Study of an Anti-OX40 Monoclonal Antibody (KHK4083) in Subjects With Moderate to Severe Atopic Dermatitis

Inclusion Criteria

• Voluntarily signed informed consent to participate in the study;
• Chronic AD, according to American Academy of Dermatology Consensus Criteria or the local diagnostic criteria, that has been present for at least 1 year before screening;
• EASI score ≥16 at screening and baseline;
• IGA score ≥3 (moderate) at both screening and baseline;
• BSA ≥10% at both screening and baseline;
• Documented recent history (within 1 year prior to screening visit) of inadequate response to treatment with topical medications or for whom topical treatments are otherwise medically inadvisable (e.g., because of important side effects or safety risks).

Exclusion Criteria

• Current or past history of clinically significant illness(es) deemed by the Investigator to be likely to affect the study conduct and assessments. Examples include, but are not limited to, clinically significant cardiovascular (e.g., New York Heart Association [NYHA] Class III or IV), uncontrolled diabetes (HbA1c ≥9%), liver (e.g., Child-Pugh class B or C), renal, respiratory, hematologic, central nervous system, psychiatric, or autoimmune diseases/disorders;
• Any of the following laboratory abnormalities at screening:
• Serum creatinine: >1.5 mg/dL
• AST or ALT: ≥2.5 times the upper limit of normal (ULN)
• Neutrophil count: <1.5×10³/μL
• Other laboratory abnormalities that may affect the completion or evaluation of the study, as judged by the Investigator;
• Active malignancies, or onset or a history of treatment of malignancies within 5 years prior to informed consent (except curatively treated in situ cervical carcinoma, cutaneous basal cell carcinoma, or cutaneous squamous cell carcinoma).