This study is a Phase III, 52-week, multi-center, placebo controlled pivotal study to evaluate the efficacy and safety of remibrutinib compared to placebo in adolescent and adult participants with peanut, milk, or egg IgE-mediated allergy.

This study will be conducted in 4 Sub-studies: Sub-study 1 to evaluate response to peanut allergen at Week 24, Sub-study 2 to evaluate response to milk allergen at Week 24, Sub-study 3 to evaluate response to egg allergen at Week 24, and Sub-study 4 to evaluate response to peanut or milk, or egg allergen at Week 4.

Treatment period 1: Participants will receive one of the two treatment groups, double-blind remibrutinib or placebo, for a period up to 24 weeks for Sub-studies 1, 2, and 3, and up to 4 weeks for Sub-study 4.

Treatment period 2: For all Sub-studies, the open label period starts at Week 24, except for Sub-study 4, where the open label period starts at Week 4. Participants from each Sub-study will continue in the study and receive, or initiate, active open label remibrutinib until Week 52.

Following completion of the treatment period 2, eligible participants may enroll in a separate open-label post-trial access study and receive remibrutinib to evaluate long-term treatment effects. Participants who do not enroll in the post-trial access study will enter a 4-week safety follow-up period off treatment, during which adverse events will be monitored.