This is a multi-center, randomized, double blind, placebo-controlled study to evaluate the efficacy, safety, tolerance, pharmacokinetics, pharmacodynamics, and immunogenicity of CM326 in moderate-severe atopic dermatitis subjects.

The study consists of 3 periods, a up-to-4-week Screening Period, a 52-week Treatment Period and a 8-week Safety Follow-up Period.

Inclusion Criteria:

• With confirmed Atopic Dermatitis (AD) at the screening.
• Age ≥ 18 years and ≤ 75 years, male or female.
• Have the ability to understand the nature of the study and voluntarily sign the informed consent.
• Be able to communicate well with investigators and follow up protocol requirements.

Exclusion Criteria:

• Not enough washing-out period for previous therapy.
• Received allergen specific immunotherapy (desensitization) within 6 months prior to baseline.
• Major surgery is planned during the study period.
• Women who are pregnant or breastfeeding, or who plan to become pregnant during the study.