A Study for AR100DP1 in Mild to Moderate Atopic Dermatitis

Inclusion Criteria:

1. Dated and signed informed consent
2. Either gender, ≥ 18 years old (the legal age of consent majority is 18 years old in Taiwan)
3. Confirmed clinical diagnosis of atopic dermatitis (based on the criteria of Hanifin and Rajka for AD)
4. Clinical diagnosis of AD with clinically consistent and stable disease status, defined as AD lesions with the Investigator's Global Assessment (IGA) score of 1(almost clear) to 3(moderate) for at least 4 weeks prior to Screening Visit, at the investigator's discretion
5. Not expected to require regular AD maintenance therapy during the study period, at the investigator's discretion
6. Have AD lesion area(s) with an IGA score of 1 to 3 at the Screening Visit and Day 1, with a maximum total treated area of 1,050 cm², as judged by the Investigator.
7. Have a pruritus NRS score of ≥ 2 for both the average itch and the worst itch in the past 24 hours, as assessed at Screening Visit and Day 1 prior to randomization
8. Subject of childbearing potential must agree to use abstinence to intercourse, or highly effective contraceptives from signing informed consent to 14 days after the last dose of study drug administration

Exclusion Criteria:

1. Fluctuating or actively infected AD judged by the investigator

2. Have any AD lesion with an IGA score of 4 at the Screening Visit or Day 1, as judged by the Investigator

3. History of the following conditions, including irritant contact dermatitis, allergic contact dermatitis, skin infections (such as scabies), or other autoimmune skin diseases

4. Active or potentially recurrent dermatologic condition other than atopic dermatitis that may confound evaluation (e.g. fungal infection), judged by the investigator

5. Received systemic medication including immunosuppressant, phototherapy, or other therapy, which could affect AD within 4 weeks before Day 1

6. Received systemic antihistamine within 5 half-lives (see Appendix 1 for half-lives of common antihistamine) prior to Day 1 (except for permitted background medication, Fexofenadine)

7. Received systemic corticosteroid within 2 days or 5 half-lives, whichever is longer, prior to Day 1

8. Received topical medication including corticosteroid, immunosuppressant, anti-histamine, phototherapy, calcineurin inhibitors, or other therapy for AD lesion area(s) within 1 week before Day 1

9. Plan to receive immunosuppressive agents (including azathioprine, mycophenolate, cyclophosphamide, chlorambucil, methotrexate, cyclosporine)

10. Unwilling or unable to comply with the criteria in Life Style Guidelines (Section 5.3) during the study

11. History of use of biologic therapy (including intravenous immunoglobulin) within 12 weeks or 5 half-lives (whichever is longer) prior to Day 1

12. Received any other investigational drug within 4 weeks prior to Day 1

13. Required or received systemic CYP3A4 inhibitors with strong potency within 1 week prior to Day 1, including but not limited to clarithromycin, itraconazole, nefazodone, and atazanavir, evaluated by the investigator

14. Treatment for any type of cancer (except squamous cell carcinoma, basal cell carcinoma, or carcinoma in situ of the skin, curatively treated with cryosurgery or surgical excision only) within 5 years before Day 1

15. Had surgery within 4 weeks prior to Day 1, or plan to have surgery during the study.

16. Known hypersensitivity to any of the components of the study drug

17. Active clinically serious infection or any known history of immunodeficiency, including human immunodeficiency virus (HIV) infection

18. Current uncontrolled asthma

19. Any of the following serum test abnormalities:

    • Total bilirubin > 1.5 × ULN
    • AST or ALT > 3.0 × ULN
    • Serum albumin < 2.5 g/dL
    • Creatinine > 1.5 × ULN
    • Any other ≥ Grade 2 (grading of NCI-CTCAE v6.0) laboratory abnormality at baseline (other than those listed above)

20. With ongoing acute diseases or within the past 2 years serious medical conditions (e.g. concomitant illness) such as cardiovascular (e.g. New York Heart Association (NYHA) grade III or IV), hepatic (e.g. Child-Pugh Class C), psychiatric condition (e.g. alcoholism, drug abuse), medical history, physical findings, or laboratory abnormality that in the investigators' opinion could interfere with the results of the trial or adversely affect the safety of the subject

21. Female subject who is lactating or has positive urine pregnancy test at Screening and Day 1

22. Other conditions not suitable for participating in this study judged by the investigator

23. Plan to donate blood, sperm, or eggs from Screening Visit until Final Visit