Study of LM-305 in Patients With Relapsed or Refractory Multiple Myeloma (RRMM) and Other Plasma Cell Diseases

Inclusion Criteria: Subjects will be enrolled into the study only if they meet all of the following inclusion criteria: 1. Subjects who are fully informed of the purpose, nature, method and possible adverse reactions of the study, and are willing to participate in the study and sign the informed consent form (ICF) prior to any procedure. 2. Aged ≥18 years old when sign the ICF, male or female. 3. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1。 4. Life expectancy ≥ 6 months. 5. Subjects must show appropriate organ and marrow function in laboratory examinations Exclusion Criteria: Subjects will be excluded from the study, if they meet any of the following criteria: 1. A history of other malignant tumors than multiple myeloma within 3 years prior to first dosing 2. Subjects who have severe cardiovascular disease。 3. Use of any live attenuated vaccines within 28 da ys prior to 1st dosing of IMP. 4. Child-bearing potential female who have positive results in pregnancy test or are lactating. 5. Subject who is judged as not eligible to participate in this study by the investigator.