Mirvetuximab soravtansine is a folate receptor alpha (FRα)-directed antibody-drug conjugate (ADC) used in oncology. It combines an anti-FRα monoclonal antibody with the maytansinoid microtubule inhibitor DM4, connected through the cleavable linker sulfo-SPDB. The antibody targets FRα-expressing cancer cells, facilitating internalization and intracellular release of DM4, which disrupts microtubules and can lead to cell-cycle arrest and apoptotic cell death.
The FDA-approved product is mirvetuximab soravtansine-gynx (Elahere). In March 2024, the FDA granted regular approval for adults with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received one to three prior systemic treatment regimens, with patient selection based on an FDA-approved test.
Mirvetuximab soravtansine is a complex biologic drug substance and should be characterized using appropriate ADC-specific analytical methods covering antibody identity, conjugation, drug-to-antibody ratio (DAR), purity, aggregates, free payload, linker-related impurities and biological activity.
Mirvetuximab soravtansine is an antibody-drug conjugate designed to selectively deliver a cytotoxic microtubule inhibitor to FRα-expressing cells.
The ADC contains three principal components:
The FDA describes mirvetuximab soravtansine-gynx as a folate receptor alpha-directed antibody and microtubule inhibitor conjugate. The antibody component is produced using mammalian Chinese hamster ovary cells, while the small-molecule components are chemically synthesized.
The product has an approximate molecular weight of 150 kDa, with an average of 3.4 DM4 molecules attached per antibody molecule.
| Parameter | Specification |
|---|---|
| Appearance | White crystalline powder or crystals |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| pH (1% Solution) | Approximately 5.0 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 1.0% |