Safety Study of AMG 557 in Subjects With Subacute Cutaneous Lupus Erythematosus

Inclusion Criteria: * Men and women, between the ages of 18 and 70 years of age, inclusive, at the time of randomization; * Body mass index from 18 to 35 kg/m2 at screening; * Diagnosis of subacute cutaneous lupus erythematosus (SCLE) with or without systemic lupus erythematosus (SLE). SCLE as defined by the Gilliam and Sontheimer classification (J Am Acad Dermatol 1981; 4(4):471-475). SLE is defined by the most recent American College of Rheumatology criteria, including positive antinuclear antibodies (ANA) during screening or by documented history (at least 1:80 by indirect immunofluorescent assay); * A history of skin biopsy consistent with the diagnosis of SCLE; * Positive SS-A and/or SS-B antibodies at screening; * Intolerance of anti-malarial therapy or ≥ 3 months of anti-malarial therapy with residual disease activity as defined by: at least 2 areas with at least level 2 erythema or 3 areas with at least level 1 erythema using cutaneous lupus erythematosus disease area and severity index (CLASI). The total CLASI activity must be ≥ 10; * Subject must have stable disease activity for 3 months prior to screening in the clinical judgment of the Principal Investigator (PI) with no anticipated changes in therapy; * Stable dose of topical steroids no stronger than medium-potency (Class III or Class VII) for ≥ 2 weeks from screening is permitted; * Prednisone ≤ 10 mg/day (or equivalent) is permitted; * Stable doses of methotrexate ≤ 20 mg/week, azathioprine ≤ 150 mg/day, and …