A Multicentric Clinical Study to Evaluate Pharmacokinetics, Efficacy, and Safety of Immune Globulin Subcutaneous 20% Weekly/Biweekly Dosing in Treatment-Experienced Patients and Loading/Weekly Maintenance Dosing in Treatment-Naïve Patients with Prima

Intravenous immunoglobulin (IVIG) therapy is a well-documented and effective treatment for primary immunodeficiencies (PI). Subcutaneous immunoglobulins (SCIG) have emerged as an effective alternative for some patients that offers additional flexibility.Currently, caprylate/chromatography purified IGSC (human) 20% is approved to treat PI in North America and many countries worldwide. In this multi-center, open-label study, the pharmacokinetics (PK), efficacy, and safety of IGSC 20% were studied after biweekly (every two weeks) dosing for 16 weeks and compared to weekly IGSC 20% administration for 16 weeks in treatment-experienced PI patients. A loading/weekly maintenance SC regimen was also studied in PI patients naïve to IG treatment.In treatment-experienced patients, the least squares mean ratio of steady-state AUC_0-7 days for biweekly dosing showed non-inferiority to weekly dosing (90% confidence interval 1.0030-1.0685). Other PK parameters (C_max, T_max, steady state trough) were similar between treatments. Efficacy and safety measures were qualitatively similar to previously published results. No serious bacterial infections were reported. Annual rates for any type of infection were similar between the treatment groups. All severe treatment-related adverse events (AEs) were unrelated to treatment. Only mild to moderate suspected adverse drug reactions were observed.PK analyses showed that biweekly dosing of IGSC 20% was non-inferior to weekly dosing in treatment-experienced PI patients. Biweekly dosing had similar patterns to weekly in prevention of serious bacterial infections, rates of all infections and hospitalizations for infections. The IGSC loading/maintenance dosing regimen in naïve patients was safe and effective during the observation period.