A Clinical Trial to Evaluate the Safety, Tolerability, Pharmacokinetics, Immunogenicity, Pharmacodynamics and Exploratory Clinical Activity of NM26-2198 in Healthy Subjects and in Patients With Moderate-to-severe Atopic Dermatitis (AD)

Inclusion Criteria: SAD: Non-Asian ethnicity with grandparents and parents of non-Asian descent or Japanese descent having all four Japanese grandparents born in Japan. SAD: Male or female aged 18 to 55 years; MAD: Male or female ≥18 years of age. Weight of 45 kg to 100 kg and BMI of 18.0 to 30.0 kg/m2. SAD: Non-childbearing, non-breastfeeding females or males willing to use double barrier contraception or abstention from sex and sperm donation during the study; MAD: Males willing to use double barrier contraception or abstention from sex and sperm donation during the study; non-childbearing females or females of childbearing potential using protocol-defined method contraception, and who is not pregnant, lactating, or breastfeeding. MAD: Diagnosis of chronic AD. MAD: EASI score ≥16. MAD: vIGA-AD™ score of ≥3. MAD: Atopic lesions cover ≥10% of body surface area (BSA). MAD: PP-NRS score ≥4. MAD: Daily use of non-prescription emollient. Note: Other protocol-defined Inclusion criteria apply. Exclusion Criteria: SAD: Any clinically-relevant medical history or lab abnormality, including positive test for SARS-CoV-2, Hepatitis B or C, or HIV; MAD: Clinically-significant, abnormal laboratory findings, or positive test for SARS-CoV-2, Hepatitis B or C, or HIV. Clinically important ECG abnormalities or history/evidence thereof. SAD: Use of prescription or non-prescription medications (except occasional use of paracetamol). MAD: Diagnosis of protocol-specified skin diseases other than AD, or history of other significant skin condition that could interfere with study assessments. MAD: History or ongoing allergy/hypersensitivity or history, or history of hypersensitivity to biological drugs. MAD: Recent receipt of immunoglobulin or blood products. MAD: Recent treatment with protocol-specified investigational treatments, or any prior treatment with dupilumab, tralokinumab, lebrikizumab, nemolizumab, or other protocol-specified drugs. MAD: AD with recent ocular involvement requiring chronic ocular corticosteroid treatment. MAD: Chronic pruritis due to conditions other than AD. MAD: Acute AD superinfection, recent superficial skin infection, or other chronic/acute infection requiring protocol-defined treatments. MAD: Recent use of sedating antihistimines, systemic corticosteroids, cytotoxic treatments, other immunosuppressive/immunomodulating agents, and other protocol-specified prohibited medications. MAD: Recent topical corticosteroid or prescription moisturizer use. Note: Other protocol-defined Exclusion criteria apply.