

Results Point of Contact

• Name/Title: Regulatory Manager
• Organization: argenx BV
• Phone: +32 9 310 34 00
• EMail: regulatory@argenx.com

• Responsible Party: argenx
• ClinicalTrials.gov Identifier: NCT04735432
• Other Study ID Numbers: ARGX-113-2001
• First Submitted: January 26, 2021
• First Posted: February 3, 2021
• Results First Submitted: November 22, 2022
• Results First Posted: February 28, 2023
• Last Update Posted: February 28, 2023