A Study to Evaluate the Efficacy and Safety of Maintenance Ublituximab Following Induction With Efgartigimod Administration in Participants With Myasthenia Gravis (MG)

• Ublituximab (Drug), also known as BRIUMVI: Administered as an IV infusion.
• Placebo (Drug): Administered as an IV infusion.

Primary outcomes

• Time to Onset of a Clinical Worsening Event [Up to Week 24]

Secondary outcomes

• Number of Participants with Treatment-Emergent Adverse Events (TEAEs) [Up to Week 72]
• Maximum Plasma Concentration (Cmax) of Ublituximab [Up to Week 72]
• Proportion of Participants with Cluster of Differentiation 19 + (CD19+) B-cell Counts [Up to Week 72]
• Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score in RCP [Baseline, Week 24]: The MG-ADL scale focuses on relevant symptoms and functional performance of activities of daily living in participants with MG. The total score varies between 0-24, with higher score indicating more severe disease.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

1. Documentation of MG diagnosis.
2. Eligible for treatment with efgartigimod per effective local product label, confirmed by serological testing at screening.
3. MG-ADL score at the time of screening more than or equal to (≥) 6 and less than or equal to (≤) 10 with more than (>) 50 percent (%) of this score attributed to non-ocular items, or an MG-ADL score ≥ 11.

Exclusion Criteria:

1. Active chronic (or stable but treated with immune therapy) disease of the immune system other than MG (e.g., rheumatoid arthritis, scleroderma, Sjögren's syndrome, Crohn's disease, ulcerative colitis, etc.) or immunodeficiency syndrome (hereditary immune deficiency, drug-induced immune deficiency, etc.).
2. Lack of efficacy or observed safety concerns from prior neonatal Fc receptor (FcRn) treatment.
3. Prior treatment with B-cell depleting therapy, alemtuzumab, total lymphoid irradiation, bone marrow transplant, T-cell vaccination therapy, or natalizumab at any time prior to screening.
4. Participants with significantly impaired organ function.
5. History of life-threatening injection/infusion related reaction (IRR/ISR), hypersensitivity, or anaphylactic reaction with components of efgartigimod or ublituximab solutions, protocol-allowed rescue medications, or protocol required pre-treatment medications.
6. Unwillingness or inability to comply with study and/or follow-up procedures outlined in the protocol.

Note: Other protocol-specified Inclusion/Exclusion criteria may apply.

NIH grants: 2025