This study was designed to investigate the safety and efficacy of CM355 in patients with refractory SLE.

This study is designed to investigate the safety and efficacy of CM355 in patients with moderately to severely active SLE who are refractory to treatment, and to analyze its pharmacokinetic profile , pharmacodynamic effects, and immunogenicity.

Inclusion Criteria:

• Ability to understand the nature of the study and voluntarily sign the informed consent form (ICF);
• Age ≥ 18 to ≤ 65 years old, male or female;
• At screening, patients must meet the 2019 European League Against Rheumatism (EULAR)/ American college of Rheumatology (ACR)classification criteria for systemic lupus erythematosus (SLE) as assessed by a qualified doctor, and have a disease course of ≥ 12 months；
• systemic lupus erythematosus disease activity index2000 (SLEDAI-2K)≥8 points at screening. If there is a low complement and/or anti-ds-DNA antibody score, the SLEDAI-2K) clinical symptoms (excluding low complement and/or anti-ds-DNA antibody) score ≥ 6 points or ≥ 1 organ system in BILAG score should be Class A at screening；
• Definition of refractory SLE;
• The treatment regimen for SLE was stable for more than 4 weeks before the first dose.

Exclusion Criteria:

• Renal disease: patients with severe lupus nephritis;
• Patients with central nervous system diseases;
• Patients who have received monoclonal antibodies targeting Cluster of Differentiation 19(CD19) or Cluster of Differentiation 20(CD20) or other B-cell depleting agents within 6months prior to the first dose ;
• Any other condition assessed by investigator as unsuitable for participation in the study.