A Randomised, Double-blind, Placebo-controlled, Single and Multiple Dose, Dose-escalation Trial of Anti-IL-20 (109-0012) 100 mg/Vial in Psoriatic Subjects, Followed by an Expansion Phase

Inclusion Criteria:

- Subjects with moderate to severe stable chronic plaque psoriasis for at least 6
months, with or without psoriatic arthritis

- Affected body surface area (BSA) greater than or equal to 15%

- Physician's Global Assessment (PGA) score of 3 or more

- Female subjects of non-childbearing potential or postmenopausal for at least 1 year.
Male subjects must agree to use effective method of birth control

- Body Mass Index (BMI) less than or equal to 38.0 kg/m2

Exclusion Criteria:

- Concomitant anti-psoriatic treatment

- Infectious disease requiring systemic anti-infectious treatment within the 2 weeks
prior to administration of trial drug

- Known history of Human Immunodeficiency Virus (HIV)

- Hepatitis B and/or C (determined by test)

- Live virus or bacteria vaccines within the last month before drug administration

- Known active herpes/herpes zoster/cold sores

- Kidney insufficiency

- Liver insufficiency

- Lymphoproliferative disease

- History or signs of malignancy within the last 5 years