facilitated subcutaneous immunoglobulin

Facilitated subcutaneous immunoglobulin (fSCIG) is a formulation of human immunoglobulin G (IgG) for replacement therapy in patients with primary or secondary antibody deficiencies. It is administered via the subcutaneous route and is "facilitated" by co-administration with recombinant human hyaluronidase, which temporarily increases tissue permeability and allows for larger volumes of IgG to be infused at one site and less frequent dosing compared to conventional SCIG. This method combines advantages of intravenous (IVIG) and conventional subcutaneous (SCIG) administration—offering fewer needle punctures, longer infusion intervals (often every 3–4 weeks), improved tolerability, stable serum IgG levels, reduced infection rates, and the convenience of home-based therapy[1][2][3][5]. The mechanism of action involves passive immunity through provision of exogenous polyclonal IgG antibodies that supplement deficient or dysfunctional endogenous antibodies; the addition of hyaluronidase does not alter the immune function but enables more efficient delivery[1][2]. Primary indications include primary immunodeficiency diseases; it may also be used in some secondary antibody deficiencies.

Other names

fSCIGhyaluronidase-facilitated subcutaneous immunoglobulinrecombinant human hyaluronidase-facilitated SCIg