Inclusion Criteria:

• 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).
• The patient participated in trial ARGX-113-1904 and completed the study or has the defined criteria for rollover.
• Women of childbearing potential:
  • Must have a negative urine pregnancy test at baseline before trial medication can be administered;
  • Must be on a stable regimen for at least 1 month of at least 1 highly effective method of contraception (i.e., failure rate of less than 1% per year) during the trial and for 90 days after the last administration of IMP.
• Non-sterilized male patients who are sexually active with a female partner of childbearing potential must use effective contraception from first administration of IMP through 90 days after the last administration of the IMP. Male patients practicing true sexual abstinence (as consistent with preferred and usual life style) can be included. Sterilized male patients who have had a vasectomy and with documented absence of sperm post-procedure can be included. Male patients are not allowed to donate sperm from first administration of IMP through 90 days after the last dose of IMP.

Exclusion Criteria:

• Pregnant and lactating women and those intending to become pregnant during the trial or within 90 days after the last administration of IMP.
• Patients with clinical evidence of other significant serious disease or patients 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 patient at undue risk.
• Known hypersensitivity to any of the components of the administered treatments.