Study Evaluating Single Dose Of ILV-095 In Psoriasis Subjects

Inclusion Criteria: * Sexually active men or women must agree to use a medically acceptable form of contraception during the study and continue it for 16 weeks after investigational product administration. * Negative urine pregnancy test result for all women. * Body mass index (BMI) \>=18 kg/m2 and body weight \>=50 kg. BMI is calculated by taking the subject's weight, in kilograms, divided by the square of the subject's height, in meters, at screening: BMI = weight (kg)/(height \[m\]). * Must meet the following criteria for disease activity, at screening and/or at study entry (subjects who washout from prior therapy may not meet this level of disease activity at screening but must before being entered into the study). * Must have stable moderate to severe chronic plaque psoriasis covering \>=15% of body surface area and be a candidate for systemic therapy or phototherapy. * Psoriasis Area Severity Index (PASI) score of \>11. * Physician Global Assessment (PGA) of psoriasis score \>=3. * Target lesion score \>=6 based on the physician rating of selected sites for erythema, plaque elevation and scaling, with a minimum of 2 on the plaque elevation score. A-12-point score will be used with a 1-4 scale for each domain. Target lesions should not be on the scalp, axillae, face, or groin. Exclusion Criteria: * Presence or history of any disorder that may prevent the successful completion of the study. * Evidence of unstable clinically significant disease (eg, unstable cardiovascular, renal, respiratory, or psychiatric disease or any serious disorder that currently requires physician care). * Acute disease state (eg, nausea, vomiting, fever, or diarrhea) within 7 days before study day 1. * Evidence of skin conditions (eg, eczema) other than psoriasis that would interfere with evaluations of the effect of study medication on psoriasis. * Presence of guttate, erythrodermic, or pustular psoriasis. * Active severe infections within 4 weeks before study day 1. * Systemic malignancy within the past 5 years including melanoma. Treated skin cancer (basal cell carcinoma or squamous cell carcinoma) is excluded. Evidence of latent tuberculosis by purified protein derivative (PPD) screening. PPD screening should be performed according to local standards using the tuberculin skin test (TST). Any result \>5mm is considered positive. Prior Bacillus Calmette-Guerin (BCG) should not be taken into account when interpreting a TST result. TST must be performed during the screening period unless one has been performed within the previous 3 months and the results are available.