D2.228 - Effectiveness and Safety of Subcutaneous Immunotherapy for Patients Allergic to Either Cat Dander or Dermatophagoides/Cat Dander: Real World Data

Sensitization to perennial allergens, particularly Dermatophagoides and cat dander, is highly prevalent across Europe and represents a major cause of persistent allergic rhinitis and allergic asthma. These allergens are associated with perennial symptoms, increased disease severity, and sustained need for pharmacological treatment. Co-sensitization to mites and animal dander is frequent and may complicate disease management. Allergen immunotherapy (AIT) is the only disease-modifying treatment for IgE-mediated respiratory allergy and has demonstrated efficacy in reducing symptoms and medication use. However, real-world data on the effectiveness and safety of high-dose allergoid-based AIT targeting Dermatophagoides and/or cat dander remain limited. Therefore, a retrospective study was conducted to evaluate the effectiveness and safety of this therapeutic approach in routine clinical practice.

A multicenter, observational, retrospective study was conducted in patients with allergic rhinoconjunctivitis, with or without asthma, treated with subcutaneous immunotherapy using glutaraldehyde-polymerized allergenic extracts of cat dander alone or Dermatophagoides/cat dander (10,000 TU/mL per allergen).

A total of 164 patients were included. In the cat dander group (n = 72), the median age was 35 years, 71% were female, and 81% had asthma. After one year of treatment, significant reductions of 50% in the Combined Symptom and Medication Score (CSMS) for rhinoconjunctivitis and 59% in asthma CSMS were observed (both p < 0.05). In the Dermatophagoides/cat dander group (n = 92), 52% of patients were female and 48% were asthmatic. After one year of AIT, rhinoconjunctivitis and asthma CSMS were reduced by 43.5% and 45.8%, respectively (p < 0.05) (Figure 1). No adverse reactions were reported.

In this real-world retrospective study, subcutaneous immunotherapy with glutaraldehyde-polymerized allergenic extracts targeting cat dander alone or in combination with Dermatophagoides resulted in clinically relevant and statistically significant improvements in rhinoconjunctivitis and asthma control over one year, supporting its effectiveness and safety in patients sensitized to perennial allergens.