D1.192 - Combined Polymerized Pollen and Animal Dander Immunotherapy Improves Rhinoconjunctivitis and Asthma in Polysensitized Patients: Real-World Evidence

Allergen-specific immunotherapy (AIT) is an established disease-modifying treatment; however, evidence on subcutaneous AIT (SCIT) combining pollen and animal dander allergens in a single formulation is limited, particularly in polysensitized patients with perennial respiratory symptoms and seasonal exacerbations of rhinoconjunctivitis and asthma. These patients often experience high disease burden and suboptimal symptom control. This study evaluated the effectiveness of combined SCIT after 12 months in a real-world setting.

This real-world, retrospective study included patients aged 8–46 years treated at Infanta Leonor University Hospital who received SCIT with highly purified, glutaraldehyde-modified allergens from pollens (grass pollens, Olea europaea, Cupressus arizonica, or Platanus acerifolia) and animal dander (cat or dog), administered as dual or triple co-formulated extracts (one or two pollens plus one pet dander). Treatment effectiveness was assessed during routine visits through changes in rhinoconjunctivitis and asthma symptom severity (according to ARIA and GINA guidelines, respectively), patient-reported clinical progression on a Likert scale, and patterns of controller and reliever medication use, assessed separately for seasonal and perennial manifestations.

A total of 21 patients (mean age 25 years; 76% female) were included. After 12 months, the proportion of patients with moderate-to-severe perennial rhinoconjunctivitis decreased from 90% to 14% (p=0.0001), and moderate asthma from 62% to 29% (p=0.023). Seasonal rhinoconjunctivitis showed significant reductions in intranasal corticosteroid use (p=0.016), antihistamine eye drops use (p=0.031), and combination therapies (p=0.008), while perennial rhinitis demonstrated decreased H1-antagonist use (p=0.031) and overall medication use (p=0.031). Both seasonal and perennial asthma showed reduced use of short-acting β₂-agonists (SABA) and combined asthma medications (p=0.0055 and 0.002 for seasonal, p=0.003 and 0.008 for perennial, respectively). Overall, 91% of participants reported subjective clinical improvement.

SCIT with combined polymerized pollen and animal dander extracts improves rhinoconjunctivitis and asthma control in polysensitized patients after 12 months. These real-world findings support the potential of combined allergen SCIT formulations in routine clinical practice, although further studies are warranted to confirm long-term effectiveness and optimize patient selection.