obexelimab

Obexelimab is an investigational bifunctional monoclonal antibody designed to inhibit B cell activity by simultaneously targeting CD19 and the inhibitory receptor Fc gamma receptor IIB (FcγRIIb) on B cells. This dual engagement mimics the natural antigen-antibody immune complex, leading to broad inhibition of B cell functions—including antibody production, proliferation, cytokine secretion, differentiation, and antigen presentation—without causing direct cytolysis or depletion of B cells. Obexelimab is being developed primarily for autoimmune diseases where pathogenic autoantibodies play a central role. It has demonstrated rapid recovery of circulating B cells after treatment discontinuation compared to traditional depleting therapies. The drug is administered via subcutaneous or intravenous injection and is currently in late-stage clinical development for IgG4-related disease (IgG4-RD), systemic lupus erythematosus (SLE), and multiple sclerosis[1][3][4][5][6][8].

Other names

obexelimabhumanized anti-CD19, Fc engineered, monoclonal antibody with enhanced binding to FcγRIIb