Inclusion Criteria:

• 1. Willing and able to provide written informed consent
• 2. Age 18 years of age or older
• 3. Weight \> 45 kg at enrollment
• 4. Adequate blood pressure control
• 5. Diagnosis of SLE by 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria or 2012 Systemic Lupus Collaborating Clinics (SLICC) criteria, including positive ANA or positive anti-dsDNA
• 6. LN participants: Active, biopsy-proven, proliferative lupus nephritis Class III or IV by 2018 International Society of Nephrology/Renal Pathology Society (ISN/RPS) criteria
• Other protocol-defined criteria apply.

Exclusion Criteria:

• 1. Any clinically significant underlying illness, other than SLE and LN, which would pose a safety risk or concern, as determined by the Investigator
• 2. Any other systemic autoimmune condition
• 3. Rapidly progressive glomerulonephritis
• 4. Active central nervous system (CNS) lupus
• 5. History of allogeneic bone marrow or stem cell transplantation or solid organ transplantation
• Other protocol-defined criteria apply.