Fc function of a new intravenous immunoglobulin product: IGIV 10% triple virally inactivated solution

Background and Objectives Baxter AG has developed a new liquid intravenous immunoglobulin product [Immune Globulin Intravenous (IGIV) 10%] using a new manufacturing procedure. A modified Cohn fractionation and ion exchange chromatography is used to produce an IgG solution with no alterations to the Fc region. Three dedicated virus reduction steps are included: solvent-detergent treatment, nanofiltration, and incubation at low pH and elevated temperature in final formulation. We applied the reference method of the European Pharmacopoeia (EP) together with a flow-cytometric binding assay for the evaluation of the Fc function of the new product. Materials and Methods The EP reference method was done as described in the EP. The flow-cytometric method measured binding of IgG to Fc receptors of human monocytic THP-1 cells after exclusion of apoptotic cells. Results Sixteen lots of the new product expressed Fc functions between 84% and 110% when analysed with the EP reference method and Fc-binding activities between 82% and 121% when determined by the flow-cytometric method. Conclusions All tested lots of the new product demonstrated a high level of Fc activity and met the requirements of the EP for Fc function.