Trends in allergen-reactive CRTH2+ T cells and TARC associated with successful outcomes in a phase 2 cashew oral immunotherapy study.

Background: We designed an oral immunotherapy (OIT) clinical trial for cashew allergy to further our understanding of immunological responses with treatment, including changes in allergen-specific T cells. This information can further assist with the design of efficacious and safe treatments. Methods: Participants were built up to and maintained on 1 g of cashew flour protein. Double-blind, placebo-controlled food challenges (DBPCFCs) were conducted before and after dosing completion (week 52) and 6 weeks after dosing discontinuation (week 58). Desensitization (DS) and sustained unresponsiveness (SU) were defined as tolerating DBPCFC to a cumulative dose of 2043 mg of the allergen at weeks 52 and 58, respectively. ClinicalTrials.gov, number NCT03504774. Results: We enrolled 40 cashew allergic participants. In the Intent-to-treat (ITT) population, both the DS and SU rate to cashew was 65% (26/40). Among cashew-reactive cells, CRTH2 Conclusion: Cashew OIT have efficacy and safety outcomes similar to other published OIT studies. Reductions in pathogenic allergen-specific T cell populations may contribute to the immune mechanisms underlying tolerance achieved towards cashew post-treatment. Clinical trial registration: ClinicalTrials.gov, identifier NCT03504774.