An Open-label Study to Investigate the Clinical Efficacy of Different Dosing Regimens of Efgartigimod IV in Patients With Generalized Myasthenia Gravis

A Phase 3b, Randomized, Open-label, Parallel-Group Study to Evaluate Different Dosing Regimens of Intravenous Efgartigimod to Maximize and Maintain Clinical Benefit in Patients With Generalized Myasthenia Gravis

The purpose of this open-label study is to investigate the efficacy, safety, and tolerability of a continuous regimen of efgartigimod compared with a cyclic regimen in participants with Generalized Myasthenia Gravis (gMG).

Participants will receive efgartigimod throughout the study. The participants will be randomized to the continuous regimen arm or to the cyclic regimen arm. The study consists of a part A (regimen comparison period) where participants will continue the treatment based on the treatment regimen arm they were assigned at randomization. Following part A, participants will enter part B (extension period) where all participants will receive efgartigimod in the continuous regimen. The study duration for participants is up to 138 weeks.

Inclusion Criteria:

• At least 18 years of age, at the time of signing the informed consent.
• Diagnosed with Generalized Myasthenia Gravis (gMG) with confirmed documentation and supported by a physical exam and confirmed seropositivity for anti-acetylcholine receptor antibodies (AChR-Abs).
• Meets the clinical criteria as defined by the Myasthenia Gravis Foundation of America (MGFA) class II, III, or IV

Exclusion Criteria:

• Any other condition that, in the opinion of the investigator, would interfere with an accurate assessment of the clinical symptoms of gMG and/or put the participant at undue risk

• A thymectomy within 3 months of screening

• Use of the following prior or concomitant therapies:

  1. intravenous immunoglobulin (IVIg) or subcutaneous immunoglobulin (SCIg) within 14 days of day 1
  2. Rituximab within 6 months of day 1
  3. Eculizumab within 1 month of day 1
  4. Other monoclonal antibodies (eg, adalimumab, tocilizumab, ixekizumab)