A Study to Test Safety, Tolerability, and the Way the Body Absorbs, Distributes, and Gets Rid of a Study Drug Called MOR106, in Healthy Subjects and in Patients With Moderate to Severe Atopic Dermatitis

The clinical study consists of three parts:

* Part 1 with healthy volunteers.
* Part 2 and Part 3 including subjects with moderate to severe atopic dermatitis (a skin disease).

For Part 1 the main goal of the study is to compare the safety, tolerability, and exposure of administration of the test drug via an injection in a skin layer just under the surface (subcutaneous), to administration of the test drug into the vein (intravenous).

For Part 2 and Part 3 the main goal of the study is to assess the safety and tolerability of administration of the test drug via an injection in a skin layer just under the surface (subcutaneous) during 12 weeks of treatment.


Eligibility Criteria:
Inclusion Criteria:

Part 1:

* Male between 18-50 years of age (extremes included), on the day of signing the informed consent form (ICF).
* Subjects between 65-88 kg (extremes included) with a body mass index (BMI) between 18-30 kg/m², inclusive.
* Judged to be in good health based upon the results of a medical history, physical examination, vital signs, 12-lead electrocardiogram (ECG), and screening laboratory profile prior to the initial investigation medicinal product (IMP) administration.

Part 2 and Part 3:

* Male or female between 18-65 years of age (extremes included), on the day of signing ICF.
* A BMI between 18-30 kg/m², inclusive.
* Diagnosis of AD for at least one year since first diagnosis as per Hanifin and Rajka Criteria.
* EASI ≥ 12 at screening and ≥ 16 at the baseline visit (Day 1 predose)
* ≥ 10% BSA of AD involvement at screening.
* IGA score ≥ 3 (on 0-4 IGA scale).
* Willingness to use an additive free, basic, bland emollient twice daily for at least seven days before the baseline visit and throughout the study.
* Subject is a candidate for systemic therapy and is not responding adequately or has a contraindication to topical corticosteroids (TCS) and / or topical calcineurin inhibitors (TCI), per investigator's judgment.

Exclusion Criteria:

Part 1, Part 2 and Part 3:

* Known hypersensitivity to IMP ingredients as determined by the investigator (such as, but not limited to, anaphylaxis requiring hospitalization).
* Prior treatment with MOR106.
* Any concurrent illness, condition, disability, or clinically significant abnormality (including laboratory tests, ≥ New York Heart Association Classification (NYHA) III/IV) or clinically significant illness in the three months prior to initial IMP administration that, in the investigator's opinion, represents a safety risk for the subject's participation in the study, may affect the interpretation of clinical safety or efficacy data, or may prevent the subject from safely completing the assessments required by the protocol.
* History of, or current immunosuppressive condition.

In addition for Part 2 and 3:

* Active chronic or acute skin infection requiring treatment with systemic (oral, sc or iv) antibiotics, antivirals or antifungals within 4 weeks of baseline, or clinical signs of infective eczema within 1 week before baseline (Day 1 pre-dose).
* Having used any of the following treatments:

  i) Exposure to a biologic therapy for AD. ii) Immunosuppressive/ immunomodulating drugs (e.g. systemic corticosteroids, cyclosporine, mycophenolate-mofetil, interferon-γ (IFN-γ), azathioprine, methotrexate, etc.) within 4 weeks of baseline. iii) Phototherapy (ultraviolet (UVB) or Psoralen Ultraviolet A \[PUVA\]) for AD within four weeks of baseline. iv) Treatment with TCS or TCI within two weeks before the baseline visit. v) Treatment with biologics (for non-AD indications) within five half-lives (if known) or 12 weeks prior to baseline visit, whichever is longer. vi) Regular use (more than two visits per week) of a tanning booth/parlor within four weeks of the screening visit.