A prospective, randomized, double-blind, placebo-controlled multi-centre study on the efficacy and safety of sublingual immunotherapy (SLIT) in children with seasonal allergic rhinoconjunctivitis to grass pollen

Background: Especially in childhood, sublingual immunotherapy (SLIT) could offer advantages over subcutaneous therapy. However, limited data on its efficacy is available. Methods: In four German centres 97 children (age 3-14 years) with allergic rhinoconjunctivitis to grass pollen were enrolled in a prospective, double-blind trial comparing SLIT (Pangramin SLIT®; ALK-SCHERAX, 0.5 μg major allergens, three times per week, 32 months) with placebo. Primary endpoint was a multiple symptom-medication score for changes in seasonal diary entries between the first and third year of the study (SLIT n = 39; placebo n = 38). Results: The multiple symptom-medication score was significantly reduced by SLIT to 77.3% of the placebo group (P = 0.0498). The subsequent analysis of the single endpoints did not reveal significant differences for symptom scores in favour of SLIT (85.1% of placebo group; P = 0.22). However, the medication score improved significantly (67.1% of placebo group; P = 0.0025). Furthermore, secondary endpoints assessing in vivo immune responses did not differ significantly between the groups. However, retrospective analysis showed some inhomogeneity for clinical and in vitro parameters at the beginning of the study. Allergic side effects with possible relation to the study drug were reported in both groups (SLIT 49%, placebo 27%, P = 0.026). Conclusion: Our study indicates that SLIT had a positive effect on the reduction of a multiple symptom-medication score, mainly by significantly reducing rescue medication use, but had no significant effect on symptoms alone in children with rhinoconjunctivitis to grass pollen compared with a placebo.