Tolerability of immunoglobulin products and outcomes after product switching: a single-center real-world retrospective study.

OBJECTIVES: We assessed the frequency of adverse drureactions (ADRs) to immunoglobulin products, associated switching patterns, and tolerability after switching in clinical practice. METHODS: This observational, retrospective study was conducted at a single center. We included all patients who were treated with immunoglobulin therapy, irrespective of indication, between June 2017 and May 2025. Data on demographics, diagnoses, immunoglobulin received, ADRs, need for switching, and post-switch ADRs were extracted from records. Analyses were mainly descriptive. RESULTS: We included 51 patients with a median (Q1, Q3) age of 54 (40, 63) years, mostly with primary or secondary immunodeficiencies, who were treated with intravenous immunoglobulins (IVIGs; n = 43) or subcutaneous immunoglobulins (SCIGs; n = 8). Among 42 patients treated with intravenous (IV) Flebogamma®, 22 (52%) experienced ADRs, and 12 (29%) required switching. No ADRs were observed after switching, regardless of whether patients switched to another IVIG or SCIG. Among the seven patients treated with facilitated SCIG (SC HyQvia®), three experienced ADRs, and one of them was switched back to conventional SCIG (SC Hizentra®) due to persistent local adverse reactions, with no further ADRs reported after the switch. CONCLUSION: ADRs associated with IVIG are common and lead to treatment switching in a high proportion of patients. Switching to an alternative immunoglobulin product appears to be a good alternative for managing ADRs.