HB2198 is a novel tetravalent bispecific antibody engineered for enhanced B-cell depletion through dual CD19/CD20 targeting and optimized Fc mediated effector function. The study uses a modified 3+3 dose escalation design, enrolling sequential cohorts to receive HB2198 IV on Day 1 and Day 8. Safety, dose limiting toxicities, pharmacokinetics, pharmacodynamics, and immunogenicity will be assessed. Participants will undergo comprehensive disease activity assessments using SLEDAI 2K, PGA, LupusQoL, FACIT Fatigue, and renal response metrics. Total participation is about 13 months.
