A Safety and Tolerability Study of ARGX-113 in Patients With Myasthenia Gravis Who Have Generalized Muscle Weakness.

A Long-Term, Single-Arm, Open-Label, Multicenter, Phase 3 Follow-on Trial of ARGX-113-1704 to Evaluate the Safety and Tolerability of ARGX-113 in Patients With Myasthenia Gravis Having Generalized Muscle Weakness

This is a Long-Term, Single-Arm, Open-Label, Multicenter Phase 3 follow-on trial of the ARGX-113-1704 study to evaluate the safety and tolerability of ARGX-113 in patients with gMG. Patients who have completed at least 1 cycle of treatment and at least 1 year of trial ARGX-113-1705 and have started Part B are eligible to enroll in the open-label trial ARGX-113-2002 to receive efgartigimod by SC administration.

Inclusion Criteria:

1. Patients with the ability to understand the requirements of the trial, provide written informed consent, and comply with the trial protocol procedures.
2. Patients who participated in trial ARGX-113-1704 and are eligible for roll over, as specified in the protocol.

Other more specific inclusion criteria are further defined in the protocol.

Exclusion Criteria:

1. Patients who discontinued early from trial ARGX-113-1704 or patients who discontinued early from randomized treatment for pregnancy or rescue reasons or an (S)AE that might jeopardize the safety of the patient in that trial.
2. Pregnant and lactating women, and those intending to become pregnant during the trial or within 90 days after the last dosing. Women or childbearing potential should have a negative urine pregnancy test at SEB.
3. Male patients who are sexually active and do not intend to use effective methods of contraception during the trial or within 90 days after the last dosing or male patients who plan to donate sperm during the trial or within 90 days after the last dosing.
4. Patients with known Hepatitis B Virus (HBV), Hepatitis C Virus (HCV) or Human Immunodeficiency Virus (HIV) seropositivity.

Other, more specific exclusion criteria are further defined in the protocol.