anti-CD20 B9E9 scFv-streptavidin fusion protein

The anti-CD20 B9E9 scFv-streptavidin fusion protein is a genetically engineered recombinant fusion protein designed for pretargeted radioimmunotherapy (PRIT) of CD20-expressing malignancies, particularly non-Hodgkin lymphoma. It consists of the single-chain variable fragment (scFv) derived from the murine monoclonal antibody B9E9, which specifically targets the CD20 antigen on B cells, fused to streptavidin. This design allows for high-affinity binding to both CD20 and biotinylated radioligands in a multistep therapeutic protocol. Upon intravenous administration, the agent binds to CD20-positive tumor cells; after clearance of unbound agent using a synthetic clearing agent, a radiolabeled biotin molecule is administered and rapidly localizes to tumor-bound streptavidin via strong biotin-streptavidin interaction. This approach increases tumor-to-normal tissue radiation ratios compared with directly labeled antibodies and has demonstrated objective responses in early-phase clinical trials for relapsed or refractory non-Hodgkin lymphoma[1][2][5][8]. The drug was developed at Fred Hutchinson Cancer Research Center.

Other names

anti-CD20 B9E9 scFv-SA fusion proteinanti-CD-20 B9E9 scFv-SA fusion proteinanti-CD 20 B9E9 scFv-SA fusion proteinsingle-chain Fv-streptavidin (scFvSA) fusion proteintetrameric single-chain anti-CD20–streptavidin fusion protein