A First In Human (FIH) Study of IBI356 in Healthy Participants and in Atopic Dermatitis Patients

• IBI356 for MAD (Drug): Receive IBI356 in a multiple dose.
• Dupilumab for MAD (Drug): Active comparator
• IBI356 for SAD (Drug): Receive IBI356 in a single dose.
• Placebo for SAD (Drug): Receive placebo in a single dose.
• Placebo for MAD (Drug): Receive placebo in a multiple dose.

Primary outcomes

• Occurrence of Adverse Event (AE) in SAD study. [Baseline to Week 20]
• Occurrence of Adverse Event (AE) in MAD study. [Baseline to Week 36]
• Occurrence of Serious Adverse Event (SAE) in SAD study. [Baseline to Week 20]
• Occurrence of Serious Adverse Event (SAE) in MAD study. [Baseline to Week 36]
• Changes in blood pressure mmHg (as a measure of safety and tolerability) in SAD study. [Baseline to Week 20]
• Changes in blood pressure mmHg (as a measure of safety and tolerability) in MAD study. [Baseline to Week 36]
• Changes in respiratory rate measured as breaths per minute (as a measure of safety and tolerability) in SAD study. [Baseline to Week 20]
• Changes in respiratory rate measured as breaths per minute (as a measure of safety and tolerability) in MAD study. [Baseline to Week 36]
• Changes in heart rate bpm (as a measure of safety and tolerability) in SAD study. [Baseline to Week 20]
• Changes in heart rate bpm (as a measure of safety and tolerability) in MAD study. [Baseline to Week 36]
• Changes in tympanic temperature °C in SAD study. [Baseline to Week 20]
• Changes in tympanic temperature °C in MAD study. [Baseline to Week 36]
• Changes in electrocardiograms PR, QR, QRS and QT intervals (as a measure of safety and tolerability) in SAD study. [Baseline to Week 20]
• Changes in electrocardiograms PR, QR, QRS and QT intervals (as a measure of safety and tolerability) in MAD study. [Baseline to Week 36]

Secondary outcomes

• Area under the concentration time curve from time 0 to last observation (AUC 0-t). [Baseline to Week 16]
• Maximum observed concentration (Cmax) after infusion. [Baseline to Week 16]
• Systemic clearance after infusion (CL). [Baseline to Week 16]
• Volume of distribution during the terminal phase after infusion(Apparent volume of distribution, V). [Baseline to Week 16]
• Elimination half-life during the terminal phase after infusion(Half-life, t1/2). [Baseline to Week 16]
• To assess immunogenicity: production of anti-drug antibodies (ADA) following SAD and Multiple ascending dose(MAD) doses. [Baseline to Week 16]

Sex: All, ages: 18 Years to 70 Years, accepts healthy volunteers

Inclusion Criteria:

1. Healthy participants:

   1. Aged 18 to 45 years,
   2. Weight 50 to 120 kgs,
   3. Good physical and mental health based on medical history, physical examination, clinical laboratory, ECG, and vital signs, as judged by the Investigator.
   4. No child-bearing potential during the trial and within 6 months after SAD doses, and adequate contraceptive measures can be taken.
2. Atopic dermatitis:

   1. Aged 18 to 75 years,
   2. body mass index (BMI): 18.0 - 32.0 kg/m2,
   3. Atopic Dermatitis (AD) for 1 year or longer at Baseline,
   4. Eczema Area and Severity Index (EASI) of 16 or higher at baseline,
   5. Investigator Global Assessment (IGA) of 3 or 4 at baseline,
   6. AD involvement of 10 percent or more of body surface area at Baseline,
   7. Documented history, within 1 year before Baseline, of either inadequate response to topical treatments or inadvisability of topical treatments,
   8. Must have applied a stable dose of topical bland emollient at least twice daily for at least 7 consecutive days before Baseline.

Exclusion Criteria:

1. History of relevant drug allergies.
2. Has any condition that, in the opinion of the investigator, would make participation not be in the best interest (for example, compromise the well-being) of the participant or that could prevent, limit, or confound the protocol-specified assessments
3. Healthy participants:

   1. History of alcohol abuse or drug addiction within 1 year before screen,
   2. Positive drug and alcohol screen at screening.
4. Atopic dermatitis:

   1. Having used any of the following treatments within 4 weeks before the baseline visit, or any condition that, in the opinion of the investigator, was likely to require Immunosuppressive/ immunomodulating drugs treatment(s) during the first 4 weeks of study treatment:
   2. Treatment with topical corticosteroids (TCS) or topical calcineurin inhibitors (TCI) within 1 week before the baseline visit.