Removing a single-arm species by Fibro PrismA in purifying an asymmetric IgG-like bispecific antibody

MabSelect PrismA is an affinity resin whose ligand is derived from the B-domain of Protein A. Compared to its predecessor resins (i.e., MabSelect SuRe LX and MabSelect SuRe), the PrismA ligand has enhanced affinity for the VH3 chain. Consistently, when being used for the purification of an asymmetric IgG-like bispecific antibody (bsAb), MabSelect PrismA resin shows certain resolution between the intact product and a single-arm byproduct, which contain the same Fc region but different numbers of VH3 domain. Fibro PrismA is a newly launched product which has the same PrismA Protein A ligand as MabSelect PrismA but uses cellulose fiber instead of resin as its matrix. It was learned that Fibro PrismA, in comparison to PrismA resin, exhibits further improved resolution, allowing efficient clearance of the single-arm byproduct as well as good recovery of the target bsAb. This finding suggests that Fibro PrismA provides a potential solution for separating antibody species containing the same Fc region but different numbers of VH3 domain, which can otherwise be difficult to separate.