Subcutaneous immunoglobulin: opportunities and outlook

Abstract

Immunoglobulin (Ig) administration via the subcutaneous (s.c.) route has become increasingly popular in recent years. The method does not require venous access, is associated with few systemic side effects and has been reported to improve patients' quality of life. One current limitation to its use is the large volumes which need to be administered. Due to the inability of tissue to accept such large volumes, frequent administration at multiple sites is necessary. Most studies conducted to date have investigated the use of subcutaneous immunoglobulin (SCIg) in patients treated previously with the intravenous (i.v.) formulation. New data now support the use of s.c. administration in previously untreated patients with primary immunodeficiencies. SCIg treatment may further be beneficial in the treatment of autoimmune neurological conditions, such as multi-focal motor neuropathy; however, controlled trials directly comparing the s.c. and i.v. routes are still to be performed for this indication. New developments may further improve and facilitate the s.c. administration route. For example, hyaluronidase-facilitated administration increases the bioavailability of SCIg, and may allow for the administration of larger volumes at a single site. Alternatively, more concentrated formulations may reduce the volume required for administration, and a rapid-push technique may allow for shorter administration times. As these developments translate into clinical practice, more physicians and patients may choose the s.c. administration route in the future.

Figures

Fig. 1

Mean serum immunoglobulin (Ig)G levels over time in patients self-administering subcutaneous immunoglobulin (SCIg) by a pump or the rapid push method. The graph represents data from those patients who switched from IVIg to SCIg. Levels as expressed as proportions of the baseline (i.e. start of study) through IgG levels while on IVIg.

Fig. 2

Serum immunoglobulin (Ig)G concentrations over time following intravenous (i.v.) (---) or subcutaneous (s.c.) (—) infusion of 10%Ig facilitated by rHuPH20. (a) Serum IgG concentrations in one patient following s.c. infusion using rHuPH20 at a concentration of 50 U/g 10%Ig. (b) Serum IgG concentrations in a second patient following s.c. infusion using rHuPH20 at a concentration of either 50 U/g 10%Ig (left panel) or 200 U/g 10%Ig (right panel). Area under the curve (AUC) was 75·83% and 77·83% of the AUC following i.v. infusion of the same IgG quantity, respectively.

Fig. 3

Study design of the US IgPro20 phase III study. The study consisted of a 12-week wash-in/wash-out period and a 12-month efficacy period.