Effectiveness of preparations with non-modified allergens for sublingual application evaluation of evidence by reference to clinical trials Background: As in the case of other preparations for specific immunotherapy, the approach taken when choosing a preparation for sublingual immunotherapy (SLIT) should, for ethical and economic reasons, be an evidence-based one. As yet, however, there is no overview available for proof of effectiveness of SLIT preparations marketed in Germany. Aim: The aim is to check, by means of a systematic review, which SLIT preparations available in Germany have had their clinical effectiveness documented. Methods: A literature search looked for randomized, double-blind, placebo-controlled effectiveness trials (DBPC trials) conducted with SLIT preparations, which are commercially available in Germany and contain native extracts from the allergen group grasses, trees and house dust mites. The evidence of effectiveness was assessed on the basis of the criteria of the World Allergy Organization (WAO) or the European Medicines Agency (EMA). Results: 85 DBPC SLIT trials were identified, of which 23 met the inclusion criteria for the review. 16 DBPC trials involved preparations with grass allergens, 1 with tree pollen allergens and 6 with house dust mite allergens. 4 SLIT grass preparations met the effectiveness criteria and for 2 SLIT tablet preparations there are 8 positively evaluated trials in children and adults. A further positively evaluated preparation has been studied in children, teenagers and adults, whilst the fourth preparation has only been studied in adults. In the group of tree pollen preparations, one preparation yielded positive evidence of effectiveness. Of the DBPC trials with mite allergens, the only statistically significant changes were seen in the symptom scores. Conclusion: Of the 12 SLIT preparations available in Germany, there are no DBPC trials providing evidence of effectiveness as per WAO/EMA criteria for 8 of the preparations. However, there is high evidence of effectiveness with a total of 8 positively evaluated trials for the two grass tablets.