A Study of HSK60002 Tablets in Participants With Moderate-to-Severe Atopic Dermatitis

This is a randomized, double-blind, placebo-controlled, Phase Ib study to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of HSK60002 tablets in approximately 60 participants with moderate-to-severe atopic dermatitis (AD). Participants are randomized within one of three dose groups (10 mg once daily \[QD\], 30 mg QD, or 30 mg once weekly \[QW\]) in a 4:1 ratio to HSK60002 or matching placebo. Treatment is given orally for up to 16 weeks (Stage 1: Weeks 1-4; Stage 2: Weeks 5-16), followed by a safety follow-up visit approximately 2 weeks after the last dose.

Inclusion Criteria: * Capable of understanding and voluntarily providing informed consent before participating in any study-specific procedures. * Aged 18 to 75 years, inclusive, of any sex. * Able to understand and complete study-related questionnaires/scales, agree to photographic documentation of skin lesions, and comply with the visit schedule and other protocol requirements. * Diagnosed with atopic dermatitis according to the 2014 American Academy of Dermatology (AAD) criteria, with a history of AD or eczema for at least 6 months before screening, and stable AD disease, in the investigator's judgment, within 4 weeks before signing the informed consent form. * EASI score ≥16 at both screening and baseline visits. * vIGA-AD score ≥3 at both screening and baseline visits. * AD-involved body surface area (BSA) ≥10% at both screening and baseline visits. * Weekly average of daily Worst Itch Numeric Rating Scale (WI-NRS) score ≥4 at baseline. * In the investigator's judgment, inadequate clinical response to and/or intolerance of AD topical therapy within 6 months before screening, or disease controlled with systemic therapy. * Use of a stable dose of drug-free topical emollient applied twice daily for at least 7 consecutive days before the baseline visit, with continued use throughout the study. * Agreement to use highly effective contraception throughout the study. Exclusion Criteria: * Any of the following treatments before the baseline visit: dupilumab or stapokibart (anti-IL-4Rα biologics) within 6 weeks; other known or potentially AD-affecting biologics within 12 weeks; systemic medications for AD within 4 weeks; topical AD therapy within 7 days; phototherapy for AD within 4 weeks. * Prior treatment with IL-4R- or IL-13-targeted biologics or JAK inhibitors with inadequate clinical response, in the investigator's judgment. * Administration of live attenuated vaccines within 12 weeks before baseline, or planned vaccination during the study. * Use of antihistamines within 1 week before baseline. * Allergen-specific immunotherapy within 6 months before baseline. * Use of any investigational product within 4 weeks or 5 half-lives before randomization, whichever is longer. * Clinically significant abnormal laboratory findings during screening. * Other active skin diseases or skin infections that may affect the assessment of AD treatment response, as assessed by the investigator. * Clinically significant chest X-ray or CT abnormality at screening. * Possible active Mycobacterium tuberculosis infection; history of TB infection or current TB infection. * History of invasive opportunistic infections. * Rheumatic fever, rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, multiple sclerosis, Sjögren's syndrome, inflammatory bowel disease, or other autoimmune diseases that may affect efficacy and safety assessment, as evaluated by the investigator. * Asthma requiring high-dose inhaled corticosteroids, systemic corticosteroids, or biologic therapy. * Major surgery within 3 months before screening or planned during the study. * Uncontrolled blood pressure despite antihypertensive treatment within 3 months before screening. * Thromboembolic events within 6 months before screening. * Uncontrolled clinically significant major medical conditions that would pose a safety risk, in the investigator's opinion. * History of malignancy within 5 years before screening. * History of atopic keratoconjunctivitis (AKC) involving the cornea, or history of vernal keratoconjunctivitis (VKC). * Dysphagia, gastrointestinal surgery, or severe gastrointestinal disease that may interfere with the pharmacokinetics of the study drug. * Active hepatitis B, positive hepatitis C antibody, syphilis infection, or HIV infection during screening. * History of drug abuse, illicit drug use, or alcohol abuse within 3 months before screening. * Use of any drugs that inhibit or induce hepatic drug-metabolizing enzymes within 28 days before the first dose of study drug. * Consumption of grapefruit (or grapefruit-containing products) within 48 hours before the first dose of study drug, or unwillingness to abstain during the study. * History of severe drug allergy or known allergy to the study drug or its excipients. * Pregnant or lactating women, or women planning pregnancy or lactation during the study. * Any other condition that, in the investigator's opinion, makes the participant unsuitable for the study.