A Study to Evaluate Efficacy of Remibrutinib Compared to Dupilumab at Early Timepoints in Adults With Chronic Spontaneous Urticaria Inadequately Controlled by Second Generation H1-antihistamines

* Adults ≥ 18 years of age at the time of signing the informed consent

* 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 sgH1-AH at the time of randomization, defined as:

* The presence of itch and hives for ≥ 6 consecutive weeks prior to screening despite the use of sgH1-AH during the 7 days prior to randomization (Day 1):

* UAS7 score (range, 0-42) ≥ 16, and

* ISS7 score (range, 0-21) ≥ 6, and

* HSS7 score (range, 0-21) ≥ 6

* Documentation of hives within 3 months before randomization (either at screening and/or at randomization); or documented in the participants medical history

* Willing and able to complete an Urticaria Patient Daily Diary (UPDD) for the duration of the study and adhere to the study protocol

* Participants must not have had more than one missing UPDD entry (either morning or evening) in the 7 days prior to randomization (Day 1)

* Previous use of remibrutinib or other bruton's tyrosine kinase (BTK) inhibitors

* Previous use of dupilumab

* Evidence of clinically significant cardiovascular (such as but not limited to myocardial infarction, unstable ischemic heart disease, NYHA Class III/IV left ventricular failure, arrhythmia and uncontrolled hypertension within 12 months prior to Visit 1), neurological, psychiatric, pulmonary, renal, hepatic (past history or current), endocrine or metabolic disorder, or immunodeficiency that, in the investigator's opinion, would compromise the safety of the participant, interfere with the interpretation of the study results or otherwise preclude participation or protocol adherence of the participant.

* Evidence of hematological disorders (including coagulation disorders or significant bleeding risk)

* History or evidence of gastrointestinal disease (including gastrointestinal bleeding, e.g., in association with use of nonsteroidal anti-inflammatory drugs (NSAID), that was clinically relevant (e.g., where intervention was indicated or requiring hospitalization or blood transfusion)

* Requirement for anti-platelet medication, except for acetylsalicylic acid up to 100 mg/d or clopidogrel up to 75 mg/d. The use of dual anti-platelet therapy (e.g., acetylsalicylic acid + clopidogrel) is prohibited.

* Requirement for anticoagulant medication (for example, warfarin or Novel Oral Anti-Coagulants [NOAC])

* History or current hepatic disease including but not limited to acute or chronic hepatitis, cirrhosis or hepatic failure or hepatic parameters at screening: Aspartate Aminotransferase (AST)/ Alanine Aminotransferase (ALT) levels more than 1.5x ULN or International Normalized Ratio (INR) > 1.5 at screening