Linvoseltamab is a recombinant human IgG4-based bispecific monoclonal antibody that simultaneously targets B-cell maturation antigen (BCMA) on malignant plasma cells and CD3 on T cells. By bringing T cells into proximity with BCMA-expressing cancer cells, linvoseltamab activates T-cell-mediated cytotoxicity against the tumor cells.
Linvoseltamab is also known as REGN5458 and is marketed in the United States as linvoseltamab-gcpt (Lynozyfic). The FDA granted accelerated approval on July 2, 2025 for adults with relapsed or refractory multiple myeloma who have received at least four prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent and an anti-CD38 monoclonal antibody.
Linvoseltamab is a specialized biological oncology API requiring recombinant-cell production, sophisticated downstream purification and extensive biological and physicochemical characterization.
Unlike small-molecule APIs, its quality evaluation focuses on protein identity, purity, aggregation, charge variants, glycosylation, biological activity, binding affinity, sterility, endotoxin and other critical quality attributes.
CAS Number: 2408319-25-3
Molecular Weight: Approximately 149 kDa
Synonym: REGN5458 / REGN-5458
USAN: Linvoseltamab
Biological Class: Bispecific Monoclonal Antibody
Antibody Subclass: Human IgG4-based
Target 1: B-cell maturation antigen (BCMA)
Target 2: CD3
Therapeutic Class: Bispecific T-cell Engager / Immunotherapy
Therapeutic Area: Oncology / Hematology
Production System: Chinese hamster ovary (CHO) cells
Linvoseltamab binds simultaneously to BCMA expressed on multiple-myeloma cells and CD3 expressed on T cells.
This dual binding:
The FDA's nonclinical assessment demonstrated concentration-dependent T-cell activation and cytotoxicity against BCMA-expressing multiple-myeloma cell lines.
Linvoseltamab-gcpt is approved for:
Linvoseltamab is also relevant to research involving:
Linvoseltamab consists of:
The antibody contains 17 disulfide bonds, including intra-chain and inter-chain disulfide bonds. FDA characterization describes it as a heterotetrameric IgG4-based bispecific antibody.
FDA's chemistry review describes linvoseltamab as a clear to slightly opalescent, colorless to pale-yellow liquid in its drug-product form. It is produced using recombinant CHO-cell technology.
A typical recombinant Linvoseltamab manufacturing process may involve:
Linvoseltamab quality assessment may include:
Linvoseltamab drug substance and drug product require controlled cold-chain storage according to validated stability data and the applicable approved specification. The commercial product is supplied as an intravenous injection. FDA's Purple Book lists Lynozyfic as 5 mg/2.5 mL and 200 mg/10 mL single-dose vials for intravenous administration.
Linvoseltamab is relevant to:
Linvoseltamab is a recombinant human IgG4-based BCMA×CD3 bispecific monoclonal antibody with CAS Number 2408319-25-3 and an approximate molecular weight of 149 kDa. It is produced in CHO cells and directs T cells toward BCMA-expressing malignant plasma cells. Linvoseltamab-gcpt received FDA accelerated approval in July 2025 for certain adults with relapsed or refractory multiple myeloma.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 5.0 – 7.0 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 1.0% |