The Urticaria Activity Score (UAS) is sum of the Hive Severity Score (HSS) and the Itch Severity Score (ISS). UAS7 is sum of the HSS7 and the ISS7 scores. Possible range of weekly UAS7 score is 0 to 42. Complete UAS7 response is UAS7 = 0. Negative change from baseline indicates improvement.

Itch Severity Score (ISS) scale is 0 to 3. Score (ISS7) is derived by adding up average daily scores of 7 days preceding visit. Possible range of weekly score is therefore 0 to 21. Itch Severity Score scale: 0 - None 1 - Mild (minimal awareness, easily tolerated) 2 - Moderate (definite awareness, bothersome but tolerable) 3 - Severe (difficult to tolerate). Negative change from baseline indicates improvement.

Hives Severity Score (HSS) scale is 0 to 3. A weekly score (HSS7) is derived by adding up the average daily scores of the 7 days preceding the visit. Possible range of the weekly score is therefore 0 to 21. Hives Severity Score scale: 0 - None 1 - Mild (1-6 hives/12 hours) 2 - Moderate (7-12 hives/12 hours) 3 - Severe (\>12 hives/12 hours). Negative change from baseline indicates improvement.

A linear regression with SBP as a covariate was employed. The change in SBP from baseline to Week 4 was predicted at the median baseline level. The change from baseline in the 24-hour weighted average SBP was calculated using the time weighted average of the area under the curve (AUC) of SBP obtained over a 24-hour period as measured by ABPM. That is, the time weighted average of AUC of 24-hour SBP obtained at baseline was subtracted from corresponding time weighted average of AUC of SBP at Week 4. In the analysis, if participants took prohibited antihypertensive treatment before Week 4, their subsequent measurements were excluded. In such cases, the excluded measurements were imputed by increasing the 24-hour SBP by 3 mmHg from the baseline value at Week 4. Moreover, participants who discontinued of study treatment due to any reason prior to the Week 4 were excluded from the analysis. The Mixed Models for Repeated Measures (MMRM) approach was used.

The efficacy of remibrutinib in CSU participants with a UAS7\<16 at Week 52 in the prior core study with respect to time to first of the three events: relapse or study treatment discontinuation due to lack of efficacy or intake of strongly confounding prohibited medication up to Week 24 compared to placebo. (Epoch 1) Time to first composite event (i.e., relapse (UAS7≥16), study treatment discontinuation due to lack of efficacy or intake of strongly confounding prohibited medication) during the randomized withdrawal period (Epoch 1) Urticaria Activity Score (UAS7) describes the number of hives with 0 being No Hives and 3 is most severe. The final score is calculated by adding together daily scores which can range from 0-6 for 7 days. The resulting maximum score is then 42.

An adverse event (AE) is any untoward medical occurrence (e.g., any unfavorable and unintended sign \[including abnormal laboratory findings\], symptom or disease) in a clinical investigation participant after providing written informed consent for participation in the study. Therefore, an AE may or may not be temporally or causally associated with the use of a medicinal (investigational) product. Treatment emergent Adverse Event (TEAEs) in this study are events that started after the first dose of study treatment and until 30 days after the last study treatment, or events present prior to the first dose of treatment which increased in severity based on preferred term within 30 days after the last study treatment.

The Weekly Urticaria Activity Score (UAS7) is a simple scoring system to evaluate urticaria signs and symptoms. It is based on scoring wheals (hive severity score) and itch (itch severity score) separately on a scale of 0 (no signs/symptoms) to 3 (intense signs/symptoms) over 7 days. The final score is calculated by adding together the daily scores, which can range from 0 to 6, for 7 days. This results in a maximum total score of 42 (highest urticaria severity), and a minimum possible score of 0. This endpoint is a secondary endpoint for testing strategy Scenario 2 with Weekly Itch Severity Score (ISS7) and Weekly Hives Severity Score (HSS7) as co-primary efficacy endpoints).

The severity of the itch was recorded by the participant twice daily in their electronic Diary, on a scale of 0 (none) to 3 (severe). A weekly score (ISS7) was derived by adding up the average daily scores of the 7 days preceding the visit. The possible range of the weekly score was therefore 0 - 21 (highest itch severity). This endpoint is a secondary endpoint for testing strategy Scenario 1 with Weekly Urticaria Activity Score (UAS7) as the primary efficacy endpoint).

The hives (wheals) severity score, defined by number of hives, was recorded by the participant twice daily in their electronic Diary, on a scale of 0 (none) to 3 (\> 12 hives/12 hours). A weekly score (HSS7) was derived by adding up the average daily scores of the 7 days preceding the visit. The possible range of the weekly score was therefore 0 - 21 (highest hives activity). This endpoint is a secondary endpoint for testing strategy Scenario 1 with Weekly Urticaria Activity Score (UAS7) as the primary efficacy endpoint).

The Weekly Urticaria Activity Score (UAS7) is a simple scoring system to evaluate urticaria signs and symptoms. It is based on scoring wheals (hive severity score) and itch (itch severity score) separately on a scale of 0 (no signs/symptoms) to 3 (intense signs/symptoms) over 7 days. The final score is calculated by adding together the daily scores, which can range from 0 to 6, for 7 days. This results in a maximum total score of 42 (highest urticaria severity), and a minimum possible score of 0. This endpoint is a secondary endpoint for testing strategy Scenario 2 with Weekly Itch Severity Score (ISS7) and Weekly Hives Severity Score (HSS7) as co-primary efficacy endpoints).

The severity of the itch was recorded by the participant twice daily in their electronic Diary, on a scale of 0 (none) to 3 (severe). A weekly score (ISS7) was derived by adding up the average daily scores of the 7 days preceding the visit. The possible range of the weekly score was therefore 0 - 21 (highest itch severity). This endpoint is a secondary endpoint for testing strategy Scenario 1 with Weekly Urticaria Activity Score (UAS7) as the primary efficacy endpoint).

The hives (wheals) severity score, defined by number of hives, was recorded by the participant twice daily in their electronic Diary, on a scale of 0 (none) to 3 (\> 12 hives/12 hours). A weekly score (HSS7) was derived by adding up the average daily scores of the 7 days preceding the visit. The possible range of the weekly score was therefore 0 - 21 (highest hives activity). This endpoint is a secondary endpoint for testing strategy Scenario 1 with Weekly Urticaria Activity Score (UAS7) as the primary efficacy endpoint.

An AE refers to any undesirable medical occurrence, such as an unintended sign (including abnormal laboratory findings), symptom, or disease, experienced by a participant. Serious AEs (SAEs) is defined as any AE that results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, results in a congenital anomaly/birth defect, or any other medically significant condition. Treatment-emergent AEs were defined as AEs that either begin on the same day or after the first dose of study medication during the treatment period in the extension study or worsen on the same day or after the first dose of study medication in the extension study and within the minimum of either 28 days post last dose or the end of the study visit. The number of participants with treatment-emergent AEs was summarized.