Clinical Research Directory

Inclusion Criteria: * Participant was eligible for MG0003 \[NCT03971422\] or MGC003 at the time of enrollment into either study and the participant either completed the observation Period of MG0003 or MGC003 or required rescue therapy during the Observation Period of the lead-in studies * Body weight ≥35 kg at Visit 1 * Study participants may be male or female Exclusion Criteria: * Evidence of active or latent tuberculosis (TB) as documented by medical history and examination, if applicable, chest X-rays (posterior anterior and lateral), and TB testing by a positive (not indeterminate) QuantiFERON®-TB Gold Plus * Participant has received a live vaccination within 8 weeks prior to the Baseline visit; or intends to have a live vaccination during the course of the study or within 8 weeks following the final dose of study medication * Study participant has experienced hypersensitivity reaction after exposure to other anti-neonatal Fc receptor (FcRn) drugs - Study participant with severe (defined as Grade 3 on the myasthenia gravis-activates of daily living (MG-ADL) scale) weakness affecting oropharyngeal or respiratory muscles, or who has myasthenic crisis or impending crisis * Participant has any laboratory abnormality that, in the opinion of the Investigator, is clinically significant, has not resolved at randomization, and could jeopardize or compromise the study participant's ability to participate in this study * Study participant met any mandatory withdrawal or mandatory study drug discontinuation criteria MG0003 \[NCT03971422\] or MGC003, or discontinued study medication in either study, with the exception of discontinuation due to a need for rescue treatment * Study participant is not considered capable of adhering to the protocol visit schedule, or medication intake according to the judgment of the Investigator * Study participant has a lifetime history of suicide attempt (including an active attempt, interrupted attempt, or aborted attempt), or had suicidal ideation since the last visit in MG0003 as indicated by a positive response (Yes) to either Question 4 or Question 5 of the Columbia-Suicide Severity Rating Scale (C-SSRS)