This is a randomized, double-blind, placebo-controlled Phase Ib clinical trial evaluating the safety tolerability, pharmacokinetics, immunogenicity and preliminary efficacy of GR2002 Injection in patients with moderate to severe atopic dermatitis. The dosing period was 12 weeks and followed up to 20 weeks.

Main Inclusion Criteria:

1. Patients need to meet Williams diagnostic criteria, have had AD for at least 1 year, and:EASI ≥16, IGA score ≥3, and AD involvement of ≥10% of BSA;
2. Inadequate response or intolerance to prior topical glucocorticoid (TCS) therapy for the treatment of AD;
3. Voluntary informed consent.

Main Exclusion Criteria:

1. Current malignancy or history of malignancy;
2. History of vital organ transplantation or hematopoietic stem cell/bone marrow transplantation;
3. Subjects may have active Mycobacterium tuberculosis infection;
4. Systemic anti-infective therapy required for chronic or acute active infection within 4 weeks prior to the baseline visit;
5. History of known or suspected immunosuppression;
6. Presence of skin comorbidities that may interfere with evaluation;
7. Suspected or confirmed allergy to the test drug (including excipients, similar drugs);
8. History of alcohol or drug abuse within 3 months prior to screening；
9. Pregnant or lactating women who need to breastfeed；
10. Major surgery planned during the trial；
11. The elution cycle of the drug of interest is not met at the baseline；
12. Subjects of childbearing potential and partners refusing to use highly effective contraception.