Study of YKST02 in Adults With Relapsed or Refractory Multiple Myeloma

The goal of this Phase 2 clinical trial is to learn whether YKST02 is effective and safe in adults with relapsed or refractory multiple myeloma. The study will also evaluate how YKST02 is processed by the body (pharmacokinetics), how it affects the body (pharmacodynamics), and whether it causes the body to produce anti-drug antibodies. The main questions it aims to answer are: Does YKST02 demonstrate clinical efficacy in adults with relapsed or refractory multiple myeloma? What side effects occur during treatment with YKST02? What are the pharmacokinetic, pharmacodynamic, and immunogenicity characteristics of YKST02? Participants will: Complete screening assessments to determine whether they are eligible for the study. Receive YKST02 by intravenous infusion according to the study treatment schedule. Undergo regular assessments to evaluate treatment response and monitor safety. Provide blood and urine samples for pharmacokinetic, pharmacodynamic, and immunogenicity testing. Complete follow-up visits after treatment discontinuation to monitor disease progression and survival. Multiple myeloma is a cancer of plasma cells that remains incurable despite advances in treatment. Although currently available therapies can improve outcomes, most patients eventually experience disease relapse or become refractory to treatment. YKST02 is an investigational humanized bispecific antibody targeting BCMA on myeloma cells and CD3 on T cells. Simultaneous binding to BCMA and CD3 may activate T cells and promote tumor cell killing. This is a multicenter, open-label study consisting of two parts (Phase IIa and Phase IIb). In Phase IIa, participants will initially receive YKST02 at the starting dose level. Safety and efficacy data from this part of the study will be reviewed to determine the dose to be evaluated in Phase IIb.