A Phase 1/1b Study to Evaluate Safety, Tolerability and Pharmacokinetics of ZL-1503 in Healthy Volunteers and Participants With Moderate to Severe Atopic Dermatitis

Other illness

• For Part B only:
  • Presence of dermatologic conditions and/or comorbidities that might confound the diagnosis of AD and/or might interfere with study assessments.
  • Uncontrolled chronic disease that might require bursts of oral corticosteroids.
  • Any other sound medical, psychiatric, and/or social reason as determined by the investigator.

Lab values

• Part A and B:
  • Significant health issues, such as positive tests for human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B surface antigen (HBsAg), active tuberculosis, immunodeficiencies or autoimmune diseases.
  • History of major metabolic, liver, kidney, hematologic or other significant disorders.
  • Abnormal Electrocardiogram (ECG) findings
  • Clinically relevant abnormal lab results, including low blood counts, or abnormal liver and kidney function.
  • History of drug abuse or addiction within 6 months prior to screening
  • Current smoker or use of any nicotine or tobacco containing products within the last 6 months prior to dosing.
  • Donated \>500mL blood within 2 months of dosing.

• Part A:
  • Healthy male and female volunteers, 18-65 years of age
  • Body mass index (BMI) between ≥ 18.5 and \< 32.5 kg/m2
  • Negative pregnancy tests for women of childbearing potential.
• Part B:
  • 18-65 years of age;
  • BMI between ≥18.5 and \<40.0 kg/m2
  • Have a diagnosis of AD at least 12 months prior to Day 1;
  • Moderate-to-severe AD at Screening and Baseline visit, defined as:
  • Eczema Area and Severity Index (EASI) score ≥ 16;
  • Affected Body Surface Area (BSA)≥ 10%;
  • vIGA-AD™ score ≥ 3
  • History of an inadequate response to treatment with topical medications
  • Average peak pruritus numeric rating scale (PP-NRS) score ≥4 in the 7 days before randomization.
  • Negative pregnancy tests for women of childbearing potential.