Phase 3b Study to Assess the Efficacy, Safety, and Tolerability of Remibrutinib in Comparison to Placebo, With Omalizumab as Active Control, in Adult CSU Patients, Followed by an Open-label 52-week Optional Extension.

The purpose of the core phase of the trial is to assess the efficacy, safety and
tolerability of remibrutinib (LOU064) 25 milligrams (mg) twice a day (b.i.d.) over
placebo for 24 weeks and in comparison to omalizumab 300 mg every 4 weeks (q4w) for 52
weeks in participants with chronic spontaneous urticaria (CSU) inadequately controlled by
H1-antihistamines (H1-AH).

The purpose of the open-label extension phase is to assess efficacy, safety and
tolerability up to two years for patients treated with remibrutinib and patients
transitioned from omalizumab to remibrutinib at Week 52. In the extension phase,
treatment will be with remibrutinib only (i.e., no background therapy). The extension
phase will also fulfill the Novartis commitment to provide post-trial access to
participants of the previous core phase. The study consists of 4 periods, and the total study duration is up to 112 weeks.
Approximately 468 adult participants with CSU are expected to be randomized in the study.

Screening period: A screening period of up to 4 weeks will allow for the assessment of
eligibility, determination of baseline disease activity and wash-out of prohibited
medications.

Core Phase Treatment Period (52 weeks):

The treatment period will be double-dummy and double-blind, with placebo injections
matching omalizumab 300 mg s.c. given to participants in the remibrutinib arm and placebo
tablets matching remibrutinib 25 mg given to participants in the omalizumab arm
(double-dummy). At the randomization visit, eligible participants will be randomized to
one of four treatment arms.

Extension Phase Treatment Period (52 weeks): Optional open-label extension where patients
receive treatment with open-label remibrutinib 25 mg, for 52 weeks.

Follow-up period:

For patients that do not enter the extension phase, there will be a 16-week,
treatment-free, safety follow-up period.

Patients that enter extension phase will have a 4-week treatment-free safety follow-up
period at the end of the extension phase.

All participants will be on a stable, local label-approved standard dose of a
second-generation H1-AH ("background therapy") throughout the entire core phase (starting
a minimum of 7 days prior to randomization until the end of the core phase).

In addition, to treat unbearable symptoms of CSU flare-ups, participants will be allowed
to use a different second-generation H1-AH on an as-needed basis ("rescue therapy").