A Study to Investigate Efficacy, Safety and Tolerability of Barzolvolimab Versus Placebo in Adults With Cold Induced Urticaria and Symptomatic Dermographism Inadequately Controlled by H1-antihistamines (EMBARQ - ColdU and SD)

Key Inclusion Criteria:

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

2. Diagnosis of cold induced urticaria or symptomatic dermographism >/= 3 months.

3. Diagnosis of cold induced urticaria or symptomatic dermographism despite the use ofa stable regimen of second generation non-sedating H1-antihistamine as defined by:

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

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

6. Cold induced urticaria: A Critical Threshold Temperature (CTT) of ≥ 15 °C and < 37 °C using the TempTest® and a numerical rating scale score of ≥ 5 for itchafter the provocation test.

7. Symptomatic dermographism: A Critical Friction Threshold (CFT) of ≥ 3 using theFricTest® and a numerical rating scale score of ≥ 5 for itch after theprovocation test.

8. Cold induced urticaria: Positive ice-cube test resulting in hives at the provocationsite during Screening

9. Normal blood counts and liver function tests.

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

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

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

Key Exclusion Criteria:

1. Women who are pregnant or nursing.

2. Clearly defined cause for chronic urticaria.

3. Active, pruritic skin condition in addition to cold induced urticaria or symptomaticdermographism.

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

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

6. Vaccination with a live vaccine within 30 days prior to screening (subjects mustagree to avoid vaccination with a live vaccine during the study). Inactivatedvaccines are allowed such as seasonal influenza injection or COVID-19 vaccine.

7. History of anaphylaxis, unless due to cold exposure over a large part of the body (such as swimming in cold water).

8. Prior treatment with barzolvolimab

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