LAUSR

Abstract Background Subcutaneous immunoglobulin is one of the standard treatments for hypogammaglobulinemia in primary immunodeficiencies (PID) worldwide. In Japan, IgPro20 (Hizentra®; l‐proline‐stabilized 20% human subcutaneous immunoglobulin) is approved for agammaglobulinemia or hypogammaglobulinemia due to PID or secondary immunodeficiency (SID); however, its safety and effectiveness has not previously been assessed in a real‐world setting. Methods This multicenter, open label post‐marketing surveillance study was conducted between January 2014 and March 2019. Patients who received IgPro20 due to PID or SID were included after informed consent. Physicians completed a case report form for each patient. Safety was determined from reported adverse events (AEs), adverse drug reactions, and serious AEs (SAEs); effectiveness was assessed by infection rates after the first IgPro20 dose. Results Of 85 patients receiving IgPro20 in the safety analysis, 39 developed AEs (45.9%; PID n = 28, SID n = 11). At least one adverse drug reaction was observed in 27 patients (31.8%; PID n = 21, SID n = 6), and the most common were injection site reactions (n = 17, 20.0%). Four patients (PID n = 3, SID n = 1) reported SAEs but two were unrelated to IgPro20 administration. The infection rate decreased from 0.54 per patient during the 6 months before IgPro20 to 0.39 per patient during IgPro20 treatment. Serious bacterial infections occurred in six patients before IgPro20 (7.9%; PID n = 2; SID n = 4) but in only one patient with SID during IgPro20 treatment (1.2%). Conclusions In Japan, IgPro20 was considered safe and effective among patients with agammaglobulinemia or hypogammaglobulinemia due to PID or SID.