D2.193 - Real-World Effectiveness of Allergen Immunotherapy in Polysensitized Patients: A Retrospective Study of 260 Cases

Polysensitization presents a therapeutic challenge in allergen immunotherapy (AIT), often raising concerns about efficacy and allergen selection. Real-world data on long-term outcomes in such populations remain limited. Objective: To assess the clinical effectiveness, safety, and adherence of AIT in a cohort of polysensitized patients undergoing treatment in a real-life setting.

A retrospective observational study was conducted on 260 patients (aged 12–60 years) with allergic rhinitis and/or allergic asthma, all sensitized to three or more aeroallergens. Patients were treated with subcutaneous (SCIT) or sublingual (SLIT) immunotherapy from 2020 to 2025, based on dominant allergen profile and clinical relevance. Data collected included symptom-medication scores (SMS), asthma control (ACT), quality of life (RQLQ), adverse events, and adherence rates, evaluated annually over a 5-year period.

A significant reduction in SMS was observed over time: 48% after one year, 65% after three years, and 72% after five years of AIT. RQLQ scores improved significantly (p < 0.01), indicating better patient-reported outcomes. Among patients with asthma (n=92), 70% showed improved ACT scores after one year of treatment. Adherence rates were 82% at year 1, 78% at year 3, and 61% at year 5. Mild local reactions occurred in 11% of patients, and mild systemic reactions in 3%; no severe adverse events were reported.

This real-world study supports the use of AIT in polysensitized patients, demonstrating sustained clinical benefits, acceptable safety, and good long-term adherence. Selecting the dominant allergen for therapy, even in complex sensitization profiles, appears to be an effective strategy.