Study of EQ001 (Itolizumab) in Systemic Lupus Erythematosus With or Without Active Proliferative Nephritis

For people ages 18-75

Type A Cohort Key Inclusion Criteria:

1. Is male or female, age ≥ 18 and ≤ 75 years
2. Has previously been documented to have met or currently meets Systemic Lupus International Collaborating Clinics (SLICC) and/or American College of Rheumatology (ACR) criteria for SLE
3. Received at least 1 immunosuppressive or immunomodulatory treatment for SLE at any time in the past or currently
4. Has documented elevation of antinuclear antibodies (ANA) in the past or during Screening
5. Restricted SLE treatments are stable and/or washed out
6. During Screening, has adequate hematologic function

Type B Cohort Key Inclusion Criteria:

1. Is male or female, age ≥ 18 and ≤ 75 years
2. Meets SLICC and/or ACR criteria for SLE
3. Kidney biopsy with a histologic diagnosis of LN Classes III or IV (+/- V)
4. Has a urine protein to creatinine ratio of > 1000 mg/g
5. Meets criterion a and/or b
6. Has previously completed induction treatment for active proliferative LN and is currently receiving one of the following: mycophenolate mofetil (MMF), mycophenolic acid (MPA), azathioprine or a calcineurin inhibitor.
7. Has been receiving induction treatment with MMF/MPA and has a < 50% reduction in proteinuria at or after 12 weeks of induction
8. During Screening has adequate hematologic function
9. Restricted SLE treatments are stable and/or washed out
10. Most recent eGFR ≥ 40 mL/min/1.73m2
11. Has evidence of serologic activity during Screening

Key Exclusion Criteria:

1. Acute or chronic infections requiring systemic antibacterial, antifungal, or antiviral therapy
2. Positive for hepatitis B virus (HBV), hepatitis C virus (HCV), or HIV
3. Active TB or a positive TB test