Comparison of Six Different Allergen Extracts for Subcutaneous Specific Immunotherapy in Children: An Open-Labelled, Prospective, Controlled Observational Trial

Background: Numerous products are available for subcutaneous (SCIT) and sublingual allergen-specific immunotherapy, but there are no information about the direct comparability regarding efficacy, safety, and tolerability of the different extracts. Aims: The aim of this open-labelled, prospective, controlled observational trial was to test the feasibility of a comparison of different products for SCIT in children. Methods: Pediatrician practices recruited patients with a confirmed diagnosis of a seasonal allergic rhinoconjunctivitis (AR) with or without asthma and an allergic sensitization against grass pollen allergen. Every patient was offered SCIT with one out of six allergen extracts: ALK SQ Depot, ALK Avanz, Allergovit, Depigoid, Purethal, Pollinex Quattro. Scores for symptoms and medications were calculated and the difference between treatment years and baseline were recorded. Results: In total, 284 were recruited and 255 children (89.8%; mean age 10.4, SD 3.54 years; 65% males) participated in this trial. Overall, 49,649 patient days were recorded in the electronic database (mean 183.2 days/patient). There was no significant difference in the AR and asthma symptom score or the medication score between the six different SCIT preparations. Similarly, no differences were observed in terms of safety and tolerability. Conclusion: The comparison of different SCIT products using an online tool is feasible. Based on our preliminary data, all extracts indicated efficacy; however, larger groups would be necessary to demonstrate superiority or non-inferiority of one specific SCIT product.