A Study Evaluating the Efficacy and Safety of Afimetoran Compared With Placebo in Participants With Active Systemic Lupus Erythematosus (SLE)

Open to people ages 18-70

• Diagnosed ≥ 12 weeks before the screening visit and qualify as having SLE according to the SLE International Collaborating Clinics (SLICC) Classification Criteria at the screening visit
• Test positive, as determined by the central laboratory, for at least one of the following lupus related autoantibodies at the time of screening: antinuclear antibody ≥ 1:80, anti-double-stranded deoxyribonucleic acid (dsDNA) antibody, or anti-Smith antibody.
• Have a total Hybrid Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score ≥ 6 points and clinical Hybrid SLEDAI score ≥ 4 points with joint involvement and/or rash

• Active severe lupus nephritis (LN) as assessed by the investigator
• Active or unstable neuropsychiatric lupus manifestations defined by the Hybrid SLEDAI
• Diagnosis of Mixed Connective Tissue Disease for which the predominant diagnosis is not SLE
• Antiphospholipid Syndrome

Other protocol-defined inclusion/exclusion criteria apply