A meta-analysis on allergen-specific immunotherapy using MCT (MicroCrystalline Tyrosine)-adsorbed allergoids in pollen allergic patients suffering from allergic rhinoconjunctivitis.

Background: The World Allergy Organization and the European Academy of Allergy and Clinical Immunology recommend to perform product-specific meta-analyses for allergen-specific immunotherapies because of the high degree of heterogeneity between individual products. This meta-analysis evaluates the efficacy and safety of Glutaraldehyde-modified and MCT (MicroCrystalline Tyrosine)-adsorbed allergoids (MATA).

Methods: The databases MEDLINE, LILACS, embase, LIVIVO, Web of Science and Google (Scholar) were searched for publications on MATA up to June 2019. Primary endpoint was the combined symptom and medication score (CSMS). Secondary endpoints were single scores, immunogenicity and improvement of allergic condition. Secondary safety endpoints were the occurrence of side effects. A random effects model was applied with (standardized) mean differences ([S]MDs) including confidence intervals (CI). Heterogeneity was analyzed using the I index and publication bias using Egger's test and Funnel plots. Subgroups were analyzed regarding age and asthma status.

Results: Eight randomized double-blind placebo-controlled trials were selected for efficacy and 43 publications for safety analysis. In total, 4531 patients were included in this analysis including eight studies containing data on children and adolescents. AIT with MATA significantly reduced allergic symptoms and medication use with a SMD for CSMS of -0.8 (CI: -1.24, -0.36) in comparison to placebo. Heterogeneity was moderate between the studies. The total symptom score (-1.2 [CI: -2.11, -0.29]) and the total medication score (-2.2 [CI: -3.65, -0.74]) were also significantly reduced after MATA treatment. Patient's condition improved significantly after treatment with MATA, with an odds ratio of 3.05 (CI: 1.90, 4.90) when compared to placebo. The proportion of patients, who developed side effects was 38% (CI: 19%, 57%). No serious side effects occurred. Safety in the subgroups of asthmatic patients, children and adolescents did not differ from the overall patient population.

Conclusions: This meta-analysis reveals a large body of evidence from publications investigating MATA. MATA significantly improved allergic symptoms and reduced the use of anti-allergic medication in comparison to placebo, with an excellent safety profile. Especially for children and asthmatic patients, the use of MATAs can be considered as safe, because the safety profiles in these groups did not differ from the total patient population.