Pharmacometric Analysis Linking Immunoglobulin Exposure to Clinical Efficacy Outcomes in Chronic Inflammatory Demyelinating Polyneuropathy
CPT: pharmacometrics & systems pharmacology. 2021
The two main objectives of this analysis were to (i) characterise the relationship between immunoglobulin (Ig) exposure and chronic inflammatory demyelinating polyneuropathy (CIDP) disease severity using data from 171 patients with CIDP who received either subcutaneous Ig (IgPro20; Hizentra®) or placebo (PATH study), and to (ii) simulate and compare exposure coverage with various dosing approaches considering weekly dosing to be the reference dose. IgG PK parameters including those from a previous population PK model were used to predict individual IgG profile and exposure metrics. Treatment-related changes in inflammatory neuropathy cause and treatment (INCAT) scores were best described by an E(max) model as a function of ΔIgG (total serum IgG at INCAT score assessment minus baseline IgG levels before intravenous Ig restabilisation). Simulations indicate that flexible dosing from daily to biweekly (every other week) provide an exposure coverage equivalent to that of a weekly Ig dose.
Long-Term Efficacy and Safety of Hizentra(R) in Patients with Primary Immunodeficiency in Japan, Europe, and the United States: a Review of 7 Phase 3 Trials
Journal of Clinical Immunology. 2018;38((8):):864-875
Many patients with primary immunodeficiency (PID) require immunoglobulin G (IgG) replacement therapy, delivered as intravenous IgG (IVIG) or subcutaneous IgG (SCIG). We aim to identify trends in efficacy and safety that would not be evident in individual studies of small patient numbers. Seven open-label, Phase 3, prospective, multicenter studies of the efficacy and safety of Hizentra(R) (a SCIG), conducted in Japan, Europe, and the US were summarized. Overall, 125 unique patients received 15,013 weekly infusions during a total observation period of 250.9 patient-years. Mean weekly doses of Hizentra(R) were 83.22-221.3 mg/kg body weight; infusion rates per patient (total body rate) were 25.2-49.3 mL/h across studies. The rates of infections and serious bacterial infections were 3.10 and 0.03 events per patient/year, respectively. Annualized rates of days hospitalized due to infection, out of work/school, and prophylactic antibiotic use were 0.95, 5.14, and 36.78 per patient, respectively. For the equivalent monthly dose, weekly Hizentra(R) SCIG administration resulted in expectedly-increased serum IgG trough levels in patients switching from IVIG, and maintained levels in patients switching from previous SCIG. Adverse events (AEs) totaled 5039 (events/infusion 0.094-0.773), almost all of which were mild/moderate. Three thousand one hundred ninety-seven were considered treatment-related, the most common of which were injection site reactions (2919 events; 0.001-0.592 AEs per infusion). Systemic AEs were very uncommon. The results from these seven studies indicate that Hizentra(R) therapy was both efficacious and well tolerated during long-term treatment. This is particularly important in patients with PID, who may require lifelong IgG replacement therapy.