The purpose of this study is to identify recommended Phase 3 doses (RP3D) for treatment combination (GR1803 injection plus anti-CD38 monoclonal antibody) and to characterize the efficacy of RP3D for the treatment combination.
Eastern Cooperative Oncology Group performance status grade of 0, 1 or 2;
Diagnosis of multiple myeloma；have received at least one prior line of therapy including Lenalidomide and a proteasome inhibitor.
Able to understand and comply with the requirements of the clinical protocol, voluntarily participate in the clinical trial, and sign informed consent.
Plasma cell leukemia , Waldenström's macroglobulinemia, POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes), or amyloidosis.
Active central nervous system involvement or exhibits clinical signs of meningeal involvement of multiple myeloma.
Prior treatment with any BCMA-targeted therapiy.
Active infecion.