A Study of the Efficacy and Safety of Monotherapy With BCD-264 and Darzalex in Subjects With Relapsed and Refractory Multiple Myeloma

Inclusion criteria

• Signed informed consent form.
• Age ≥ 18 years at the time of signing of the informed consent form.
• Documented diagnosis of multiple myeloma according to IMWG criteria
• Measurable disease at screening:

• M-protein in serum ≥ 1.0 g/dL (10 g/L) or in 24-hour urine ≥ 200 mg; or
• light chain myeloma: serum "involved" FLC level ≥ 10 mg/dL (100 mg/L) and abnormal κ/λ FLC ratio .
• At least a partial response according to IMWG criteria to at least 1 prior line of therapy.
• Subjects with relapsed and refractory multiple myeloma who previously received therapy with proteasome inhibitors and immunomodulatory drugs, and who had disease progression on prior therapy
• ECOG score 0-2.
• Not pregnant and willing to use contraception.
• Consent to bone marrow biopsy in the study.

Exclusion criteria

• Prior treatment with daratumumab or other anti-CD38 therapy.
• Prior treatment for multiple myeloma within 2 weeks or 5 half-lives before the date of randomization, except for a short course of glucocorticoids
• Autologous hematopoietic stem cell transplantation within 12 weeks prior to the date of randomization.
• Allogeneic hematopoietic stem cell transplantation, regardless of timing.
• Scheduled hematopoietic stem cell transplantation prior to progressive disease during this study.
• Plasma cell leukemia, POEMS syndrome or amyloidosis.
• Waldenstrom macroglobulinemia or other concomitant diseases with hyperproduction of monoclonal IgM (M-protein) in the absence of clonal proliferation of plasma cells with lytic bone involvement.
• A history of other malignancies within the last 5 years, with the exception of squamous cell and basal cell skin cancer, cervical, breast carcinoma in situ, or other non-invasive malignancies that, in the Investigator's opinion are considered to have been adequately treated and have a minimal risk of recurrence for 5 years.
• Plasmapheresis within 28 days prior to randomization.
• Clinical signs of meningeal involvement of multiple myeloma.
• Pregnancy or breastfeeding, as well as planning pregnancy throughout the study and within 3 months after the last dose of daratumumab; for male subjects, planning to conceive a child throughout the study and within 3 months after the last dose of daratumumab.