This is a randomized double-blind/placebo study evaluate the efficacy of ASN002 in subjects with moderate to severe atopic dermatitis (AD).

This is a placebo controlled study where subjects with moderate to severe atopic dermatitis will be randomized (1:1:1:1) to receive ASN002 at 40 mg, 60 mg, or 80 mg, or placebo once daily for 12 weeks. Eligible subjects will get the opportunity to enroll in the 24 month open-label extension study (OLE). There will be a 4-week follow up period for subjects not participating in the OLE study. This study will also characterize the pharmacokinetics and pharmacodynamics of ASN002 through blood sampling and three or four biopsies from subjects who consent.

Inclusion Criteria:

• Written informed consent obtained prior to any study-related procedure being performed;

  • Male or female, 18≤ years and ≤75 years of age with chronic AD for at least 6 months.
  • At least 10% body surface area (BSA) of AD involvement at the baseline visits
  • Has a body mass index (BMI) ≤35 kg/m2
  • History of inadequate response to topical corticosteroids or calcineurin inhibitors as treatment for AD within 1 year before the screening visit.
  • Willing to apply only a basic bland emollient once or twice-daily for at least 7 days before the baseline visit.
  • Willing to comply with discontinuation of certain treatments for AD, as directed by the Investigator.
  • Willing to use medically effective methods of birth control
  • Females of reproductive potential must have a negative serum pregnancy test at screening and negative urine pregnancy test at Day 1..
  • Willing and able to comply with clinic visits and study-related procedures

Exclusion Criteria:

• Clinically infected atopic dermatitis.

  • Presence of any of the following laboratory abnormalities at the screening visit: Hemoglobin < 11 g/dL, White blood cell (WBC) < 3.0 x 103 /μL, Platelet count < 125 x 103 /μL, Neutrophils < < 2.50 x 103 /μL, Lymphocytes ≤ 1.2 x 103 /μL, Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) > 1.5 x the upper limit of normal (ULN),Total bilirubin > ULN (except for elevated indirect bilirubin secondary to Gilbert's syndrome), Creatinine > ULN
  • A serious uncontrolled condition including hypertension, history of tuberculosis, hepatitis B or C infection, immune deficiency, heart disease, heart conduction disorder, diverticulitis, diabetes, reflux disease requiring protocol pump inhibitor therapy, malabsorption syndrome, or cancer.
  • Any condition requiring the use of anticoagulants.
  • History of hypertrophic scarring or keloid formation in scars or suture sites.
  • Any medical or psychiatric condition which, in the opinion of the investigator or the sponsor's medical monitor, would place the patient at risk, interfere with participation in the study, or interfere with the interpretation of study results
  • Pregnant or breast-feeding women
  • Known hypersensitivity to ASN002 or its excipients;
  • Prior treatment with SYK or JAK inhibitors for which the subject received no clinical benefit, or the subject relapsed whilst on therapy.
  • Has received any marketed or investigational biological agent within 12 weeks or 5 half-lives (whichever is longer) prior to Day 1.
  • Planned major surgical procedure during the length of the patient's participation in this study
  • There will be a waiting period of 4 weeks before receiving the first does for anyone who has used oral or intravenous treatments (other than biologics) that could affect atopic dermatitis, received a non-biological investigational product or device, excessive sun exposure, is planning a trip to a sunny climate, or has used tanning booths, or received or plans to receive a live attenuated vaccine one four weeks after the last day of taking the drug.