Rilzabrutinib for the Treatment of Chronic Spontaneous Urticaria in Patients Who Remain Symptomatic Despite the Use of H1 Antihistamine

Inclusion criteria

• Participants who have a diagnosis of CSU refractory to H1-AH at the time of randomization
• Diagnosis of CSU ≥3 months prior to screening visit (Visit 1).
• The presence of itch and hives for ≥6 consecutive weeks at any time prior to screening visit (Visit 1) despite the use of H1-AH during this time period.
• Participants using a study defined H1-AH for CSU treatment. For participants on stable doses of non-study-approved H1-AH, investigators may switch participants to an equivalent dose of a study-approved H1-AH maintenance medication.
• Participants who are omalizumab naïve OR omalizumab-incomplete responders.
• Participants must be willing and able to complete a daily symptom e-diary for the duration of the study.
• During the 7 days before randomization: UAS7 ≥16 and ISS7 ≥8.
• Contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.

Exclusion criteria

• Clearly defined underlying etiology for CUs other than CSU (main manifestation being physical urticaria).
• Presence of skin morbidities other than CSU that may interfere with the assessment of the study outcomes.
• Participants with active atopic dermatitis (AD).
• Severe concomitant illness(es) that, in the Investigator's judgment, would adversely affect the patient's participation in the study.
• Known or suspected immunodeficiency, or otherwise recurrent infections of abnormal frequency or prolonged duration suggesting an immune compromised status, as judged by the Investigator.
• History of serious infections requiring intravenous (IV) therapy with the potential for recurrence (as judged by the Site Investigator) with less than 4 weeks interval between resolution of serious infection and first dose of study drug, or currently active moderate to severe infection at Screening (Grade 2 or higher), including active coronavirus disease 2019 (COVID-19).
• Live vaccine except Bacille Calmette Guerin-vaccination within 28 days prior to Day 1 or plan to receive one during the trial; Bacille Calmette Guerin-vaccination within 12 months prior to Screening.
• Active malignancy or history of malignancy within 5 years.
• Conditions that may predispose the participant to excessive bleeding
• Any participant with an uncontrolled disease state as judged by the Investigator, such as asthma, psoriasis, or inflammatory bowel disease, etc. that are typically treated with oral or parenteral corticosteroids
• Previous use of a BTK inhibitor.
• Has received any investigational drug (or is currently using an investigational device) within the 30 days before Day 1, or at least 5 times the respective elimination half-life time (whichever is longer).
• Previous exposure to another investigative drug for CSU.
• Positive for human immunodeficiency virus (HIV) antibody test.
• Presence of hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb) with positive DNA test result at screening or within 3 months prior to the screening visit.
• Positive hepatitis C antibody test result at screening or within 3 months prior to the screening visit.
• Tuberculosis infection.
• Any of significant laboratory abnormalities and ECG findings at the screening visit.

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.