This trial is a multi-center, single-arm phase 2 study to evaluate the efficacy and safety of TJ202 combined with dexamethasone in subjects with relapsed or refractory multiple myeloma (RRMM) who received at least 2 prior lines of treatment.

A total of 82 subjects with relapsed or refractory multiple myeloma (RRMM) who have received at least 2 prior lines of treatment will be enrolled in this study. Prior lines of treatment must include a proteasome inhibitor (PI) and an immunomodulator (IMiD). All subjects will receive TJ202 and dexamethasone (DEX) in the study. The treatment will continue until endpoint events such as intolerance or progressive disease (PD).

Inclusion criteria:

1. Age ≥ 18, male or female;
2. Subject must have had documented MM;
3. At screening phase, subject must have measurable disease;
4. Subject is in a state of progressive disease (PD);
5. Subject must have life expectancy of no less than 6 months;
6. Subject must have an ECOG (Eastern Cooperative Oncology Group) performance status score of 0~2;

Exclusion criteria:

1. Subject has received anti-CD38 monoclonal antibody treatment previously;
2. Subject has received CAR-T cell therapy previously;
3. Subject has previously received allogenic stem cell transplant, or subject has received autologous stem cell transplant within 3 months before administration of the study agent;
4. Primary refractory multiple myeloma (subject failed to generate any minimal response or any degree of response to any therapy);
5. Subject has received anti-myeloma treatment (radiotherapy is excluded) within 4 weeks or 5 PK half-lives of the treatment, whichever longer, before the first study agent administration.