A Study to Assess the Long-term Safety and Efficacy of a Subcutaneous Formulation of Efgartigimod PH20 SC in Adults With Pemphigus (Vulgaris or Foliaceus)

Inclusion Criteria:

1. Ability to understand the requirements of the trial, to provide written informed consent (including consent for the use and disclosure of research-related health information), willingness and ability to comply with the trial protocol procedures (including required trial visits).
2. The participant participated in trial ARGX-113-1904 and completed the study or has the defined criteria for rollover.

Contraceptive use by men and women should be consistent with local regulations regarding the methods for contraception for those participating in clinical trials and:

Male participants:

Male participants must agree to use an acceptable method of contraception as described in the protocol, from signing the ICF until the last dose of the study drug.

Female participants

Women of childbearing potential (WOCBP) must:

1. have a negative urine pregnancy test at baseline before the IMP can be administered,
2. agree to use a highly effective or acceptable contraception method (as described in the protocol), which should be maintained at minimum until after the last dose of IMP

Exclusion Criteria:

1. Pregnant and lactating women and those intending to become pregnant during the trial.
2. Participants with clinical evidence of other significant serious disease or participants who recently underwent or have planned a major surgery during the period of the trial, or any other condition in the opinion of the investigator, that could confound the results of the trial or put the participant at undue risk.
3. Known hypersensitivity to any of the components of the administered treatments.