A Study of BBT001 in Healthy Volunteers (HVs) and in Adult Patients With Atopic Dermatitis (AD)

Key Inclusion Criteria

• Negative pregnancy tests for women of childbearing potential.
• Willingness to refrain from alcohol consumption for 24 hours prior to each study visit.
• Non-smokers, healthy current smokers (≤5 cigarettes/day), or ex-smokers.
• Adequate contraception use (for men and women of childbearing potential).

Key Inclusion Criteria (Parts A, B, and D)

• Age of 18-65 years.
• Body mass index of 18 to 32 kg/m², weight capped at 120 kg.
• No clinically significant abnormalities or history of relevant diseases.

Key Inclusion Criteria (Parts C and E only)

• Age of 18-72 years.
• Body mass index ≥16 kg/m², weight capped at 125 kg.
• Must have dermatologist-confirmed chronic atopic dermatitis (≥12 months). Inadequate response to topical treatments or where they are medically inadvisable.
• Moderate to severe atopic dermatitis
• Validated investigator's global assessment for atopic dermatitis (vIGA-ADTM) score ≥3
• Atopic lesions cover ≥10% of body surface area (BSA)
• Average peak pruritus numeric rating scale (PP-NRS) score ≥4 in the 7 days before randomization.

Key Exclusion Criteria

• Significant health issues, such as: diabetes, positive tests for human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B surface antigen (HBsAg), immunodeficiencies, autoimmune diseases, or cancer, history of conditions predisposing to infections.
• History of major metabolic, dermatological, liver, kidney, hematological, or other significant disorders.
• Clinically relevant abnormal lab results, including low blood counts, liver issues, or abnormal kidney function.
• Positive drug/alcohol tests or abnormal vital signs at screening or Day -1.
• Abnormal Electrocardiogram (ECG) findings
• History of drug/alcohol abuse in the past 2 years.
• Donated >500mL blood within 2 months of screening.
• History of severe allergic reactions or hypersensitivity.

Key Exclusion Criteria (Parts A, B, and D only)

• History of atopic dermatitis

Key Exclusion Criteria (Parts C and E only)

• Skin diseases other than atopic dermatitis, significant tattoos, or scarring.
• Receipt of immunoglobulin or blood products within 30 days.
• Atopic dermatitis with ocular symptoms or chronic ocular steroid use.
• Chronic pruritus from conditions other than atopic dermatitis.
• Acute/treated infections or chronic skin infections.
• Current use of sedating antihistamines or corticosteroids.