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

ANCOVA Analysis of Percent Change From Baseline in Total IgG Level at Day 29 (ie, 7 days after the fourth IV or SC administration).

Total IgG level percent change from baseline over time for the overall population.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.