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

The study consists of two parts:

Part A (single dose in HVs in sequential ascending dose cohorts, SAD in HVs part) Part B (seven repeated doses in patients with moderate to severe AD, multiple ascending Dose in patients part)

Key Inclusion Criteria ( Part A and B):

• Age of 18-65 years.
• Body mass index between 18-28 kg/m², capped at 120 kg.
• 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).
• No clinically significant abnormalities or history of relevant diseases.

Key Inclusion Criteria (Part B only):

• 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.
• Eczema Area and Severity Index (EASI) score ≥16 at screening and randomization visits.
• （for biologic/JAKi experienced subjects) Patients with prior systemic exposure to the following agents are eligible for enrollment: biologics targeting IL-4/IL-13 or IL-31 pathway or JAK inhibitors.

Key Exclusion Criteria for (Part A&B)

• 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 for (Part B 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.