Study of YK012 in Moderate to Severe Systemic Lupus Erythematosus

This clinical trial consists of Phase Ib and Phase II. Phase Ib consists of dose escalation stage and dose expansion stage. The main goal of dose escalation stage is to evaluate the safety and tolerability of YK012 in participants with Moderate to Severe Systemic Lupus Erythematosus (SLE), and the main goal of dose expansion stage is to evaluate the safety, tolerability and effectiveness in reducing disease activity of YK012 in participants with SLE. The main goal of phase II is to assess the efficacy of YK012 in participants with Moderate to Severe SLE. Pharmacokinetics, pharmacodynamics and immunogenicity of YK012 in participants are evaluated as secondary objectives in both phases.