An Open-label Study of GB261 in Refractory Seropositive Systemic Lupus Erythematosus

Inclusion Criteria: 1. 18 to 75 years old at the time of signing the informed consent form (ICF) 2. Diagnosis of SLE according to the 2019 American College of Rheumatology (ACR), European Alliance of Associations for Rheumatology (EULAR) classification criteria 3. 3\. Positive for 2 out of 3 antibodies at Screening: a. Anti-dsDNA; b. Anti-Smith antibodies; c. Antinuclear antibody (ANA) titer ≥1:80 4. Active SLE disease 5. Inadequate response 6. Current and stable use of some medication up to Day 1 7. Current and stable use of some medication must be discontinued ≥1 week prior to Day 1 Additional Inclusion Criteria for SLE with Active LN SLE patients with active LN are eligible to be included in the study only if all of the following additional criteria apply: 1. Active, biopsy-proven, proliferative LN Class III or IV according to the 2018 International Society of Nephrology/Renal Pathology Society criteria 2. Inadequate response 3. Stable angiotensin-converting enzyme inhibitors/angiotensin receptor blockers for at least 4 weeks prior to Screening Exclusion Criteria: 1. Inadequate clinical laboratory parameters at Screening: 2. Patients will be excluded if they are known to have active infection 3. Receipt of or inability to discontinue any excluded therapies 4. Receipt of live vaccine within 4 weeks prior to Screening 5. Presence of any concomitant autoimmune disease 6. Active or known history of catastrophic anti-phospholipid syndrome (APS) 7. APS or thrombotic event not adequately controlled by anticoagulation therapy 8. History of progressive multifocal leukoencephalopathy 9. History of primary immunodeficiency or a hereditary deficiency of the complement system 10. Central nervous system (CNS) disease 11. Presence of 1 or more significant concurrent medical conditions per investigator judgment 12. Have a diagnosis or history of malignant disease within 5 years prior to Screening 13. Serious mental illness, alcohol or drug abuse, dementia, or any other condition that would impair the patient's ability to receive the planned treatment or to understand informed consent at the study site as determined by local practice 14. Inability to comply with protocol-mandated requirements 15. History of severe allergic or anaphylactic reactions to mAb therapy (or recombinant antibody-related fusion proteins) or any constituents of study drug. 16. History of or planned organ transplant and/or autologous or allogeneic hematopoietic stem cell transplantation for the duration of the study. 17. Major surgery requiring use of general anesthesia within 12 weeks prior to Screening or planned or expected major surgery during the study period (from Screening to patient's last visit). 18. Any serious medical condition or abnormality on clinical laboratory testing 19. Women who are pregnant or breastfeeding. 20. Sexually active male patients who do not agree to refrain from donating semen