YKST02

The purpose of this clinical trial is to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and preliminary efficacy of YKST02 administered alone or in combination with YK012 in participants with active or refractory systemic lupus erythematosus (SLE).
The main questions this study aims to address are:
* Whether YKST02 alone or in combination with YK012 is safe and well tolerated in participants with active or refractory SLE
* Whether YKST02 alone or in combination with YK012 demonstrates preliminary efficacy in treating SLE
* What the PK and PD characteristics of YKST02 are when administered alone or in combination with YK012
* Whether treatment with YKST02 induces anti-drug antibody responses
Participants will:
* Receive intravenous infusions of YKST02 alone or in combination with YK012 according to the assigned cohort
* Undergo safety assessments, including monitoring for adverse events
* Provide blood samples for PK, PD, and immunogenicity analyses
* Be followed for approximately 49 weeks to assess safety and efficacy