Inclusion Criteria:

Rescreening will be allowed once during the study in case there is new evidence for an inclusion criterion that was not fulfilled at the first screening or in case a study participant no longer meets an exclusion criterion or screening period exceeded the maximum duration due to delays in screening processes

Study participant must be ≥16 years of age, unless restricted by local regulation, at the time of signing the Informed Consent form (ICF)

Study participants who have moderate to severe disease activity due to either persisting active SLE or due to an acute worsening of SLE in the scope of frequent flaring/relapsing-remitting systemic lupus erythematosus (SLE) despite stable standard of care (SOC) medication defined as:

a. Diagnosed with SLE at least 24 weeks before the Screening Visit (Visit 1) study entry by a qualified physician b. Classified by 2019 SLE European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for SLE c. With serological evidence for SLE at Screening as demonstrated by at least 1 of the following: i) Evidence for anti-dsDNA (in central laboratory at Screening) ii) Either complement C3 < lower limit of normal (LLN) OR complement C4

1. Anti-Smith (anti-Sm) antibodies (central laboratory) 2. Anti-Sjögren's syndrome antibody A (Anti-SSA) (Ro)/Anti-Sjögren's syndrome antibody B (anti-SSB) (La) autoantibodies (central laboratory) 3. Historic evidence for anti-dsDNA antibodies

d. Moderately to severely active defined as

British Isles Lupus Assessment Group Disease Activity Index 2004 (BILAG 2004) Grade B in ≥2 organ systems and/or a BILAG 2004 Grade A in ≥1 organ systems at Screening and Baseline Visit AND

Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) ≥6 at Screening Visit AND

SLEDAI-2K without labs ≥4 at Baseline Visit

e. Receiving the following SOC medication at stable dose:

Antimalarial treatment in combination with corticosteroids and/or immunosuppressants or as stand-alone treatment if justified OR Treatment with corticosteroids and/or immunosuppressants if anti-malarial treatment is not possible