A Ph1/2 Study of EMB-06 in Participants With Relapsed or Refractory Myeloma

Inclusion Criteria: * Able to understand and willing to sign the informed consent form (ICF) * Patients who have been diagnosed with multiple myeloma according to IMWG diagnostic criteria 2014 and have relapsed or refractory multiple myeloma with at least one measurable lesion. * The patient must have received at least two lines (for patients in the US, at least three lines which should include anti-CD38 antibody) of prior antimyeloma therapies, and must have received treatment with proteasome inhibitors, immunomodulatory agents, and if accessible, an anti-CD38 targeting monoclonal antibody. * ECOG performance status 0 or 1 for phase I, and ≤2 for phase II. * Adequate organ function and reasonable laboratory test results to participate in the trial. * Highly effective contraception Exclusion Criteria: * Life expectancy is less than 3 months. * Patient participated in any other clinical study within 1 month prior to enrollment in this clinical study. * Patients with ongoing AE. * Previously treated with any BCMA-targeted therapy.(Exception: in Phase 2 portion, up to 10 patients who have received prior anti-BCMA ADC or BCMA targeted CAR-T can be enrolled) * History of allogeneic stem cell transplantation. * Previously treated with the following anti-tumor therapy (prior to first dosing of EMB-06) 1. Treated with monoclonal antibody for multiple myeloma within 28 days 2. Treated with proteasome inhibitors within 14 days 3. Treated with immunomodulatory agents within 14 days 4. Treated with cytotoxic therapy within 14 days 5. Received investigational drug within 28 days or at least 5 half-lives, whichever is shorter (if a, b, c, d not applicable) 6. Received radiotherapy within 21 days. Except that the radiation portal covered ≤ 5% of the bone marrow reserve, the patient will be eligible to participate in the study regardless of the end date of radiation therapy 7. Plasmapheresis within 7 days * Patient received autologous stem cell transplantation within 12 weeks prior to the start of study treatment. * Active or historically multiple myeloma related central nervous system involvement. * Patients requiring high dose of systemic treatment with corticosteroids. * Patients with active infections, including COVID-19, hepatitis, etc.. * History of severe allergic reactions * Patients with severe or uncontrolled cardiovascular disorder requiring treatment * Pre-existing other serious medical conditions