New approaches to the design of sublingual immunotherapy clinical trials

Author(s): Enrico Compalati, Anthi Rogkakou, Alberto Bordo, Giorgio Walter Canonica, Giovanni Passalacqua

The aim of this article is to assess and discuss the recently raised key issues concerning the new approaches in conducting clinical trials for sublingual immunotherapy (SLIT), with a special remark on the need for real-life studies exploring those factors able to affect the clinical relevance of the treatment. Although SLIT clinical efficacy in respiratory allergy has been investigated by numerous double-blind, randomized trials and meta-analyses, shortcomings in the execution and reporting of some studies may explain the difficulties in identifying a potential role of SLIT for allergic diseases therapy. This issue prompted the international scientific communities to discuss and reach a consensus on the mainstays to follow during clinical trial designing, carrying out and reporting. It was found that particular attention should be paid to the methodological aspects. Indications about patients’ selection, baseline assessment, statistical analysis, choice of primary and secondary end points and types of allergen vaccines have been suggested to ensure the robustness of findings. The Consolidated Standards of Reporting Trials checklist should be considered in the phase of reporting the studies to improve transparency, paying attention to the measures aimed at reducing the probability of selection and publication bias. Being safe is a crucial aspect, uniform classifications of adverse events are also desirable to support reliable assessments worldwide. Beyond methodological issues, SLIT should be explored in the context of real-life studies. Clinical trials, rigorous in their methodology and characteristics, extended to all the most relevant allergens, are needed to provide clear evidence of short-term and disease-modifying effects of SLIT in respiratory allergy.