BASALIT-trial: Double blind placebo controlled allergen immunotherapy with rBet v 1-FV in birch related soy allergy

Abstract

Background

Conflicting results exist on the effect of allergen immunotherapy (AIT) on pollen related food allergy. We aimed to investigate the efficacy of one year AIT with the folding variant (FV) of recombinant (r) Bet v 1 on birch related soy allergy.

Methods

Out of 138 subjects with Bet v 1 sensitization, 82 were positive at double blind placebo controlled food challenge (DBPCFC) with soy. 56/82 were randomized 2:1 (active: placebo). Per protocol population (PPP) had received >150μg of allergen or placebo preparation. Outcome measures: lowest observed adverse effect levels (LOAEL), post interventional occurrence of objective signs (objS) at any dose level, sIgE/IgG4 against Bet v 1 and Gly m 4. Between-group changes were investigated (ANCOVA, Mann-Whitney-U-, Fisher exact test).

Results

Baseline characteristics including LOAELs were comparable in both groups with objS and subjS occurring in 82% and 95% of active (n=38) versus 78% and 83% of placebo group (n=18). After AIT, objS occurred in 24% and 47%, respectively. LOAEL group differences showed a beneficial tendency (p=0.081) for LOAEL_objective in PPP (30 verum, 15 placebo). sIgG4 raised only in active group (Bet v 1: p=0.054, Gly m 4: p=0.037), no relevant changes occurred for sIgE. Only 56% of the intended sample size was recruited.

Conclusion

For the first time, we present data on the effect of rBet v 1-FV on birch related soy allergy. rBet v 1-FV AIT induced significant immunogenic effects. Clinical assessment showed a tendency in favor of the active group but did not reach statistical significance.

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