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 6-mercaptopurine ≤ 150 mg/day for 12 weeks prior to screening are permitted. * Exclusion Criteria: * Drug-induced SCLE; * Any disorder (including psychiatric), condition or clinically significant disease (other than a diagnosis of SCLE, SLE, or Sjögren's syndrome) that would, by its progressive nature and/or severity, interfere with the study evaluation, completion and/or procedures per the investigator's discretion. This includes any age related co-morbidities such as presence of congestive heart failure, angina, chronic obstructive pulmonary disease, and asthma; * Presence or history of vasculitis (comprising internal organs or extremities or leading to peripheral neuropathy) within the last 3 years, presence or history of active Central Nervous System (CNS) lupus (defined as seizure disorder, cerebral vascular accident, psychosis ascribed to SLE , encephalitis, meningitis, and myelitis) requiring therapy within the last 3 years; * History of malignancy; * Signs or symptoms of a viral, bacterial or fungal infection within 30 days of study randomization, or recent history of repeated infections; * Underlying condition other than SCLE, SLE, Sjögren's syndrome that predisposes one to infections (eg, history of splenectomy); * Administration of \>10 mg/day prednisone (or equivalent) in the 30 days prior to randomization; * Prior use of any following biological agents: Rituximab, Lymphostat-B, TACl-Ig, and CTLA4-Ig; * Current treatment (within 3 months or 5 half-lives of screening) with thalidomide, mycophenolate mofetil, cyclosporine, tacrolimus, sirolimus, Intravenous (IV) immunoglobulin, plasmapheresis, oral or IV cyclophosphamide; * Receiving or has received any investigational drug (or is currently using an investigational device) within the 30 days or 5 half-lives (whichever is longer), prior to receiving the first dose of study medication). * 29\. Use of any other over-the-counter or prescription medications within the 14 days or 5 half-lives (whichever is longer), prior to receiving the first dose of study medication. Acetaminophen (up to 2 g per day) for analgesia and hormone replacement therapy (eg, estrogen, thyroid) will be allowed. In addition, prescription drugs for hypertension or hypercholesterolemia, oral hypoglycemic drugs, or NSAIDs will be allowed; however, NSAIDS are not permitted within 24 hours of skin biopsies to reduce the risk of bleeding. Other medications may be approved following review by the Principal Investigator and the Amgen Medical Monitor. Written documentation of this review and Amgen acknowledgement is required for subject participation;