A Phase 3 Study of Barzolvolimab in Participants With Chronic Spontaneous Urticaria

Key Inclusion Criteria:

1. Males and females, >/= 18 years of age.

2. Diagnosis of chronic spontaneous urticaria (CSU) >/= 6 months.

3. CSU despite the use of a stable regimen of second generation non-sedatingH1-antihistamine as defined by:

4. The presence of hives for >/= 6 weeks at any time prior to Visit 1 despite theuse of non-sedating H1-antihistamines.

5. Must be on a stable regimen of second generation non-sedating H1-antihistaminefor >/= 4 weeks prior to study treatment.

6. UAS7 of >/= 16 and ISS7 of >/= 8 during the 7 days prior to treatment.

7. Normal blood counts and liver function tests.

8. Both males and females of child-bearing potential must agree to use highly effectivecontraceptives during the study and for 150 days after treatment.

9. Willing and able to complete a daily symptom electronic diary and comply with studyvisits.

10. Participants with and without prior biologic experience are eligible.

Key Exclusion Criteria:

1. Women who are pregnant or nursing.

2. Chronic inducible urticaria that would confound the study endpoints.

3. Other diseases associated with urticaria.

4. Active pruritic skin condition in addition to CSU.

5. Medical condition that would cause additional risk or interfere with studyprocedures.

6. Known HIV, hepatitis B or hepatitis C infection.

7. Vaccination of a live vaccine within 2 months prior to study treatment (subjectsmust agree to avoid live vaccinations during the study). Inactivated vaccines areallowed such as seasonal influenza injection or COVID-19 vaccine.

8. History of anaphylaxis

9. Prior treatment with barzolvolimab

There are additional criteria that your study doctor will review with you to confirm you are eligible for the study.