D1.215 - Safety of subcutaneous immunotherapy with purified native protein Alt a 1, a major allergen of Alternaria alternata: 7-year real-world data

The effectiveness of allergen immunotherapy (AIT) depends on the appropriate identification of the clinically relevant allergen and on its adequate representation in the AIT product. Allergen extracts usually present a complex and variable composition that may include clinically non-relevant allergens, with a potential impact on treatment safety. Component-resolved diagnosis allows a precise molecular characterization of the patient’s sensitization profile, facilitating a more personalized indication of treatments. Alt a 1 is the major allergen of Alternaria alternata, with a sensitization prevalence of approximately 90%. Molecular immunotherapy based on the use of purified native protein Alt a 1 enables standardized and controlled dosing.

The Pharmacovigilance Department of Diater Laboratorio de Diagnóstico y Aplicaciones, S.A. conducts continuous safety surveillance of all products marketed worldwide, in accordance with current regulatory requirements. Safety data reported for subcutaneous immunotherapy with purified native protein Alt a 1 extract, administered at a maintenance dose of 0.37 µg per injection, were analysed based on spontaneously reported local reactions (LRs) and systemic reactions (SRs) from routine clinical practice over a 7-year period. SRs were graded according to the WAO 2010 classification.

Within this period, over 240,000 injections were administered. The mean incidence for subcutaneous purified native protein Alt a 1 extract was 0.0067 LRs per 100 injections, 0.0055 Grade 1, 0.0017 Grade 2 and 0.0008 Grade 3 SRs per 100 injections. No Grade 4 or 5 SRs were reported. In addition, all reported LRs were mild reactions commonly observed and expected with subcutaneous administration.

These results show that subcutaneous immunotherapy with purified Alt a 1 protein extract demonstrated an excellent real-world safety profile, with a low incidence of adverse reactions over long-term pharmacovigilance follow-up. LRs were mild, and SRs were infrequent and predominantly mild. Overall, real‑world evidence supports the favourable safety profile of subcutaneous purified native protein Alt a 1 extract, confirming its safety and tolerability in patients with Alternaria alternata allergy and its relevance within a precision medicine framework.