Nipocalimab Dose Selection in Generalized Myasthenia Gravis.

Area of Science:

• Immunology
• Pharmacology
• Neurology

Background:

• Generalized myasthenia gravis (gMG) is an autoimmune disorder characterized by pathogenic IgG autoantibodies.
• Current treatments may not fully address the underlying mechanisms of IgG-mediated pathology.

Purpose of the Study:

• To develop a mechanistic model for nipocalimab, an anti-FcRn monoclonal antibody.
• To characterize the relationship between nipocalimab pharmacokinetics (PK), FcRn occupancy, IgG reduction, and clinical outcomes in gMG.

Main Methods:

• Integrated PK/pharmacodynamic (PD) data from Phase 1 and Phase 2 studies.
• Developed a mechanistic model linking nipocalimab concentration, FcRn occupancy, and total IgG reduction.
• Characterized the relationship between IgG reduction and MG-Activities of Daily Living (ADL) scores.

Main Results:

• Nipocalimab demonstrated nonlinear FcRn-mediated disposition, leading to rapid, concentration-dependent IgG reduction (up to 85%).
• PK and IgG reduction were consistent between healthy participants and those with gMG, with no accumulation on Q2W dosing.
• Model simulations identified a recommended Phase 3 dose (15 mg/kg Q2W after loading dose) for gMG.

Conclusions:

• Nipocalimab effectively reduces circulating IgG, including pathogenic autoantibodies, in gMG.
• The developed mechanistic model supports dose selection for Phase 3 studies.
• Nipocalimab represents a promising therapeutic strategy for gMG by targeting IgG recycling.