This study will evaluate the efficacy and safety of two concentrations (0.3 percent [%] and 1%) of twice daily LNK01004 ointment for the topical treatment in adult subjects with atopic dermatitis. This is a multicenter, randomized, double-blind, vehicle-controlled, 3-arm, parallel-group, dose-finding study in adult subjects with atopic dermatitis. Two concentrations of LNK01004 ointment (0.3% and 1%) and a vehicle control ointment will be equally randomized and evaluated following application to all atopic dermatitis lesions (except on the scalp) twice daily (morning and evening) for 8 weeks.

This study will consist of 3 periods: up to 4 weeks screening, 8 weeks double-blind treatment, and 2 weeks post-treatment follow-up.

Approximately 75 subjects (25 subjects for each group) with moderate to severe AD will be enrolled overall.

Inclusion Criteria:

• Aged 18 to 65 years at screening.
• Diagnosis of AD as defined by the Hanifin and Rajka (1980) criteria for at least 3 months at screening.
• Stable course of AD (not spontaneously improving or rapidly deteriorating) as determined by the investigator in the 3 weeks before screening.
• IGA score of 3 to 4 at screening and baseline.
• BSA of AD involvement, excluding the Scalp, Palms, and Soles, of 5% to 35% at screening and baseline.
• Willingness to avoid pregnancy or fathering children based on the criteria as outlined in the protocol.

Exclusion Criteria:

• Any serious illness or medical, physical, or psychiatric condition(s) that, in the investigator's opinion, would pose a significant risk to the participant or interfere with the interpretation of study data.

• Concurrent conditions and history of:

  • Chronic or acute infection requiring treatment with systemic antibiotics, antivirals, antiparasitics, antiprotozoals, or antifungals within 2 weeks before Baseline.
  • Active acute bacterial, fungal, or viral skin infection within 1 week before Baseline.
  • Any other concomitant skin disorder, pigmentation, or extensive scarring that, in the opinion of the investigator, may interfere with the evaluation of AD lesion.
  • Any other concomitant non-skin disorder with the treatment that may interfere with the evaluation of AD.

• Use of any of the following treatments within the indicated period before Baseline:

  • 6 weeks: Dupilumab
  • 5 half-lives or 12 weeks, whichever is longer: biologic agents (except dupilumab).
  • 4 weeks: Janus kinase (JAK) inhibitors.
  • 5 half-lives or 4 weeks, whichever is longer: Systemic therapy for AD, including but not limited to corticosteroids, methotrexate, cyclosporine, azathioprine, phosphodiesterase type 4 (PDE4)-inhibitors, Ultraviolet (UV) light therapy, or traditional Chinese medicine.
  • 2 weeks: Sedating antihistamines.
  • 1 week: Topical AD treatments (except topical emollient treatments), including but not limited to TCS, TCIs, or topical PDE-4 inhibitors.

• Hepatitis B surface antigen (HBs Ag) positive (+); HCV ribonucleic acid (RNA) detectable in any subject with anti-HCV antibody (HCV Ab); Human immunodeficiency virus (HIV) positive (+).

• Participants with the following hematologic abnormalities at screening:

  • ALT or AST ≥ 2 × ULN
  • TBiL ≥ 2 × ULN
  • Creatinine ≥ 1.5 × ULN

• History of alcoholism or drug addiction within 6 months before screening or current alcohol or drug use.

• Current treatment or treatment within 30 days or 5 half-lives (whichever is longer) before Baseline with another investigational medication or current enrollment in another investigational drug protocol.

• Participants who are pregnant, nursing, or planning a pregnancy during the study period.

• Participants with known allergies to components or excipients of the test drug.

This is due to proprietary and regulatory considerations. The data will remain confidential to protect intellectual property and participant privacy.