Clinical efficacy and immunological response in children is similar to that of adults after the first treatment season with SQ-standardized grass allergy immunotherapy tablet in two randomized trials

Background: Specific immunotherapy is the only treatment of IgE-mediated allergic diseases with the potential to modify the underlying cause of disease and prevent disease progression or even cure the disease. Treatment in children is therefore desirable. However, it is an open question whether immunotherapy in children and adolescents works as effective as demonstrated in adults. Objective: This post-hoc study compares the clinical efficacy and immunological response in children and adults based on two separate randomized, double-blind, placebo-controlled trials with the SQ-standardized grass allergy immunotherapy tablet (AIT) (ALK, Denmark). Methods: Children and adults were treated with grass AIT or placebo prior to and during one grass pollen season. To account for seasonal and geographical variabilities in grass pollen counts between trials, data for the peak 2 weeks of the grass pollen season has been compared. Endpoints included rhinoconjunctivitis symptom scores, medication scores and percentages well-days. Furthermore results for the entire pre- and co-seasonal periods of each trial in Phleum pratense-specific IgE-blocking factor and Igat have been compared. Results: The measured treatment efficacy during the peak grass pollen season from the pediatric and the adult trials were similar in difference relative to placebo for symptom scores (27%; 28%; p-values for both <0.01), medication scores (64%; 56%; p-values for both <0.01) and percentages of well-days (44%; 46%; p-values for both <0.01). Grass MT induced comparable IgE-blocking factor and IgG(4) responses in children and adults. All assessments were in favor of active treatment. Conclusion: Treatment with grass MT for one grass pollen season is as efficacious in children as in adults and induces comparable immunological responses.