Study to Evaluate BIIB059 in Cutaneous Lupus Erythematosus (CLE) With or Without Systemic Lupus Erythematosus (SLE)

Key Inclusion Criteria:

Part A:

1. Diagnosis of systemic lupus erythematosus (SLE) fulfilling at least 4 out of 11 of the
1997 revised American College of Rheumatology (ACR) classification criteria for SLE
along with active skin manifestations and joint involvement.

2. At least 4 tender joints and at least 4 swollen joints with at least 4 of the swollen
joints in the proximal interphalangeal (PIP) joints, metacarpophalangeal (MCP) joints
and/or wrist.

3. Demonstrate at least one sign of active lupus skin disease, including acute cutaneous
lupus erythematosus (ACLE), subacute cutaneous lupus erythematosus (SCLE), and/or
chronic cutaneous lupus erythematosus (CCLE) (e.g., discoid lupus erythematosus
(DLE)), with skin activity defined by SLE Disease Activity Index 2000 (SLEDAI-2K) at
the time of Screening and randomization.

Part B:

1. Active skin manifestations Cutaneous Lupus Erythematosus Disease Area and Severity Index
Activity (CLASI-A) ≥8)) and a diagnosis of cutaneous lupus erythematosus (CLE) that has
been histologically confirmed (in the past or at Screening), with or without SLE
manifestations.

Key Exclusion Criteria:

1. Active lupus nephritis or moderate-to-severe or chronic kidney disease.

2. Any active skin conditions other than CLE that may interfere with the study (e.g.,
psoriasis, non-LE skin lupus, drug-induced lupus).

3. History of chronic, recurrent, or recent serious infection.

4. History of chronic, recurrent (3 or more of the same type of infection in a 12-month
period), or recent serious infection (e.g., pneumonia, septicemia, herpes zoster) as
determined by the Investigator and requiring anti-infective treatment within 12 weeks
prior to Screening.

5. Use of immunosuppressive or disease-modifying treatments for SLE or CLE that were
initiated less than 12 weeks prior to Randomization.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply