A Study of Baricitinib in Participants With Systemic Lupus Erythematosus

Inclusion Criteria:

- Have a clinical diagnosis of SLE at least 24 weeks prior to screening.

- Have documentation of having met at least 4 of 11 Revised Criteria for Classification
of Systemic Lupus Erythematosus according to the 1997 Update of the 1982 American
College of Rheumatology (ACR) criteria for classification of SLE prior to
randomization.

- Have a positive antinuclear antibody (ANA) (titer ≥1:80) and/or a positive
anti-double-stranded deoxyribonucleic acid (dsDNA), and/or a positive anti-Smith
(anti-Sm) as assessed by a central laboratory during screening.

- Have a total Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K)
score ≥6 during screening.

- Have a clinical SLEDAI-2K score ≥4 at randomization.

- Have at least 1 British Isles Lupus Assessment Group (BILAG) A score or 2 BILAG B
scores during screening.

- Are receiving at least one of the following standard of care medications for SLE:

- A single antimalarial at a stable dose for at least 8 weeks prior to screening

- A single immunosuppressant at a stable dose for at least 8 weeks prior to
screening

- An oral corticosteroid, initiated at least 4 weeks prior to screening, at a
stable dose ≤40 milligrams/day prednisone (or equivalent) for at least 2 weeks
prior to screening. If the participant is not receiving an antimalarial or
immunosuppressant, the dose of corticosteroid must be ≥7.5 milligrams/day
prednisone (or equivalent)

Exclusion Criteria:

- Have severe active lupus nephritis.

- Have active central nervous system (CNS) lupus.

- Have a history or presence of cardiovascular, respiratory, hepatic, gastrointestinal,
endocrine, hematological, neurological, or neuropsychiatric disorders or any other
serious and/or unstable illness that, in the opinion of the investigator, could
constitute an unacceptable risk when taking investigational product or interfere with
the interpretation of data.

- Have a current or recent clinically serious viral, bacterial, fungal, or parasitic
infection.

- Have received cyclophosphamide (or any other cytotoxic agent) within 12 weeks prior to
screening.