A Study of GR1803 Injection in Combination With Anti-CD38 Monoclonal Antibody for the Treatment of Participants With Multiple Myeloma

An Open-Label, Multicenter, Phase Ib/II Clinical Trial of GR1803 Injection in Combination With an Anti-CD38 Monoclonal Antibody Evaluating Safety, Pharmacokinetics, Immunogenicity, and Preliminary Efficacy in Subjects With Relapsed/Refractory Multiple Myeloma Previously Treated With at Least One Line of Therapy Including Lenalidomide and a Proteasome Inhibitor

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.

Inclusion Criteria:

• 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.

Exclusion Criteria:

• 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.
• Known allergies, hypersensitivity, or intolerance to the study drug or its excipients.