<br>        Inclusion Criteria:<br><br>          -  Positive antinuclear antibodies (ANA) at Screening (Visit 1)<br><br>          -  Current clinical diagnosis of Systemic Lupus Erythematosus (SLE) by American College<br>             of Rheumatology (ACR) criteria such that at least 4 of the 11 criteria are met<br><br>          -  Active moderate to severe SLE activity as demonstrated by the British Isles Lupus<br>             Assessment Group Index (BILAG)<br><br>          -  Active moderate to severe SLE disease as demonstrated by SLEDAI total score.<br><br>          -  On stable SLE treatment regimen, including mandatory corticosteroids and<br>             immunosuppressants or antimalarials<br><br>        Exclusion Criteria:<br><br>          -  Subjects who are breastfeeding, pregnant, or plan to become pregnant<br><br>          -  Subjects with active, severe SLE disease activity which involves the renal system<br><br>          -  Subjects with active, severe, neuropsychiatric SLE, defined as any neuropsychiatric<br>             element scoring BILAG level A disease.<br><br>          -  Subjects with the evidence of an immunosuppressive state<br><br>          -  Subjects who, in the opinion of the investigator, are at a particularly high risk of<br>             significant infection<br><br>          -  History of malignant cancer, except the following treated cancers: cervical carcinoma<br>             in situ, basal cell carcinoma, or dermatological squamous cell carcinoma.<br><br>          -  Subjects receiving any live vaccination within the 8 weeks prior to screening (Visit<br>             1).<br><br>          -  Subjects with history of infections, including but not limited to concurrent acute or<br>             chronic viral hepatitis B or C<br><br>          -  Subjects with substance abuse or dependence or other relevant concurrent medical<br>             condition<br><br>          -  Subjects with history of thromboembolic events within 1 year of screening Visit.<br><br>          -  Subjects with significant hematologic abnormalities<br><br>          -  Subject has received treatment with other anti- B cell antibodies within 12 months<br>             prior to screening (visit 1)<br><br>          -  Subject use of oral anticoagulant (not including) nonsteroidal anti-inflammatory drugs<br>             (NSAIDs) within 12 weeks prior to screening (Visit 1)<br><br>          -  Subject has previously participated in this study or has previously received<br>             epratuzumab treatment.<br>