Study of BLU-808 in Chronic Inducible Urticaria (CIndU) and Chronic Spontaneous Urticaria (CSU)

Key Inclusion Criteria:

• Part A: Confirmed diagnosis of CIndU for ≥3 months prior to Day 1 that isinadequately controlled with second generation H1-antihistamines.

• Part B: Confirmed diagnosis of CSU for ≥3 months prior to Day 1 that is inadequatelycontrolled with second generation H1-antihistamines.

Key Exclusion Criteria:

• Part A: Any active urticaria that may interfere with study assessments.

• Part B: Participant has a clearly defined predominant cause of chronic urticaria orsole trigger such as symptomatic dermographism and cold-induced urticaria.

• Part A and Part B: Any other skin disease associated with chronic itching orangioedema that might influence the study evaluations and results, skin diseasesassociated with only wheals and no itch, or autoinflammatory diseases withurticarial lesions.

• Part A and Part B: Significant medical, psychiatric, or surgical conditions, orphysical findings that may affect participant safety, study drug metabolism, studyparticipation, or assessment of study results.

• Part A and Part B: Abnormal laboratory values that may pose risks or interfere withstudy participation.

• Part A and Part B: Pregnancy or plans for pregnancy; breastfeeding.