Effectiveness, Safety, and Treatment Satisfaction of 20% Subcutaneous Immunoglobulin Replacement Therapy in Pediatric Patients with Primary and Secondary Immunodeficiencies

Objective: Primary immunodeficiencies (PID) and secondary immunodeficiencies (SID) increase the risk of severe and recurrent infections. Immunoglobulin replacement therapy (IGRT) is essential for these patients, administered as intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (SCIG). Subcutaneous immunoglobulin therapy, notably the high-concentration 20% immune globulin subcutaneous solution (Ig20Gly), provides significant advantages, including home administration, reduced systemic adverse reaction (SAR), and enhanced patient autonomy through less frequent dosing and lower infusion volumes. This study aims to evaluate the effectiveness, safety, and treatment satisfaction of Ig20Gly in patients with PID and SID, offering insights into optimizing IGRT and the impact of high-concentration SCIG on improving outcomes. Materials and Methods: The authors conducted a retrospective cohort study of 22 pediatric patients with PID or SID who transitioned from IVIG to SCIG. The authors gathered clinical and demographic data, including infection rates, immunoglobulin G (IgG) levels, school absenteeism, and parental workday loss. Treatment satisfaction was assessed using the treatment satisfaction questionnaire for medication-9, and statistical analyses were performed to compare outcomes before and after the transition. Results: Transitioning to SCIG raised median IgG levels from 690 mg/dL during IVIG to 850 mg/dL after 12 months of SCIG (P < .001). Severe bacterial and lower respiratory tract infections decreased significantly, along with parenteral antibiotic use (P = .003, P = .005, P = .009, respectively). School absenteeism and caregiver workday loss also declined (P < .001). While no SARs were observed with SCIG, mild local reactions were reported, which diminished over time. Treatment satisfaction improved significantly, with younger children under 9 reporting lower convenience scores. Patients on IVIG for over 24 months before SCIG had higher satisfaction scores. Conclusion: Twenty percent SCIG therapy has demonstrated a favorable safety and tolerability profile, providing substantial practical advantages for pediatric patients and their families. This therapy not only streamlines the management of pediatric immunodeficiencies but also effectively maintains optimal Ig levels, thereby decreasing infection rates and improving overall patient well-being. These results underscore the potential of SCIG therapy to enhance treatment satisfaction and quality of life. However, additional research is necessary to confirm these findings and evaluate long-term outcomes.