Study of Epratuzumab Versus Placebo in Subjects With Moderate to Severe General Systemic Lupus Erythematosus (SLE)

Inclusion Criteria:

- Positive antinuclear antibodies (ANA) at Screening (Visit 1)

- Current clinical diagnosis of Systemic Lupus Erythematosus (SLE) by American College
of Rheumatology (ACR) criteria such that at least 4 of the 11 criteria are met

- Active moderate to severe SLE activity as demonstrated by the British Isles Lupus
Assessment Group Index (BILAG)

- Active moderate to severe SLE disease as demonstrated by SLE disease activity index
(SLEDAI) total score

- On stable SLE treatment regimen, including mandatory corticosteroids and
immunosuppressants or antimalarials

Exclusion Criteria:

- Subjects who are breastfeeding, pregnant, or plan to become pregnant

- Subjects with active, severe SLE disease activity which involves the renal system

- Subjects with active, severe, neuropsychiatric SLE, defined as any neuropsychiatric
element scoring BILAG level A disease.

- Subjects with the evidence of an immunosuppressive state

- Subjects who, in the opinion of the investigator, are at a particularly high risk of
significant infection

- History of malignant cancer, except the following treated cancers: cervical carcinoma
in situ, basal cell carcinoma, or dermatological squamous cell carcinoma.

- Subjects receiving any live vaccination within the 8 weeks prior to screening (Visit
1).

- Subjects with history of infections, including but not limited to concurrent acute or
chronic viral hepatitis B or C

- Subjects with substance abuse or dependence or other relevant concurrent medical
condition

- Subjects with history of thromboembolic events within 1 year of screening Visit.

- Subjects with significant hematologic abnormalities

- Subject has received treatment with other anti- B cell antibodies within 12 months
prior to screening (visit 1)

- Subject use of oral anticoagulant (not including) nonsteroidal anti-inflammatory drugs
(NSAIDs) within 12 weeks prior to screening (Visit 1)

- Subject has previously participated in this study or has previously received
epratuzumab treatment.