A Study of IBI3003 in Subjects With Relapsed or Refractory Multiple Myeloma

This study tests a new immunotherapy drug called IBI3003 in patients with multiple myeloma (a blood cancer affecting plasma cells in the bone marrow) whose cancer has returned or stopped responding to prior treatments. The drug is designed to help the immune system recognize and attack myeloma cells. **You may be eligible if...** - You are 18 or older (up to 75 for the initial dose-escalation phase) - You have been diagnosed with multiple myeloma according to standard criteria - Your cancer has returned or is not responding to treatment - You have good overall health (ECOG 0 or 1) - Your expected survival is at least 3 months - You can give written informed consent **You may NOT be eligible if...** - Your myeloma has spread to the brain or nervous system - You have related conditions like AL amyloidosis, plasma cell leukemia, or POEMS syndrome - You have had spinal cord compression in the last 6 months - You have had another cancer within the past 3 years (except certain skin or in-situ cancers) - You have a primary immune deficiency Talk to your doctor to see if this trial is right for you.