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Radiation Combined With BCMA/CD3 Bispecific Antibody Therapy for Solitary Bone Plasmacytoma With Mild Bone Marrow Infiltration

A Prospective Single-Arm Clinical Trial of Radiation Combined With BCMA/CD3 Bispecific Antibody Therapy for Solitary Bone Plasmacytoma With Mild Bone Marrow Infiltration

Status
Recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07115667
Enrollment
21
Registered
2025-08-11
Start date
2025-08-25
Completion date
2027-12-01
Last updated
2025-09-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Plasma Cell Disorders, Plasmacytoma of Bone, Solitary Bone Plasmacytoma

Keywords

solitary bone plasmacytoma, BCMA/CD3 bispecific antibody

Brief summary

This is a prospective, single-arm, single-center clinical trial designed to evaluate the safety and efficacy of radiation combined with a BCMA/CD3 bispecific antibody (CM336) in patients with solitary bone plasmacytoma (SBP) with mild bone marrow infiltration.

Detailed description

This is a prospective, single-arm, single-center clinical trial designed to evaluate the safety and efficacy of radiation combined with a BCMA/CD3 bispecific antibody (CM336) in patients with solitary bone plasmacytoma (SBP) with mild bone marrow infiltration. SBP is a rare plasma cell malignancy with a high risk of progression to multiple myeloma (MM), particularly in patients with minimal bone marrow involvement. Although radiotherapy is the standard treatment, it is often insufficient to eradicate clonal plasma cells and prevent progression in high-risk patients. CM336, a novel BCMA/CD3 bispecific antibody, has demonstrated promising activity in relapsed/refractory multiple myeloma. In this trial, eligible patients will receive radiotherapy followed by a 12-cycle limited treatment course of CM336, aiming to achieve deep clearance of residual malignant cells and reduce progression risk.

Interventions

DRUGBCMA/CD3 bispecific antibody (CM336)

Patients with solitary bone plasmacytoma (SBP) with mild bone marrow infiltration will receive radiation combined with a BCMA/CD3 bispecific antibody (CM336)

Sponsors

Institute of Hematology & Blood Diseases Hospital, China
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 78 Years
Healthy volunteers
No

Inclusion criteria

* ≥18 years old * Histologically confirmed SBP with \<10% clonal plasma cells in marrow * ECOG ≤ 2 * No prior anti-myeloma therapy. Previous local radiotherapy for SBP is not an exclusion criterion. * Meets laboratory and imaging criteria

Exclusion criteria

1. Patients who have previously received anti-plasma cell therapy, including melphalan, cyclophosphamide, proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, bispecific antibodies, or chimeric antigen receptor T-cell (CAR-T) therapy. 2. Any condition that, in the opinion of the investigator, would make the patient unsuitable for participation in this study.

Design outcomes

Primary

MeasureTime frameDescription
Safety and TolerabilityFrom first dose through 28 days after last doseThe primary outcome is to evaluate the safety and tolerability of the combination therapy. This includes the incidence, severity, and type of adverse events (AEs) and serious adverse events (SAEs), graded according to NCI CTCAE v5.0. Particular attention will be paid to cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Safety assessments will include laboratory parameters, vital signs, ECGs, and clinical symptoms.

Secondary

MeasureTime frameDescription
Progression-Free Survival (PFS)Up to 5 yearsPFS is defined as the time from the start of treatment to the first documentation of disease progression or death from any cause, whichever occurs first. Disease progression will be assessed using IMWG criteria for progression from solitary plasmacytoma to multiple myeloma.
Multiple Myeloma Free Survival (MMFS)Up to 5 yearsMMFS is defined as the time from the start of treatment to the first documented diagnosis of multiple myeloma, based on IMWG criteria. Patients who do not progress to MM will be censored at the date of last follow-up. The diagnosis of MM will be confirmed by clinical, laboratory, and imaging criteria.

Countries

China

Contacts

Primary ContactGang An, MD
angang@ihcams.ac.cn13502181109

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026