- Arms 1 and 2: Averaged Mean Change from Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score Over Weeks 8, 10 and 12
Average mean change from baseline in MG-ADL total score over Weeks 8, 10 and 12 will be reported. The MG-ADL provides a rapid assessment of the participant's MG symptom severity. Eight functions (talking, chewing, swallowing, breathing, impairment of ability to brush teeth or comb hair, impairment of ability to arise from a chair, double vision, eyelid droop) are rated on a 4-point scale: 0 (no impairment) to 3 (severe impairment). The total score will be sum of eight function scores and can range from 0 to 24. A higher score indicates greater symptom severity.
- Arms 1 and 2: Mean Percent Change from Baseline in Total IgG Between Arm 1 at EoT and Arm 2 at EoC Based on Clinical Evaluation
Mean percent change from baseline in total IgG between Arm 1 at end of treatment (EoT) and Arm 2 at end of cycle (EoC) based on clinical evaluation will be reported. EoC based on clinical evaluation is defined as the timepoint at which after completion of one cycle of efgartigimod, based on MG-ADL score clinical criteria, the treatment decision would be made to start a second cycle of efgartigimod, an MG rescue medication, or Week 12/EoT, whichever occurs first.
- Arms 1 and 2: Mean Percent Change from Baseline in MG-ADL Total Score Between Arm 1 at EoT and Arm 2 at EoC Based on Clinical Evaluation
Mean change from baseline in MG-ADL total score between Arm 1 at EoT and Arm 2 at EoC based on clinical evaluation will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arms 1 and 2: Mean Percent Change from Baseline in Total IgG Levels at Week 8
Mean percent change from baseline in total IgG levels at Week 8 will be reported.
- Arms 1 and 2: Mean Change from Baseline in MG-ADL Total Score at Week 8
Mean change from baseline in MG-ADL total score at Week 8 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arms 1 and 2: Averaged Mean Change from Baseline in Quantitative Myasthenia Gravis (QMG) Total Score Over Weeks 8 and 12
Average mean change from baseline in QMG total score over Weeks 8 and 12 will be reported. The QMG test is a standardized quantitative strength assessment comprising 13 components. The quantitative results of each strength component are mapped to the following 4-point scale: 0 = None, 1 = Mild, 2 = Moderate and 3 = Severe. The total score can range from 0 to 39. A higher score indicates greater weakness.
- Arms 1 and 2: Mean Percent Change from Baseline in QMG Total Score Between Arm 1 at EoT and Arm 2 at EoC Based on Clinical Evaluation
Mean change from baseline in QMG total score between Arm 1 at EoT and Arm 2 at EoC based on clinical evaluation will be reported. The QMG test is a standardized quantitative strength assessment comprising 13 components. The quantitative results of each strength component are mapped to the following 4-point scale: 0 = None, 1 = Mild, 2 = Moderate and 3 = Severe. The total score can range from 0 to 39. A higher score indicates greater weakness.
- Arms 1 and 2: Mean Change from Baseline in QMG Total Score at Week 8
Mean change from baseline in QMG total score at Week 8 will be reported.
- Arms 1 and 2: Percentage of Participants Maintaining >= 2-Point Improvement in MG-ADL Total Score for At Least 6 Weeks During Randomized Treatment Phase
Percentage of participants maintaining \>= 2-point improvement in MG-ADL total score for at least 6 weeks during the 12 week randomized treatment phase between Arms 1 and 2 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arms 1 and 2: Percentage of Participants Maintaining >= 2-Point Improvement in MG-ADL Total Score for At Least 8 Weeks During Randomized Treatment Phase
Percentage of participants maintaining \>= 2-point improvement in MG-ADL total score for at least 8 weeks during the 12 week randomized treatment phase between Arms 1 and 2 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arms 1 and 2: Percentage of Participants Maintaining >= 2-Point Improvement in MG-ADL Total Score for 50% of Postbaseline Observations
Percentage of participants maintaining \>= 2-point improvement in MG-ADL total score for at least 50% of study duration between Arms 1 and 2 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arms 1 and 2: Percentage of Participants Maintaining >= 2-Point Improvement in MG-ADL Total Score for 75% of Postbaseline Observations
Percentage of participants maintaining \>= 2-point improvement in MG-ADL for at least 75% of study duration between Arms 1 and 2 will be reported.
- Arms 1 and 2: Percentage of Participants with MG-ADL Total Score of 0 or 1 at Week 12
Percentage of participants with MG-ADL total score of 0 or 1 at end of study treatment between Arms 1 and 2 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arm 3: Mean Percent Change in Total IgG from Switch Day 1 to Switch Week 12
Mean percent change in total IgG from pre-nipocalimab exposure to end of nipocalimab study treatment in Arm 3 will be reported.
- Arm 3: Mean Change in MG-ADL Total Score from Switch Day 1 to Switch Week 12
Mean change in MG-ADL total score from pre-nipocalimab exposure to end of nipocalimab study treatment in Arm 3 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arm 3: Percentage of Participants with >= 2-Point Improvement in MG-ADL Total Score at Switch Week 12
Percentage of participants with \>= 2-point improvement in MG-ADL total score at switch week 12 in Arm 3 will be reported.
- Arm 3: Percentage of Participants Maintaining >= 2-Point Improvement in MG-ADL Total Score for At Least 6 Weeks During Treatment Phase
Percentage of participants maintaining \>= 2-point improvement in MG-ADL total score while on nipocalimab for at least 6 weeks during treatment phase in Arm 3 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arm 3: Percentage of Participants with MG-ADL Total Score of 0 or 1 at Switch Week 12
Percentage of participants with MG-ADL total score of 0 or 1 at switch week 12 in Arm 3 will be reported. MG-ADL provides a rapid assessment of the participant's MG symptom severity. The total score can range from 0 to 24. A higher score indicates greater symptom severity.
- Arms 1 and 2: Number of Participants with Adverse Events (AEs), Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs)
An AE is any untoward medical occurrence in a clinical study participant administered with a pharmaceutical (investigational or non investigational) product. An AE does not necessarily have a causal relationship with the intervention. An SAE is any untoward medical occurrence that at any dose results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a suspected transmission of any infectious agent via a medicinal product and is medically important. Treatment-emergent AEs associated with a. infections that are severe or require IV anti-infective or operative/invasive intervention, b. events of hypoalbuminemia \<20 g/L and c. serious and non-serious venous thromboembolism (VTE; deep vein thrombosis \[DVT\] and/or pulmonary embolism \[PE\]) will be considered AESIs.
- Arm 3: Number of Participants with AEs, SAEs and AESIs
An AE is any untoward medical occurrence in a clinical study participant administered with a pharmaceutical (investigational or non investigational) product. An AE does not necessarily have a causal relationship with the intervention. An SAE is any untoward medical occurrence that at any dose results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a suspected transmission of any infectious agent via a medicinal product and is medically important. Treatment-emergent AEs associated with a. infections that are severe or require IV anti-infective or operative/invasive intervention, b. events of hypoalbuminemia \<20 g/L and c. serious and non-serious venous thromboembolism (VTE; DVT and/or PE) will be considered AESIs.