ABSTRACT
Background: Hymenoptera venom immunotherapy (VIT) is a safe and effective treatment for Hymenoptera venom allergy (HVA). Unexpected events, such as venom extracts shortage or COVID-19 pandemic, can impact HVA management, and a change in VIT supplier may became necessary. We aimed to evaluate the safety of switching VIT manufacturer without any dose adjustments. Method(s): A retrospective study of patients treated with VIT between 2013 and 2021, in the maintenance phase and without any previous systemic reactions was performed. All the patients switched to another manufacturer while keeping the same venom without any dose modification. All venom extracts were aqueous preparations. Demographic and clinical data were also analyzed. Result(s): A total of 40 patients were included (31 male, median age 44 years old);76% lived in a rural environment, 58% had apiaries <3km from home or work, and 18% were medicated with beta-blockers and/or angiotensin converting enzyme inhibitors. Most patients (68%) were treated with bee venom and the remaining wasp venom. The median time between the beginning of the maintenance phase and the switch to a different VIT supplier was 18 months [1-52 months]. A total of 42 changes between 4 suppliers were performed without any dose adjustments (39 Roxall to Leti;2 Stallergenes to Roxall;1 Inmunotek -> Roxall), with only local reaction reported. This healthy 50-year- old female patient treated with wasp VIT for 3-months in the maintenance phase, switched from Inmunotek to Roxall and presented a local reaction, similar to previous reactions with the former manufacturer. Two years later, she did not react when VIT was changed from Roxall to Leti. No systemic reactions occurred, and no one discontinued VIT. Conclusion(s): International recommendations regarding changing VIT supplier are scarce. Our results suggest that is safe to switch venom extracts from different manufacturers without the need for dose adjustment in patients on maintenance VIT without any previous systemic reactions.