A Multicenter, Open-label Phase 3 Study: Ambulatory Blood Pressure Monitoring in Adult Patients With Chronic Spontaneous Urticaria Inadequately Controlled by H1-antihistamines Treated With Remibrutinib up to 12 Weeks.

Inclusion Criteria:

1. Signed informed consent must be obtained prior to participation in the study.
2. Male and female adult participants ≥18 years of age at the time of screening.
3. CSU duration for ≥ 6 months prior to screening (defined as the onset of CSU determined by the investigator based on all available supporting documentation).

Diagnosis of CSU inadequately controlled by second generation H1-AH at the time of baseline (Day 1) defined as:

1. The presence of itch and hives for ≥6 consecutive weeks prior to screening despite the use of second generation H1-AH during this time period.
2. UAS7 score (range 0-42) ≥16, ISS7 score (range 0-21) ≥ 6 and HSS7 score (range 0-21) ≥ 6 during the 7 days prior to baseline (Day 1).
3. Documentation of hives within three months before baseline (either at screening and/or at baseline (Day 1); or documented in the participants' medical history).
4. Willing and able to complete an Urticaria Patient Daily Diary (UPDD) for the duration of the study and adhere to the study protocol.
5. Participants must not have had more than two missing UPDD entry (either morning or evening) in the 7 days prior to baseline (Day 1).

Exclusion Criteria:

1. Use of other investigational drugs within 5 half-lives or within 30 days (for small molecules) prior to Screening or until the expected pharmacodynamic (PD) effect has returned to baseline (for biologics), whichever is longer; or longer if required by local regulations.
2. Previous use of remibrutinib or other BTK inhibitors.
3. History of hypersensitivity to any of the study treatments or its excipients or to drugs of similar chemical classes.
4. Participants having a clearly defined predominant or sole trigger of their chronic urticaria (chronic inducible urticaria) including urticaria factitia (symptomatic dermographism), cold-, heat-, solar-, pressure-, delayed pressure-, aquagenic-, cholinergic-, or contact-urticaria.
5. Ongoing or past history of hypertension and/or SBP ≥140 or ≤90 and/or DBP ≥90 or ≤60 mmHg at screening.
6. Participants unable to tolerate 24-hour ambulatory blood pressure measurement prior to baseline.
7. Participants with an arm circumference greater than 50cm.