Efficacy and safety of a new 20% immunoglobulin preparation for subcutaneous administration, IgPro20, in patients with primary immunodeficiency

Abstract

Subcutaneous human IgG (SCIG) therapy in primary immunodeficiency (PID) offers sustained IgG levels throughout the dosing cycle and fewer adverse events (AEs) compared to intravenous immunoglobulin (IVIG). A phase I study showed good local tolerability of IgPro20, a new 20% liquid SCIG stabilized with L-proline. A prospective, open-label, multicenter, single-arm, phase III study evaluated the efficacy and safety of IgPro20 in patients with PID over 15 months. Forty-nine patients (5-72 years) previously treated with IVIG received weekly subcutaneous infusions of IgPro20. The mean serum IgG level was 12.5 g/L. No serious bacterial infections were reported. There were 96 nonserious infections (rate 2.76/patient per year). The rate of days missed from work/school was 2.06/patient per year, and the rate of hospitalization was 0.2/patient per year. Ninety-nine percent of AEs were mild or moderate. No serious, IgPro20-related AEs were reported. IgPro20 effectively protected patients with PID against infections and maintained serum IgG levels without causing unexpected AEs.

Fig. 1

Serum IgG trough levels (patients with PID). Blood samples were taken before infusion start at screening (S); at weeks 1, 2, 3, 4, 8, and 12; every 4 weeks thereafter; and at the completion visit (CV). For most infusions and for the completion visit, data from at least 29 patients were available; for the following infusions, the number of patients with available data was lower: infusion 60, n = 28; infusion 64, n = 27. Note that the patient’s regular IVIG infusion was given just after screening, and SCIG administration was begun 1 week later

Fig. 2

Rate of injection site reactions over time (patients with PID). Investigator assessments were performed at 15 to 45 minutes after infusion at study visits (every 4 weeks). Patient assessments were made 24 ± 3 hours after every infusion until the completion visit (week 66). For both assessments, the number of infusions with available data decreased from 49 at week 1 to 28 at week 64