SLEek

Inclusion Criteria:

- Participant has clinical diagnosis of Systemic Lupus Erythematosus (SLE) at least 24
weeks prior to Screening, meeting at least 4 of the 11 revised Criteria for
Classification of SLE according to the 1997 Update of the 1982 American College of
Rheumatology (ACR) OR meeting at least 4 of the 2012 SLICC classification criteria,
including at least 1 clinical criterion and 1 immunologic criterion.

- At Screening, must have at least one of the following:

- antinuclear antibody (ANA)+ (titer ≥ 1:80)

- anti-dsDNA+

- anti-Smith+

- SLEDAI-2K (SLE Disease Activity Index) ≥ 6 despite background therapy as reported and
independently adjudicated (clinical score ≥ 4, excluding lupus headache and/or organic
brain syndrome) at Screening:

- If 4 points of the required entry points are for arthritis, there must also be a
minimum of 3 tender and 3 swollen joints.

- If participant has rash and Principal Investigator (PI) considers it to be
attributable to SLE, participant must consent to skin photograph collection for
adjudication.

- Score must be re-confirmed at the Baseline visit.

- Physician's Global Assessment (PhGA) ≥ 1 during screening period.

- Must be on background treatment, stable for 30 days prior to Baseline and throughout
the study with antimalarial(s), prednisone (or prednisone equivalent) (≤ 20 mg),
azathioprine (≤ 150 mg), mycophenolate (<2 g), leflunomide (≤ 20 mg), cyclosporine,
tacrolimus, and/or methotrexate (MTX) (≤ 20 mg).

- No combinations of the above with immunomodulators other than prednisone (or
equivalents) and antimalarials.

Exclusion Criteria:

- Participant using intravenous (IV) or intramuscular (IM) corticosteroids greater than or
equal to a 40 mg prednisone-equivalent bolus within 30 days of planned randomization.