Transition from subcutaneous to intravenous immunoglobulin therapy in primary immunodeficiency: A case series highlighting patient-centered treatment optimization

Background: Immunoglobulin replacement therapy (IgRT) is a cornerstone therapy for managing primary immuneodeficiency (PID) and other immune-related disorders. While both intravenous immunoglobulin (IVIg) and subcutaneous immunoglobulin (SCIg) are effective, patient tolerance and preferences can influence treatment success. Objective: To evaluate the reasons for switching from SCIg to IVIg in 4 PID patients and to assess the resulting clinical outcomes and patient-reported experiences. Methods: This case series includes 4 individuals with PID who transitioned from SCIg to IVIg due to persistent side effects. Data were collected on adverse reactions during SCIg therapy, changes in immunoglobulin (IgG) levels, and patient-reported outcomes following the switch to IVIg. Results: All patients experienced adverse effects with SCIg, including headaches, fatigue, shortness of breath, and difficulty managing infusions. Following the transition to IVIg, patients reported improved tolerance, fewer side effects, and greater convenience with treatment schedules. IgG levels remained stable or improved post-switch, indicating sustained therapeutic efficacy. Conclusion: IVIg is a viable and effective alternative for PID patients who experience intolerance to SCIg. Individualized IgRT strategies that consider side effect profiles and patient preferences can enhance treatment adherence and quality of life. Statement of Novelty: This case series highlights patient-driven transitions from SCIg to IVIg therapy in primary immunodeficiency patients. This study provides insights into a subset of patients who experience persistent SCIg-related side effects, underscoring the importance of personalized IgRT approaches based on patient tolerance and quality-of-life considerations.