IgG Level in Primary Immunodeficiency Switching From Standard SCIG to Every Other Week HyQvia

Most immunodeficiencies are related to severe immunoglobulin deficiencies which require lifelong replacement therapy with immunoglobulin G (IgG) to reduce the incidence and severity of infections. IgG can be administered intravenously (IGIV) every 21 or 28 days or subcutaneously every week or every other week (IGSC) for subjects who do not tolerate IV infusions or have difficulties with venous access. No head-to-head data are available to directly compare HyQvia with conventional SCIG. However, SCIG is indicated for administration frequencies from daily up to every other week dosing while HyQvia is indicated for infusion frequencies every 2-4 weeks. This study is designed to assess the IgG trough level after switching from standard SCIG to every other week HyQvia and HyQvia every 3-4 weeks