A Study of KZR-616 in Patients With SLE With and Without Lupus Nephritis

Key Inclusion Criteria: Phase 1b: * Fulfilled the 2012 Systemic Lupus International Collaborating Clinics (SLICC) classification for SLE * Had a positive antinuclear antibody (ANA) titer, anti-double stranded DNA (dsDNA) antibody titer, or a positive anti-Smith antibody titer * Had active SLE (as indicated by Systemic Lupus Erythematosus Disease Activity Index 2000 \[SLEDAI-2K\] score ≥4), and * Had received at least 1 prior therapy for SLE Phase 2: * Had active proliferative LN (Class III or IV, with or without Class V disease) * Had a UPCR ≥1.0 measured in 24-hour urine collection * Had a histologic diagnosis of LN on renal biopsy within the prior 2 years; for biopsies \> 1 year before the Screening visit, one of the following must also be present at screening: low C3, low C4, or anti-ds-DNA elevated to above normal range * Fulfilled the 2012 SLICC classification for SLE * Had a positive ANA titer, anti-dsDNA antibody titer, or anti-Smith antibody titer, and * Were currently receiving ≥1 immunosuppressive agent at a stable dose and route of administration for ≥8 weeks. If the patient is also on corticosteroids then must be on a stable dose for ≥ 2 weeks prior to Baseline Key Exclusion Criteria: Phase 1b: * Current or medical history of: * Central nervous system manifestations by autoimmune disease * Overlapping autoimmune condition that may affect study assessments/outcomes * Antiphospholipid syndrome with history of thromboembolic event of within the 52 weeks…